Serum creatinine levels are increased. The most likely diagnosis is which of the following?

A 7-year-old boy is brought to your office because he had developed some facial swelling and his urine was an unusual color. On physical examination, he is found to have moderate periorbital edema and mild hypertension. His mother states that, other than a sore throat 2 or 3 weeks ago, he has been in good health. Urinalysis reveals proteinuria with RBCs, WBCs, and cellular casts. Serum creatinine levels are increased. The most likely diagnosis is which of the following?

(A) acute postinfectious glomerulonephritis
(B) acute pyelonephritis
© focal segmental glomerulonephritis
(D) lupus nephritis
(E) minimal change disease

Explanation:

(A)This boy has nephritic syndrome and since he recently had a sore throat but was otherwise in good health, the most likely diagnosis is postinfectious (poststreptococcal) glomerulonephritis. Acute pyelonephritis (choice B) is unusual in a young healthy boy. Also it is usually accompanied by changes in urination (frequency, burning, nocturia), fever, and malaise not seen in this patient. Focal segmental glomerulosclerosis (choice C) is associated with the nephrotic syndrome, not the nephritic syndrome. Patients with lupus nephritis (choice D) can present with either nephritic or nephrotic
syndrome but this boy, already an unlikely candidate for this disease, has no signs or symptoms of having lupus. Minimal change disease (choice E) is the most common cause of nephrotic syndrome in children and does not cause the nephritic syndrome.