The muscle weakness of botulism characteristically starts in the muscles supplied by the
cranial nerves. A group of twelve nerves controls
eye movements, the
facial muscles and the muscles controlling
chewing and
swallowing.
Double vision,
drooping of both eyelids, loss of facial expression and swallowing problems may therefore occur, as well as
difficulty with talking. The weakness then spreads to the arms (starting in the shoulders and proceeding to the forearms) and legs (again from the thighs down to the feet).
[9]
Severe botulism leads to reduced movement of the
muscles of respiration, and hence problems with
gas exchange. This may be experienced as
dyspnea (difficulty breathing), but when severe can lead to
respiratory failure, due to the buildup of unexhaled
carbon dioxide and its resultant depressant effect on the brain. This may lead to
coma and eventually death if untreated.
[9]
In addition to affecting the
voluntary muscles, it can also cause
disruptions in the autonomic nervous system. This is experienced as
a dry mouth and throat (due to decreased production of saliva),
postural hypotension (decreased blood pressure on standing, with resultant lightheadedness and risk of blackouts), and eventually
constipation (due to decreased
peristalsis).
[9] Some of the toxins (B and E) also precipitate
nausea and
vomiting.
[9]
Clinicians frequently think of the symptoms of botulism in terms of a classic triad:
bulbar palsy and descending paralysis, lack of fever, and clear senses and mental status ("clear sensorium").
[10][
self-published source?]
Botulism - Wikipedia, the free encyclopedia