How do the physical findings of botulism change as the disease progresses?

Updated: Feb 15, 2019
  • Author: Kirk M Chan-Tack, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
  • Print

More than 90% of patients with botulism have 3-5 of the following signs or symptoms: nausea, vomiting, dysphagia, diplopia, dilated/fixed pupils, and an extremely dry mouth unrelieved by drinking fluids.

Generally, botulism progresses as follows:

  • Preceding or following the onset of paralysis are nonspecific findings such as nausea, vomiting, abdominal pain, malaise, dizziness, dry mouth, dry throat, and, occasionally, sore throat. Except for nerves I and II, the cranial nerves are affected first.

  • Cranial nerve paralysis manifests as blurred vision, diplopia, ptosis, extraocular muscle weakness or paresis, fixed/dilated pupils, dysarthria, dysphagia, and/or suppressed gag reflex. Additional neurologic manifestations include symmetric descending paralysis or weakness of motor and autonomic nerves.

  • Respiratory muscle weakness may be subtle or progressive, advancing rapidly to respiratory failure. Progressive muscle weakness occurs and often involves the muscles of the head and neck, as well as intercostal diaphragmatic muscles and those of the extremities.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!