Contributed by Juan M. Bilbao, MD, FRCP(C)
University of Toronto, Department of Laboratory Medicine (Pathology), 30 Bond Street, Toronto, Ontario, M5B 1W8, CANADA
Published on line in November 1998
A 70 year old woman developed, 12 years previously, polyarticular arthritis, butterfly rash, Sicca syndrome and was found to be ANA positive, Coombs positive and ENA positive. Investigations also revealed an IgG lambda paraprotein in serum and urine and 10% of plasma cells in bone marrow biopsy. Plaquenil, 250 mg per day, was started for the treatment of cutaneous manifestation of SLE. At the age of 63, she reported hand tingling. All medication was discontinued at the age of 65 because of clinical improvement but hydrochloroquine was restarted because of recurrent flare of skin rash. The disease was suppressed with a regimen of Prednisone and Isoniazide. At the age of 68, the patient complained of symmetrical numbness and tingling in hands and feet which progressed to weakness of foot dorsiflexion, and reduced vibration and pinprick sensation in the feet. Deep tendon reflexes were decreased throughout and electrophysiological studies demonstrated diffuse moderate mixed axonal and demyelinating polyneuropathy. Symptoms progressed until March 1996 when a sural nerve biopsy was done. At that time the patient was on Plaquenil 250 mg per day. A circulating paraprotein was still present in concentrations unchanged from before. There was no clinical evidence of active SLE. The sural nerve biopsy was processed for paraffin embedding, snap frozen in liquid nitrogen, and embedded in plastic resin.