botulin

Botulin, commonly written as botulinum toxin, is a family of extremely potent neurotoxins produced by Clostridium botulinum and related species. Seven serotypes (A–G) are recognized, with types A, B, and E most often implicated in human botulism. Toxins can form in improperly processed food, in wounds, or by gut colonization in infants. Even tiny amounts are potentially fatal, making prompt clinical management essential.

Mechanism: The neurotoxins enter nerve terminals and cleave SNARE proteins, blocking acetylcholine release at the neuromuscular junction. This causes flaccid paralysis that typically begins with cranial nerves and can descend to involve limb muscles. Recovery occurs as new nerve terminals and synapses are formed over weeks to months.

Clinical forms include foodborne botulism from preformed toxin in contaminated foods, infant botulism from intestinal colonization by spores, and wound botulism from contaminated wounds. Early symptoms include blurred vision, dry mouth, dysphagia, and symmetric weakness; severe cases may involve respiratory failure. Diagnosis combines clinical findings with detection of toxin in serum, stool, or food.

Medical and cosmetic uses: Small, controlled doses of botulinum toxin types A or B treat several neuromuscular disorders (cervical dystonia, blepharospasm, spasticity) and reduce chronic migraine symptoms and overactive bladder. They are also used cosmetically to lessen facial wrinkles. Commercial products include onabotulinumtoxinA, abobotulinumtoxinA, incobotulinumtoxinA (type A) and rimabotulinumtoxinB (type B).

Management and safety: Suspected botulism requires airway support and timely antitoxin administration; antitoxins neutralize circulating toxin but do not reverse established paralysis. Wound botulism requires antibiotics and debridement. Prevention focuses on proper food handling and storage; infants under one year should not be given honey to reduce risk of infant botulism.