With a high degree of neuromuscular blockade, RNS at even 50 Hz may be insufficient to boost acetylcholine release. Electromyography of the limb muscles in botulism may be normal in early or mild disease. The diagnosis is supported by the presence of short-duration, low amplitude MUAPs. Evidence of denervation, including positive waves and fibrillation potentials, is a variable finding and indicative of a severe course. Return to normal neuromuscular transmission requires new terminal sprouting to establish motor end plates.
Infant botulism is the most common type of botulism now reported in the United States.
Types A and B are the most frequently implicated. It typically presents between the ages of 2 and 6 months of age with almost all patients demonstrating generalized weakness with limb involvement and hyporeflexia. Constipation is also frequently observed. Less consistent findings are facial and bulbar weakness, sluggish pupils, autonomic instability, and respiratory compromise. Honey should not be given to children less than one year of age as the intestinal flora of infants is susceptible to colonization with Clostridium botulinum.