objectives of this lecture:
To know1.The types of dehyration
2.ORS, IVF indications in dehydration
3.Additional therapies for GE.
4.Prevention of GE
5.Specific types of food-born diarrhea
6.Complications of GE
7.Chronic diarrhea
• 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 pts who have diarrhea and consume a hypotonic fluid (water or diluted formula).Volume depletion stimulates secretion of ADH, preventing water excretion that should correct the hypoN.
It produces a more substantial IV volume depletion owing to the shift of water from the EC space into IC space. In addition, some pts develop symptoms, predominantly neurologic, from hypoN .
Most pts with hypoN dehy do well with the same general approach for isotonic dehy.
Overly rapid correction of hypoN(>12 mEq/L/24 hr) should be avoided because of the remote risk of central pontine myelinolysis (CPM).• Hypernatremic Dehydration
• It is the most dangerous form of dehyd due to: complications of hyperN & of therapy.• Hyperna can cause serious neurologic damage, including CNS hemorrhages & thrombosis. This damage appears to be 2ry to the movement of water from the brain cells into the hypertonic EC fluid, causing brain cell shrinkage and tearing bd 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.
• Movement of water from the ICS to the ECS during hyperN dehy partially protects the IV volume. Pt often appear less ill than pt with a same degree of isotonic dehy.
• UOP may be preserved longer, and there may be less tachycardia. Pts are often lethargic and irritable when touched.
• HyperN may cause: fever, hypertonicity, & hyperreflexia. Some infants have a high-pitched cry and hyperpnea.
• Alert pts are very thirsty, even though nausea may be present.
• Probably because of IC water loss, the pinched abdominal skin of a dehydrated, hypernatremic infant has a “doughy” feel.
Too-rapid treatment of hyperN dehyd may cause significant morbidity & mortality.
Idiogenic osmoles (IO) are generated within the brain during the development of hyperN.These IO ↑ osmolality within brain cells , providing protection against brain cell shrinkage 2ry to movement of H2O out of cells into the hypertonic ECF. These IO dissipate slowly during correction of hyperN.
With rapid lowering of the EC osmolality during correction of hyperN, there may be a new gradient created that causes water movement from the EC space into the cells of the brain, producing cerebral edema
( seizures, brain herniation, & death).
To minimize the risk of cerebral edema during correction of hypern dehyd.the serum Na conc. should not decrease ˃ 12 mEq/L every 24 hours. The deficits in severe hypern dehyd may need to be corrected over 2 to 4 days(based on initial Na concentration).
• Oral Rehydration:
• Mild - moderate dehydration from diarrhea of any cause can be treated effectively using a simple, oral rehydration solution (ORS) containing glucose and electrolytes.ORS is less expensive than IV therapy and has a lower complication rate.• IV therapy still may be required for patients with:
• severe dehydration.
• uncontrollable vomiting.
• unable to drink because of extreme fatigue, stupor, coma
• gastric or intestinal distention.
Guideline for oral rehydration:
50 mL/kg of the ORS should be given within 4 hours to pt with mild dehy.100 mL/kg should be given over 4 hours to pts with moderate dehy.
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 ↓ if the pt appears fully hydrated earlier than expected or develops periorbital edema.
Breastfeeding should be allowed after rehydration in infants who are breastfed; in other pts, 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 (ORS) containing 75 mEq of sodium and 75 mmol of glucose per liter, with total osmolarity of 245 mOsm per liter 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.
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 for GE:
• Probiotics nonpathogenic bacteria for prevention & Rx of diarrhea has been successful in developing countries. In addition to restoring beneficial intestinal flora, they can enhance host protective immunity. A variety of organisms (Lactobacillus, Bifidobacterium) have a good safety record.
• Antimotility agents (loperamide) are C.I in children with dysentery & probably have no role in the management of acute watery diarrhea in otherwise healthy children.
• Antiemetic agents such as phenothiazines are of little value. Nonetheless, ondansetron is an effective and less-toxic antiemetic agent. Because persistent vomiting can limit ORT, 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 In GE:
• Shigella dysentery(Ciprofloxacin''˃18 yr age", ampicillin, ceftriaxone, azithromycin, or TMP-SMX)• Yersinia (aminoglycoside, TMP-SMX)
• Campylobacter (Erythromycin or azithromycin)
• pseudomembranous colitis(Clostridium difficile) Metronidazole (1st line), Discontinue initiating antibiotic .Vancomycin (2nd line)
• Salmonella infections in infants ˂ 6 months, in older pts who have enteric fever or complications of bacteremia (same as shigella)
• EPEC, ETEC, EIEC: TMP-SMX or ciprofloxacin
• E. histolytica: Metronidazole followed by iodoquinol or paromomycin
• Giardia lamblia: Furazolidone or metronidazole or albendazole or quinacrine.
• Nitazoxanide, an anti-infective agent, has been effective in Rx of a wide variety of pathogens including G. lamblia, E. histolytica, 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 & 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 & associated mortality.
• Improved Water and Sanitary Facilities & 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 & other Shiga toxin–producing E. coli (STEC): IP 1-8 days, Severe diarrhea that is often bloody; abdominal pain & v. 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), diar( Stools might contain bd & 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, D,V fever, abdominal cramps.S. typhi & S. paratyphi produce typhoid with insidious onset char. by fever, headache, constipation, malaise, chills, and myalgia; diarrhea is uncommon, & vomiting is not usually severe; duration of illness 4-7ds
• Dx stool culture
• Rx Supportive careOther 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 infectionConsider ampicillin, gentamicin, TMP-SMX, or quinolones if indicatedA vaccine exists for S. typhi
• Vibrio cholerae (toxin) IP 1-3ds, Profuse watery d & v, which can lead to severe dehydration & 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 IV rehydrationIn cases of confirmed cholera, tetracycline or doxycycline is recommended for adults, & TMP-SMX for children <8 yr
• 2.viral:
• Rotavirus (groups A-C):IP 1-3ds, V, watery d, 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), D, dark urine, jaundice, & flulike symptoms, i.e., fever, headache, nausea, and abdominal pain, duration of illness Variable 2 wk-3 mo.
Dx ↑ ALT, bilirubin, Positive IgM and anti-hepatitis A antibodies
• Rx Supportive care Prevention with immunization
• 3.parasitic:
• Entamoeba histolytica (amebic dysentery),IP 2-3 ds to 1-4 wk, Diarrhea (often bloody), lower abdominal pain , duration of illness: may be protracted (several wks - several ms)• 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, wt 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,hypona,hyperna,hypoca,hypoma,hypogly,meningitis & cerebral vascular thrombosis)
Chronic Diarrhea
• defined as a diarrheal episode that lasts for ≥14 days, it is often the result of an intestinal infection that lasts longer than expected.
• This syndrome is often defined as( protracted diarrhea), & there is no clear distinction between protracted & 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
CommonLess common
Chronic infection e,g with Yersinia, Salmonella,E.coli
Food allergy(cow’s milk or soy protein or others)
Toddler’s diarrhea
Disacchride intolerance
Celiac disease
Cystic fibrosis
IBD
UTI
Postenteritis bile acid malabsorption
immunodeficiency
Autoimmune enteropathy
Adrenal insufficiency & hyperthyroidism
Intestinal lymphangiectasia
Acrodematitis entropathica
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 wt gain in well-appearing subjects.
In younger children diarrhea is often watery, at times containing undigested food particles, more severe in the morning. If the dietary Hx suggests that the child is ingesting significant amounts of fruit juices, then the offending juices should be ↓.
In older children, IBS is often associated with abdominal pain and may be related to anxiety, depression, and other psychological disturbances.
Symptoms may begin initially after an apparent acute enteritis (postinfectious irritable bowel).
• Treatment :
• (1) restricting the frequency of feedings, whether liquids or solids, in an effort to ↓ stimulation of the gastrocolic reflex (in the toddler, three meals and a bedtime snack with NPO in between)• (2) restricting the volumes of fluids ingested when xs. If the child's fluid intake is >150 mL/kg/24 hr, fluid intake should be ↓ 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 ↓ in the stool frequency & volume
• (3) avoiding xs 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
(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.