What Is Botulism?

Botulism is a very serious, potentially fatal condition that occurs as a result of a toxin that is most often produced by a bacterium called Clostridium botulinum. People who develop botulism usually end up ingesting the bacteria from eating home-canned foods or items that came from a can dented enough to let bacteria in.

The toxin leads to muscle paralysis, with early botulism symptoms usually beginning in the face (e.g., droopy eyelids and/or slurred speech). The paralysis may then spread downward, affecting the muscles in your neck, chest, arms, and legs. Immediate medical attention is needed.

This article discusses the types, causes, and symptoms of botulism, as well as how it is diagnosed and treated. It also provides information about botulism prevention.

Botulism Symptoms 

The bacterium that causes botulism produces botulinum toxin, a neurotoxin that binds to the tiny space between a nerve and a muscle. This prevents the nerve from sending a message to the corresponding muscle. When a nerve cannot send a message to direct a muscle to move, the muscle becomes paralyzed.

Botulism classically causes paralysis of the facial muscles first. This may cause one or more of the following:

• Droopy eyelids
• Blurred or double vision
• Difficulty speaking or slurred speech
• Trouble swallowing
• Dry mouth

As the bacteria can produce large amounts of botulinum toxin, it can end up spreading throughout the body, paralyzing many muscles at a time. These may be in the neck, arms, chest/trunk, or legs.

In Babies and Kids

Anyone can develop botulism, including babies and young children. Instead of the above symptoms, though, infants with botulism may:

• Appear "floppy" and lethargic
• Have a weak cry
• Be constipated
• Feed poorly
  

Types and Causes of Botulism

Botulism is most often caused by Clostridium botulinum, but it may also be caused by Clostridium butyricum and Clostridium baratii.

There are five types of syndromes related to botulism. They all cause similar symptoms related to muscle paralysis, though their origins differ.

Foodborne Botulism

This is the most common type of botulism. Botulinum toxin can enter a canned food item through a dent, slit, or a small hole in the can and grow prior to the food's consumption. Consuming even a small amount of a food that is contaminated can have serious effects.

Certain foods are at greater risk than others, as C. botulinum will not grow in very acidic conditions. There is also less risk of the bacteria growing in foods stored at low temperatures or that have a high salt content. Of course, which foods pose the most risk of botulism may differ from country to country, depending on their food preparation and storage practices.

In general, canned foods that are prepared at home without the use of safe processing methods are at the highest risk. But there are also outbreaks of botulism related to professionally and industrially canned foods, though these outbreaks are few and far between.

According to the Centers for Disease Control and Prevention, the most common foods related to botulism from home-canned goods are:

• Asparagus
• Beets
• Corn
• Green beans
• Potatoes

Infant Botulism

Infant botulism occurs when the spores of the bacteria get into a baby's intestines, grow, and eventually produce the neurotoxin.

Adult Intestinal Toxemia Botulism

Adult intestinal toxemia botulism is very rare and occurs when, as with infants, the spores of Clostridium botulinum get into a person's intestines and then grow and make the toxin.

Iatrogenic Botulism

Sometimes botulinum toxin (Botox) is deliberately used for cosmetic injections to temporarily prevent the appearance of wrinkles, prevent migraine headaches, or relieve muscle stiffness.

While it is not common, injections of botulinum toxin for medical or cosmetic reasons can cause unwanted paralysis of eye movement or facial muscles, which is usually temporary.

Wound Botulism

Wound botulism is a very rare botulism syndrome. Wounds that become infected with Clostridium botulinum are generally associated with injection drug use, especially the injection of black-tar heroin (a sticky, dark-colored type of heroin) into the skin or muscle.

Surgical incisions, abrasions, lacerations, and open fractures can also increase the risk of this type of infection.

Diagnosis 

Botulism is not a common medical condition, but if you experience face, eye, or mouth weakness, your medical team will do a thorough medical history and physical examination to determine the cause.

Botulism may be considered alongside other, more likely diagnoses.

Medical History and Physical Examination

During a person's evaluation for potential botulism, a doctor will look for the presence of three criteria, based on data from the United States National Botulism Surveillance Database:

• Lack of fever
• A symptom of cranial neuropathy (such as blurred or double vision or difficulty speaking)
• A sign of cranial neuropathy (such as drooping of the upper eyelid or facial paralysis)

In infants, a doctor will look for a sudden onset of weak suck, drooping eyelid, lack of activity, and constipation.

In order to assess for potential botulism exposures, various questions may be asked, such as:

• Has your infant been exposed to honey?
• Do you can foods on your own at home?
• Have you recently been out of the country or consumed foods from another country?
• Do you have a history of trauma or injection drug use?
• Have you recently undergone Botox injections for cosmetic reasons?

Specialized Tests

Special tests may be required to make a diagnosis because botulism symptoms can mimic several other neurological conditions. These conditions include:

• Guillain-Barré syndrome
• Stroke
• Myasthenia gravis
• Opioid overdose
• Poliomyelitis
• Transverse myelitis
• Tick paralysis

Some of the tests that may be ordered to sort out the correct diagnosis include:

• Computed tomography (CT) scan of the brain
• Spinal tap with cerebrospinal fluid (CSF) analysis
• Electroencephalogram (EEG)
• Nerve conduction velocity study (NCVS) with electromyography (EMG)

Laboratory Tests

Various laboratory tests are used to confirm a diagnosis of botulism. These tests evaluate blood, stool, wounds, or food sources to either look for the presence of the toxin or the bacteria.

Botulism Treatment

The treatment of botulism starts with immediate hospitalization and delivery of an antitoxin medication.

Hospitalization

Hospitalization and close monitoring, usually in an intensive care unit (ICU), is the mainstay of treatment of people with botulism.

Some patients require intubation with mechanical ventilation (a breathing machine) for symptoms or signs of respiratory failure from paralysis of the breathing muscles.

Medication

In addition to hospitalization with close monitoring, patients with botulism will be given an antitoxin drug.

The antitoxin works by binding to and preventing the botulinum toxin from paralyzing the muscles. An antibiotic, most commonly penicillin, is also given to kill the Clostridium bacteria.

Surgery

Surgical wound debridement, in which a wound is vigorously cleaned out to remove the infected tissue, is reserved for the treatment of wound botulism. It is used in addition to antibiotics and antitoxin.

How to Prevent Botulism

Infant botulism is the most common type to occur in the U.S., with foodborne illness accounting for about 25% of cases. Proper food handling and preparation are among your best bets for preventing botulism.

Proper Food Handling and Preparation

Always examine cans before purchasing or using them. Throw away cans with any damage.

In addition, if you have a can of food that shows signs of liquid bubbling or a bad smell, it's safest to discard it.

If you practice home canning, be sure to follow pressure cooker/canner instructions precisely to destroy spores produced by Clostridium botulinum. Boiling any home-canned foods for at least 10 minutes is also important, considering the botulin toxin is very heat labile.

Avoiding Honey in Infants

Avoid giving honey to babies less than 1 year old to help prevent infant botulism. Their digestive systems are not developed enough to fight botulism bacteria before it can cause harmful effects.

Practice Proper Wound Care

Be sure to obtain prompt treatment of all wounds. Likewise, avoid injection drug use to protect yourself from related skin damage.

A Word From Verywell

With the discovery of a botulinum antitoxin and the advances in medical education and monitoring about this condition, less than five out of every 100 people with botulism die.

That said, botulism still remains a very serious illness that requires immediate treatment.