Response of CSF IgG to steroids in an 18-month-old with chronic inflammatory polyradiculoneuropathy

During recovery from a upper respiratory infection, an acquired chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) developed in a previously healthy 18-month-old girl. The CIDP followed a monophasic course and left her severely quadriparetic. One year after her neurologic deficit had stabilized, the cerebrospinal fluid (CSF) IgG synthesis rate was markedly elevated, and oligoclonal bands were identified in her CSF, suggesting ongoing inflammation. Her electromyogram (EMG) and nerve biopsy were consistent with a severe acquired segmental demyelinating polyradiculoneuropathy. A course of corticosteroid therapy resulted in dramatic, sustained, clinical and electromyographic improvement, normalization of CSF IgG synthesis rate, and disappearance of the oligoclonal bands. We are not aware of any previous reports that correlate serial measurements of CSF IgG synthesis rate and oligoclonal bands with clinical and electromyographic responses to corticosteroids in a child with acquired CIDP. We suggest that these CSF parameters are potentially useful in demonstrating active inflammation in cases of acquired CIDP even after clinical stabilization of neurologic deficits, predicting response to therapy, and monitoring resolution of the pathologic process.