Permanent neuropathy and reinnervation in the Guillain-Barré Syndrome

This PhD dissertation was defended on June 11, 2004.

Opponents: Flemming Bach, Christian Krarup and Pieter van Doorn.

Supervisors: Johannes Jakobsen and Anders Fuglsang-Frederiksen.

Authors address: Rosenvej 24, DK-8240 Risskov. E-mail: clacour@dadlnet.dk

Dan Med Bull 2004;51:301.

ABSTRACT

The PhD dissertation presents work performed during the years 1999-2003 at the Department of Neurology, Aarhus University Hospital, Denmark. The dissertation is based on clinical studies on a cohort of patients, who all had suffered from the Guillain-Barré Syndrome (GBS) 1-13 years previously, and furthermore on examinations of acutely affected GBS patients.

All parts of the peripheral nervous system can be affected during the acute phase of GBS. Permanent damage, therefore, resulting in potentially disabling sequelae, might occur including motor, sensory, and autonomic dysfunction. Previous long-term follow-up studies do not include a systematic search for neuropathy in patients after GBS. The basis for permanently impaired motor function is partly unknown.

A population based cohort of 40 patients given a confirmed diagnosis of GBS during a ten year period was evaluated one to thirteen years after the acute episode with the following methods: The Neuropathy Symptom Score (NSS), the Neuropathy Disability Score (NDS), isokinetic dynamometry testing of muscle strength at ankle and wrist, quantitative sensory testing (QST) of thresholds for vibration, cold and pain, macroelectromyography (macro-EMG), fiber density measurements (FD), and standard nerve conduction studies (NCS). Patients were also answering the SF-36 questionnaire and other questions about daily life. The tests (except electrophysiology) were also done in matched, healthy controls.

Furthermore, seven consecutive GBS patients were studied prospectively with macro-EMG, FD and Medical Research Council sumscore of muscle strength to study the reinnervation in the acute phase and convalescence of the disease.

The dissertation is based on three papers and these are the main results:

1) Forty-eight per cent of unselected GBS patients were neuropathic (based on NSS, NDS, QST and NCS) one to thirteen years after GBS. Muscle strength was reduced by 14% at ankle dorsal flexion, sensory thresholds were increased and the physical SF-36 scores were significantly lower in patients compared to controls, and furthermore correlated with scores for neuropathy in the patients.

2) Seventy-five percent of unselected GBS patients showed signs of reinnervation, interpreted as a measure of axonal loss, which correlated with isokinetic muscle strength and with scores of neuropathy.

3) All patients showed signs of reinnervation on macro-EMG. Patients with progressive reinnervation had poor recovery.

In conclusion, these studies show a high prevalence of chronic, mild sensory-motor post-GBS neuropathy affecting large and medium-sized myelinated nerve fibers in unselected adult patients one to thirteen years after the acute episode of GBS. Permanently impaired motor function is mainly due to motor axonal loss.