Botulism, Lambert-Eaton Myasthenic Syndrome, and Congenital Myasthenic Syndromes.

Objective: This article covers the clinical presentations, investigations, differential diagnosis, and principles of management of botulism, Lambert-Eaton myasthenic syndrome (LEMS), and congenital myasthenic syndromes.

Latest developments: Well-recognized guidelines exist for the management of botulism and LEMS, but resource limitations may affect implementation globally. Several genes recently reported to cause congenital myasthenic syndromes are involved in ubiquitously expressed proteins and present with a complex non-neuromuscular junction phenotype, wherein abnormal neuromuscular junction transmission is only one component of the gene defect. There have been a few promising preclinical studies on novel treatments in congenital myasthenic syndromes, including gene replacement therapy, raising the prospect of clinical trials in the near future.

Essential points: Early recognition, diagnosis, and initiation of treatment are crucial in managing all three disorders to reduce morbidity and mortality. Congenital myasthenic syndromes should be considered in patients with seronegative myasthenia gravis. Tumor screening is essential in patients with LEMS. Botulism can mimic other cranial neuropathies.