09-25-2007, 07:25 PM
Two weeks ago, a 27 year-old man was admitted to the hospital because of progressive fever and weight loss. He had a normal kidney function with a serum creatinine of 1.2 mg/dL but was found to have positive blood cultures (4/4) for alpha-hemolytic streptococci and therapy with ceftriaxone was begun. You are asked to evaluate this patient after two weeks of therapy because serum creatinine has risen to 3.5 mg/dL. His general condition has improved (Tmax 37.2 C) but a diffuse maculopapular rash has developed on the trunk. Repeat blood cultures are negative. The following laboratory results were obtained: Serum creatinine 3.5 mg/dL; Serum electrolytes (mEq/L): Na 137, K 5.6, Cl 95, bicarb 18; Serum complement C3 150 mg/dL (normal 100-233), CH50 150 units/mL (normal 110-190). Urinalysis showed protein 1+, glucose negative, blood 3+, many RBCs, WBCs, and WBC casts.
Which of the following is the most likely cause of the elevation in serum creatinine?
A. Ceftriaxone-associated acute tubular necrosis
B. Glomerulonephritis secondary to subacute bacterial endocarditis
C. Acute interstitial nephritis
D. Intratubular crystal deposition
E. Renal emboli
Which of the following is the most likely cause of the elevation in serum creatinine?
A. Ceftriaxone-associated acute tubular necrosis
B. Glomerulonephritis secondary to subacute bacterial endocarditis
C. Acute interstitial nephritis
D. Intratubular crystal deposition
E. Renal emboli