A 55-year-old man with IgG kappa multiple myeloma on third-line therapy develops severe neuropathic pain, bilateral foot drop, and autonomic dysfunction (orthostatic hypotension, bladder retention). He had previously received bortezomib and thalidomide. Which toxicity is most likely responsible?
- A AL amyloidosis with peripheral neuropathy ✓
- B Lenalidomide-induced peripheral neuropathy
- C Bortezomib-induced peripheral neuropathy
- D Thalidomide-induced sensorimotor neuropathy
Explanation
In myeloma patients, progressive severe neuropathy with autonomic involvement (orthostatic hypotension, bladder dysfunction) should raise the possibility of systemic AL amyloidosis rather than drug-induced neuropathy. AL amyloidosis complicates ~10–15% of myeloma cases and deposits in peripheral nerves, autonomic ganglia, heart, and kidneys. Drug-induced neuropathies (bortezomib = painful sensory neuropathy; thalidomide = length-dependent sensorimotor neuropathy) rarely cause prominent autonomic dysfunction. Tissue biopsy with Congo red staining confirming apple-green birefringence under polarized light is diagnostic.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.