A 62-year-old hospitalized man is evaluated for new-onset renal failure. The patient was admitted 3 days ago due to precordial chest pain. He was found to have an elevated troponin I level but no ST-segment elevation on ECG. Percutaneous catheterization revealed 3-vessel coronary artery disease, and no coronary interventions were performed. The patient has continued to receive medical treatment while awaiting coronary artery bypass graft surgery. Today, he was noted to have elevated blood urea nitrogen and serum creatinine levels. The patient has had no fever, and blood pressure and heart rate have been within normal limits. Physical examination shows no new findings. Which of the following pathologic findings is most likely present in this patient?

Question

A 62-year-old hospitalized man is evaluated for new-onset renal failure.  The patient was admitted 3 days ago due to precordial chest pain.  He was found to have an elevated troponin I level but no ST-segment elevation on ECG.  Percutaneous catheterization revealed 3-vessel coronary artery disease, and no coronary interventions were performed.  The patient has continued to receive medical treatment while awaiting coronary artery bypass graft surgery.  Today, he was noted to have elevated blood urea nitrogen and serum creatinine levels.  The patient has had no fever, and blood pressure and heart rate have been within normal limits.  Physical examination shows no new findings.  Which of the following pathologic findings is most likely present in this patient?

Quizplus · Accepted Answer

11ec160b_3a27_5498_9249_0108be730009_MD0001_00 This patient developed acute kidney injury after undergoing percutaneous catheterization, a procedure that uses contrast material to evaluate the patency of the coronary arteries. In a patient with normal vital signs, this presentation suggests contrast-induced nephropathy (CIN). Patients with CIN typically have an acute rise in creatinine and blood urea nitrogen within 24-48 hours of contrast administration, followed by a gradual return to baseline. The etiology of CIN remains unclear but is likely multifactorial and includes: Preventive measures include avoidance of nonsteroidal anti-inflammatory drugs, which can worsen vasoconstriction, periprocedural administration of intravenous normal saline, and using the smallest possible volume of contrast medium. (Choice B) Glomerular crescents are seen in crescentic glomerulonephritis, which can occur in multiple renal diseases (eg, Goodpasture syndrome, microscopic polyangiitis). However, patients typically have nephritic syndrome, characterized by hematuria with red blood cell casts, hypertension, and edema. (Choice C) Fibrinoid necrosis is visualized histologically as fibrin material lining the arteriolar walls. This pattern is typically seen in the setting of hypertensive (malignant) nephrosclerosis, which occurs due to markedly elevated blood pressure causing vascular endothelial damage. This patient's blood pressure has been normal. (Choice D) Mononuclear cell infiltrate in the interstitium is consistent with interstitial nephritis. Interstitial nephritis typically occurs after initiation of new drugs (eg, penicillin, cephalosporin) and typically presents with fever, rash, and sterile pyuria. (Choice E) Needle-shaped clefts in the arterioles is seen in atheroembolization (ie, embolization of cholesterol plaques), which can occur following coronary angiography; however, it typically presents with sequelae of atheroemboli in other organs and tissues (eg, livedo reticularis, blue toes). Educational objective: Contrast-induced nephropathy is characterized by an acute rise in creatinine and blood urea nitrogen after radiologic contrast administration, followed by a gradual return to baseline. It is characterized histologically by diffuse necrosis of the proximal tubular cells (ie, acute tubular necrosis). Urinalysis usually demonstrates muddy brown casts.

A 62-Year-Old Hospitalized Man Is Evaluated for New-Onset Renal Failure