General information regarding types of Botulism, a neurotoxin that causes flaccid paralysis of muscles.
Botulism is a serious illness that causes flaccid paralysis of muscles. It is caused by a neurotoxin, generically referred to as, 'botulinum toxin,' produced by the bacteria Clostridium botulinum. There are seven distinct neurotoxins that Clostridium botulinum produces, yet types A, B and E are the most common that produce flaccid paralysis in people.
Botulism is a rare but serious paralytic illness caused by a nerve toxin that is produced by the bacterium Clostridium botulinum and sometimes by strains of Clostridium butyricum and Clostridium baratii. The disease begins with weakness, trouble seeing, feeling tired, and trouble speaking. This may then be followed by weakness of the arms, chest muscles, and legs. The disease does not usually affect consciousness or cause a fever. Botulinum toxins are one of the most lethal substances known.
The other types largely cause disease in birds and animals, which also develop flaccid paralysis. Most Clostridium species produce only one type of neurotoxin; however, the effects of A, B, E, or F on people are essentially the same. Botulism is not transmitted from person to person. Botulism develops if a person ingests the toxin, or if the Clostridium organisms grow in a person's intestines or wounds in the body and toxin is released.
Neurotoxin, synthesized and secreted by Clostridium botulinum bacteria, cause botulism. The toxin causes the disease by blocking the release of acetylcholine from motor nerve endings. The result is symptoms associated with botulism.
Three main types of botulism exist, they are categorized by the way in which the disease is acquired. What follows are descriptions of these main types:
Three additional kinds of botulism have been described, yet are rarely seen. The first is adult intestinal colonization that is seen in older children and adults with non-average gastrointestinal tracts. Only on rare occasion does intestinal infection with Clostridium botulinum happen in adults because the adult GI tract inactivates ingested Clostridium botulinum bacteria through enzymatic activity and gastric acid. Usually, the adults form of this intestinal botulism is related to abdominal surgical procedures that interfere with inactivation mechanisms. The second kind is seen in people injected with inappropriately high amounts of therapeutic neurotoxin. The third kind, inhalation botulism,' has happened in laboratory personnel who work with the neurotoxins. All types of botulism are potentially fatal.
Botulinum neurotoxin is considered to be one of the most potent and lethal substances known. As little as around one nanogram may be lethal to a person and scientists have estimated that approximately one gram could possibly kill one million people. The fact that such a small amount of toxin capable of killing people has made the toxin a candidate for use in weapons for biowarfare and bioterrorism. Every form of botulism can be fatal and are considered medical emergencies. Food-borne botulism can be particularly dangerous because many people can be poisoned by eating event tiny amounts of neurotoxin contaminated food. A botulism outbreak is indeed a public health emergency.
A neurotoxin paralyzes a person's nerves so their muscles cannot contract. This occurs when the neurotoxin enters nerve cells and eventually interferes with the release of acetylcholine so the nerve cannot stimulate that muscle to contract. Unless the nerve can regenerate a new axon that has no exposure to the neurotoxin, the interference at the neuromuscular junction becomes permanent. For this reason it takes a long time to recover from botulism and explains why cosmetic and therapeutic uses of diluted neurotoxin can be effective for fairly lengthy periods of time. Signs and symptoms of botulism include the following:
A doctor's examination might reveal that a person's gag reflex and deep tendon reflexes such as the, 'knee-jerk,' reflex are decreased or even absent. Infants with botulism appear weak, lethargic and floppy - they feed poorly and become constipated. An infant with botulism has a weak cry and poor muscle tone. In infants, constipation is often times the first symptom to appear.
All of these signs and symptoms related to muscle paralysis are caused by the bacterial neurotoxin. If left untreated, the signs and symptoms might progress to cause paralysis in different parts of a person's body, often seen as a descending paralysis of the person's legs, arms, trunk and breathing muscles which may lead to the person's death.
The person's history and a physical examination might suggest botulism, yet these clues are usually not enough to permit a diagnosis of botulism. Symptoms of other diseases such as Guillain-Barre syndrome, stroke and myasthenia gravis may appear similar to those of botulism. Certain tests might need to be performed to exclude other conditions. The tests may include:
However, if botulism is strongly suspected, samples should be obtained for a mouse inoculation test and then the person should be treated immediately with botulism antiserum. The tests will help to distinguish botulism from infections with E. coli, Salmonella and additional Clostridium species.
The most direct way to confirm the diagnosis is to identify the botulinum neurotoxin in the person's stool, blood or serum. The process involves injecting the person's serum or stool into the peritoneal cavity of mice. An equal amount of stool or serum from the person is treated with multivalent antitoxin and injected in other mice. If the antitoxin treated serum, or stool-injected mice live while those injected with untreated stool or serum perish, then it is a positive test for botulism and is called the, 'mouse inoculation test.' The bacteria may also be isolated from the stool of people with infant and food-borne botulism, although this is not a definitive test. Stool cultures; however, may help to differentiate botulism from Salmonella, E. coli and other infectious agents.
If diagnosed early, wound and food-borne botulism can be treated with an antitoxin that blocks the action of neurotoxin circulating in the blood. The trivalent antitoxin is dispensed from quarantine stations. The antitoxin may prevent the disorder from becoming worse, although recover will still take a number of weeks. Another heptavalent antitoxin may be available.
Doctors might remove any contaminated food remaining in a person's gut by inducing vomiting or by using enemas. Wounds should be treated - usually surgically, to remove the source of the toxin-producing bacteria. Good supportive care in a hospital is the main form of therapy for all botulism types.
Enemas might be used to remove unabsorbed toxin; however, citrate, magnesium salts and sulfate are not used because they might add to the strength of the toxin. Antibiotics are not used in food-borne botulism but are used in wound botulism – surgical debridement may also be needed. Consultation with an infectious-disease specialist is recommended to help manage treatment protocols.
Antitoxin was not routinely administered for the treatment of infants with botulism. Now; however, recommend use of BabyBIG is considered to be both safe and effective. The reported cost is around $45,000. The respiratory failure and paralysis that happen with severe botulism may require a person to be on a breathing machine for weeks and might require intensive medical and nursing care. After a number of weeks, the paralysis slowly improves as axons and nerves are regenerated.