Nephrotic Syndrome

NEPHROTIC SYNDROME 54A

A 40-year-old woman with Hodgkin lymphoma is admitted to the hospital because of anasarca. She has no known history of renal, liver, or cardiac disease. Her serum creatinine level is 1.4 mg/dL, serum albumin level is 2.8 g/dL, and liver test results are normal. Urinalysis shows no red or white blood cell casts but 4+ protein. A 24-hour urine documents a protein excretion of 4 g/24 hr. She is diagnosed with nephrotic syndrome. Renal biopsy shows minimal change disease. Corticosteroids and diuretics are instituted, with gradual improvement of edema. Her hospital course is complicated by a deep venous thrombosis of the left calf and thigh that requires systemic anticoagulation.

What are the salient features of this patient’s problem? How do you think through her problem?

Salient features: Anasarca; elevated serum creatinine; hypoalbuminemia; bland urine sediment; proteinuria above 3 g/24 hr; minimal change disease on renal biopsy; resolution with corticosteroid therapy; associated thrombosis from hypercoagulability

How to think through: In a patient with new edema, the urinalysis is essential in diagnosis of possible nephritic or nephrotic syndromes. What is the criterion for nephrotic range proteinuria? (>3.5 g/d.) Along with proteinuria, what are the other components of nephrotic syndrome? (Hypoalbuminemia <3.0 g/dL; edema, periorbital edema, pulmonary edema, pleural effusion, and anasarca; hyperlipidemia with fat bodies in the urine; hypercoagulability.) Acute kidney injury does not always accompany nephrotic syndrome, and a normal serum creatinine level should not halt investigation. What are the four most common causes of nephrotic syndrome? (Minimal change disease, focal glomerular glomerulosclerosis, membranous nephropathy, membranoproliferative glomerulonephropathy.) What common medication may precipitate nephrotic syndrome, mimic minimal change disease, and increase the chance of acute kidney injury? (Nonsteroidal antiinflammatory drugs.) Patients with nephrotic syndrome have impaired immune defenses, and a significant fraction have a thrombotic event. Why? (Urinary loss of proteins [IgG, antithrombin, and plasminogen] likely plays a role.) Was renal biopsy needed in this case? (Yes. A firm diagnosis is needed to choose the correct treatment.) With the biopsy result, how should she be managed? (Corticosteroids, tapered over several months; diuretic; angiotensin-converting enzyme [ACE] inhibitor; warfarin; and low-sodium diet.)