Patient with AL amyloidosis with recurrent syncope as the first symptom: case report and literature review.

Background: Immunoglobulin light-chain (AL) amyloidosis is a rare systemic disease caused by the extracellular deposition of misfolded light chains. Nonspecific manifestations, especially those dominated by severe autonomic neuropathy, frequently delay diagnosis. Methods and results: A 68-year-old woman was admitted after five months of recurrent syncope. The clinical picture was dominated by refractory orthostatic hypotension, nausea and vomiting alternating with diarrhea and constipation, stocking-glove paresthesias, and proteinuria. Bone marrow examination showed the presence of clonal plasma cells with positive M protein, which was confirmed by the serum free light chain test. AL amyloidosis was diagnosed based on positive Congo red staining in renal biopsy specimens. The patient was enrolled in a daratumumab-based protocol combined with daratumumab, bortezomib, cyclophosphamide, and dexamethasone. After three cycles, complete hematological remission was achieved, and the autonomic nerve function improved gradually over the subsequent six months. Conclusion: This case and literature review suggest that AL amyloidosis should be considered whenever a patient presents with multisystem dysfunction dominated by autonomic nerve dysfunction. Although such presentations are associated with poor prognosis, prompt initiation of daratumumab-based therapy can produce rapid hematologic remission and clinically meaningful improvement.