Botulism is a life-threatening form of bacterial food poisoning that, unlike common forms of food poisoning, affects the central nervous system. Symptoms usually appear approximately 12 to 36 hours after eating contaminated food, and currently the disease is fatal in about 10 percent of cases, most often because of respiratory failure.
Patients who exhibit symptoms in less than 24 hours of infection tend to experience the most severe course of the disease and have the highest mortality rate; those that survive the first few days can usually expect full recovery. The most common form of the disease involves infants younger than six months old. Both the incidence of botulism and its mortality rate are declining.
What Causes Botulism?
- Botulism is caused by consumption of food contaminated with the bacterium Clostridium botulinum, which can produce the deadly toxin (botulin) that interferes with the transmission of signals across neural synapses. Undercooked foods or those with a low acid content are most likely to transmit botulism.
- The disease may rarely occur when spores of the bacterium infect an open wound.
Symptoms of Botulism
- Dry mouth and sore throat
- Blurred and double vision
- Fixed, dilated pupils
- Breathing and swallowing difficulty
- Slurred speech
- Abdominal cramps, diarrhea, nausea, and vomiting
- Weakness in arms and legs, leading to paralysis, and in facial muscles
- Drooping eyelids
Prevention of Botulism
- Never eat even a minuscule amount of food from a can that is bulging (a sign of bacterial activity), leaking, or has an unusual odor or color.
- Do not feed honey to children less than a year old. Contaminated honey is a common cause of infant botulism, but does not appear to pose a problem for children or adults.
- Be cautious with the following foods, which are most likely to be contaminated: home-canned fruits and vegetables (green beans in particular), fish, undercooked sausage and other pork products, smoked meats, red meat, and milk products.
- Keep foods at room temperature for no more than one hour before or after cooking. Refrigerate any leftovers promptly (divide large amounts of food into smaller batches before refrigerating).
Diagnosis of Botulism
- Patient history is taken and physical examination is performed.
- Blood, stool, or stomach contents as well as the suspected food may be tested for the presence of botulin toxin and the bacterium, but the ultimate diagnosis rests on the presentation of symptoms.
The following tests may be performed to rule out other disorders:
- Electromyogram (EMG), which tests the conduction of electrical impulses along the nerves.
- Computed tomography scan (CT or CAT scan), which provides detailed images of the brain, bones, muscles, fat, organs and other parts of the body.
- Spinal tap (lumbar puncture), which involves using a special needle to withdraw cerebrospinal fluid (CSF) from the spinal canal in the lower back to test from infection or other conditions.
- Tensilon test to determine the cause for muscle weakness (e.g., caused by myasthenia gravis).
How Botulism is Treated
- Call an ambulance immediately; emergency care and hospitalization are necessary.
- If only a few hours have passed since eating contaminated food, induce vomiting.
- If possible, try to refrigerate some of the suspected contaminated food for analysis.
- When diagnosed early, doctors will administer a botulism antitoxin, which can be lifesaving but can have pronounced unpleasant side effects. If botulism is strongly suspected, the antitoxin is given before laboratory confirmation of the diagnosis.
- Penicillin is also frequently given, but this is controversial as the actual bacteria is not the primary problem.
- Enemas and drugs that induce bowel evacuation may be given to help rid the body of the toxin.
- Mechanical respiration may be needed in the case of severe breathing difficulty.
- Infected wounds are treated surgically to remove the source of the toxin
In March 2013, the U.S. Food and Drug Administration approved botulism antitoxin heptavalent (A, B, C, D, E, F, G) -equine to treat known or suspected exposure to botulinum neurotoxin. This is the first treatment approved to neutralize all 7 serotypes of botulinum neurotoxin and the only available treatment for botulism in adults and infantile botulism caused by serotypes other than A and B.
Botulism antitoxin heptavalent was tested in a botulism treatment program conducted by the Centers for Disease Control and Prevention (CDC), as well as in 40 healthy, volunteer participants. Side effects include headache, fever and chills, rash, itching and nausea. Because it is manufactured from horse plasma, it may cause an allergic reaction or hypersensitivity reaction in people who are sensitive to horse proteins.
When to Call a Doctor
- Botulism is an EMERGENCY Get immediate medical help if you develop any of the symptoms of botulism.
Johns Hopkins Symptoms and Remedies: The Complete Home Medical Reference
Simeon Margolis, M.D., Ph.D., Medical Editor
Prepared by the Editors of The Johns Hopkins Medical Letter: Health After 50
Updated by Remedy Health Media