Demyelinating lesions are usually limited either to the central or to the peripheral nervous system. Rarely, lesions can occur simultaneously or successively resulting in a combined central and peripheral demyelination (CCPD). We performed a comparative nerve conduction and ultrasound in CCPD patients and CIDP (chronic inflammatory demyelinating polyneuropathy) controls.

We enrolled consecutive patients seen at the neuromuscular outpatient clinic of the UMC Utrecht: 4 CCPD and 10 incident CIDP controls. All patients underwent standardized nerve conduction studies, and a sonographic protocol assessed nerve size at predetermined sites of brachial plexus and median nerves. In addition, all CCPD patients underwent brain and spinal cord imaging MRI.

Except for stiffness, facial palsies and visual disturbances (central nervous system involvement), there was no differences in term of sensory or motor symptoms between CCPD and CIDP. All CCPD patients showed multiple demyelinating lesions on MRI, meeting the revised Mcdonald criteria for diagnosis of multiple sclerosis (MS). We found patchy electrodiagnostic features of demyelination in all CCPD and CIDP patients, fulfilling the definite criteria of the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) for CIDP. Ultrasound revealed a similar pattern of multifocal nerve enlargement along the length of nerves and brachial plexus in both CCPD and CIDP.

This study demonstrates that neuro-imaging allows visualization of both peripheral and central nervous system involvement in CCPD. The fact that electrophysiologic and morphological patterns in CCPD and CIDP are similar, indicate shared underlying immune-pathophysiologic mechanisms. At the conference we will present an update of the study cohort, including an additional group of MS patients.