g.i.t word file

Normal Digestive Tract Phenomena :

Gastrointestinal function varies with maturity; what is a physiologic event in a newborn or infant might be a pathologic symptom at an older age. A fetus can swallow amniotic fluid as early as 12 wk of gestation, but nutritive sucking in neonates 1st develops at about 34 wk of gestation. The coordinated oral and pharyngeal movements necessary for swallowing solids develop within the 1st few months of life .
The recommendation to begin solids at 6 mo of age is based on nutritional and cultural concepts rather than maturation of the swallowing process. A number of normal anatomic variations may be noted in the mouth:
short lingual frenulum (tongue-tie) may be worrisome to parents but only rarely interferes with eating or speech, generally requiring no treatment.
Surface furrowing of the tongue (a geographic or scrotal tongue) is usually a normal finding.
bifid uvula may be normal or associated with a submucous cleft of the soft palate.
Regurgitation, the result of gastroesophageal reflux, occurs commonly in the 1st year of life. Effortless regurgitation can dribble out of an infant's mouth but also may be forceful. Episodes can occur from <1 to several times per day. Regurgitation gradually resolves in 80% of infants by 6 mo of age and in 90% by 12 mo. If complications develop or regurgitation persists, gastroesophageal reflux is considered pathologic rather than merely developmental and deserves further evaluation and treatment.
The number, color, and consistency of stools can vary greatly in the same infant and between infants of similar age without apparent explanation. The earliest stools after birth consist of meconium, a dark, viscous material that is normally passed within the 1st 48 hr of life. With the onset of feeding, meconium is replaced by green-brown transition stools, often containing curds, and, after 4-5 days, by yellow-brown milk stools.
Stool frequency is extremely variable in normal infants and can vary from none to 7 per day. Breast-fed infants can have frequent small, loose stools early (transition stools), and then after 2-3 wk can have very infrequent soft stools. Some nursing infants might not pass any stool for 1-2 wk and then have a normal soft bowel movement.
The color of stool has little significance except for the presence of blood or absence of bilirubin products (white-gray rather than yellow-brown).
The presence of vegetable matter, such as peas or corn, in the stool of an older infant or toddler ingesting solids is normal and suggests poor chewing and not malabsorption.
A protuberant abdomen is often noted in infants and toddlers, especially after large feedings. This can result from the combination of weak abdominal musculature, relatively large abdominal organs, and lordotic stance.
In the 1st yr of life, it is common to palpate the liver 1-2 cm below the right costal margin. The normal liver is soft in consistency and percusses to normal size for age. A Riedel lobe is a thin projection of the right lobe of the liver that may be palpated low in the right lateral abdomen. A soft spleen tip might also be palpable as a normal finding. In thin young children, the vertebral column is easily palpable,

and an overlying structure may be mistaken for a mass. Pulsation of the aorta can be appreciated. Normal stool can often be palpated in the left lower quadrant in the descending or sigmoid colon.
Blood loss from GIT is never normal, but swallowed blood may be misinterpreted as GI bleeding. Maternal blood may be ingested at the time of birth or later by a nursing infant if there is bleeding near the mother's nipple. Nasal or oropharyngeal bleeding is occasionally mistaken for GI bleeding . Red dyes in foods or drinks can turn the stool red but do not produce a positive test result for occult blood.
Jaundice is common in neonates, especially among premature infants, and usually results from the inability of an immature liver to conjugate bilirubin.It could be physiological or pathological.
Major Symptoms and Signs of GIT Disorders:
Disorders of organs outside GIT can produce symptoms and signs that mimic GIT disorders and should be considered in the differential diagnosis.
Dysphagia:
Difficulty in swallowing . Painful swallowing is termed odynophagia. Globus is the sensation of something stuck in the throat without a clear etiology.
It is classified as: Oropharyngeal dysphagia(transfer dysphagia) occurs when the transfer of the food bolus from the mouth to the esophagus is impaired . The striated muscles of the mouth, pharynx and upper esophageal sphincter are affected in oropharyngeal dysphagia. Neurologic and muscular disorders can give rise to oropharyngeal dysphagia . The most serious complication of oropharyngeal dysphagia is life-threatening aspiration. Esophageal dysphagia occurs when there is difficulty in transporting the food bolus down the esophagus. Esophageal dysphagia can result from neuromuscular disorders or mechanical obstruction.
Regurgitation(spitting): effortless movement of stomach contents into the esophagus and mouth.
Anorexia: prolonged lack of appetite.
Vomiting:
highly coordinated reflex process that may be preceded by increased salivation and begins with involuntary retching. Violent descent of the diaphragm and constriction of the abdominal muscles with relaxation of the gastric cardia actively force gastric contents back up the esophagus.
Vomiting caused by obstruction of the GI tract is probably mediated by intestinal visceral afferent nerves stimulating the vomiting center. If obstruction occurs below the 2nd part of the duodenum, vomitus is usually bile stained. Emesis can also become bile stained with repeated vomiting in the absence of obstruction when duodenal contents are refluxed into the stomach. Nonobstructive lesions of the digestive tract can also cause vomiting as diseases of the upper bowel, pancreas, liver, or biliary tree. CNS or metabolic derangements can lead to severe, persistent emesis.
Cyclic vomiting is a syndrome with numerous episodes of vomiting interspersed with well intervals.


Diarrhea :
Diarrhea is best defined as excessive loss of fluid and electrolyte in the stool. Acute diarrhea is defined as sudden onset of excessively loose stools of >10 mL/kg/day in infants and >200 g/24 hr in

older children, which lasts <14 days. When the episode lasts >14 days, it is called chronic or persistent diarrhea. Steatorrhea signifies an excess of fat in the stool and is a symptom of malabsorption.
Disorders that interfere with absorption in the small bowel tend to produce voluminous diarrhea( Under normal circumstances, approximately 90% of fluid absorption takes place in the small bowel), whereas disorders compromising colonic absorption produce lower-volume diarrhea.
Dysentery (small-volume, frequent bloody stools with mucus, tenesmus, and urgency) is the predominant symptom of colitis.
Movement of water across the gastrointestinal tract mucosa is passive, following osmotic gradients created by electrolytes and other osmotically active solutes such as glucose and amino acids.
Many nutrients, including glucose and most amino acids, are absorbed by active, carrier-mediated transport, which is coupled with sodium transport. The osmotic gradient created promotes the absorption of water. Movement of water, in turn, also carries small solutes such as sodium and chloride. This process is known as solvent drag and appears to be an important route for sodium absorption during normal digestion. These mechanisms of sodium movement associated with carrier-mediated nonelectrolyte transport are important to preserve normal fluid and electrolyte balance during some episodes of diarrhea (and this is the base for oral rehydration).
The pathophysiologic mechanisms for diarrhea fall into 4 basic groups:
osmotic diarrhea:
The ingestion of a poorly absorbable, osmotically active substance and its presence in the bowel lumen create an osmotic gradient that encourages movement of water into the lumen and subsequently into the stool. Electrolyte losses increase because electrolytes will follow water into the lumen through solvent drag and will tend not to be reabsorbed because of unfavorable electrochemical gradients. Two main groups of poorly absorbed solutes exist, the ingestion of which result in osmotic diarrhea.
The first group includes normal dietary components that may be malabsorbed either transiently or permanently. For example, disaccharides are usually hydrolyzed to monosaccharides before they are absorbed. If a mucosal disaccharidase (eg, lactase) is deficient, then the disaccharide (in this case lactose) will be malabsorbed and will represent an osmotic load that will produce diarrhea. Medium-chain triglycerides are also osmotically active, Malabsorption of long-chain triglycerides (LCTs) does not lead to osmotic diarrhea because LCTs are large hydrophobic molecules,however, may lead to secretory diarrhea. Protein malabsorption does not appear to be associated with diarrhea except in the rare instance of congenital trypsinogen or enterokinase deficiency.

The second group of poorly absorbed solutes includes substances that are transported in limited amounts, even by healthy individuals. This group includes magnesium, phosphates, and sulfates. Because these ions invariably lead to diarrhea when given in large enough quantities, they are used as cathartics. The introduction of lactulose in the treatment of hepatic encephalopathy takes advantage of its being a nondigestible disaccharide that leads to acidification of colonic contents by bacterial fermentation of nonabsorbed sugar.

The key characteristic of an osmotic diarrhea is its association with the ingestion of the offending solute. When a patient who has an osmotic diarrhea is given no oral or enteral feeding, the

diarrhea will stop dramatically within 24 hours or less. If the agent is reintroduced, the diarrhea will reappear. The diarrhea is of a moderate volume compared with that in secretory diarrhea. The sodium and potassium ion concentrations in the stool fluid are useful in establishing a diagnosis. As ileal and colonic sodium absorption continue to function against a concentration gradient, stool sodium concentration will be lower than it is in the plasma. Normally, the electrolyte concentration in the stool is roughly twice its combined sodium and potassium concentration. When this number is much less than the total stool osmolality (usually approximately 290 mOsm/kg), osmotically active nonelectrolytes must be in the stool, and osmotic diarrhea is present. An osmotic gap of more than 100 mOsm/kg indicates osmotic diarrhea. In some instances, the clinician may be able to find the osmotic component in the stool, such as a reducing substance in lactose malabsorption.
Ion(osmotic) gap =stool osmolality-[(stool Na+stool K)×2]

diarrhea resulting from secretion or altered absorption of electrolytes(secretory diarrhea):
occurs when a physiologic electrolyte secretory process is pathologically stimulated. Under such circumstances, a net increase in luminal electrolytes and, subsequently, a secondary increase in water occur. In addition, an associated decrease in absorptive processes may occur. The electrolytes that have been implicated are sodium, chloride, and perhaps bicarbonate. Itis usually of large volume and persists even with fasting. The ion gap is 100 mOsm/kg or less & stool osmolality is normal. The prototype for a secretory diarrhea is cholera. Cholera enterotoxin increases intestinal secretion of chloride and inhibits the absorption of sodium by stimulating surface epithelial adenylate cyclase.Another examples, Toxigenic Escherichia coli, congenital chloride diarrhea&bile salt malabsorption.

exudative diarrhea:

A break in the integrity of the mucosal surface of the intestine can result in water and electrolyte loss, driven by hydrostatic pressure in blood vessels and lymphatics. The exudate contains mucus, protein, and blood cells. Examples include infectious(Salmonella, Shigella, infection; amebiasis; Yersinia, Campylobacter ), allergic, or ulcerative colitis.
diarrhea resulting from abnormal intestinal motility:
The intestine has a cyclical, orderly pattern of motility. Increased, decreased, or disordered movement can lead to diarrhea. Rapid intestinal transit often occurs in association with osmotic and secretory diarrheas. Increased intraluminal volume has been implicated in stimulating increased peristaltic action. Increased motility may cause diarrhea by allowing less time for the contact of intraluminal contents with absorptive surfaces. Slowed transit and severely disordered motility lead to intraluminal stasis which leads to the development of bacterial over-growth.Best

examples are short-bowel syndrome, irritable bowel syndrome. Disordered motility frequently is an associated factor in chronic inflammatory bowel disease. Stools associated with motility diarrhea, except those secondary to fatty acid malabsorption, tend to be small in volume. The response to feeding is variable, and the gastrocolic reflex may be heightened. Patients who have chronic inflammatory bowel disease may find that meals stimulate intestinal activity, resulting in postprandial abdominal cramps and bowel movements.
ACUTE GASTROENTERITIS :
It denotes infections of the gastrointestinal (GI) tract caused by bacterial, viral, or parasitic pathogens. Many of these infections are foodborne illnesses. The most common manifestations are diarrhea and vomiting, which can also be associated with systemic features such as abdominal pain and fever. The term diarrheal disorders is more commonly used to denote infectious diarrhea in public health settings, although several noninfectious causes of GI illness with vomiting and/or diarrhea are well recognized. It is common in children, transient and usually self-limited. The role of the physician is to rule out causes that require specific treatment, to advise parents in supportive management, and to provide follow-up for possible complications.
Causes of Acute Diarrhea:
USUALLY WITHOUT BLOOD IN STOOL
Viral enteritis : rotavirus, orbivirus, noroviruses (includes Norwalk virus), other caliciviruses, enteric adenovirus, astrovirus, sapoviruses
Enterotoxin : E coli, Klebsiella organisms, cholera, Clostridium perfringens, Staphylococcus organisms, Bacillus cereus, and Vibrio species
Parasitic : Giardia, Cryptosporidium, Cyclospora, Dientamoeba fragilis, and Blastocystis hominis organisms
Extraintestinal infection( parenteral) : otitis media and urinary tract infection
Antibiotic-induced and Clostridium difficile toxin (without pseudomembranous colitis)
COMMONLY ASSOCIATED WITH BLOOD IN STOOL
Bacterial : Shigella, Salmonella, and Campylobacter organisms, Yersinia enterocolitica, invasive E coli, gonococcus (venereal spread), enteroadherent E coli, enteroaggregative E coli, Aeromonas hydrophilia, and Plesiomonas shigelloides
Cytomegalovirus (especially in immunocompromised individuals)
Amebic dysentery, Trichuris trichiura (whipworm)
Hemolytic-uremic syndrome (enterohemorrhagic E coli—E coli O157:H7 and other Shiga toxin-producing E coli)
Henoch-Schonlein purpura
Pseudomembranous enterocolitis (C difficile toxin)
Ulcerative or granulomatous colitis (acute presentation)
Necrotizing enterocolitis (neonates)


Pathogenesis of Infectious Diarrhea:
Enteropathogens elicit noninflammatory diarrhea through enterotoxin production by some bacteria, destruction of villus (surface) cells by viruses, adherence by parasites, and adherence and/or translocation by bacteria. Inflammatory diarrhea is usually caused by bacteria that directly invade the intestine or produce cytotoxins with consequent fluid, protein, and cells (erythrocytes, leukocytes) that enter the intestinal lumen. Some enteropathogens possess >1 virulence property. Some viruses, such as rotavirus, target the microvillus tips of the enterocytes and can enter the cells by direct invasion or calcium-dependent endocytosis. This can result in villus shortening and loss of enterocyte absorptive surface through cell shortening and loss of microvilli.

Risk Factors for Gastroenteritis :

Major risks include environmental contamination and increased exposure to enteropathogens. Additional risks include young age, immunodeficiency, measles, malnutrition, and lack of exclusive or predominant breast-feeding.
The risks are particularly higher with micronutrient malnutrition; in children with vitamin A deficiency, the risk of dying from diarrhea, measles, and malaria is increased by 20-24%. Zinc deficiency is estimated to increase the risk of mortality from diarrhea, pneumonia, and malaria by 13-21%.

Neonatal Diarrhea

Neonates with acute diarrhea must be considered differently from older infants and children because of both lower tolerance to the associated fluid shifts and the greater likelihood of severe infection or of a congenital anomaly. In addition, signs of necrotizing enterocolitis, including gastric retention (frequently bilious), distention, and occult or bright red blood in the stool, should raise concern. Although this disease usually occurs in premature infants, it also has been reported in full-term infants. The presence of pneumatosis intestinalis, gas in the portal vein, or free intraperitoneal gas seen on abdominal radiographs supports this diagnosis. Epidemics of diarrhea associated with rotavirus, enteropathogenic E coli, salmonellae, and other organisms, including Klebsiella organisms, have been reported in nurseries. If the onset of diarrhea is associated with initial feedings, then the clinician should consider congenital digestive defects, especially sugar intolerance. Hirschsprung disease may produce acute diarrhea and enterocolitis in the neonatal period and should be considered, especially in the infant who has not passed meconium in the first 24 hours. Bloody diarrhea that results from cow milk or soy protein intolerance may develop as early as the first few days of life. Resolution and exacerbation on removal and reintroduction of cow milk or soy formula, as well as an atopic family history, are clues to the diagnosis.

Differential Diagnosis in the Older Infant and Child:

Most episodes of acute diarrhea are transient and benign. On the initial visit, the physician must evaluate the course in terms of both possible causes and the status of hydration. The

diarrhea is usually the result of viral enteritis, typically occurring with low-grade fever, vomiting, and frequent watery stools. Generally, the stools are without blood or white blood cells. Enterotoxin-producing organisms (eg, toxigenic E coli) are associated with watery stools and are without evidence of mucosal invasion (no high fever or blood in the stool). G lamblia produces watery diarrhea associated with intestinal gas and crampy abdominal pain. Diarrhea in association with extraintestinal infections, most notably otitis media and pyelonephritis, has been called parenteral diarrhea; its mechanism is obscure. An associated viral enteritis may occur in some cases of otitis media. Certain antibiotics, especially ampicillin, have been associated with transient diarrhea. Less common but of greater danger is antibiotic-associated pseudomembranous colitis, which may occur acutely or as a more chronic illness of 1 or 2 months' duration. C difficile toxin, the cause of most cases of pseudomembranous colitis, may also be associated with chronic childhood diarrhea in the absence of colitis.
The presence of blood in the stool, especially with symptoms of colonic involvement (tenesmus, urgency, and crampy lower abdominal pain), should make the clinician think of infection with Campylobacter, Shigella, or Salmonella organisms or with C difficile toxin-associated pseudomembranous colitis. The symptoms of dysentery may be less striking with Salmonella. When the Shigella is an enterotoxin-producing organism, watery diarrhea may actually precede the onset of dysentery.
Patients who have Shigella organisms tend to appear severely ill and may have meningismus or seizures. The stools tend to be foul smelling. Up to 40% of individuals who have Guillain-Barre syndrome have evidence of a Campylobacter infection occurring before the onset of neurologic symptoms.Yersinia enterocolitis also may be associated with blood in the stool. E coli can produce diarrhea by several pathogenic mechanisms; the enteroadherent, enteroinvasive, enterohemorrhagic, and enteroaggregative forms can all be associated with blood in the stool. Hemolytic-uremic syndrome is the result largely of enterohemorrhagic E coli (especially serotype O157) and less commonly Shigella infections.
Amebiasis ( Entamoeba histolytica) can produce a picture of acute colitis. Causes of bloody diarrhea that are not obviously infectious include intussusception and immune deficiencies. Chronic inflammatory bowel disease can produce an initial episode of acute dysentery, although the history may reveal previous episodes; arthralgia or growth failure may have preceded the diarrhea. A history of recent similar diarrheal illness in family members or friends suggests an infectious diarrhea.
Food-borne spread of organisms or toxins is an important cause of acute diarrheal illness. Improperly prepared poultry and eggs are the major source for both campylobacteriosis and salmonellosis, and the major source for E coli O157 infection is ground beef.

Clinical Evaluation of Diarrhea :

The most common manifestation of GIT infection in children is diarrhea, abdominal cramps, and vomiting. Systemic manifestations are varied and associated with a variety of causes. The evaluation of a child with acute diarrhea includes:
HISTORY
1. Length of illness
2. Characterization of stools: frequency, looseness (watery versus mushy), and presence of gross blood
3. Oral intake: diet, quantity of fluids and solids taken
4. Presence of vomiting
5. Associated symptoms: fever, rash, and arthralgia
6. Urine output: frequency and qualitative amount
7. Possible exposure to diarrheal illness, child-care center attendance
PHYSICAL EXAMINATION
1. Hydration status: weight (stable or loss), mucosa (moist or dry), saliva and tears (present or absent), skin turgor (normal or poor), eyeballs and fontanelle (normal or sunken), and vital signs
2. Alertness
3. Infant: vigor of suck
LABORATORY (PERFORMED AS INDICATED)
1. Stool evaluation: culture, ova and parasites, smear for WBC, C. difficile toxin assay, occult blood & reducing substances
2. CBC: Hemoconcentration from dehydration causes an increase in PCV and Hb.
3. If hydration status is in question: blood urea nitrogen (BUN),serum creatinine & electrolytes
4. Urinalysis:the urine specific gravity is usually elevated (≥1.025) in cases of significant dehydration, but decreases after rehydration. With dehydration, a urinalysis may show hyaline and granular casts, a few white blood cells and red blood cells, and 30 to 100 mg/dL of proteinuria
5. If child is lethargic or has had a seizure, culture for sepsis: measure the BUN and serum electrolyte and glucose levels and examine and culture the cerebrospinal fluid.


A stool culture should be obtained if blood or leukocytes are noted in the stool and the child is severely ill. Examination of the stool for leukocytes is helpful in establishing the presence of colitis. In the presence of both infectious and noninfectious colitis, white blood cells (WBCs) are usually found in high numbers, frequently in sheets. The absence of WBCs in grossly bloody diarrheal stool occurs with enterohemorrhagic E coli infection but should also direct attention to entities such as intussusception and Meckel diverticulum when these diagnoses seem clinically appropriate.
Amebic colitis also may not be associated with WBCs in the stool, although the trophozoites and numerous red blood cells may be visible on a saline wet mount preparation of the stool. Invasive bacterial diarrhea frequently is associated with a peripheral blood leukocytosis.

Assessment of Degree of Dehydration:

Mild
Moderate
Severe
Infant(wt loss)
5%
10%
15%
Adolescent
3%
6%
9%
Infants and young children
Thirsty; alert; restless
Thirsty; restless or
lethargic but
irritable or drowsy
Drowsy; limp, cold, sweaty, cyanotic
extremities; may be
comatose
Older children
Thirsty; alert; restless
Thirsty; alert (usually)
Usually conscious
(but at reduced level), apprehensive
; cold, sweaty, cyanotic
extremities; wrinkled skin
on fingers and toes; muscle cramps


Signs and Symptoms
Tachycardia
Absent
Present
Present
Palpable pulses
Present
Present (weak)
Decreased
Blood pressure
Normal
Orthostatic hypotension
Hypotension
Cutaneous perfusion
Normal
Normal
Reduced and mottled
Skin turgor
Normal
Slight reduction
Reduced
Fontanel
Normal
Slightly depressed
Sunken
Mucous membrane
Moist
Dry
Very dry
Tears
Present
Present or absent
Absent
Respirations
Normal
Deep, may be rapid
Deep and rapid
Urine output
Normal
Oliguria
Anuria and severe oliguria


Calculation for correction of dehydration(deficit+maintenance+ongoing losses):
1.deficit

A child with dehydration has lost water; there is usually a concurrent loss of sodium and potassium. Most patients have isotonic dehydration . The following guidelines are used for calculating the deficits in isotonic dehydration secondary to gastroenteritis. The water deficit is the percentage of dehydration multiplied by the patient's weight (for a 10-kg child, 10% of 10 kg = 1 L deficit).The sodium and potassium deficits are derived from the water deficit .

Water deficit =%dehydration× weight

Sodium deficit = Water deficit × 80 mEq/L
Potassium deficit = Water deficit × 30 mEq/L
2.
Maintenance Therapy:

Maintenance fluids are most commonly necessary in preoperative and postoperative surgical patients; many nonsurgical patients also require maintenance fluids. Maintenance fluids are composed of a solution of water, glucose, sodium, and potassium.
Sources of Water losses:
(Urine 60%,Insensible losses (skin and lungs)35%,Stool 5%)
BODY WEIGHT METHOD FOR CALCULATING DAILY MAINTENANCE FLUID VOLUME
BODY WEIGHT
FLUID PER DAY
0-10 kg
100 mL/kg
11-20 kg
1,000 mL + 50 mL/kg for each kg >10 kg
>20 kg
1,500 mL + 20 mL/kg for each kg >20 kg*


*
The maximum total fluid per day is normally 2,400 mL.

Maintenance requirements of electrolytes:

Sodium: 2 - 3 mEq/kg/day
Potassium: 1 - 2 mEq/kg/day.

Adjustments in Maintenance Water:للاطلاع فقط

Source
Causes of Increased Water Needs
Causes of Decreased Water Needs
Skin
Radiant warmer
Mist tent

Phototherapy
Incubator (premature infants)

Fever


Sweat

Burns

Lungs
Tachypnea
Humidified ventilator

Tracheostomy

Mist tent

Gastrointestinal
Diarrhea

Emesis

Nasogastric suction

Renal
Polyuria
Oliguria/anuria
Miscellaneous
Surgical drain
Hypothyroidism

Third space losses(edema &ascites)


3.ongoing losses:
Adjusting Fluid Therapy for Gastrointestinal Lossesللاطلاع فقط

Average Composition

Approach to Replacement
Diarrhea
Replacement of Ongoing Stool Losses
Sodium: 55 mEq/L
Solution: 5% dextrose in ¼ normal saline + 15 mEq/L bicarbonate + 25 mEq/L potassium chloride
Potassium: 25 mEq/L
Replace stool mL/mL every 1-6 hr
Bicarbonate: 15 mEq/L

Gastric Fluid
Replacement of Ongoing Gastric Losses
Sodium: 60 mEq/L
Solution: 5% dextrose in half normal saline + 10 mEq/L potassium chloride
Potassium: 10 mEq/L
Replace output mL/mL every 1-6 hr
Chloride: 90 mEq/L



Fluid Management of Dehydration

1.Restore intravascular volume( fluid bolus or shoot):

Normal saline or Ringer's lactate : 20 mL/kg over 20 min (repeat until intravascular volume restored, 3 times)
2.Calculate 24-hr water needs
Calculate maintenance water
Calculate deficit water
3.Calculate 24-hr electrolyte needs
Calculate maintenance sodium and potassium
Calculate deficit sodium and potassium
4.Select an appropriate fluid (based on total water and electrolyte needs) For a patient with isotonic dehydration, D5 half NS with 20 mEq/L of potassium chloride is usually an appropriate fluid. For a child weighing less than 10 to 20 kg with mild dehydration, a reduction of the sodium concentration is usually reasonable (1/4 NS) because the sodium deficit is small. Potassium usually is not included in the IV fluids until the patient voids, unless significant hypokalemia is present. So it will be:
D5 1/2NS + 20 mEq/L KCl or D5 0.2NS + 20 mEq/L KCL
Administer half the calculated fluid during the first 8 hr, first subtracting any boluses from this amount
Administer the remainder over the next 16 hr
5.Replace ongoing losses as they occur
In all children, it is critical to carefully monitor vital signs, weight, urine output, and electrolytes to identify overhydration or underhydration, hyponatremia, and other electrolyte disturbances, and to then adjust the rate or composition of the intravenous solution accordingly.

Types of dehydration are 3 according to sodium level:

1.isotonic (isonatremic: S.Na 135-145mEq/L)
2.hypotonic(hyponatremic:S.Na <135 mEq/L)
3.hypertonic(hypernatremic:S.Na >145 mEq/L)


Hyponatremic dehydration occurs in children who have diarrhea and consume a hypotonic fluid (water or diluted formula). Volume depletion stimulates secretion of ADH, preventing the water excretion that should correct the hyponatremia. Hyponatremic dehydration produces a more substantial intravascular volume depletion owing to the shift of water from the extracellular space into the intracellular space. In addition, some patients develop symptoms, predominantly neurologic, from the hyponatremia . Most patients with hyponatremic dehydration do well with the same general approach outlined above. Overly rapid correction of hyponatremia (>12 mEq/L/24 hr) should be avoided because of the remote risk of central pontine myelinolysis.
Hypernatremic Dehydration
It is the most dangerous form of dehydration due to complications of hypernatremia and of therapy. Hypernatremia can cause serious neurologic damage, including central nervous system hemorrhages and thrombosis. This damage appears to be secondary to the movement of water from the brain cells into the hypertonic extracellular fluid, causing brain cell shrinkage and tearing blood vessels within the brain.It is usually a consequence of an inability to take in fluid, owing to a lack of access, a poor thirst mechanism (neurologic impairment), intractable emesis, or anorexia. The movement of water from the intracellular space to the extracellular space during hypernatremic dehydration partially protects the intravascular volume. Children with hypernatremic dehydration often appear less ill than children with a similar degree of isotonic dehydration. Urine output may be preserved longer, and there may be less tachycardia. Children with hypernatremic dehydration are often lethargic and irritable when touched. Hypernatremia may cause fever, hypertonicity, and hyperreflexia. Some infants have a high-pitched cry and hyperpnea. Alert patients are very thirsty, even though nausea may be present.
Probably because of intracellular water loss, the pinched abdominal skin of a dehydrated, hypernatremic infant has a “doughy” feel.
Too-rapid treatment of hypernatremic dehydration may cause significant morbidity and mortality. Idiogenic osmoles are generated within the brain during the development of hypernatremia. These idiogenic osmoles increase the osmolality within the cells of the brain, providing protection against brain cell shrinkage secondary to movement of water out of cells into the hypertonic ECF. These idiogenic osmoles dissipate slowly during correction of hypernatremia. With rapid lowering of the extracellular osmolality during correction of hypernatremia, there may be a new gradient created that causes water movement from the extra-cellular space into the cells of the brain, producing cerebral edema. Symptoms of the resultant cerebral edema can produce seizures, brain herniation, and death. To minimize the risk of cerebral edema during correction of hypernatremic dehydration, the serum sodium concentration should not decrease more than 12 mEq/L every 24 hours. The deficits in severe hypernatremic dehydration may need to be corrected over 2 to 4 days(based on initial sodium concentration).

N.B:The resuscitation phase (treatment of shock state ) is same in iso, hypo, & hypernatremic dehydration
Oral Rehydration:
Mild to moderate dehydration from diarrhea of any cause can be treated effectively using a simple, oral rehydration solution (ORS) containing glucose and electrolytes.Oral rehydration therapy(ORT) is less expensive than IV therapy and has a lower complication rate. IV therapy still may be required for patients with severe dehydration; patients with uncontrollable vomiting; patients unable to drink because of extreme fatigue, stupor, or coma; or patients with gastric or intestinal distention.
As a guideline for oral rehydration, 50 mL/kg of the ORS should be given within 4 hours to patients with mild dehydration, and 100 mL/kg should be given over 4 hours to patients with moderate dehydration. Supplementary ORS is given to replace ongoing losses from diarrhea or emesis. An additional 10 mL/kg of ORS is given for each stool. Fluid intake should be decreased if the patient appears fully hydrated earlier than expected or develops periorbital edema. Breastfeeding should be allowed after rehydration in infants who are breastfed; in other patients, their usual formula, milk, or feeding should be offered after rehydration.

When rehydration is complete, maintenance therapy should be started, using 100 mL of ORS/kg/24 hr until the diarrhea stops.
The low-osmolality WHO oral rehydration solution (ORS) containing 75 mEq of sodium and 75 mmol of glucose per liter, with total osmolarity of 245 mOsm per liter, is more effective than other formulations in reducing stool output without the risk of hyponatremia, and it is now the global standard of care.
Zinc Supplementation :
There is strong evidence that zinc supplementation in children with diarrhea in developing countries leads to reduced duration and severity of diarrhea and could potentially prevent a large proportion of cases from recurring. In addition to improving diarrhea recovery rates, administration of zinc in community settings leads to increased use of ORS and reduction in the inappropriate use of antimicrobials.WHO and UNICEF recommend that all children with acute diarrhea in at-risk areas should receive oral zinc in some form for 10-14 days during and after diarrhea (10 mg/day for infants <6 mo of age and 20 mg/day for those >6 mo).
Additional Therapies :
The use of probiotic nonpathogenic bacteria for prevention and therapy of diarrhea has been successful in developing countries. In addition to restoring beneficial intestinal flora, probiotics can enhance host protective immunity.A variety of organisms (Lactobacillus, Bifidobacterium) have a good safety record.
Antimotility agents (loperamide) are contraindicated in children with dysentery and probably have no role in the management of acute watery diarrhea in otherwise healthy children. Similarly, antiemetic agents such as the phenothiazines are of little value. Nonetheless, ondansetron is an effective and less-toxic antiemetic agent. Because persistent vomiting can limit oral rehydration therapy, a single sublingual dose of an oral dissolvable tablet of ondansetron (4 mg 4-11 yr and 8 mg for children >11 yr [generally 0.2 mg/kg]) may be given.
Antibiotic Therapy:
are useful in specific situations: Shigella dysentery(Ciprofloxacin''˃18 yr age", ampicillin, ceftriaxone,


azithromycin, or TMP-SMX)
Yersinia(aminoglycoside, TMP-SMX,) or Campylobacter gastroenteritis(Erythromycin or azithromycin),
pseudomembranous colitis(Clostridium difficile) Metronidazole (first line), Discontinue initiating antibioticVancomycin (2nd line)
Salmonella infections in infants younger than 6 months, and Salmonella infections in older patients who have enteric fever, typhoid fever, or complications of bacteremia(same as shigella)
EPEC, ETEC, EIEC: TMP-SMX or ciprofloxacin
Entamoeba histolyticaMetronidazole followed by iodoquinol or paromomycin
Giardia lamblia Furazolidone or metronidazole or albendazole or quinacrine
Nitazoxanide, an anti-infective agent, has been effective in the treatment of a wide variety of pathogens including C. parvum, G. lamblia, E. histolytica, Blastocystis hominis, C. difficile, and rotavirus.
Prevention:
Exclusive breast-feeding (administration of no other fluids or foods for the 1st 6 mo of life) protects very young infants from diarrheal disease through the promotion of passive immunity and through reduction in the intake of potentially contaminated food and water.
Improved Complementary Feeding Practices:Contamination of complementary foods can be potentially reduced through caregivers’ education and improving home food storage. Improved vitamin A status has been shown to reduce the frequency of severe diarrhea
Rotavirus Immunization(live-attenuated) associated with a significant reduction in severe diarrhea and associated mortality.
Improved Water and Sanitary Facilities and Promotion of Personal and Domestic Hygiene
Improved Case Management of Diarrhea:through prompt identification and appropriate therapy significantly reduces diarrhea duration, its nutritional penalty, and risk of death in childhood

Specific infective(foodborn) diarrheas:

1.bacterial:
Enterohemorrhagic Escherichia coli (EHEC) including E. coli O157:H7 and other Shiga toxin–producing E. coli (STEC):IP 1-8 days, Severe diarrhea that is often bloody; abdominal pain and vomiting Usually, little or no fever is present More common in children <4 yr old,duration of illness 5-10 ds,Dx stool culture Rx is supportive & monitor renal function,Hb platelet count as hemolytic uremic syndrome(HUS) is a possible complication[ which is triad of microangiopathic hemolytic anemia" MAHA",uremia & thrombocytopenia]. Studies indicate that antibiotics might promote the development of HUS

Shigella spp(bacillary dysentery).IP 1-2ds, Abdominal cramps, fever(that may cause fits), diarrhea( Stools might contain blood and mucus) or its toxins may cause fits( toxic encephalopathy),duration of illness 4-7 ds,Dx stool culture Rx Supportive care. TMP-SMX if organism is susceptible; nalidixic acid or other quinolones may be indicated if organism is resistant


Salmonella spp.IP 1-3ds, Diarrhea, fever, abdominal cramps, vomitingS. typhi and S. paratyphi produce typhoid with insidious onset characterized by fever, headache, constipation, malaise, chills, and myalgia; diarrhea is uncommon, and vomiting is not usually severe.duration of illness 4-7ds Dx stool culture Rx Supportive care

Other than for S. typhi and S. paratyphi, antibiotics are not indicated unless there is extra-intestinal spread, or the risk of extra-intestinal spread, of the infection

Consider ampicillin, gentamicin, TMP-SMX, or quinolones if indicatedA vaccine exists for S. typhi

Vibrio cholerae (toxin) IP 1-3ds, Profuse watery diarrhea and vomiting, which can lead to severe dehydration and death within hours duration of illness 3-7 ds,Dx Stool cultureV. cholerae requires special media to grow; if V. cholerae is suspected, must request specific testing Rx Supportive care with aggressive oral and intravenous rehydrationIn cases of confirmed cholera, tetracycline or doxycycline is recommended for adults, and TMP-SMX for children <8 yr

2.viral:

Rotavirus (groups A-C):IP1-3ds, Vomiting, watery diarrhea, low-grade feverTemporary lactose intolerance can occurInfants and children, elderly, and immunocompromised are especially vulnerable.duration of illness 4-8 ds Dx Identification of virus in stool via immunoassay Rx Supportive care
Hepatitis A:IP 28 days average (15-50 days), Diarrhea, dark urine, jaundice, and flulike symptoms, i.e., fever, headache, nausea, and abdominal pain, duration of illness Variable 2 wk-3 mo,Dx Increase in ALT, bilirubinPositive IgM and anti-hepatitis A antibodies,Rx Supportive care Prevention with immunization
3.parasitic:
Entamoeba histolytica (amebic dysentery),IP 2-3 days to 1-4 wk, Diarrhea (often bloody), frequent bowel movements, lower abdominal pain. , duration of illnessMay be protracted (several weeks to several months)Dx Examination of stool for cysts and parasites; may need at least 3 samples Serology for long-term infections Rx Metronidazole and a luminal agent (iodoquinol or paromomycin)
Giardia lamblia IP 1-2wk, Diarrhea, stomach cramps, gas, weight loss, duration of illness Days to weeks Dx Examination of stool for ova and parasites; may need at least 3 samples,Rx metronidazole

COMPLICATIONS OF GASTROENTERITIS:

Renal failure Dehydration,acute tubular necrosis,HUS,renal vein thrombosis"RVT"
Hypokalemia & paralytic ileus
2ry lactose intolerance
Fluid overload & pulmonary edema
Convulsions( febrile,hyponatremia,hypernatremia,hypocalcemia,hypomagnesmia,hypoglycemia,meningitis & cerebral vascular thrombosis)
CHRONIC DIARRHEA
defined as a diarrheal episode that lasts for ≥14 days,itis often the result of an intestinal infection that lasts longer than expected. This syndrome is often defined as( protracted diarrhea), and there is no clear distinction between protracted and chronic diarrhea. The younger the infant is, the more likely he or she will be to enter the cycle of diarrhea and secondary malnutrition that leads to further diarrhea, malnutrition, and susceptibility to infection


Causes of chronic diarrhea:
Common :
Chronic enteric infection:Salmonella organisms; Yersinia enterocolitica; Campylobacter, Giardia, Clostridium difficile toxin; enteroadherent Escherichia coli; rotavirus (in immunodeficient patients); cytomegalovirus; adenovirus; and HIV
Food allergy(cow's milk or soy proteins, others)
Chronic non specific diarrhea(toddler's diarrhea, irritable colon of childhood)
Disaccharide intolerance(Congenital or acquired lactase deficiency)
Cystic fibrosis
Celiac disease
Inflammatory bowel disease(CD & UC)
UTI
Immunodeficiency
Postenteritis bile acid malabsorption
Less common:
toautoimmune enteropathy
adrenal insufficiency and hyperthyroidism
Inintestinal lymphangiectasia
A acrodermatitis enteropathica
Hirschsprung disease with enterocolitis
Congenital chloride-losing diarrhea
Immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX)


chronic nonspecific diarrhea

The most benign etiology that encompasses functional diarrhea (or toddler's diarrhea) in children <4 yr of age and irritable bowel syndrome in those ≥5 yr.
The disease is the same with a slightly different age presentation, in that abdominal pain is more common and clearly associated with the diarrhea in older children. The hallmark of the syndrome is diarrhea associated with normal weight growth in well-appearing subjects. In younger children diarrhea is often watery, at times containing undigested food particles. It is usually more severe in the morning.. If the dietary history suggests that the child is ingesting significant amounts of fruit juices, then the offending juices should be decreased.. In older children, irritable bowel syndrome is often associated with abdominal pain and may be related to anxiety, depression, and other psychologic disturbances.

Symptoms may begin initially after an apparent acute enteritis (postinfectious irritable bowel).
Treatment may include (1) restricting the frequency of feedings, whether liquids or solids, in an effort to decrease stimulation of the gastrocolic reflex (in the toddler, three meals and a bedtime snack with nothing by mouth in between); (2) restricting the volumes of fluids ingested when excessive.If the child's fluid intake is >150 mL/kg/24 hr, fluid intake should be reduced to no more than 90 mL/kg/24 hr. The child is often irritable in the first 2 days after the fluid restriction; however, persistence with this approach for several more days results in a decrease in the stool frequency and volume; (3) avoiding excessive intake of juices.Sorbitol, which is a nonabsorbable sugar, is found in apple, pear, and prune juices and it can cause diarrhea in toddlers. Apple and pear juices contain higher amounts of fructose than glucose, a feature postulated to cause diarrhea in toddlers; and (4) reassuring the parents of the benign nature of this entity. A high-fat diet may be helpful in some children, although probably is of less importance. Cholestyramine (2 g by mouth 1 to 3 times daily) is also effective at times; however, the duration of use should be restricted because of the potential for interference with fat-soluble vitamin absorption.
In any event, this condition is self-limited and typically resolves by 3.5 years of age.
Food Allergy & hypersensitivity
Defined as ‘an immune response to food proteins,it occurs in 4-8% children commonly with those of +ve family history of atopy or allergies. Food allergy may be IgE mediated or non-IgE mediated. If a non-immunological reaction to a specific food occurs this is called non-allergic food hypersensitivity or intolerance.
Presentation of food allergy varies with the agent and the child's age:
in infants the most common causes are milk, egg and peanut
in older children peanut, tree nut and fish.
Fruit allergy, although common, is usually mild, causing an itchy mouth but no systemic symptoms. This is called 'oral allergy syndrome' and is usually associated with spring hay fever due to cross-reaction with tree pollens. Kiwi fruit, however, can cause anaphylaxis.

Food hypersensitivity is not related to food aversion, where the person refuses the food for psychological or behavioural reasons.

Management

The management of a food allergic child involves avoidance of the food but, especially for milk and nuts, this is very difficult as they may be present in small quantities in many foods and food labels are often unclear. The advice of a paediatric dietician is essential.


In addition, the child and family must be able to manage an allergic attack. Written self-management plans and adequate training are essential.
Drug management for mild reactions (no cardiorespiratory symptoms) is with antihistamines.

If the child had a severe reaction or has asthma, treatment is with epinephrine (adrenaline) given intramuscularly by auto-injector (e.g. Epipen), which the child or parent should carry with them at all times.
Cow’s Milk Protein Allergy(CMPA):
Results from an immunological reaction to one or more of milk proteins,only 0.5% of exclusively breast fed infants are affected & 5-15% of infants show syggestive symptoms.It is either IgE- or non-IgE mediated.
27% show symptoms within 45 minutes,58% within 2hrs
Its incidence 2-6% of children, Prevalence highest < 1 year
Cow’s Milk Intolerance:
A transient intolerance to lactose and/ or protein found in cow’s milk following an infective episode of diarrhoea
Carbohydrate intolerance is due to mucosal damage which results in reduced activity of disaccharide enzymes
Protein intolerance is an immunomediated reaction to cow’s milk protein following mucosal damag.
Clinical presentation:
Early reactions (within 45 minutes):
Urticaria
Angio-oedema
Vomiting
Acute flare up of atopic detmatitis
Medium (45 minutes to 20 hours)
Pallor
Gastro intestinal tract symptoms
Late reactions (after 20 hours)
Atopic dermatitis
Respiratory symptoms
Diarrhoea
IgE mediated (within 30mins)
Anaphylaxis
Skin (50-60%):
Angio-oedema
Urticaria
Pruritis
GI (50-60%):
Nausea/Vomiting
Colicky abdo pain


Resp (20-30%):
Wheezing
Rhinitis
Laryngeal oedema
Asthma
Non IgE Mediated (hours-days)
Skin: Dermatitis
GIT:
Chronic diarrhoea( intestinal protein loss produces edema and a protein-losing enteropathy)
Iron deficiency anaemia
Colic
Food refusal and poor growth
GORD
Blood in stool
Constipation
Enterocolitis
Eosinophilic oesophagogastroenteropathy
Respiratory:asthma
Evaluation of a child with suspected CMPA:
A comprehensive history:atopic one parent( risk 20-40%) or both(risk 40-50%) or sibling.
Symptoms:either GIT,skin or respiratory
CMPA in Breast fed Infants:
Symptoms include skin or GIT
Most of symptoms are mild to severe.
Infants with atopic dermatitis:
Risk of CMPA x 4
Risk of egg allergy x 8
Diagnosis:
Comprehensive allergy focused clinical history with careful & complete physical examination
IgE specific antibody (RAST)
Skin Prick Testing
Elimination Diet & Food Challenge
the diagnosis can be confirmed safely and easily by rectal mucosal biopsy; this shows eosinophilic inflammation of the mucosa. Visual findings at proctoscopy usually include mucosal friability and lymphoid hyperplasia, giving a lumpy, "mosquito-bitten" appearance to the rectal mucosa.


Treatment:
Breast fed infants: Maternal exclusion diet avoiding food containing CMP( dairy products)
Bottle fed infants: Cows Milk Free formula.
Extensively hydrolysed Formulae (e.g., Nutramigen, Pregestamil, or Alimentum).
Amino Acid based Formulae
Prognosis:
50% resolve in first year of life
60-70% resolve by second year of life
80-90% resolve by fifth year of life
Parental reported rate 4x higher
Lactose intolerance:
It also called lactase deficiency and hypolactasia, is the inability to digest lactose, a sugar found in milk and to a lesser extent milk-derived dairy products. It is not a disorder as such, but a genetically-determined characteristic. Lactose intolerant individuals have insufficient levels of lactase, an enzyme that catalyzes hydrolysis of lactose into glucose andgalactose, in their digestive system.
Lactase deficiency has a number of causes and is classified as one of three types:
Primary lactase deficiency(Primary adult type-hypolactasia) is genetic, only affects adults and is caused by the absence of a lactase persistence allele. It is the most common cause of lactose intolerance as a majority of the world's population lacks these alleles. The brush border lactase is expressed at low levels during fetal life; activity increases in late fetal life and peaks from term to 3 yr, after which levels gradually decrease with age.
Secondary, acquired, or transient lactase deficiency is caused by an injury to the small intestine, usually during infancy, from acute gastroenteritis(rotavirus infection),celiac disease,chemotherapy, intestinal parasites or other environmental causes.
Congenital lactase deficiency(CLD) is a very rare, HYPERLINK "http://en.wikipedia.org/wiki/Autosomal_recessive" \o "Autosomal recessive"autosomal recessive genetic disorder that prevents lactase expression from birth. It is particularly common in Finland. People with congenital lactase deficiency cannot digest lactose from birth, and therefore cannot digest breast milk.
Lactose intolerance is not an allergy because it is not an immune response, but rather a problem with digestion caused by lactase deficiency.
Clinical presentation:
The principal symptom of lactose intolerance is an adverse reaction to products containing lactose (primarily milk), including abdominal bloating and cramps, flatulence,diarrhea, nausea, borborygmi (rumbling stomach) and vomiting (particularly in adolescents). These appear thirty minutes to two hours after consumption. The severity of symptoms typically increases with the amount of lactose consumed; most lactose-intolerant people can tolerate a certain level of lactose in their diet without ill-effect.

Pathophysiology:

Lactose, a disaccharide, is present in milk and processed foods. Dietary lactose must be hydrolyzed to a monosaccharide in order to be absorbed by the small intestinal mucosa. A deficiency of intestinal lactase prevents hydrolysis of ingested lactose. The osmotic load of the unabsorbed lactose causes secretion of fluid and electrolytes until osmotic equilibrium is reached. Dilation of the intestine caused by the osmosis induces an acceleration of small intestinal transit, which increases the degree of maldigestion. Within the large intestine, free lactose is fermented by colonic bacteria to yield short-chain fatty acids and hydrogen gas.The combined increase in fecal water, intestinal transit, and generated hydrogen gas accounts for the wide range of GIT symptoms.

Laboratory Studies

not mandatory, and often simple dietary changes that reduce or eliminate lactose from the diet relieve symptoms.
Stool exam: acidic stool PH(A stool pH less than 5.3 is suggestive of carbohydrate malabsorption, whereas a stool pH more than 5.6 is evidence against this diagnosis). &+ve for reducing substances(non specific)
Lactose tolerance test
This test is rarely done in clinical practice.
Measure serial blood glucose levels after an oral lactose load. A fasting serum glucose level is obtained, after which 50 g of lactose is administered. Measure the serum glucose level at 0, 60, and 120 minutes.
False-negative results occur in presence of diabetes and small bowel bacterial overgrowth. The diagnosis is confirmed if the serum glucose level fails to increase by 20 g/dL above baseline.
Breath hydrogen test(H2-breath test)
This is the diagnostic test of choice.

Subjects are administered lactose after an overnight fast, after which expired air samples are collected before and at 30-minute intervals for 3 hours to assess hydrogen gas concentrations.
A rise in breath hydrogen concentration greater than 20 parts per million over the baseline after lactose ingestion suggests lactase deficiency.
Small bowel biopsy
This is the criterion standard; however, it is invasive and rarely performed usually necessary. A major advantage is that it provides definitive information. Biopsy samples from the small bowel are assayed for lactase activity. The biopsy results may be normal if deficiency is focal or patchy
DDxHYPERLINK "http://emedicine.medscape.com/article/184332-overview"
Giardiasis
Inflammatory Bowel Disease
Irritable Bowel Syndrome


Treatment:
Dietary adjustment is the primary form of therapy for patients with lactose intolerance. Advise patients to reduce or restrict products containing lactose. Lactose-free formulas(LF based on either soy or cow's milk) are very effective. Yogurt and fermented products, such as cheeses, are better tolerated than regular milk.
Commercially available lactase enzyme preparations (eg, LACTAID, Lactrase) are effective in reducing symptoms; however, they may not be effective in some patients, partially due to insufficient dosing.
Supplemental calcium should also be recommended.
In secondary lactase deficiency, treatment is directed at the underlying cause.
Diet
Avoid or reduce intake of lactose-containing foods.
Most patients who are lactose intolerant can ingest as much as 240 mL of milk without an exacerbation of their symptoms.
Certain medications and foods contain hidden lactose, such as breads, margarine, salad dressings, and candies.

Complications of lactose intolerance: may include osteopenia.

Coeliac disease( Gluten-Sensitive Enteropathy GSE )
It is an enteropathy in which the gliadin fraction of gluten provokes a damaging immunological response in the proximal small intestinal mucosa. As a result, the rate of migration of absorptive cells moving up the villi (enterocytes) from the crypts is massively increased but is insufficient to compensate for increased cell loss from the villous tips. Villi become progressively shorter and then absent, leaving a flat mucosa.
The incidence 1:3000. It is considered an autoimmune condition because of the presence of anti–TG2 antibodies and the association with other autoimmune diseases (thyroid, liver, diabetes, adrenal).It is triggered by the ingestion of wheat gluten and related prolamines from rye and

barley.

A genetic predisposition is suggested by the family aggregation and the concordance in monozygotic twins, which approaches 100% but environmental factors might affect the risk of developing celiac disease or the timing of its presentation. Prolonged breastfeeding has been associated with a reduced incidence of symptomatic disease.
classical presentation is at 8-24 months of life with failure to thrive following the introduction of gluten in cereals. General irritability, abnormal stools(steatorrheal i,e offensive greasy bulky or not), abdominal distension and buttock wasting are the usual symptoms. Increasingly, children may present in later childhood with anaemia (iron and/or folate deficiency) or growth failure or short stature, with little or no gastrointestinal symptoms. Occasionally there is constipation, rectal prolapse, or intussusception.
Diagnosis
Serologic tests have a crucial role in the diagnosis of celiac disease; sensitivity of the IgA anti- tissue transglutaminase TG2 is ˷ 87%), and specificity is ˷ 95%). Some 10% of patients whose disease is diagnosed earlier than 2 yr of age show absence of IgA anti-TG2. For them, the measurement of serum antigliadin antibodies is generally advised. Antibodies against gliadin-derived deamidated peptides (D-AGA) have been assessed. A problem with serology is represented by the association of celiac disease with IgA deficiency. Serum IgA should always be checked, and in the case of IgA deficiency, D-AGA, IgG anti-endomysium, or TG2 should be sought. Negative serology should not preclude a biopsy examination when the clinical suspicion is strong.
Confirmation depends upon the demonstration of a flat mucosa on jejunal biopsy followed by the resolution of symptoms and catch-up growth upon gluten withdrawal. There is no place for the empirical use of a gluten-free diet as a diagnostic test for coeliac disease in the absence of a jejunal biopsy.
OTHER CAUSES OF FLAT MUCOSA: Tropical sprue, Giardiasis, Cow's milk & soy protein enteropathy…….etc
Silent celiac disease( No apparent symptoms in spite of histologic evidence of villous atrophy) is being increasingly recognized, mainly in asymptomatic 1st-degree relatives of celiac patients .
Treatment :
The only treatment for celiac disease is lifelong strict adherence to a gluten-free diet


Screening for celiac disease is indicated in the following:
DM type 1,Down ,Turner& William syndromes, Unexplained iron deficiency anaemia, 1st-degree relatives, Autoimmune thyroiditis, Addison disease ,Dermatitis herpetiformis, Short stature, Unexplained osteoporosis

Acrodermatitis Enteropathica :

Acrodermatitis enteropathica is a rare autosomal recessive disorder caused by an inability to

absorb sufficient zinc from the diet. The genetic defect is in the intestinal zinc specific transporter gene . Initial signs and symptoms usually occur in the first few months of life, often after weaning from breast milk to cow's milk. The cutaneous eruption consists of vesiculobullous, eczematous, dry, scaly, or psoriasiform skin lesions symmetrically distributed in the perioral, acral, and perineal areas and on the cheeks, knees, and elbows . The hair often has a peculiar, reddish tint, and alopecia of some degree is characteristic. Ocular manifestations include photophobia, conjunctivitis, blepharitis, and corneal dystrophy detectable by slit-lamp examination. Associated manifestations include chronic diarrhea, stomatitis, glossitis, paronychia, nail dystrophy, growth retardation, irritability, delayed wound healing, intercurrent bacterial infections, and superinfection with Candida albicans. Lymphocyte function and free radical scavenging are impaired. Without treatment, the course is chronic and intermittent but often relentlessly progressive. When the disease is less severe, only growth retardation and delayed development may be apparent.
The diagnosis is established by the constellation of clinical findings and detection of a low plasma zinc concentration. Histopathologic changes in the skin are nonspecific
Oral therapy with zinc compounds is the treatment of choice. Optimal doses range from 50 mg/24 hr of zinc sulfate, acetate, or gluconate daily for infants up to 150 mg/24 hr for children.
DDx: secondary zinc deficiency

Intestinal Lymphangiectasia :

Obstruction of the lymphatic drainage of the intestine can be due to either congenital defects in lymphatic duct formation or to secondary causes . The congenital form is often associated with lymphatic abnormalities elsewhere in the body, as occur with Turner, Noonan, and Klippel-Trenaunay-Weber syndromes. Causes of secondary lymphangiectasia include constrictive pericarditis, heart failure, retroperitoneal fibrosis, abdominal tuberculosis, and retroperitoneal malignancies. Lymph rich in proteins, lipids, and lymphocytes leaks into the bowel lumen, resulting in protein-losing enteropathy, steatorrhea, and lymphocyte depletion. Hypoalbuminemia, hypogammaglobulinemia, edema, lymphopenia, malabsorption of fat and fat-soluble vitamins, and chylous ascites often occur.
The diagnosis is suggested by the typical findings in association with an elevated fecal α1-antitrypsin clearance. Radiologic findings of uniform, symmetric thickening of mucosal folds throughout the small intestine are characteristic but nonspecific. Small bowel mucosal biopsy can show dilated lacteals with distortion of villi and no inflammatory infiltrate.
Treatment includes restricting the amount of long-chain fat ingested and administering a formula containing protein and medium-chain triglycerides (MCTs). Supplementing a low-fat diet with MCT oil in cooking is used in the management of older children with lymphangiectasia. Rarely, parenteral nutrition is required. If only a portion of the intestine is involved, surgical resection may be considered.

Cystic Fibrosis (CF):

An autosomal recessive disorder, is the most common life-limiting genetic disease. The gene for CF, localized to the long arm of chromosome 7, is a large gene that encodes a polypeptide termed cystic fibrosis transmembrane regulator (CFTR) is mutated causing dysfunctional epithelial transport & leading to the clinical manifestations of CF. The secretory and absorptive characteristics of epithelial cells are affected.
Most patients with CF have exocrine pancreatic insufficiency early in life (if not at birth) as a result of inspissation of mucus in the pancreatic ducts. Maldigestion with secondary malabsorption results in steatorrhea (large, fatty, floating, foul-smelling stools) and many secondary deficiency states (vitamins A, D, E, and K) in untreated patients.This is in addition to chronic chest infection,finger clubbing & other respiratory symptoms.
Approximately 10% of patients are born with intestinal obstruction resulting from inspissated meconium (meconium ileus). In older patients, intestinal obstruction may occur because of maldigestion and thick mucus in the intestinal lumen (distal intestinal obstruction syndrome).
The diagnosis of CF has been based on a positive quantitative chloride sweat test (Cl− ≥ 60 mEq/L) in conjunction with 1 or more of the following features: typical chronic obstructive pulmonary disease, documented exocrine pancreatic insufficiency, and a positive family history.
Newborn Screening: immunoreactive trypsinogen results and limited DNA testing on blood spots, which are then coupled with confirmatory sweat analysis.
Rx of Intestinal Complications:
pancreatic enzyme replacement
When meconium ileus is suspected, a nasogastric tube is placed for suction and the newborn is hydrated. In many cases, gastrografin enemas with reflux of contrast material into the ileum not only confirm the diagnosis but have also resulted in the passage of a meconium plug and clearing of the obstruction.
Constipation:


AAny definition of constipation is relative and depends on stool consistency, stool frequency, and difficulty in passing the stool. A normal child might have a soft stool only every 2nd or 3rd day without difficulty; this is not constipation. A hard stool passed with difficulty every 3rd day should be treated as constipation. Constipation can arise from defects either in filling or emptying the rectum . other definitions( Passage of hard scybalous pebblelike or cylindrical cracked stools, Straining or painful defecation).
DDx:
Functional constipation
Anal & rectal disorders( like anal fissure,anal stenosis, Imperforate anus…)
Neurological/ neuromuscular( Hirschsprung disease,CP,Down syndrome….)

Metabolic & endocrine( hypothyroidism,hypokalemia,hypercalcemia,DI…..)

Medications(anticholinergics,antihistamines,opiods….)
Toxins(lead poisoning, botulism…..)
Miscellaneous( CMPA,celiac disease…..)
Abdominal Pain
is one of the most common symptoms in children and adolescents and is estimated to account for about 5% of unscheduled office visits. Recurrent abdominal pain (RAP) as a recognizable entity in childhood was first characterized by pain that occurs at least three times over a period of 3 or more months severely enough to affect daily activities in children older than 3 years.
Causes of recurrent or chronic abdominal pain:
Associated with upper GI symptoms
GERD
Peptic ulcer
Crohn disease
Henoch-Schonlein purpura
Parasitic infection (Giardia)
Motility disorders
Idiopathic gastroparesis
Associated with altered bowel pattern
inflammatory bowel disorders(UC,CD idiopathic)
Parasitic
Bacterial (Clostridium difficile, Yersinia, Campylobacter, tuberculosis)
Lactose intolerance
Chronic constipation
Neoplasia (lymphoma)
Psychiatric disorders such as anxiety
Presenting as isolated paroxysmal abdominal pain
Obstructive disorders


Small bowel lymphoma
Postsurgical adhesions
Abdominal migraine
Acute intermittent porphyria
Vascular disorders
Mental disorders (school phobia)
Functional abdominal pain
Others
Chronic pancreatitis
Sickle cell crisis
Chronic hepatitis
Chronic cholecystitis & Choledochal cyst
Ureteropelvic junction obstruction & Hydronephrosis
Familial Mediterranean fever
Surgical:
Meckel's diverticulum
Recurrent intussusception
Internal, inguinal, or abdominal wall hernia
Chronic appendicitis
The alarming signs & symptoms that suggest organic rather than functional causes for RAP:
involuntary weight loss, deceleration of linear growth, gastrointestinal blood loss, significant vomiting, chronic severe diarrhea, persistent right upper or right lower quadrant pain, unexplained fever, and family history of inflammatory bowel disease & etc..
Gastrointestinal Hemorrhage
Bleeding can occur anywhere along the GIT, and identification of the site may be challenging. Hematemesis is bloody vomitus, which usually represents bleeding proximal to the ligament of Treitz. Blood, which is altered by gastric acid, becomes dark and coffee-ground in appearance. Bleeding that has little or no contact with gastric acid will be bright red. GI bleeding that occurs proximal to the ileocecal valve and is passed rectally will usually appear as melena: black, tarry, sticky stools that


result from the denaturing of hemoglobin by intestinal bacteria and enzymes. Hematochezia, red bloody stools passed rectally, usually results from distal GI bleeding. Blood is usually mixed with the

stool or passed just before or just after defecation. Occasionally, rapid bleeding from an upper GI source combined with the cathartic action of blood can speed transit time and cause hematochezia. Specific types of hematochezia include maroon-colored stools, seen with significant bleeding usually from the distal small bowel, and currant-jelly stools indicative of intestinal vascular congestion and hyperemia.
DDx:
The appearance of red color in the stool is often assumed to be blood. However, many other substances cause change in stool color. Foods that contain a high concentration of red pigments such as tomatoes, cranberries, beets, and red fruit juices and gelatin can cause red stools. Similarly, red-colored medications such as acetaminophen and amoxicillin can be passed in the stools, especially if diarrhea is present. Spinach, licorice, iron, and bismuth often lead to dark, black stools, which can be confused with true melena. In infants, Serratia marcescens can cause red diaper syndrome as a result of the formation of red pigment in soiled diapers stored for longer than 1 day.
Causes of GI Bleeding:
Newborn:
Common causes of GI bleeding in the first 24 hours of life include maternal blood swallowed during delivery and local trauma after nasogastric suctioning. Hemorrhagic disease of the newborn as a result of inherited deficits of coagulation factors or delay in administration of postnatal vitamin K occasionally produces GI bleeding
Premature infants and newborns who have birth asphyxia are at increased risk for having gastric ulcerations and erosions that can bleed & Necrotising enterocolitis "NEC".
Infant:
Bacterial enteritisMilk protein allergyIntussusceptionAnal fissure
Child & Adolescent:
Bacterial enteritisAnal fissureColonic polyps Peptic ulcer/gastritisSwallowed epistaxisMallory-Weiss syndrome& Prolapse (traumatic) gastropathy producing subepithelial hemorrhageEsophagitis/Esophageal varices
Meckel diverticulumHenoch-Schonlein purpuraForeign bodyHemangioma, arteriovenous malformationInflammatory bowel diseaseCoagulopathy
Diagnosis:
Upper intestinal bleeding is evaluated with an OGD (oesophagogastroduodenoscopy)
Evaluation of the small intestine is facilitated by capsule endoscopy. The capsule-sized imaging device is swallowed in older children or placed endoscopically in younger children.
Lower GI bleeding is investigated with a colonoscopy
Occult blood in stool is usually detected by using commercially available fecal occult blood testing cards, which are based on a chemical reaction between the chemical guaiac and oxidizing(peroxidase) action of a substrate (hemoglobin), giving a blue color. The guaiac test is very sensitive, but random testing can miss chronic blood loss, which can lead to iron-deficiency anemia. Foods that have peroxidase activity may cause false-positive results if eaten within 3 days of testing: red meat, liver, processed meats, and raw fruits and vegetables, especially melon, turnip, radishes, and horseradish. High vitamin C intake interferes with the peroxidase reaction and can cause false-negative results. Similarly, outdated guaiac cards and prolonged storage may affect the accuracy of the test. Stool guaiac cards are not accurate for testing emesis for the presence of blood because gastric acid can affect the reaction that causes the color change.

Gastroesophageal Reflux Disease (GERD)

Gastroesophageal reflux (GER) signifies the retrograde movement of gastric contents across the lower esophageal sphincter (LES) into the esophagus & it is usually phsiological in young infant. GERD is defined as symptoms or complications resulting from exposure of the esophagus, the oropharynx, or the airway to gastric refluxate (acid, food, bile);I,e pathological GER & it is the most common esophageal disorder in children of all ages.
Measurement of lower oesophageal pH shows that in normal individuals there is acidity from reflux of stomach contents for less than 4% of a 24-hour period. Reflux occurring more frequently than this results from functional immaturity of the lower oesophageal sphincter leading to episodes of inappropriate relaxation so Transient LES relaxation (TLESR) is the primary mechanism allowing reflux to occur. A short intra-abdominal length of oesophagus probably also contributes. It is common in the first year of life. By 12 months of age, nearly all symptomatic reflux will have resolved spontaneously, presumably due to a combination of maturation of the lower oesophageal sphincter, assumption of an upright posture and more solids in the diet. A sliding hiatus hernia is present in some symptomatic infants, but many children with a hiatus hernia are symptom-free.
Clinical Manifestations :
Most of the common clinical manifestations of esophageal disease can signify the presence of GERD.


Infantile reflux manifests more often with regurgitation (especially postprandially), signs of esophagitis
(irritability, arching, choking, gagging, feeding aversion), and resulting failure to thrive
Older children can have regurgitation during the preschool years; complaints of abdominal and chest pain supervene in later childhood and adolescence. Occasional children present with neck contortions (arching, turning of head), designated Sandifer syndrome.
The respiratory presentations are also age dependent: GERD in infants can manifest as obstructive apnea or as stridor or lower airway disease in which reflux complicates primary airway disease such as laryngomalacia or bronchopulmonary dysplasia. Otitis media, sinusitis, lymphoid hyperplasia, hoarseness, vocal cord nodules, and laryngeal edema have all been associated with GERD. Airway manifestations in older children are more commonly related to asthma or to otolaryngologic disease such as laryngitis or sinusitis.
Infant reflux becomes evident in the 1st few months of life, peaks at ∼4 mo, and resolves in up to 88% by 12 mo and nearly all by 24 mo. Symptoms in older children tend to be chronic, waxing and waning, but completely resolving in no more than half, which resembles adult patterns.
Diagnosis
For most of the typical GERD presentations, particularly in older children, a thorough history and physical examination suffice initially to reach the diagnosis.
Contrast (usually barium) radiographic study of the esophagus and upper GIT is performed in children with vomiting and dysphagia to evaluate for achalasia, esophageal strictures and stenosis, hiatal hernia, and gastric outlet or intestinal obstruction. It has poor sensitivity and specificity in the diagnosis of GERD due to its limited duration and the inability to differentiate physiologic GER from GERD.
Extended esophageal pH monitoring of the distal esophagus, no longer considered the sine qua non(not necessary ) of a GERD diagnosis, provides a quantitative and sensitive documentation of acidic reflux episodes. The distal esophageal pH probe is placed at a level corresponding to 87% of the nares-LES distance, Normal values of distal esophageal acid exposure (pH <4) are generally established as <5-8% of the total monitored time, but these quantitative normals are insufficient to establish or disprove a diagnosis of pathologic GERD. The most important indications for esophageal pH monitoring are for assessing efficacy of acid suppression during treatment, evaluating apneic episodes in conjunction with a pneumogram and perhaps impedance, and evaluating atypical GERD presentations such as chronic cough, stridor, and asthma.
Endoscopy allows diagnosis of erosive esophagitis and complications such as strictures or Barrett esophagus; esophageal biopsies can diagnose histologic reflux esophagitis in the absence of erosions while simultaneously eliminating allergic and infectious causes.
Empirical antireflux therapy, using a time-limited trial of high-dose proton pump inhibitor (PPI), is a cost-effective strategy for diagnosis in adults; although not formally evaluated in older children, it has also been applied to this age group.

Management:

Dietary measures for infants include normalization of any abnormal feeding techniques, volumes, and frequencies.
Thickening of feeds or use of commercially prethickened formulas increases the percentage of infants with no regurgitation, decreases the frequency of daily regurgitation and emesis, and increases the infant's weight gain. the addition of a Tbsp of rice cereal per oz of formula results in a greater caloric density (30 kcal/oz), and reduced crying time, although it might not modify the number of nonregurgitant reflux episodes.
A short trial of a hypoallergenic diet may be used to exclude milk or soy protein allergy before pharmacotherapy.
Older children should be counseled to avoid acidic or reflux-inducing foods (tomatoes, chocolate, spicy foods , mint) and beverages (juices, carbonated and caffeinated drinks, alcohol), avoiding lying down after meals
Weight reduction for obese patients and elimination of smoke exposure are other crucial measures at all ages.
Positioning measures are particularly important for infants, who cannot control their positions independently. Seated position worsens infant reflux and should be avoided in infants with GERD. Esophageal pH monitoring demonstrates more reflux episodes in infants in supine and side positions compared with the prone position, but evidence that the supine position reduces the risk of sudden infant death syndrome has led the AAP to recommend supine positioning during sleep. When the infant is awake and observed, prone position and upright carried position can be used to minimize reflux. The efficacy of positioning for older children is unclear, but some evidence suggests a benefit to left side position and head elevation during sleep. The head should be elevated by elevating the head of the bed, rather than using excess pillows, to avoid abdominal flexion and compression that might worsen reflux.
Pharmacotherapy is directed at ameliorating the acidity of the gastric contents or at promoting their aboral movement.
Antacids are the most commonly used antireflux therapy and are readily available over the counter. They provide rapid but transient relief of symptoms by acid neutralization. The long-term regular use of antacids cannot be recommended because of side effects of diarrhea (magnesium antacids) and constipation (aluminum antacids) and rare reports of more serious side effects of chronic use.
Histamine-2 receptor antagonists (H2RAs: cimetidine, famotidine, nizatidine, and ranitidine) are widely used antisecretory agents that act by selective inhibition of histamine receptors on gastric parietal cells. There is a definite benefit of H2RAs in treatment of mild-to-moderate reflux esophagitis. H2RAs have been recommended as first-line therapy because of their excellent overall safety profile, but they are being superseded by PPIs in this role.





PPIs (omeprazole, lansoprazole, pantoprazole, rabeprazole, and esomeprazole) provide the most potent antireflux effect by blocking the hydrogen-potassium ATPase channels of the final common pathway in gastric acid secretion. PPIs are superior to H2RAs in the treatment of severe and erosive esophagitis. Pharmacodynamic studies have indicated that children require higher doses of PPIs than adults on a per-weight basis.rabe-&panto- are not FDA-approved in children. The effective dose of omeprazole ranges from 0.3 to 3.5 mg/kg/day (maximum 80 mg/day) and for lansoprazole is from 0.73 to 1.66 mg/kg/day (maximum 30 mg/day).
Prokinetic agents available in the United States include metoclopramide (dopamine-2 and 5-HT3 antagonist), bethanechol (cholinergic agonist), and erythromycin (motilin receptor agonist). Most of these increase LES pressure; some improve gastric emptying or esophageal clearance. None affects the frequency of TLESRs. The available controlled trials have not demonstrated much efficacy for GERD. Baclofen is a centrally acting γ-aminobutyric acid (GABA) agonist that has been shown to decrease reflux by decreasing TLESRs in healthy adults and in a small number of neurologically impaired children with GERD.
Surgery, usually fundoplication( fundus of the stomach is wrapped around the intra-abdominal oesophagus) is effective therapy for intractable GERD in children, particularly those with refractory esophagitis or strictures and those at risk for significant morbidity from chronic pulmonary disease. It may be combined with a gastrostomy for feeding or venting.
Complications of GERD:
Reflux is often problematic:
in children with cerebral palsy or other neuro developmental disorders, when energetic management, surgical if necessary, may transform the child's quality of life
in preterm infants who develop bronchopulmonary dysplasia (chronic lung disease of prematurity)
following surgery for oesophageal atresia or diaphragmatic hernia.
1.Esophageal: Esophagitis can manifest as irritability, arching, and feeding aversion in infants; chest or epigastric pain in older children; and, rarely, as hematemesis, anemia(iron deficiency), or Sandifer syndrome at any age. Prolonged and severe esophagitis leads to formation of strictures producing dysphagia, and requiring repeated esophageal dilations and often fundoplication. Long-standing esophagitis predisposes to metaplastic transformation of

the normal esophageal squamous epithelium into intestinal columnar epithelium, termed Barrett esophagus, a precursor of esophageal adenocarcinoma.
2.Nutritional:
Esophagitis and regurgitation may be severe enough to induce failure to thrive because of caloric deficits. Enteral (nasogastric or nasojejunal, or percutaneous gastric or jejunal) or parenteral feedings are sometimes required to treat such deficits.
3. Extraesophageal: Respiratory (“Atypical”) Presentations: GERD can produce respiratory symptoms" chronic cough, stridor, and hoarseness, aspiration pneumonia and chronic pulmonary fibrosis and may occur without esophagitis" by direct contact of the refluxed gastric contents with the respiratory tract (aspiration, laryngeal penetration, or microaspiration) or by reflexive interactions between the esophagus and respiratory tract (inducing laryngeal closure or bronchospasm). Often, GERD and a primary respiratory disorder, such as asthma, interact and a vicious cycle between them worsens both diseases.
Apnea & stridor had been linked in some studies. Apparent life-threatening events (ALTEs) or sudden infant death syndrome (SIDS) - controversial .
Hypertrophic Pyloric Stenosis(HPS)
In PS, there is hypertrophy of the pylorus causing gastric outlet obstruction. It is more common in boys (4 : 1), particularly first-borns, and there may be a family history, especially on the maternal side. The incidence of PS is increased in infants with B and O blood groups. PS is occasionally associated with other congenital defects, including tracheoesophageal fistula.
Etiology:
The cause of PS is unknown, but many factors have been implicated. PS is usually not present at birth . An association has been found with the use of erythromycin in neonates with highest risk if the medication is given within the 1st 2 wk of life. Investigators have proposed that deficiency of nitric oxide, a ubiquitous mediator of smooth-muscle relaxation, may be associated with the development of PS because nitric oxide synthase is selectively depleted in the pyloric muscle of patients with PS.
Clinical Manifestations:
Nonbilious vomiting is the initial symptom of PS. The vomiting may or may not be projectile initially but is usually progressive, occurring immediately after a feeding. Emesis might follow each feeding, or it may be intermittent. The vomiting usually starts after 3 wk of age ( irrespective of gestational age), but symptoms can develop as early as the 1st wk of life and as late as the 5th mo. About 20% have intermittent emesis from birth that then progresses to the classic picture. After vomiting, the infant is hungry and wants to feed again. Greater awareness of PS has led to earlier identification of patients with fewer instances of chronic malnutrition and severe dehydration and at times a subclinical self-resolving hypertrophy.
Pathophysiology: Persistent vomiting caused by gastric outlet obstruction results in the continuous loss of gastric


hydrochloric acid. Dehydration causes an increase in aldosterone production, leading to increased renal excretion of potassium. The potassium excretion results in a hypochloremic, hypokalemic metabolic alkalosis. The depletion of chloride in the blood leads to an exchange of hydrogen and potassium for sodium in the distal tubule, resulting in a paradoxic aciduria. However, a spectrum of electrolyte abnormalities may be seen. Hypoglycemia may be present and may cause seizures.
Hyperbilirubinemia is the most common clinical association of pyloric stenosis, also known as icteropyloric syndrome. Unconjugated hyperbilirubinemia is more common than conjugated and usually resolves with surgical correction. It may be associated with a decreased level of glucuronyl transferase as seen in ∼5% of affected infants. Other coexistent clinical diagnoses have been described, including eosinophilic gastroenteritis, hiatal hernia, peptic ulcer, congenital nephrotic syndrome, congenital heart disease, and congenital hypothyroidism.
Diagnosis:
The diagnosis has traditionally been established by palpating the pyloric mass. The mass is firm, movable, ∼2 cm in length, olive shaped, hard, best palpated from the left side, and located above and to the right of the umbilicus in the mid-epigastrium beneath the liver's edge. The olive is easiest palpated after an episode of vomiting. After feeding, there may be a visible gastric peristaltic wave that progresses across the abdomen.
Ultrasound examination confirms the diagnosis in the majority of cases. Criteria for diagnosis include pyloric thickness 3-4 mm, an overall pyloric length 15-19 mm, and pyloric diameter of 10-14 mm. Ultrasonography has a sensitivity of ∼95%.
When contrast studies are performed, they demonstrate an elongated pyloric channel (string sign), a bulge of the pyloric muscle into the antrum (shoulder sign), and parallel streaks of barium seen in the narrowed channel, producing a “double tract sign”
DDx:
GERD, adrenogenital syndrome, Inborn errors of metabolism, pyloric membrane or pyloric duplication, Duodenal stenosis proximal to the ampulla of Vater.
Rx:
Preoperative Management
The anatomic correction of PS is not a surgical emergency because, although PS is a form of intestinal obstruction, gangrene and intestinal perforation do not occur with this condition. Infants should not undergo surgery until the fluid and electrolyte deficits have been corrected. If infants undergo surgery with uncorrected alkalosis, then the profound effect that surgical stress has on the urinary excretion of sodium may intensify the electrolyte abnormalities. Given that gastric decompression is necessary for surgery and induction of anesthesia, nasogastric decompression should be performed during fluid and electrolyte resuscitation.
Surgical Management
Once the volume and electrolyte status is corrected, the infant is ready for surgery. Ramstedt

pyloromyotomy through a right upper quadrant transverse incision has been the traditional treatment for hypertrophic PS.