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Edema, hematuria, and oliguria suggest acute glomerulonephritis.
Children with nephrotic syndrome are usually immunocompromised and are at risk for life-threatening infection.
Patients with hemolytic uremic syndrome are at risk for hypertension and seizures.
Hemodialysis may be needed for fluid overload in patients with acute renal failure who are refractory to medical management.
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ACUTE GLOMERULONEPHRITIS
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Glomerulonephritis is a histopathologic diagnosis acutely associated with clinical findings of hematuria, edema, and hypertension. It commonly follows a skin or throat infection caused by nephritogenic strains (serotypes 12 and 49) of group A β-hemolytic streptococcus (serotypes 12 and 49) in children between 3 and 7 years of age, with males being more commonly affected. Viral infections such as cytomegalovirus and coxsackievirus have also been implicated. Patients younger than 2 years are rarely affected. Timely treatment of pharyngitis does not clearly decrease the incidence of acute glomerulonephritis.
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Glomerulonephritis probably results from the deposition of circulating immune complexes in the kidney. These immune complexes are deposited on the basement membrane, causing glomerular inflammation and injury and thereby reducing glomerular filtration.1
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There is usually a preceding streptococcal infection or exposure 1 to 2 weeks before the onset of glomerulonephritis. An interval of less than 4 days may imply that the illness is an exacerbation of pre-existing disease rather than an initial attack. Skin infections may have a latent period of 3 to 6 weeks. Henoch–Schönlein purpura, nephritis associated with subacute bacterial endocarditis, or shunt infection may also be causative. Fever, malaise, abdominal pain, and decreased urine output are often noted.
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The physical findings reflect the duration of illness. Initial findings may be mild facial or extremity edema only, with a minimal rise in blood pressure. Patients uniformly develop fluid retention and edema and commonly have hematuria (90%), hypertension (60%–70%), and oliguria (80%). Fever, malaise, and abdominal pain are frequently reported. Anuria and renal failure occur in 2% of children. Circulatory congestion as well as hypertensive encephalopathy may be noted.
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Urinalysis reveals microscopic or gross hematuria. Erythrocyte casts are present in 60% to 85% of hospitalized children. Proteinuria is generally less than 2 g/m2 per 24 hours. Hematuria (Fig. 88-1) and proteinuria (Fig. 88-2) may present independently and require a specific evaluation.2–4 Leukocyturia and hyaline and granular casts are common. If the diagnosis and etiology are unclear, renal biopsy may be indicated to exclude other diagnoses.
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