A 76-year-old man with a pre-existing diagnosis of
myasthenia gravis was admitted to an intensive care unit with
pneumonia and type II
respiratory failure. In addition,
muscle weakness, widespread
myokymia, neuropsychiatric disturbance and autonomic disturbance were present. Antivoltage gated
potassium channel antibodies, antistriated muscle
antibodies and antiacetylcholine receptor
antibodies were positive. Nerve-conduction studies demonstrated findings consistent with patchy
demyelination. Electromyography confirmed widespread
myokymia, and there was evidence of diffuse
encephalopathy on electroencephalography. Diagnoses of Morvan syndrome and chronic inflammatory demyelinating
polyradiculopathy (
CIDP) were made. Treatment with
intravenous immunoglobulin,
plasma exchange and high-dose
steroids were ineffective, and the patient remained dependent on
mechanical ventilation. The coexistence of possibly three humorally mediated
autoimmune diseases led to treatment with
rituximab.
Rituximab treatment was followed by an improvement in muscle strength, allowing successful weaning from
mechanical ventilation, diminution in
myokymia and improved cognition. At follow-up, there was reversal of the neuropsychiatric manifestations and normal muscle strength. This case suggests that
rituximab may be useful in the treatment of autoimmune neurological disease refractory to other
immunosuppressant therapies. Specifically, it adds further evidence for the use of
rituximab in
CIDP. As indications for
rituximab in humorally mediated disease continue to expand, international multicentre randomised controlled trials are required to prove the effectiveness of this important emerging
biological agent.