168 Rituximab in the treatment of Multifocal Acquired Demyelinating Sensory and Motor Neuropathy (MADSAM)

Multifocal Acquired Demyelinating Sensory and Motor Neuropathy (MADSAM) presents with asymmetric peripheral nerve involvement affecting both sensory and motor fibres with evidence of conduction block and demyelination on neurophysiology. A 25-year-old man presented with a rapidly progressive sensory loss. He had asymmetrical distal sensory loss, depressed reflexes and sensory ataxia. The clinical diagnosis was of sensory ganglionopathy but the initial neurophysiology was inconclusive. MRI brain and spine, CSF, ganglioside antibodies, nerve biopsy and PET scan were normal. He rapidly deteriorated despite steroids and became wheelchair dependent. Repeat neurophysiology provided support for the diagnosis of MADSAM with asymmetric sensory and motor slowing of conduction velocity affecting predominantly the upper limbs with prolongation of F wave latency. He had two courses of intravenous immunoglobulin9s (IVIG) followed by plasma exchange with no effect. He continued on steroids and mycophenolate was introduced. Despite this the repeat neurophysiology suggested worsening of motor conduction parameters with development of new conduction blocks. He received a course of rituximab with significant clinical response. The nerve conduction study correlated with the clinical improvement. MADSAM usually responds to corticosteroids or IVIG. This case provides support for the role of Rituximab as another therapeutic intervention in MADSAM.