RESPONSE TO IVIg TREATMENT IN CANOMAD

The acronym CANOMAD (Chronic Ataxic Neuropathy, Ophthalmoplegia, IgM paraproteinemia, cold Agglutinin and Disialosyl antibodies) indicates a very rare form of dysimmune neuropathy. We observed a 73-year-old male patient who had suffered from diplopia, disequilibrium and paresthesiae for about 8 years. The disease ran a fluctuating course with alternating periods of spontaneous worsening and improvement. On clinical examination, he showed diplopia and strabismus in all gaze directions, ataxia of stance and gait, positive Romberg sign, generalized deep tendon areflexia; distal sensory loss to all modalities was found, and was particularly severe for position and vibration sense. Hematologic work-up revealed the presence of an IgM-k monoclonal gammopathy. Nerve conduction studies showed a marked decrease of conduction velocities in motor and sensory nerves; sensory action potentials were greatly reduced, while compound muscle action potentials were only mildly affected. Serum immunologic investigations revealed the presence of high titers of anti-disialosyl IgM antibodies. Therefore, all the features of CANOMAD but cold agglutinin (reported in 50% of patients) were present. Data on response to treatment in CANOMAD are very scanty. We administered to the patient two courses of high dose intravenous immunoglobulin (IVIg) and he showed dramatic improvement of diplopia, ataxia and paresthesiae, which started during the infusion period and lasted for 1–2 months. Treatment with low dose steroids after the first IVIg course did not prevent progressive worsening, which was reverted by a further IVIg course.