A 65-year-old woman comes to the office due to a 2-month history of fatigue and weight gain. The patient has rheumatoid arthritis, peptic ulcer disease, and hypertension. She takes hydrochlorothiazide and acetaminophen. She does not use tobacco, alcohol, or illicit drugs. The patient's blood pressure is 120/70 mm Hg, pulse is 80/min, and respirations are 14/min. Physical examination shows generalized edema; liver is palpated 5 cm below the costal margin. Urinalysis shows 4+ proteinuria. Ultrasound of the kidneys shows bilateral enlargement. Renal biopsy was performed. Which of the following is the most likely finding on pathological examination?

Question

A 65-year-old woman comes to the office due to a 2-month history of fatigue and weight gain.  The patient has rheumatoid arthritis, peptic ulcer disease, and hypertension.  She takes hydrochlorothiazide and acetaminophen.  She does not use tobacco, alcohol, or illicit drugs.  The patient's blood pressure is 120/70 mm Hg, pulse is 80/min, and respirations are 14/min.  Physical examination shows generalized edema; liver is palpated 5 cm below the costal margin.  Urinalysis shows 4+ proteinuria.  Ultrasound of the kidneys shows bilateral enlargement.  Renal biopsy was performed.  Which of the following is the most likely finding on pathological examination?

Quizplus · Accepted Answer

11ec25c8_d4d3_f486_bc81_bfcd5545d4fa_MD0003_00 This patient has nephrotic syndrome, evidenced by edema and a high degree of proteinuria. Common causes of nephrotic syndrome in adults are membranous glomerulopathy, focal segmental glomerulosclerosis, and amyloidosis. Amyloidosis is the most probable cause of nephrotic syndrome in this patient. Clues to this diagnosis include a history of rheumatoid arthritis (that predisposes to amyloidosis), enlarged kidneys, and hepatomegaly (from amyloid inflitration). The typical findings on renal biopsy are amyloid deposits that stain with Congo red and demonstrate a characteristic apple-green birefringence under polarized light. These amyloid deposits are seen in the glomerular basement membrane, blood vessels, and interstitium of the kidneys and can be seen on electron microscopy as randomly arranged thin fibrils. Amyloid deposits may consist of light chains (AL amyloidosis), most commonly due to multiple myeloma, or abnormal proteins (AA amyloidosis), generally in response to chronic inflammatory diseases. Rheumatoid arthritis (as seen in this patient) is the most common cause of AA amyloidosis in the United States. amyloid deposits that stain with Congo red apple-green birefringence under polarized light thin fibrils (Choice A) Crescent formation on light microscopy is the characteristic finding in rapidly progressive glomerulonephritis. (Choice C) Hyalinosis that affects both afferent and efferent arterioles is seen with hypertensive nephropathy. (Choice D) Linear deposits on immunofluorescence microscopy are typical for antiglomerular basement membrane disease (eg, Goodpasture's syndrome). Granular deposits are usually present in immune complex glomerulonephritis (eg, lupus nephritis, IgA nephropathy, postinfectious glomerulonephritis). (Choice E) Normal light microscopy findings in a patient with nephrotic syndrome usually suggest minimal change disease. Educational objective: Rheumatoid arthritis predisposes to amyloidosis. Renal involvement is characterized by nephrotic syndrome. The classic pathologic finding is amyloid deposits that stain with Congo red and demonstrate apple-green birefringence under polarized light. Multiple myeloma is the most common cause of AL amyloidosis, and rheumatoid arthritis is the most common cause of AA amyloidosis. References: Nephrotic syndrome secondary to amyloidosis. (http://www.ncbi.nlm.nih.gov/pubmed/10884998) Immunoglobulin light chain amyloidosis: 2014 update on diagnosis, prognosis, and treatment. (http://www.ncbi.nlm.nih.gov/pubmed/25407896)

A 65-Year-Old Woman Comes to the Office Due to a 2-Month