Myasthenia gravis (MG) is still a disease of young women and old men, as reflected by the hospital admission rates. In-hospital mortality of MG is low. Hospital utilization of i.v. immunoglobulin has significantly increased compared to plasma exchange and thymectomy.

The mortality rate in Guillain-Barré syndrome is low, and predictors of death are similar to those predicting poor disability outcome. The disease incidence was stable over the 5 years included in this study.

ContributorsGIW wrote and revised the manuscript in response to co-author comments. He finalized all the figures and tables, performed the literature search, and assisted with data interpretation. HJK critically reviewed the manuscript and made important suggestions to improve it. He assisted with data interpretation. IBA performed the data analysis, constructed the figures and tables, and made important suggestions to improve the manuscript. H-CK assisted with the data analysis and also reviewed the manuscript. GRC critically reviewed the manuscript and made important suggestions to improve it. He assisted with data interpretation. All other authors were given the opportunity to review the manuscript and make suggestions which GIW received, either revising the paper or providing explanations. All who are not deceased were involved with approval of the manuscript.

Compared to PLEX, IVIG appears of similar clinical (mortality and complications) and perhaps of superior economic (length of stay and total inpatient charges) outcomes in the treatment of MG. Elderly and those with complex comorbid diseases including acute respiratory failure may be better treated with IVIG.

A variety of electrodiagnostic methods are used to confirm the diagnosis of acute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are frequent during the first few weeks of weakness. We compared the nerve conduction studies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with graded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definite) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95-100%, P < 0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute demyelination (sensitivity 48%, specificity 96%, P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory response amplitudes were lower in the CIP group, with comparable mean motor and sensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The frequency of absent or delayed F waves and absent H reflex was similar in both groups. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r = 0.9). We conclude that a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.

The clinical and electrodiagnostic presentation of peroneal neuropathies are detailed in this article. There is a special emphasis on nerve conduction study findings and their relationship to prognosis and management. The differential diagnosis of foot drop, including when caused by the anterior compartmental syndrome of the leg, is also discussed.

The relative preservation (sparing) of sural sensory nerve action potentials (SNAPs) is a useful diagnostic finding in patients with acute inflammatory demyelinating polyneuropathy (AIDP). However, recording of sural SNAPs is not always technically feasible, especially in obese, edematous, or elderly individuals. Hence, we systematically evaluated the predictive values of the commonly employed SNAPs in the diagnosis of AIDP within 2 weeks from onset of symptoms. Sensory sparing patterns and sensory ratios of the sural, radial, median, and ulnar SNAPs of AIDP patients were included in a retrospective and blinded analysis, and compared to patients with diabetic polyneuropathy (DPN) and controls. Logistic regression models for the sural plus radial SNAPs/median plus ulnar SNAPs (sensory ratio) were constructed. A sural sparing pattern was present only in the AIDP group (34.4%, P < 0.001). A radial sparing pattern did not discriminate the AIDP from the DPN groups. The sural/radial sensory ratio was useful to ascertain DPN, but did not discriminate AIDP from controls. The sensory ratio was higher in AIDP compared to DPN and controls and was an independent predictor for AIDP. This study implies that the sensory ratio is a useful predictor for the diagnosis of AIDP and may substitute for sural sparing in technically difficult situations.

Biologic therapy with tumor necrosis factor (TNF)-alpha antagonists for rheumatoid arthritis has been well established. We describe two patients with rheumatoid arthritis who developed chronic inflammatory demyelinating polyneuropathy (CIDP) during their course of therapy with TNF-alpha antagonists. A 45-year-old woman and a 49-year-old man, both with a history of rheumatoid arthritis, were treated with etanercept and infliximab, respectively. Clinical signs of peripheral neuropathy developed 2 weeks and 12 months after the initiation of TNF-alpha antagonists. Electrodiagnostic studies at variable points during the disease course showed signs of acquired demyelination consistent with CIDP. Cerebrospinal fluid examination showed albuminocytologic dissociation (total protein concentration 118 mg/dl and 152 mg/dl, respectively). Both patients failed to improve after discontinuation of the offending agent, and they responded poorly to corticosteroids. However, there was clinical and electrophysiologic recovery after initiation of intravenous immunoglobulin (IVIg) therapy. CIDP may occur early or late during the treatment course with TNF-alpha antagonists. IVIg may reverse and stabilize the inflammatory process.