Guillain-Barré syndrome in a patient with multiple myeloma after bortezomib therapy: A case report.

BACKGROUND: Bortezomib is a first-line drug approved for patients with multiple myeloma (MM) and has significantly increased their overall survival. However, bortezomib-induced peripheral neuropathy (PN) remains a significant side effect that has led to its discontinuation in some patients. Guillain-Barré syndrome (GBS) is recognized as an immune-mediated PN characterized by the involvement of multiple nerve roots and peripheral nerves and albuminocytologic dissociation in cerebrospinal fluid (CSF) tests. Intravenous immunoglobulin (IVIG) and plasmapheresis are effective. CASE SUMMARY: A 45-year-old man diagnosed with stage III MM (λ type) was treated with bortezomib and dexamethasone. Fourteen days after the second course, he complained of intense burning sensation in the lower limbs and hands, loss of tactile sensation, and pain in the distal area of both thighs and in the distal part of both wrist joints. Neurological examination revealed absence of knee and ankle reflexes. CSF examination revealed albuminocytologic dissociation. Nerve conduction studies indicated sensory nerve action potential amplitudes, conduction velocity decrease, and F wave latency prolongation. He was diagnosed as MM complicated with GBS. Subsequently, he was treated with high-dose IVIG (400 mg/kg/d for five days). His symptoms fully resolved without relapse at the 6-month follow-up. CONCLUSION: Our case highlights the differential diagnosis and management of complications after bortezomib treatment in MM.