An 80-year-old man with slowly progressive exertional dyspnea has concentric LV wall thickening on echo with a sparkling granular appearance of the myocardium. Endomyocardial biopsy shows amorphous eosinophilic deposits that stain with Congo red and show apple-green birefringence under polarized light. In this age group, the protein most commonly deposited is:

• A Immunoglobulin light chain
• B Wild-type transthyretin ✓
• C Serum amyloid A
• D Beta-2 microglobulin

Explanation

Senile systemic amyloidosis of the elderly heart is caused by deposition of wild-type transthyretin and predominantly affects men over 70 years with concentric hypertrophy and heart failure with preserved or reduced EF. Light chain amyloid occurs in plasma cell dyscrasias at younger ages, serum amyloid A is secondary to chronic inflammation, and beta-2 microglobulin amyloid targets joints in dialysis patients, not the myocardium.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.