Nephrotic syndrome is a clinical disorder characterised by edema, proteinuria (>3g per day), hypoalbuminemia and hypercholesterolemia. Minimal change glomerulonephritis accounts for 80–85% of nephrotic syndrome in childhood. Complications include infections, thrombosis and renal impairment.
History
Edema is the primary feature. This may be subtle or gross and is usually noticed in the peri-orbital region, scrotum or labia. It may include, in addition, peripheral edema of the limbs and sacrum. The history is often of weight gain, poor urine output and sometimes of discomfort as a result of the edema. A history of preceding upper respiratory tract infection or diarrhea may be present.
Examination
Examination should confirm the presence of edema. Ascites and pleural effusions may be present when edema is gross. Peripheral perfusion and blood pressure should be assessed. Examination should include a search for signs suggesting the onset of complications such as infected ascites, renal vein thrombosis (e.g. enlarged renal mass, loin tenderness and marked hematuria) and cerebral vein thrombosis. Urinalysis should always be included to make the diagnosis as other causes of edema such as protein losing enteropathy or cardiac failure may occur.
Investigation
Urinalysis usually shows +++ or ++++ protein on dipstick. The degree of proteinuria is variable and is usually of the selective type. Microscopic hematuria is present in 15–20% of patients with minimal change nephrotic syndrome. Microscopy of the urine may show red blood cells or granular casts, which suggests the alternative diagnosis of chronic glomerulonephritis as the underlying cause for nephrotic syndrome.
A timed collection of urine for protein excretion is not necessary when the diagnosis is clear. Blood urea and creatinine tests are important to establish the presence or absence of renal impairment. Blood electrolytes, total protein, albumin, globulin and cholesterol should also be measured.
Treatment
All children should be admitted to hospital with their first presentation of nephrotic syndrome. With relapses, they can sometimes be managed as outpatients after consultation with their treating physician. The components of the treatment will be considered individually
a. Albumin
In nephrotic syndrome, acute renal impairment is due to renal hypoperfusion. Albumin is the treatment of choice. Intravenous albumin is indicated for:
• anuria
• hypotension
• poor skin perfusion with skin mottling
• poor capillary return.
These are all indicators of a depleted vascular space. Albumin should be given only in consultation with the treating consultant. The dose is 20% albumin 5 ml/kg weight(1 g/kg weight) over 4 hr i.v. Beware of the possibility of hypertension and pulmonary edema. Gross genital edema causing discomfort may also be an indication for albumin.
b. Furosemide
Furosemide (1 mg/kg weight i.v.) should be given only if the peripheral perfusion markedly improves following the albumin or there are signs of pulmonary edema or hypertension.
c. Steroids
Corticosteroids are usually given in the form of prednisolone. Occasionally their use may be delayed until postrenal biopsy at the discretion of the treating physician. The usual dose of prednisolone is 60 mg/m2 per day as single dose up to a maximum of 80 mg per day until remission of proteinuria (to trace or negative on urinalysis) for 4 days, then in reducing doses. There are various regimens for dose reduction. One example is:
• prednisolone 45 mg/m2 per day for 8 days then
• 60 mg/m2 per alternate day for 8 days (four doses) then
• 45 mg/m2 per alternate day for 8 days then
• 30 mg/m2 per alternate day for 8 days then
• Reduce by 5 mg every 8 days until finished
d. Antibiotics
The altered immune system in patients with nephrotic syndrome is responsible for their enhanced risk of infection. Oral penicillin 12.5 mg/kg weight per dose b.d. is effective prophylaxis during the edematous phase. If the child is profoundly ill or appears to have sepsis, give cefotaxime 50 mg/kg weight per dose 6 hourly to a maximum of 2 g per dose (to cover Streptococcus pneumoniae, Hemophilus influenzae and Escherichia coli).
e. Anticoagulants
Renal, femoral, cerebral and pulmonary thrombosis can occur in nephrotic patients owing to hypovolemia, high platelet counts and loss of antithrombin III. Thus low-dose aspirin (10 mg/kg weight alternate days) is recommended in edematous nephrotic patients.
General measures
Other general measures include:
• Free fluid intake
• Diet with no added salt
• Strict fluid balance
• Daily weight
Relapses
Over 75% of patients will experience at least one relapse. A relapse is defined as proteinuria ++++ or +++ for 4 days. Management should be discussed with a physician. Prednisolone 60 mg/m2 per day should be given until the urine is protein-free for 3 days and then the dose should be slowly reduced as above. If edema is absent, these relapses may not require penicillin and aspirin. Infrequent relapses (less than two relapses within a 6-month period) can be managed in the manner outlined above.
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