Botulism: Types, Symptoms, Causes, Diagnosis, Treatment and More

Botulism is a potentially fatal infectious disease that causes muscle paralysis and breathing problems. Botulism is caused by a toxin produced by a bacteria named Clostridium botulinum. Other bacteria from the Clostridium family, like Clostridium butyricum and Clostridium baratii, can also cause botulism. These bacteria are usually found in soil and some natural bodies of water, but they can also grow in different settings, including in food products that are not processed properly.

The C. botulinum bacteria makes the toxin as it grows on a surface or food. These bacteria can also make spores, which are small reservoirs of dormant (inactive) bacteria that are protected from extreme environments. These spores can contaminate food and cause botulism.

Botulism can affect anyone. Infection usually happens by eating food contaminated with the bacteria or having an open wound come in contact with the bacteria. The symptoms caused by the botulism toxin target the nervous system.

Botulism is rare. However, botulism cases have a high mortality rate with up to 10% of cases being fatal. Because of this, botulism infections need to be diagnosed and addressed quickly with antitoxin and respiratory care.

Types

There are five main types of botulism. They are classified according to a few factors, including how old you are, how you get infected with the bacterial toxin, and where it enters your body.

Foodborne Botulism

This type of botulism occurs when a person eats food contaminated with live C. botulinum bacteria. The bacteria produces the toxin as it grows in the contaminated food. This can happen when food products are not properly preserved or when there are issues with the product post-production

Foodborne botulism can occur when damage is caused to the packaging of a food. For example, sometimes canned goods are damaged, allowing bacteria to enter the can and taint the food inside. The food may be consumed before it has visibly changed. Do not consume the contents of a canned food item if the can is bulging, leaking, or has significant dents (especially with a sharp edge).

Infant Botulism

This type of botulism affects infants under 12 months of age. This botulism is different from foodborne botulism because it happens when infants consume food contaminated with C. botulinum bacteria spores, rather than live bacteria. These spores continue to grow in the infant's intestines and release the toxin, causing symptoms. For this reason, infants under 12 months should not be given honey

Consuming C. botulinum bacteria spores does not usually result in an infection in adults because over time your intestines develop defenses to fight infections from bacteria spores.

Adult Intestinal Toxemia

In some very rare cases, adults experience this type of botulism as a result of consuming C. botulinum bacteria spores. Adults who have conditions that affect gut health might be more likely to get this type of botulism.

Wound Botulism

This type of botulism is caused when an open wound comes in contact with C. botulinum spores. This type is commonly caused by using contaminated syringes during injectable drug use

In rare cases, dirt or soil can get into a traumatic injury (like an open fracture) and cause wound botulism.

Latrogenic Botulism

A purified and diluted version of the botulinum toxin, known commercially as Botox, is often used for cosmetic purposes to smooth wrinkles. It also has some medical use cases, such as migraine treatment. Latrogenic botulism happens when too much of the toxin is injected during the treatment.

Botulism Symptoms

The symptoms of botulism are caused by the bacteria’s toxin attacking the body’s nervous system and causing muscle paralysis. The symptoms of botulism include:

• Muscle weakness (in arms, legs, and torso, including muscles used in breathing)
• Muscle paralysis 
• Difficulty breathing
• Blurry vision, double vision, and difficulty moving eyes
• Vomiting, nausea, stomach pain
• Difficulty swallowing
• Slurred speech
• Fever (this only happens in cases of wound botulism)
  

Symptoms usually happen 12 to 72 hours after consuming a contaminated food item. 

If left untreated, the affected muscles can end up being fully paralyzed. When the paralysis affects the muscles that regulate breathing, cases can be fatal. Approximately 5 out of every 100 people who get botulism die because of respiratory failure, which occurs due to paralysis of the muscles that control breathing.

Symptoms In Infants

Symptoms in infants are slightly different. Symptoms of infant botulism include:

• Reduced facial expressions
• A weak cry that is different from the child’s usual cries
• Pupils that react slowly to light
• Poor feeding
• Floppy head and limbs (infant cannot control muscles or movements)
  

What Causes Botulism?

Botulism happens when you become infected with bacteria or bacteria spores that produce the botulinum toxin. 

During infection, the botulism toxin gets into your bloodstream and travels to the nervous system. Here, it attaches to presynaptic nerve terminals, which are the parts of the nervous system cells that control cell-to-cell communication. The botulism toxin attaches to nerve terminals that control muscle movement, and this is what causes the common symptoms of botulism like muscle weakness and muscle paralysis.

Botulism can affect anyone who consumes food infected with the bacteria and/or comes into contact with the bacteria’s toxin. Here are some situations that can increase your risk of getting botulism:

• Consuming damaged or improperly prepared home-canned, preserved, or fermented food
• Improperly storing or refrigerating store-bought food
• Drinking home-made alcohol that has not been processed properly
• Drug consumption that involves the use of used needles/syringes
• Getting excessive Botox injections
  

Diagnosis

Botulism diagnosis can be difficult because symptoms can be subtle and easily missed. Additionally, some of the symptoms of botulism are similar to those presented by other muscle paralysis conditions like Guillain-Barré syndrome, meningitis, and stroke. The tests that your healthcare provider might use to diagnose a case of botulism include physical evaluation and samples from blood, serum, or stool.

Physical Evaluation

Your healthcare provider will perform a physical examination to identify signs of major botulism symptoms, primarily focused on muscle weakness and breathing difficulties. 

If a case of botulism is suspected because of your physical symptoms, your healthcare provider will ask you questions to identify potential sources of exposure to the botulism toxin. They may ask for you to detail if you have recently eaten any home-canned foods, had Botox injections, or have used any needles.

A physical evaluation could also include some diagnostic tests to evaluate your nervous system. Nerve and muscle function tests are used to test communication between nerve cells and muscles. 

Additionally, if a case of infant botulism is suspected, a healthcare provider might ask if the child has consumed honey recently. Honey contaminated with botulism spores is one of main sources of infant botulism. 

Lab Tests

Lab tests can help healthcare providers identify if you have a C. botulinum infection, or if there is botulinum toxin in your bloodstream. These tests are usually performed in special laboratories with additional safety measures.

Your healthcare provider will take blood, serum, and stool samples. Samples are sent to a microbiology laboratory where they add these samples onto bacteria plates that allow for the growth of the C. botulinum bacteria. Samples from people with active infection will result in C. botulinum bacteria growth on the plates.

Additionally, the samples provided can be used for other diagnostic tests:

• Polymerase chain-reaction (PCR) test: This can be used to identify bacterial genetic material in your sample.
• Enzyme-linked immunosorbent assay (ELISA): This can be used to detect the presence of botulism toxin.

Finally, if it is found that a case of botulism is a result of contaminated food, your healthcare provider will contact public health authorities to perform an investigation of suspected contaminated food sources. Every case of foodborne botulinum requires an investigation by public health authorities.

Treatments for Botulism

The purpose of botulism treatment is to counter the effects of the botulism toxin, help manage muscle weakness symptoms, and prevent respiratory paralysis from happening. Botulism needs to be treated quickly to prevent the toxin from causing long-term harm. With appropriate medical treatment, paralysis caused by the toxin can improve slowly and you can recover. The main ways botulism is treated are:

• Botulism antitoxin: This is the main form of botulism treatment. Administration of the botulism antitoxin blocks the effects of the botulism toxin, preventing any further paralysis from happening. The antitoxin is usually provided immediately after a diagnosis is confirmed. 
• Ventilator/breathing machine: If botulism symptoms progress quickly and you are experiencing breathing muscle paralysis, your healthcare provider may put you on a ventilator while the antitoxin effects improve your paralysis symptoms and allow you to breathe on your own.
• Surgery: In some cases of wound botulism, surgery might be recommended to remove the area infected with the bacteria.
• Antibiotics: In cases of wound botulism, healthcare providers prescribe antibiotics in order to get rid of the infection quicker.
  

Prevention

Botulism is a preventable condition. There are many practices that can help you avoid a botulism infection. Prevention methods include:

• Storing and refrigerating food products according to label instructions
• Following USDA guidelines to store home-made food products
• Not consuming food that is moldy or smells poorly
• Refrigerating any canned foods after opening
• Cooking food thoroughly 
• Keeping wounds protected and clean (to prevent wound botulism)
• Not utilizing used needles/syringes (to prevent wound botulism)
• Not feeding honey to infants younger than 15 months (to prevent infant botulism)
  

The C. botulinum bacteria grows in low-oxygen, low-salt, and low-acid conditions. Specifically, there are some foods with low-acid content that are more likely to provide the environment for the bacteria to grow than others. Examples of these are:

• Asparagus
• Green beans
• Beets
• Corn
• Potatoes
• Spinach
• Mushrooms
• Canned tuna 
• Ham and sausage
  

Make sure to take special care when storing any of these low-acid food products. The use of pressure canners helps prevent the chance of stored foods being contaminated with C. botulinum.  

Related Complications

While botulism can be cured with the antitoxin and other supportive medical treatment, people who experience botulism can experience complications that can last months or years. These complications are a result of the paralysis damage caused by the botulism toxin and/or potential infections acquired at the same time as a botulism wound infection. Some of the complications include:

• Long-term fatigue
• Shortness of breath
• Urinary tract infections
• Contractures (the hardening of muscles/muscle rigidity)
• Pressure sores (ulcers)
• Deep vein thrombosis
  

A Quick Review

Botulism is a serious medical condition caused by the botulinum toxin produced by the bacteria C. botulinum. The toxin attacks a person's nervous system. This results in a variety of symptoms including muscle paralysis, difficulty breathing, and, in some severe cases, death.

Botulism can be treated with a botulism antitoxin and it is a preventable disease that most people can avoid by making sure proper food storage practices are followed.