An International Perspective on Preceding Infections in Guillain-Barré Syndrome: The IGOS-1000 Cohort.

BACKGROUND AND OBJECTIVES: Infections play a key role in the development of Guillain-Barré syndrome (GBS) and have been associated with specific clinical features and disease severity. The clinical variation of GBS across geographical regions has been suggested to be related to differences in the distribution of preceding infections, but this has not been studied on a large scale. METHODS: We analyzed the first 1,000 patients included in the International GBS Outcome Study with available biosamples (n = 768) for the presence of a recent infection with Campylobacter jejuni, hepatitis E virus, Mycoplasma pneumoniae, cytomegalovirus, and Epstein-Barr virus. RESULTS: Serologic evidence of a recent infection with C. jejuni was found in 228 (30%), M. pneumoniae in 77 (10%), hepatitis E virus in 23 (3%), cytomegalovirus in 30 (4%), and Epstein-Barr virus in 7 (1%) patients. Evidence of more than 1 recent infection was found in 49 (6%) of these patients. Symptoms of antecedent infections were reported in 556 patients (72%), and this proportion did not significantly differ between those testing positive or negative for a recent infection. The proportions of infections were similar across continents. The sensorimotor variant and the demyelinating electrophysiologic subtype were most frequent across all infection groups, although proportions were significantly higher in patients with a cytomegalovirus and significantly lower in those with a C. jejuni infection. C. jejuni-positive patients were more severely affected, indicated by a lower Medical Research Council sum score at nadir (p = 0.004) and a longer time to regain the ability to walk independently (p = 0.005). The pure motor variant and axonal electrophysiologic subtype were more frequent in Asian compared with American or European C. jejuni-positive patients (p < 0.001, resp. p = 0.001). Time to nadir was longer in the cytomegalovirus-positive patients (p = 0.004). DISCUSSION: Across geographical regions, the distribution of infections was similar, but the association between infection and clinical phenotype differed. A mismatch between symptom reporting and serologic results and the high frequency of coinfections demonstrate the importance of broad serologic testing in identifying the most likely infectious trigger. The association between infections and outcome indicates their value for future prognostic models.

Residual neuropathy in long-term population-based follow-up of Guillain-Barré syndrome.

OBJECTIVE: To estimate the occurrence of residual neuropathy and its self-reported health consequences in a population-based group of patients with Guillain-Barré syndrome (GBS) and to characterize quantitatively the concomitant motor, sensory, and autonomic impairments. METHODS: Forty patients (mean age 46 years) with a confirmed diagnosis of GBS were studied a mean of 7 years (range 1 to 13 years) after the acute attack together with 40 healthy control subjects. The Dyck minimal criteria of neuropathy, the Neuropathy Symptom Score, the Neuropathy Disability Score, the Short Form-36 (SF-36) generic health questionnaire, isokinetic dynamometry at ankle and wrist, quantitative sensory testing of thresholds for vibration, cold, and pain, autonomic function tests, nerve conduction studies, and a summed Neuropathy Rank Sum Score (NRSS) were applied. RESULTS: Nineteen patients (48%) had residual neuropathy, which was independent of follow-up time. The patients with GBS reported lower health status than control subjects on the SF-36 Physical Component Summary Scale (PCS; p = 0.01), and the PCS scores correlated with the NRSS (r = -0.41, p = 0.009). In patients with GBS, muscle strength at ankle dorsal flexion was reduced by 13.9% (p = 0.001), sensory thresholds for vibration were increased in the foot (p < 0.05), and sensory thresholds for cold were increased in the hand and foot (p < 0.05), whereas autonomic functions and pain thresholds were unaffected. CONCLUSIONS: Residual neuropathy affecting large- and medium-sized myelinated fibers endures long after the acute attack of Guillain-Barré syndrome in approximately half of all patients, leads to motor and sensory dysfunction, and shows a trend toward impairing self-reported physical health status.

Electrophysiological signs of permanent axonal loss in a follow-up study of patients with Guillain-Barré syndrome.

The neurophysiological mechanisms for persisting impairment of motor function after Guillain-Barre syndrome (GBS) were assessed in 37 unselected patients 1-13 years after diagnosis. For evaluation of reinnervation and axonal loss, macroelectromyography (macro-EMG) including measurement of fiber density (FD) was performed. Data from neuropathy symptom score, neuropathy disability score, nerve conduction studies, and quantitative sensory examination were ranked and summed to a neuropathy rank sum score (NRSS). The isokinetic muscle strength at the ankle was measured. Signs of axonal loss with increase of either macro motor unit potential (macro-MUP) amplitude or FD occurred in 76% of patients. The macro-MUP amplitude correlated with muscle strength and with NRSS. Patients with evidence of residual neuropathy had increased macro-MUP amplitude and FD as well as decreased muscle strength compared to patients without evidence of residual neuropathy. We conclude that axonal loss takes place in a substantial number of GBS patients and is associated with permanent muscle weakness caused by insufficient reinnervation. Possible patterns of pathology are discussed in relation to the macro-EMG findings.