A 52-year-old woman with known liver cirrhosis comes to the emergency department with bright red bleeding per rectum for 2 days. She also has increasing abdominal distension and discomfort. The patient has been on daily furosemide and spironolactone as well as water and sodium restriction. She had variceal banding after an episode of esophageal bleeding due to esophageal varices 3 months ago. The patient's temperature is 36.5 C (97.7 F), blood pressure is 91/55 mm Hg, pulse is 116/min, and respirations are 18/min. Her abdomen is distended and nontender with positive shifting dullness and has normal bowel sounds. There is 2+ peripheral pitting edema. Laboratory results are as follows: After blood transfusion and holding diuretics for a day, the patient's urine output decreases despite adequate intravenous volume resuscitation. Urine dipstick is negative for protein and blood. Urine sodium is 5 mEq/L. Which of the following is the most likely cause of this patient's acute kidney injury?

Question

A 52-year-old woman with known liver cirrhosis comes to the emergency department with bright red bleeding per rectum for 2 days.  She also has increasing abdominal distension and discomfort.  The patient has been on daily furosemide and spironolactone as well as water and sodium restriction.  She had variceal banding after an episode of esophageal bleeding due to esophageal varices 3 months ago.  The patient's temperature is 36.5 C (97.7 F), blood pressure is 91/55 mm Hg, pulse is 116/min, and respirations are 18/min.  Her abdomen is distended and nontender with positive shifting dullness and has normal bowel sounds.  There is 2+ peripheral pitting edema.  Laboratory results are as follows:  After blood transfusion and holding diuretics for a day, the patient's urine output decreases despite adequate intravenous volume resuscitation.  Urine dipstick is negative for protein and blood.  Urine sodium is 5 mEq/L.  Which of the following is the most likely cause of this patient's acute kidney injury?

Quizplus · Accepted Answer

11ec25c8_d4de_7bec_bc81_9f6226578928_MD0003_00 The most likely diagnosis in this patient is renal hypoperfusion secondary to hepatorenal syndrome. Patients with severe liver cirrhosis have increased nitric oxide generation in the splanchnic circulation secondary to portal hypertension. This is thought to cause systemic vasodilation, which reduces peripheral vascular resistance and blood pressure, causing renal hypoperfusion. Reduced renal perfusion would then activate compensatory pathways (the renin-angiotensin-aldosterone system, sympathetic nervous system, and antidiuretic hormone) that increase water and sodium retention and worsen volume overload. Any factor that may further reduce glomerular capillary pressure (such as hypotension from gastrointestinal bleeding) causes an acute decline in glomerular filtration and can precipitate hepatorenal syndrome. Laboratory results are similar to those of prerenal azotemia: elevated serum creatinine (>1.5 mg/dL) and a very low urine sodium level, typically <10 mEq/L. The urine sediment is usually bland (no red cells, casts, or protein), reflecting absence of intrinsic renal pathology. However, patients do not respond to intravenous fluids and withdrawal of diuretics, and renal function continues to decline. (Choice A) Membranoproliferative glomerulonephritis is associated with hepatitis C infection. Glomerular disease is unlikely in this patient as the urine dipstick does not show protein or blood. (Choice B) Interstitial nephritis usually presents with eosinophils or leukocytes in the urine. This patient's very low urine sodium makes a prerenal cause, such as hepatorenal syndrome, more likely than an intrinsic renal process such as interstitial nephritis. (Choice C) Acute kidney injury is not seen in obstructive uropathy unless both ureters are obstructed. (Choice E) Renal vein thrombosis usually occurs in patients with a predisposing condition, such as hypercoagulability, trauma, nephrotic syndrome, or severe dehydration. Acute renal vein thrombosis presents with abdominal pain and hematuria. Educational objective: Hepatorenal syndrome is seen in patients with severe liver cirrhosis secondary to systemic and renal hypoperfusion. Patients have acute renal failure (creatinine >1.5 mg/dL) with a very low urine sodium level, typically <10 mEq/L, and an absence of blood, casts, or protein in urine. Renal function does not improve with intravenous fluid resuscitation. References: Pathophysiology, diagnosis and clinical management of hepatorenal syndrome: from classic to new drugs. (http://www.ncbi.nlm.nih.gov/pubmed/24678726)

A 52-Year-Old Woman with Known Liver Cirrhosis Comes to the Emergency