A 59-year-old man with acute onset of paralysis.

Botulism is a neuroparalytic illness resulting from the action of a potent toxin produced by the organism Clostridium botulinum. It can present with a classic triad of clear mentation, bulbar palsy and symmetric descending paralysis. Treatment is symptomatic and includes a botulinum antitoxin.

A young man with altered mental status and new-onset seizures.

Signs and symptoms of a subacute, progressive, imaging-negative encephalopathy can be misdiagnosed as a neuropsychiatric or progressive neurodegenerative disorder. However, encephalopathies often can be reversed if the autoimmune component is recognized early through a careful history and diagnostic testing, including cerebrospinal fluid analysis for antibodies.