Ophthalmologic Manifestations of Botulism Differential Diagnoses

Updated: May 19, 2016
  • Author: Bhupendra C K Patel, MD, FRCS; Chief Editor: Hampton Roy, Sr, MD  more...
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Diagnostic Considerations

An absence of bulbar paralysis excludes the diagnosis of botulism.

A botulism outbreak should be suspected when there is clustering of cases of the neurologic syndrome. The differential diagnoses of foodborne botulism includes myasthenia graves, Guillain-Barre syndrome, cerebrovascular accident, Eaton-Lambert syndrome, paralytic shellfish poisoning, chemical intoxication, tick paralysis, and psychiatric disease.

An edrophonium test is performed to exclude myasthenia gravis. In myasthenia gravis, there is sparing of pupillary and oculomotor function. In Guillain-Barre syndrome, protein content in cerebrospinal fluid is elevated in the absence of cells. Guillain-Barre syndrome also shows more typical electromyography findings that distinguish it from botulism.

Infants with botulism are frequently admitted with a diagnosis of sepsis. When hypotonia progresses, other conditions considered include hypothyroidism, inborn errors of metabolism, poliomyelitis, encephalitis, and poisoning. 

Differential Diagnoses