1
Fifth stage
Pediatric
Lec-3
د.ندى العلي
19/10/2015
Nephrotic Syndrome
Nephrotic syndrome is defined by the clinical findings of heavy proteinuria,
hypoalbuminemia, generalized edema and hyperlipidemia.
EPIDEMIOLOGY
1- examples of Primary and Secondary Causes
Minimal change nephrotic syndrome
Focal segmental glomerulosclerosis
Mesangial hypercellularity
Membranoproliferative glomerulonephritis
Membranous nephropathy
2- Secondary Nephrotic Syndrome
Inherited diseases (congenital nephrotic syndrome ,
diffuse mesangial sclerosis,
Alport syndrome , nail-patella syndrome, Lowe syndrome)
Vasculitides (lupus nephritis, Henoch-Schönlein purpura nephritis, Wegener's
granulomatosis
,
Goodpasture's syndrome (
Postinfectious (poststreptococcal, human immunodeficiency virus, hepatitis B and C,
malaria
,
syphilis, intrauterine infections, other viruses and bacteria (
Drugs and toxins (nonsteroidal antiinflammatory drugs, gold (
Diabetes mellitus (rare in children
Minimal change nephrotic syndrome (MCNS) is the most common histologic form of
primary nephrotic syndrome in children.
More than 80% of children under 7 years of age with nephrotic syndrome have MCNS.
Children 7 to 16 years old with NS have a 50% chance of having MCNS, and males are
affected more frequently than females (2:1).
The male-to-female ratio is reported to be 2:1 for children and 1:1 in adolescents and
adults. most of minimal change nephrotic syndrome (MCNS)
have remission of their disease with a course of
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Pathophysiology
Nephrotic syndrome (NS) is characterized by persistent heavy proteinuria (mainly
albuminuria) (>2 g/24 hours); hypoproteinemia (serum albumin <3.0 g/dL);
hypercholesterolemia (>250 mg/dL); and edema. Age, race, and geography affect the
incidence of NS.
Certain HLA types (HLA-DR7, HLA-B8, and HLA-B12) are associated with an increased
incidence of NS. The increased glomerular permeability to serum proteins is due to
alterations in glomerular basement membrane proteins and their normal negative
charge that restricts filtration of serum proteins
The resultant massive proteinuria leads to a decline in serum proteins, especially
albumin. Plasma oncotic pressure is diminished, resulting in fluid shifts from the
vascular to the interstitial compartment and plasma volume contraction..
Edema formation is enhanced by reduction in effective circulating blood volume and
increase in tubular sodium chloride reabsorption secondary to activation of the renin-
angiotensin-aldosterone system
Hypoproteinemia stimulates hepatic lipoprotein synthesis and diminishes lipoprotein
metabolism, leading to elevated serum lipids (cholesterol, triglycerides) and
lipoproteins
PRESENTATION
signs &symptoms
typically presents with the gradual development of edema and inappropriate weight
gain
The presence of periorbital edema upon arising in the morning that resolve during the
course of the day often is mistaken for allergy.
Clothing may be tight and socks may leave indentations in the skin of the shins and
ankles.
The abdomen may be distended, and a fluid wave may be discernible on examination.
Breath sounds may be decreased at the lungs bases because of accumulation of
pleural fluid .
Although intravascular volume is low in most children with nephrotic syndrome, in
some it will be increased. These latter children may present with a gallop on
auscultation of the heart, rales over the lung fields, and hepatomegaly
The child or parents may report decreased frequency of urination and the passage of
a dark, amber-colored, concentrated-appearing urine that appears to foam when
voided into the toilet. Overall, 16% of children with nephrotic syndrome have diastolic
hypertension on presentation .The presence of significant hypertension should raise
the possibility of underlying glomerulonephritis .
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LABORATORY EVALUATION
Laboratory evaluation begins with a urinalysis in the child with edema. This will
demonstrate significant proteinuria in cases of nephrotic syndrome .
Urinary protein losses can be quantified with a 24-hour urine collection
Nephrotic-range proteinuria is defined as (1) urinary protein excretion on a timed
urine collection of greater than 2 g/day or greater than 40mg per M 2 per hr.
Proteinuria of 1+ or higher on two to three random urine specimens suggests
persistent proteinuria that should be further quantified.
Urinary protein quantification is not critical in the management of the nephrotic child
who has heavy proteinuria as demonstrated by dipstick (+3 or+4 )determination and a
typical clinical presentation. It is more helpful for following the response of children
with resistant forms of nephrotic syndrome .
A small amount of protein is found in the urine of healthy children (<4 mg/m2/hour or
UPr/Cr < 0.2).
Nephrotic proteinuria in children is defined as protein greater than 40 mg/m2/hour
or UPr/Cr greater than 2.0. Proteinuria between these two levels is mildly to
moderately elevated, but not nephrotic.
The presence of significant microscopic hematuria or gross hematuria should suggest
that nephrotic syndrome might be secondary to an underlying nephritic process. The
presence of glycosuria in untreated children with nephrotic syndrome suggests
underlying tubular injury that may be seen with focal segmental glomerulosclerosis.
Blood urea and creatinine values generally are normal or only slightly elevated in
primary nephrotic syndrome.
Serum total protein and albumin levels are low.
Mild hyponatremia may be present because of water retention.
Total calcium levels are low because of the low serum albumin level, but ionized
calcium levels usually are normal.
The serum cholesterol level usually is elevated.
The third component of complement generally is normal. A depressed level suggests
membranoproliferative glomerulonephritis, poststreptococcal glomerulonephritis, or
lupus nephritis.
Chest radiographs usually will show a small cardiac silhouette and, in severe cases,
the presence of pleural fluid. Cardiomegaly may be seen in those cases with increased
intravascular volume .
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COMPLICATIONS
1- Infection
Morbidity and mortality were high in nephrotic syndrome before the introduction of
corticosteroids and antibiotics.
Infection was the leading cause of death in children with nephrotic syndrome.
Infectious complications include
spontaneous bacterial peritonitis, sepsis, cellulitis, and pneumoniae .
Staphylococcus and gram-negative bacteria are responsible for the majority of
infections in nephrotic syndrome .
Predisposing factors for the development of bacterial :infections include
tissue edema that may facilitate the spread of infection,
defective opsonization of invading bacteria caused by loss into the urine of small
components of the alternative pathway of complement,
and impaired cellular immunity.
In addition, the effects of immunosuppressive therapies used in the treatment of
nephrotic syndrome may increase the susceptibility to infection.
Children with recurrent nephrotic syndrome should receive multivalent
pneumococcal vaccination. A role for prophylactic antibiotic therapy has not been
established .
2- Thromboembolism
Thromboembolic events such as deep-vein thrombosis, pulmonary embolism, and
renal vein thrombosis are well-described complications of nephrotic syndrome in both
children
Contributory factors include elevated plasma levels of procoagulant factors, urinary
loss of inhibitors of coagulation, and thrombocytosis .
The predisposition to thrombus formation may be exacerbated by decreased
intravascular volume, especially in the face of vigorous forced diuresis .
3- Hyperlipidemia
Elevated plasma cholesterol in nephrotic syndrome results from increased hepatic
lipoprotein synthesis caused by generalized increased hepatic protein synthesis in
response to a lowered plasma albumin level.
In addition, in severe disease there may be decreased lipolysis, resulting in elevated
triglycerides
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SPECIFIC HISTOPATHOLOGICAL ENTITIES ASSOCIATED WITH PRIMARY NEPHROTIC
SYNDROME OF CHILDHOOD
Minimal Change Nephrotic Syndrome
Minimal change nephrotic syndrome (MCNS), also known as lipoid nephrosis
is the most common pathological diagnosis in nephrotic children and as noted
previously, 92% will achieve a remission with a course of corticosteroid, Hematuria is
found in about 13% and hypertension in 10% to 20%.
Relapses are common, but the long-term prognosis is excellent.
Relapses tend to become less frequent with age, and the disorder usually resolves
around the time of puberty without permanent renal impairment.
Often, the diagnosis is assumed in most children since biopsy generally is not
performed in those who follow a typical course and respond to steroids.
These children should more correctly be considered to have the clinical diagnosis of
steroid-responsive idiopathic nephrotic syndrome of childhood
MANAGEMENT
Eighty-five percent of nephrotic children regardless of underlying pathology will
respond to a trial of
Seventy-five percent of those who will respond do so within 2 weeks of starting
corticosteroids, and 94% will have responded by 4 weeks .
The majority of steroid-responsive patients have MCNS. However, up to 25% of
steroid-resistant nephrotic children have MCNS on biopsy, whereas 5% to 10% of the
steroid-responsive patients have FSGS
In general, nephrotic patients who achieve a remission on steroids, whether they
have MCNS or FSGS by biopsy, do not progress to renal failure if they remain steroid
responsive .
Children between the ages of 1 and 6 years are most likely to have MCNS by renal
biopsy and respond clinically to a trial of steroids by achieving a remission
Therefore, it is now customary to treat a child in this age range (or even up to age 10)
who presents with the new onset of typical, pure nephrotic syndrome with a trial of
corticosteroids
Treatment consists of prednisone 2 mg/kg/day or 60 mg/M day (maximum 60 to 80
mg/day) for 4 to 6 weeks .This usually is given in divided doses
This is followed by a single dose of 2 mg/kg or 60 mg/M for an additional 4 to 6
weeks given in the morning on alternate days . with the medication gradually tapered
off after that
Depending on the treatment regimen employed, from 36% to 61% of children will
have a relapse of nephrotic syndrome within the first year of the initial episode.
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A relapse is diagnosed if the urine tests 2+ or greater for protein for 3 consecutive
days with edema
Relapses usually are triggered by intercurrent illnesses or allergies, and parents can be
taught to use albumin test sticks or sulfo
at home to monitor urinary protein
excretion. Relapses are treated with prednisone 2 mg/kg/day or 60 mg/M day until
the urine is free of protein(negative or trace or+1) for 3 consecutive days That is in the
same manner of the first episode .
About 25% of children with relapses will follow a frequently relapsing course, defined
as 2 relapses occurring within 6 months of completing a course of steroids or 3
relapses within 1 year.
Children who develop a relapse while corticosteroids are being tapered or within 2
weeks of completing a course of steroids are considered to be steroid-dependent.
Both children who have frequently relapsing and steroid-dependent nephrotic
syndrome are more likely to develop steroid toxicity. Secondary, tertiary, and
complementary therapies for difficult cases of nephrotic syndrome are listed
Secondary, Tertiary, and Complementary Therapies for Difficult Cases of Nephrotic
Syndrome:
Angiotensin-converting enzyme inhibitors
Nonsteroidal antiinflammatory drugs
Children who fail to respond to the initial or subsequent courses of corticosteroids
have steroid-resistant nephrotic syndrome and a more guarded prognosis.
Consultation with a pediatric nephrologist should be made for consideration of a
renal biopsy and more aggressive treatment
Side effects of treatment
significant complications of therapy include the development of cushingoid features,
cataract formation, glaucoma, gastritis, peptic ulcer disease, pancreatitis, hypokalemia,
hypertension, increased risk of infection, behavioral changes, and growth delay if treatment
is prolonged .
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Cytotoxic agents
cyclophosphamide ,chlorambucil ,nitrogen mustard, and cyclosporine
can be associated with increased risk of infection,
malignancy, and sterility, but usually only with higher doses than those typically used
for nephrotic syndrome or after repeated or prolonged courses. Cyclophosphamide
can cause hemorrhagic cystitis. Therefore, a large fluid intake and frequent voiding
should be encouraged. Chlorambucil therapy has been associated with induction of
seizure activity .
Nonsteroidal antiinflammatory drugs can cause salt retention and edema. There is a risk of
renal failure, especially in patients with severely decreased intravascular volume .
Diuretics are used judiciously given the already reduced intravascular volume in most
nephrotic patients and the attendant risk of thromboembolism .
combination with a thiazide diuretic is used for significant edema. Severe edema interfering
with ambulation, compromising respiratory status, or causing tissue breakdown can be
treated with intravenous 25% albumin, 1 g/kg, followed by intravenous furosemide if renal
function and urine output are fairly well maintained
Angiotensin-converting enzyme (ACE) inhibitors (e.g
can be tried in resistant nephrotic syndrome, even in the presence of normotension, to
decrease urinary protein excretion. The ACE inhibitors act by decreasing glomerular
capillary pressure and can cause a reversible rise in serum creatinine and hyperkalemia that
must be monitored
When to Refer
Complicated nephrotic syndrome
Outside the expected age range (younger than 1 year old or older than10 years old
Accompanied by signs of glomerulonephritis (renal insufficiency, hypertension,
hematuria, hypocomplementemia (
Refractory edema
Frequently relapsing nephrotic syndrome
Steroid-dependent nephrotic syndrome
Steroid-resistant nephrotic syndrome
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When to Hospitalize
Initial episode for teaching of parents
Anasarca interfering with ambulation or compromising ventilation
Pleural effusions or ascites interfering with ventilation
Signs of volume overload (congestive heart failure(
Infection (e.g., severe cellulitis, peritonitis
Significant hypertension
Significant electrolyte abnormalities
Compromised renal function