A 31-year-old woman comes to the office with a 6-week history of periorbital edema and abdominal distention. Her temperature is 37.1 C (98.9 F), blood pressure is 125/75 mm Hg, pulse is 80/min, and respirations are 14/min. Examination shows moderate ascites and lower extremity edema. Urinalysis shows proteinuria and 24-hour urinary protein excretion is 4 g/day, total serum protein is 5 g/dL, and serum albumin is 2.5 g/dL. Renal ultrasound is unremarkable. A renal biopsy is performed. The patient is started on diuretics and salt and protein intake is restricted. The edema begins to improve. However, the patient suddenly develops severe right-sided abdominal pain, fever, and gross hematuria. Which of the following is the most likely diagnosis revealed by renal biopsy?

Question

A 31-year-old woman comes to the office with a 6-week history of periorbital edema and abdominal distention.  Her temperature is 37.1 C (98.9 F), blood pressure is 125/75 mm Hg, pulse is 80/min, and respirations are 14/min.  Examination shows moderate ascites and lower extremity edema.  Urinalysis shows proteinuria and 24-hour urinary protein excretion is 4 g/day, total serum protein is 5 g/dL, and serum albumin is 2.5 g/dL.  Renal ultrasound is unremarkable.  A renal biopsy is performed.  The patient is started on diuretics and salt and protein intake is restricted.  The edema begins to improve.  However, the patient suddenly develops severe right-sided abdominal pain, fever, and gross hematuria.  Which of the following is the most likely diagnosis revealed by renal biopsy?

Quizplus · Accepted Answer

Renal vein thrombosis (RVT) and other thromboembolism are important complications of nephrotic syndrome. Loss of antithrombin III (an inhibitor of multiple coagulation factors) in the urine increases the risk of venous and arterial thrombosis. Thrombosis of the renal vein can be acute and present with abdominal pain, fever, and hematuria, as in this patient. However, RVT is more commonly progressive, causing gradual worsening of renal function and proteinuria in an asymptomatic patient. RVT can occur in any etiology of nephrotic syndrome, but it is most commonly seen with membranous glomerulopathy. antithrombin III (Choices A, D, and E) Focal segmental glomerulosclerosis, minimal change disease, and systemic amyloidosis can all cause nephrotic syndrome and subsequent renal vein thrombosis; however, RVT is less frequent with these disorders. (Choice B) IgA nephropathy usually presents with gross or microscopic hematuria with minimal proteinuria after an upper respiratory tract infection. Patients rarely develop rapidly progressive glomerulonephritis or nephrotic syndrome. This patient's presentation of nephrotic syndrome and symptoms of renal infarction is not consistent with IgA nephropathy. Educational objective: Renal vein thrombosis is an important complication of all causes of nephrotic syndrome. However, it is most commonly associated with membranous glomerulopathy. References: Disease-specific risk of venous thromboembolic events is increased in idiopathic glomerulonephritis. (http://www.ncbi.nlm.nih.gov/pubmed/21918501)

A 31-Year-Old Woman Comes to the Office with a 6-Week