Botulism

Botulism is an intoxication that affects the peripheral nerves and is caused by botulinum toxins produced by the Clostridium botulinum bacterium. This bacterium produces eight different types of neurotoxins, five of which affect humans (types A, B, E, F, and F/A), and they are considered the most potent toxins known. Botulism is a rare, but very serious, potentially fatal condition.

Several types of botulism are classified based on the origin of the neurotoxin. When the neurotoxin is produced in vivo by the bacteria inside the organism, the types of botulism are:

• Wound botulism: the neurotoxin is produced in the infected tissue.
• Intestinal toxemia botulism: the Clostridium botulinum spores are ingested, producing the neurotoxin in the digestive tract.
• Infant botulism: affects infants under one year old.
• Adult intestinal botulism: occurs in adults. It is very rare.

In other cases, the pre-formed neurotoxin is introduced into the body:

• Foodborne botulism: the neurotoxin is present in food.
• Iatrogenic botulism: certain types of neurotoxin are injected for therapeutic purposes.
• Inhalation botulism: the neurotoxins are inhaled in aerosol form.

Symptoms

Botulism symptoms can appear within hours after toxin exposure or be delayed for several days. Common symptoms include:

• Speech disturbances.
• Difficulty swallowing.
• Dry mouth.
• Drooping eyelids.
• Blurred or double vision.
• Bilateral, progressive, descending muscle weakness that leads to paralysis: from the face to the lower limbs.
• Digestive disturbances such as nausea, vomiting, diarrhea, or abdominal cramps. These appear before neurological symptoms in foodborne botulism cases.
• Constipation, weak crying, irritability, limp movements, and difficulty sucking, in cases of infant botulism.

Causes

Clostridium botulinum produces latent cells, or spores, that are commonly present in the environment, especially in soil, stagnant water, and decaying plants. In the presence of moisture and nutrients, and in the absence of oxygen, the spores transform into bacteria and release toxins that can enter living organisms. The botulinum toxin acts by causing muscle weakness and paralysis by inhibiting the release of acetylcholine, a neurotransmitter that interacts with muscle receptors to stimulate contraction.

Intestinal toxemia botulism has no clear cause, but its occurrence in infants is linked to consuming honey or exposure to contaminated soils. In adults, it is associated with surgical interventions in the stomach or intestines, antibiotic use, or the presence of inflammatory bowel disease. Wound botulism can develop in any cut or wound exposed to Clostridium botulinum spores, but most cases are due to intravenous drug use, as the drug or needle may be contaminated.

The most common source of foodborne botulism is improperly cooked or inadequately canned or preserved foods. These can include fruits, vegetables, raw or smoked fish, sauces, hot peppers, garlic in oil, honey, cured meats, or baked potatoes wrapped in aluminum foil.

Injection of excessive amounts of botulinum toxin types A and B for medical or cosmetic purposes, such as wrinkle reduction or migraine relief, may result in iatrogenic botulism, although it is very rare. Inhalation botulism does not occur naturally but results from the artificial manipulation of toxins to convert them into aerosols for use as a biological weapon. It can be inhaled during a bioterrorism attack or accidentally in a laboratory setting.

Risk Factors

The following factors increase the risk of contracting botulism:

• Homemade canning practices.
• Inadequate or insufficient cooking of foods.
• Intravenous drug use.
• Interaction with contaminated soils, especially common in infants: putting dirt into the mouth via hands, pacifiers, or other objects in contact with the ground.

Complications

The mortality rate of botulism depends largely on respiratory system involvement, as diaphragm or laryngeal muscle paralysis can cause respiratory failure, which is incompatible with life. Additionally, difficulty swallowing can lead to food or saliva being diverted into the lungs, causing choking and increasing the risk of aspiration pneumonia, a type of pneumonia caused by bacteria from ingested material infecting the lungs. Moreover, most botulism survivors require months of rehabilitation to recover from the usual symptoms.

Prevention

The following measures should be taken to prevent botulism:

• Handle food carefully:
• Maintain proper hygiene when preparing food.
• Separate raw food from cooked food.
• Boil homemade preserves at 121°C for 20 to 100 minutes and an additional 10 minutes before serving.
• Store food in the refrigerator, especially garlic-infused oils or other spices and preserves once opened.
• Do not consume food from bulging, dented, or improperly sealed cans or questionable deli meats.
• Keep wounds clean.
• Do not inject or inhale illicit drugs.
• Avoid allowing infants under one year old to consume honey.
• When undergoing Botox treatments, ensure it is done at an authorized medical center by trained professionals.

Which doctor treats botulism?

Botulism is evaluated and treated by specialists in neurology.