A 40-year-old man seeks evaluation for edema. Two days ago, he had sudden onset of swelling in his legs. There was no associated warmth, redness, or tenderness. The patient had a mild cold a week ago and was taking over-the-counter cold remedies. He thought the swelling was an allergic reaction that would go away, but it has not. His past medical history is unremarkable. The patient does not use tobacco, alcohol, or illicit drugs. He takes no prescription or over-the-counter medications. There is no family history of kidney disease.
The patient's temperature is 36.7 C (98.1 F), blood pressure is 120/70 mm Hg, and pulse is 78/min. He has 3+ pitting edema to the mid-thigh bilaterally. Otherwise, his physical examination is unremarkable.
Laboratory results are as follows:

Which of the following diagnoses is most likely to be made with renal biopsy?

Question

A 40-year-old man seeks evaluation for edema.  Two days ago, he had sudden onset of swelling in his legs.  There was no associated warmth, redness, or tenderness.  The patient had a mild cold a week ago and was taking over-the-counter cold remedies.  He thought the swelling was an allergic reaction that would go away, but it has not.  His past medical history is unremarkable.  The patient does not use tobacco, alcohol, or illicit drugs.  He takes no prescription or over-the-counter medications.  There is no family history of kidney disease.
The patient's temperature is 36.7 C (98.1 F), blood pressure is 120/70 mm Hg, and pulse is 78/min.  He has 3+ pitting edema to the mid-thigh bilaterally.  Otherwise, his physical examination is unremarkable.
Laboratory results are as follows:

Which of the following diagnoses is most likely to be made with renal biopsy?

Quizplus · Accepted Answer

11ec193a_98f6_eef5_853d_91e740fc2d99_MD0002_00 This patient has explosive-onset nephrotic syndrome (edema, 4+ proteinuria, low albumin, elevated cholesterol) occurring shortly after an upper respiratory infection and characterized by lack of red cells or casts on urinalysis, well-maintained glomerular filtration rate, and normal blood pressure. Taken together, these findings are most consistent with minimal change or nil (nothing in light microscopy) disease. Minimal change disease accounts for a large percentage (70%-90%) of childhood and 10%-15% of adult non-diabetic nephrotic syndromes, but the cause remains unknown in the majority of cases. Sudden-onset nephrotic syndrome (as opposed to more progressive proteinuria seen with other forms of nephrotic syndrome) and occurrence after an upper respiratory or systemic infection are typical; some (but not most) patients will have acute kidney injury and hypertension. Renal biopsy usually shows normal-appearing glomeruli on light microscopy and no immune deposits by immunofluorescence. Electron microscopy usually shows effacement of the podocyte foot processes. Adults with new-onset nephrotic syndrome should undergo a renal biopsy to confirm diagnosis, guide therapy, and determine prognosis. Treatment of minimal change disease typically involves corticosteroids. (Choice A) Patients with allergic interstitial nephritis usually do not have proteinuria or nephrotic syndrome. The triad of fever, rash, and eosinophilia due to drug reaction (most frequently nonsteroidal inflammatory drugs, penicillins, or other antibiotics) is classic though not commonly seen. (Choice B) Almost all patients with IgA nephropathy have hematuria (either microscopic or macroscopic), sometimes following upper respiratory tract infection ("synpharyngitic hematuria"). (Choice C) Membranoproliferative glomerulonephritis is usually associated with hematuria and red blood cell casts on urinalysis. These features are not present in this patient. (Choice E) Postinfectious glomerulonephritis often presents with edema, hematuria, leukocyturia, and hypertension, typically 2 weeks after skin or respiratory tract infection in adults. This patient's urine sediment shows no significant leukocytes or erythrocytes. Educational objective: Explosive-onset nephrotic syndrome characterized by heavy proteinuria and profound hypoalbuminemia and that occurs shortly following an upper respiratory infection is typical for minimal change disease. Because the clinical phenotype does not accurately predict renal histopathology, most adults with non-diabetic nephrotic syndrome should undergo renal biopsy to confirm diagnosis and guide therapy. __________ References: Adult minimal change disease: clinical characteristics, treatment and outcome. (http://www.ncbi.nlm.nih.gov/pubmed/17699450) Postinfectious glomerulonephritis in the elderly. (http://www.ncbi.nlm.nih.gov/pubmed/21051737)

A 40-Year-Old Man Seeks Evaluation for Edema