Differential effect of botulinal toxin on esophageal motor function in infants.

The effect of Clostridium botulinum toxin on esophageal motor function was studied in four infants (ages 5-9 months) with confirmed infant botulism. Esophageal motility studies using a perfused catheter assembly were performed during the acute phase in all patients, and during the recovery phase in one patient. Motor function of the proximal esophagus and upper esophageal sphincter was abnormal in each, while motor function of the distal esophagus and lower esophageal sphincter was normal. Mean lower esophageal sphincter pressure was 24 mm Hg for the group (normal: 15-30 mm Hg). Sequential studies of proximal esophageal motility in one infant revealed a return of normal motor function which correlated with recovery of peripheral muscle strength and gag reflexes. C. botulinum toxin impairs proximal, but not distal, esophageal motor function in the infant botulism model. This effect appears to be consistent with the known action of the toxin on synaptic acetylcholine release and current concepts regarding distribution of cholinergic and noncholinergic neurotransmitter receptors in the esophagus.