We report an atypical form of CIDP in a 16 year old child.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common acquired immune-mediated neuropathy worldwide and is clinically heterogeneous. Diagnosis is challenging particulary in atypical forms.

A 16 year old boy was brought to the neurological department for a 2 months history of weakness in the legs and frequent falls. Evolution has been towards the extension of weakness to upper limbs. Neurological examination revealed weakness in legs and arms, generalized areflexia, proprioceptive ataxia and myoclonia. CSF showed a protein concentration of 128 mg/ with normal white blood cell count and glucose concentration. Blood cell count and chemistry were normal. NCSs showed prolonged distal motor latencies, conduction slowing, and decreased amplitude of compound.muscle action potentials, Current serum studies for antibodies against components of the nodal and paranodal regions of peripheral nerves (neurofascin 155) were positive. The patient was treated with IV immunoglobulins 2 g/kg . No improvement was noted. Treatment with prednisolone was ineffective, but IV rituximab (375 mg/m2/week for 1 month) resulted in substantial improvement.

CIDP is a rare, disabling and treatable disease in children. Antibodies against neurofascin 155 have been recently described in several subsets of patients with CIDP. In particular, CIDP associated with antibodies against the 155 isoform of neurofascin develop at younger ages, including pediatric patients.These antibodies are predominantly IgG4 subclass and associate with a form of CIDP that manifests with an aggressive symptom onset with predominant motor weakness, ataxia and absent or limited response to IVIg or steroids but an excellent response to rituximab. Our patient had a similar presentation with predominant motor involvement and NCSs and EMG suggesting demyelinating features accompanied by early axonal damage. However, the response to rituximab wasn’t excellent.