In the USA, an average of 110 cases of botulism are reported each year. Of these, approximately 25% are food borne, 72% is infant botulism and the rest are wound botulism.
Neurologic symptoms of blurred vision, diplopia, dysarthria, dysphagia and descending paralysis are typical of botulinum toxin.
Other early symptoms are: ptosis, depressed reflex, ophtalmoplegia, facial paralysis, tongue weakness and nystagmus. The diverse neurophthalmological signs may include quivering eye movements.
Shortly after the onset of the initial symptoms, generalized, symmetrical limb weakness affecting the proximal muscles more severely than the diastal muscles occurs in more than one half of patients.
Consumption of as little as 30 ng of neurotoxin is sufficient to cause illness and even death. Because the quantity of neurotoxin consumed is so small, the body is unlikely to raise its own antibodies of the neurotoxin and several individuals have contracted food borne botulism more than once.
A history of ingestion of home-canned fruits and vegetables or commercial fish products, a predisposing wound, or ingestion of honey by a child less than 1 year of age, combined with such neurologic symptoms, is highly suspicious and the diagnosis of botulism should be made presumptively, as aggressive early treatment is required.
Neurologic effect of botulinum toxin
