Electrolytes disturbances
Hypernatremia resulting from hypovolemia stimulating of the release of antidiuretic hormone (ADH) with decreased free water excretion may be present in same cases. Hypocalcaemia and hypomagnesaemia are common in patients given diuretics and sometimes are symptomatic necessitating replacement therapy.
Screening for secondary causes of nephrotic syndrome
In developing countries secondary forms of NS are common and hence it is important to exclude these based in clinical and laboratory findings. Although the clinical presentation of NS is stereotyped, some findings on clinical examination such as lymphadenopathy, skin rash, arthritis, hepatosplenomegaly, signs of chronic lung disease and nutritional status with severe wasting may suggest a secondary aetiology.
Routine screening for common aetiological agents is therefore undertaken in most units based in the epidemiology of disease in the particular region. Viral studies include the following: hepatitis, human immunodeficiency virus cytomegalovirus, Epstein Barr virus, parvovirus, herpes type 1 and 2 or other viruses endemic to the region. Screening for common bacterial infections include: β-haemolytic streptococcal infections (throat swab anti-streptolysin O antigen or anti-DNAase) and tuberculosis (tuberculin skin testing, chest X ray, Quantiferon gold, and the geneExpert tests). In various regions parasitic infestations e.g. schistosomiasis are common and should be excluded. Screening for anti-immune disease (e.g. systemic lupus erythematosus) should include tests for anti-nuclear antibodies.
Differential diagnosis
Need to exclude other causes of oedema in childhood. NS is distinguished from other causes of oedema by the presence of hypoalbuminaemia and nephrotic range (massive proteinuria (>50 mg/ kg per day or ≥ 40 mg/m²/hour). The differential diagnosis for oedema includes:
• Heart failure
• Protein energy malnutrition
• Chronic liver disease
• Protein losing enteropathy
• Increased capillary permeability due to allergic reaction or hereditary angioedema. The oedema in this setting is typically found to be focal