Role in disease
Botulinum toxin produced by Clostridium botulinum is the cause of botulism. Humans most commonly ingest the toxin from eating improperly canned foods in which C. botulinum has grown. However, the toxin can also be introduced through an infected wound. In infants, the bacteria can sometimes grow in the intestines and produce botulinum toxin within the intestine and can cause a condition known as floppy baby syndrome. In all cases, the toxin can then spread, blocking nerves and muscle function. In severe cases, the toxin can block nerves controlling the respiratory system or heart, resulting in death. Botulism can be difficult to diagnose, as it may appear similar to diseases such as Guillain–Barré syndrome, myasthenia gravis, and stroke. Other tests, such as brain scan and spinal fluid examination, may help to rule out other causes. If the symptoms of botulism are diagnosed early, various treatments can be administered. In an effort to remove contaminated food that remains in the gut, enemas or induced vomiting may be used. For wound infections, infected material may be removed surgically. Botulinum antitoxin is available and may be used to prevent the worsening of symptoms, though it will not reverse existing nerve damage. In severe cases, mechanical respiration may be used to support patients with respiratory failure. The nerve damage heals over time, generally over weeks to months. With proper treatment, the case fatality rate for botulinum poisoning can be greatly reduced.Two preparations of botulinum antitoxins are available for treatment of botulism.
Botulinum toxin, often shortened to BoNT, is a neurotoxic protein produced by the bacterium Clostridium botulinum and related species. It prevents the release of the neurotransmitter acetylcholine from axon endings at the neuromuscular junction, thus causing flaccid paralysis. The toxin causes the disease botulism. The toxin is also used commercially for medical and cosmetic purposes. The seven main types of botulinum toxin are named types A to G (A, B, C1, C2, D, E, F and G). New types are occasionally found. Types A and B are capable of causing disease in humans, and are also used commercially and medically. Types C–G are less common; types E and F can cause disease in humans, while the other types cause disease in other animals. Botulinum toxin types A and B are used in medicine to treat various muscle spasms. Botulinum toxins are among the most potent toxins known. Intoxication can occur naturally as a result of either wound or intestinal infection or by ingesting formed toxin in food. The estimated human lethal dose of type A toxin is 1.3–2.1 ng/kg intravenously or intramuscularly, 10–13 ng/kg when inhaled, or 1000 ng/kg when taken by mouth. Commercial forms are marketed under the brand names Botox (onabotulinumtoxinA), Dysport/Azzalure (abobotulinumtoxinA), Xeomin/Bocouture (incobotulinumtoxinA), and Jeuveau (prabotulinumtoxinA). Medical uses
Botulinum toxin is used to treat a number of therapeutic indications, many of which are not part of the approved drug label.