A 6-year-old black boy has brown urine and healing impetigo lesions. He presents with hypertension, dyspnea, periorbital edema, and hepatomegaly. The most likely cause of his problem is
A. IgA nephropathy
B. Poststreptococcal glomerulonephritis
C. Idiopathic hypercalciuria
D. Pyelonephritis
The answer is b. Acute post-streptococcal glomerulonephritis follows a skin or throat infection with certain
nephritogenic strains of group A, -hemolytic streptococci. Hematuria often colors the urine dark, and decreased
urinary output can result in circulatory congestion from volume overload with pulmonary edema, periorbital
edema,tachycardia, and hepatomegaly. This can be avoided by fluid restriction. Acute hypertension is common and
can be associated with headache, vomiting, and encephalopathy with seizures. Pyelonephritis and sexually
transmitted diseases can cause bloody urine, but rarely the other symptoms of impetigo as described in the
question. IgA nephropathy is rare in black children and rarely presents with hypertension. Idiopathic hypercalciuria
can present with blood and renal stones, but the other findings are distinctly unusual.
