Botulism overview
Michael Maddaleni, B.S.

# Overview
Botulism (Latin, botulus, sausage) is a rare, but serious paralytic illness caused by a nerve toxin, botulin, that is produced by the bacterium Clostridium botulinum. Botulinic toxin is one of the most powerful known toxins: about one microgram is lethal to humans. It acts by blocking nerve function and leads to respiratory and musculoskeletal paralysis. Botulism is an acute paralytic illness caused by a neurotoxin produced by Clostridium botulinum. Supportive care, including intensive care, is key but the role of other medical treatments is unclear. Botulism is an acute paralytic rare illness with a high mortality rate. It is caused by the action of bacterium Clostridium botulinum neurotoxin. yet there is no known medical treatment for it. Supportive care, including intensive care, is the best treatment for now.

# Historical perspective
Clostridium botulinum botulism was named In 1870 by Muller (German physician). In 1895 Clostridium botulinum was first isolated by Emile Van Ermengem and It was in 1949 when Burgen's group discovered that botulinum toxin blocks neuromuscular transmission.

# Classification
Botulism can be classified into foodborne, wound and infant botulism. Iatrogenic botulism and adult intestinal toxemia are rare types of botulism. They are differed from each other according to the mode of infection and the clinical presentation.

# Pathophysiology
Botulism is most commonly caused by neurotoxins produced by C. botulinum.  but C. baratii produces similar neurotoxins (5, 6). The neurotoxins which cause botulism are the most potent toxins currently known and cause paralysis through the inhibition of acetlylcholine release in human nerve endings. Clostridium botulinum is an obligate anaerobe that forms spores.

# Causes
Clostridium botulinum is found in soil and untreated water throughout the world. It produces spores that survive in improperly preserved or canned food, where they produce toxin. When eaten, even tiny amounts of this toxin can lead to severe poisoning. The foods most commonly contaminated are home-canned vegetables, cured pork and ham, smoked or raw fish, and honey or corn syrup. Botulism may also occur if the organism enters open wounds and produces toxin there.
Infant botulism occurs when living bacteria or its spores are eaten and grow within the baby's gastrointestinal tract. The most common cause of infant botulism is eating honey or corn syrup. Clostridium botulinum also occurs normally in the stool of some infants.
It has also been speculated that it is possible to acquire botulism through inhalation. So far, the only human cases of this occurring have been due to factory workers inadvertently inhaling it. It has been suspected that the botulinun toxin could be aerosolized into a weapon for use in a bioterrorist attack.

# Differentiating botulism from other diseases
Botulism must be differentiated from neuromuscular disorders, neurotoxins, infections, and vascular diseases that present with muscle weakness, hypotonia, and flaccidity.

# Epidemiology and demographics
Globally, botulism is fairly rare. In the United States, for example, an average of 110 cases are reported each year.  Of these, roughly 70% are infant botulism, 25% are foodborne botulism, and 5% are wound botulism. The number of cases of food borne and infant botulism has changed little in recent years, but wound botulism has increased because of the use of black tar heroin, especially in California. Wound botulism may be caused even by inhaled cocaine.

# Risk Factors
Botulism risk factors can be based upon the different types of the disease. The infants are more vulnerable to get infected with botulinum toxin. Honey and corn ingestion are common risk factors for the infants to get infected. Ingestion of preformed food and canned food increase the susceptibility of the infection. The intravenous drug abusers are vulnerable to get infected with wound botulism as well.

# Screening
According to the United States Preventive Services Task Force (USPSTF), there are no screening recommendations for botulism. 

# Natural history, complications and prognosis
If botulism left untreated it may cause respiratory failure and even death. Common complications of botulism include, respiratory failure, difficult swallowing, speech difficulties, fatigue, and death. Botulism's prognosis depends on the amount of the ingested toxins and prompt treatment.

# Diagnosis

## History and symptoms
Botulism symptoms ranges from mild to very severe in some cases. The common symptoms generally are nausea, vomiting, diarrhea and dysphagia. The common symptoms in adult are double vision, blurred vision and slurred speech. The common in the infants constipation and weak crying. Botulism affects mainly the nervous system and may lead to paralysis.

## Physical examination
Botulism physical examination is very important in order to suggest or exclude the disease. The patients with botulism appear dizzy and tired. The following signs are observed in the botulism patients: eyelid dropping, weakness of tongue muscle, nystagmus and decreased gag reflex. Paralytic ileus also may present. Botulism presentation shows many neurological manifestations like: generalized muscle weakness, abscent tendon reflexes, facial nerve impairment and speech impairment.

## Laboratory Findings
Clinical  diagnosis of botulism is confirmed by specialized laboratory testing that often  requires days to complete. Routine laboratory test results are usually  unremarkable. Therefore, clinical diagnosis is the foundation for early recognition  of and response to a bioterrorist attack with botulinum toxin, and all  treatment and management decisions should be made based on clinical diagnosis.

## CT
There are no CT findings associated with botulism.

## MRI
There are no MRI findings associated with botulism.

## Other Diagnostic Studies
There are no other diagnostic findings associated with botulism.

# Treatment

## Medical Therapy
The mainstay of therapy for botulism is antitoxin therapy. Antimicrobial therapy is recommended for wound botulism after antitoxin has been administered. Breathing requires the use of many muscles, inluding the diaphragm. Therefore, botulism will make breathing very difficult and interventions to aid in the breathing process will be essential. 
Many people with botulism will need to be on a mechanical ventilator for a significant period of time. There are also other therapies such as antitoxin treatment. This method is not readily used on infants because of adverse side effects.

## Surgery
Surgical intervention is not recommended in the treatment of botulism.

## Primary Prevention

## Secondary Prevention
After someone has been exposed to the clostridium botulinum bacteria, there needs to be ways to stop it from spreading and eventually causing damage to the host. This can be done through different techniques such as administering antitoxin and decontaminating suspected food sources.

## Cost-Effectiveness of Therapy
Since there are only a few major treatments for Botulism, the financial aspect of the treatment will be relatively straight forward. The financial costs will revolve around things such as a prolonged hospital stay as well as antitoxin therapy. It should also be noted that cosmetic Botox will be at a different cost.

## Future or Investigational Therapies
Classically, the treatment for botulism has been to deliver an antitoxin to the patient once exposed.  Also, putting the patient on a mechanical ventilator has been a successful treatment method because patients with botulism have extreme trouble breathing on their own. Even though these treatments have been successful, there have been tests on a new drug that will block potassium channels in order to restore neuromuscular function after botulinum intoxication.