Acquired factor V deficiency in a patient with myeloma and amyloidosis.

Introduction: We describe our experience with managing an unusual case of acquired Factor V deficiency (aFVd) in a myeloma patient with demonstrated amyloidosis.

Methods: Following diagnosis, records of previous investigations were sought. Specific clotting factors and inhibitors were tested. The clinical progress and treatment response measured by serial factor V levels and coagulation parameters was then prospectively tracked.

Results: A 57 year-old woman presented with spontaneous right knee haemarthrosis in association with bilateral symmetrical polyneuropathy and proteinuria. Coagulation screen showed prolongation of both PT (18.6 s, normal range [9.9-11.4 s]) and aPTT (41.4 s, normal range [25.7-32.9 s]), which were both fully correctable following a mixing study. Liver function, fibrinogen, clotting factor II/VIII/X assays and disseminated intravascular coagulopathy screen was normal. FV level was reduced (19%, normal range [70-170%]). Inhibitor titer was undetectable. Congenital FVd was excluded as her previous coagulation screen was normal. Bone marrow investigation performed for suspected underlying plasma cell dyscrasia showed 60% neoplastic plasma cells. Congo red staining was positive for amyloid within vascular walls of the marrow trephine. She was diagnosed with light chain myeloma and aFVd. She received Bortezomib/Cyclophosphamide/Dexamethasone (VCD) chemotherapy. After one cycle of VCD, serum kappa free light chain (SFLC) was reduced from 6951 mg/L to 3354 mg/L with serial measurements of FV levels showing increment to 76% and normalization of PT/aPTT.

Conclusion: Plasma cell dyscrasia with amyloidosis should be sought as a cause for aFVD, in particular one where bleeding manifestation is profound even with the absence of demonstrable inhibitors.