- Botulism is a muscle-paralyzing illness caused by a neurotoxin made by the bacterium Clostridium botulinum.
- Characterized by acute onset of bilateral cranial nerve involvement (diplopia, difficulty swallowing or speaking) associated with symmetric descending weakness, intact mental state, no fever, and no sensory dysfunction
- 7 types of C. botulinum (A–G) are distinguished by their antigenic characteristics. Types A, B, E, and, in rare cases, F, cause disease in humans.
- Forms include:
- Foodborne: Caused by ingestion of preform toxin
- Infant botulism: Caused by ingestion of C. botulinum that produce toxin in the gastrointestinal (GI) tract
- Wound: Caused by wound infection with C. botulinum that secretes the toxin
- Aerosolized/inhalational botulinum: Bioterrorism attack potential because of high toxicity; <1 µg is lethal human dose
- Injection related: Rare
- Adult colonization botulism: Rare
- System(s) affected: Neuromuscular; Respiratory; GI
- Diagnosis is made through history and clinical exam.
- Laboratory confirmation demonstrates presence of toxin in serum, stool, or wound; or culturing C. botulinum from stool, wound, or food
- Treatment should not wait for laboratory confirmation.
- Synonym(s): Sausage poisoning; Kerner disease
- A purified and diluted form of Type A neurotoxin is used to produce Botox injections.
- Average of 110 cases of botulism reported annually in US
- ∼20% of cases are foodborne; 30–40% wound-related; 65% infant botulism
- Wound botulism incidence increasing due to IV heroin use and cocaine abuse
- Hidden or intestinal: More common in disorders of the GI tract, such as prior surgery, Crohn disease, or recent antibiotic use
- Inhalation: Only a single incident involving 3 laboratory workers has been described.
- Predominant age:
- Foodborne: Mean age is 46 years; range of 3–78 years
- Infantile: Mean age of onset 13 weeks, with range of 1–63 weeks
- Wound: Median age is 41 years with a range of 23–58 years
- Predominant gender:
- Foodborne and infantile: Male = Female
- Wound: Female > Male
- Foodborne: Ingestion of home-canned or prepared contaminated foods
- Infantile: From ingestion of honey or corn syrup; breastfeeding (controversial)
- Wound: IV drug use (black tar heroin; IM/SC) or “skin popping”
- Foodborne: Proper handling, processing, preparation (heating), and storage of food; avoid eating food from bulging cans and food that smells/looks spoiled.
- Infant: Avoid honey before 1 year of age.
- Wound: Proper wound care
- Health care providers: Standard precautions
- If meningitis is suspected in patients with flaccid paralysis, medical personnel should use droplet precautions.
- Heat potentially contaminated food or drink to an internal temperature of 85°C for at least 5 minutes.
- After exposure to C. botulinum toxin, clothing and skin should be cleaned with soap and water.
- Contaminated objects or surfaces should be cleaned with 0.1% bleach solution. All food suspected of contamination should be promptly removed from potential consumers.
- Disease results from hematogenous spread of toxin from mucosal surface (stomach, small intestine) or from an infected wound.
- The toxin prevents acetylcholine release at presynaptic membranes, blocking neuromuscular transmission in cholinergic nerve fibers.
- Toxin produced by C. botulinum, an encapsulated, anaerobe, gram-positive, spore-forming, rod-shaped bacillus
- Ingestion of C. botulinum neurotoxins (A, B, and E most common)
- Foodborne, usually from home-canned vegetables, prepared foods, or foods incubated in anaerobic conditions
- Infantile from ingestion of spores in environment or occasionally in honey
- Wound due to contamination with toxin-producing C. botulinum
- Inadvertent: IM injections of botulinum toxin
- Incubation: Typically 12–36 hours after toxin ingestion. Rare case as late as 10 days after ingestion.
- Wound and infant botulism: Incubation time cannot be ascertained.
- Inhalational: Same as foodborne botulism
- Adults: Acute onset of symmetric neuropathies. Difficulty in swallowing or speaking, dry mouth. Diplopia, blurred vision, dilated or nonrelated ptosis (drooping eyelids).
- Symmetric descending, flaccid paralysis in oriented, afebrile patient
- Respiratory dysfunction
- Infant botulism: Disease presentation and severity variable:
- Constipation, shortly followed by weakness, feeding difficulties, descending or global hypotonia, drooling, anorexia, irritability, and weak cry
- Ask about diet, travel, drug use, and other persons with same symptoms.
- General appearance: Oriented, flaccid, may complain of malaise, dizziness, nausea, vomiting
- Vital signs, afebrile (fever may occur in wound botulism due to secondary infection), normal blood pressure
- Head, eyes, ears, nose, throat: Dry mouth
- Chest/lungs: Respiratory muscle weakness, respiratory dysfunction, paralysis
- Heart: Normal or slow rate
- Abdomen: Distention, constipation (early sign in infant form); may be absent in wound form
- Genitourinary: Urinary retention
- Symmetrical descending weakness beginning with the cranial nerves
- Ptosis; extraocular muscle paresis; fixed, dilated pupils; dysphagia
- Infant botulism: Poor muscle tone (loss of head control and facial expression), poor feeding (loss of suck), drooling, feeding difficulties, weak cry
- Diminished or absent deep tendon reflexes
Diagnostic Tests & Interpretation
Initial lab tests
- Laboratory confirmation is done by demonstrating the presence of toxin in serum or stool, or by culturing C. botulinum from stool, wounds, or food.
- Mouse neutralization assay confirmation:
- Standard method of diagnosis (1)[B]
- Available from Centers for Disease Control and some state laboratories; takes ∼4 days for results
- Routine tests (complete blood count, electrolytes, liver function tests, urinalysis) generally not helpful/show no characteristic abnormalities
- Cerebrospinal fluid testing: Normal helps differentiate from Guillain-Barré syndrome. Occasionally a borderline elevation in protein is seen.
- Toxin detected in gastric contents, serum, stool, and suspected food and containers:
- PCR tests are also available for rapid detection of clostridia in food samples (2)[B].
- A normal Tensilon test helps to differentiate botulism from myasthenia gravis; borderline can occur in botulism
CT or MRI to rule out neurologic pathology
- Presumptive evidence in patients with negative bioassay studies (3)[C]
- Brief, small-amplitude motor potential with incremental response on repetitive nerve stimulation
- Adult botulisms:
- Guillain-Barré syndrome
- Encephalitis, meningitis
- Tick paralysis
- Myasthenia gravis
- Eaton Lambert myasthenic syndrome
- Cerebrovascular accident: Basilar artery stroke
- Congenital neuropathy or myopathy
- Hypokalemic periodic paralysis
- Other poisonings (organophosphate, shellfish, Amanita mushrooms, atropine, and aminoglycosides)
- Miller-Fisher variant of Guillain-Barré syndrome
- Diphtheritic neuropathy
- Carbon monoxide intoxication
- Infant botulism:
- Electrolyte–mineral imbalance
- Reye syndrome
- Congenital myopathy
- Leigh disease
- Werdnig-Hoffman disease
- Antitoxin therapy with trivalent A-B-E antitoxin:
- Call CDC Assistance (770) 488-7100
- Initiating botulinum antitoxin therapy is primarily based on symptoms and physical examination findings that are consistent with botulism (4)[B].
- Early administration is important (4)[B].
- Horse serum derived: Up to 20% reaction incidence. Consider skin testing or pretreatment with steroids or antihistamines.
- Treatment with human botulism immune globulin (BIG-IV or Baby BIG) for botulism types A and B (5)[B]
- Available only through the California State Health Department (510) 540-2646 or (510) 231-7600
- Antitoxin therapy with trivalent A-B-E antitoxin, 1 vial IV and 1 vial IM, repeat in 2–4 hours if persistent symptoms
- Antibiotics unproven by clinical trial, but widely used and recommended:
- Penicillin G (3 million units IV q4h in adults)
- Metronidazole (500 mg IV q8h) for penicillin-allergic patients
- Vaccine: Pentavalent vaccine available:
- Efficiency in terrorist attack is unknown
- Newer vaccines being developed
Supportive care, including mechanical ventilation (6)[C]
Safety of botulism antitoxin during pregnancy and breastfeeding unknown or controversial (6)
Issues for Referral
- Nutrition: For hyperalimentation and later, tube feeding
- Physical/occupational therapy: Including swallow evaluation
- Stress ulcer and deep vein thrombosis prophylaxis
- Pulmonary and physical rehabilitation
Hospital admission with meticulous airway management
All suspected cases must be admitted.
Keep patient well hydrated.
- Prevent decubitus ulcer, IV line infections, other nosocomial infections
- Before administration of antitoxin, skin testing should be performed for sensitivity.
Outpatient follow-up with physical/occupational therapy, nutrition specialist, and psychiatry as needed
- Pulmonary function testing
- Cardiorespiratory monitoring
Nasogastric feedings, if needed
- Spores destroyed by pressure cooking at 250°F (120°C) for 30 minutes
- Toxin destroyed by boiling for 10 minutes or cooking at 175°F (80°C) for 30 minutes
- Avoid honey in 1st year of life.
- Avoid IV drug use.
- Do not eat/sample foods that look and smell rotten or come from bulging cans.
- Delay in administering antitoxin: Most important factor affecting clinical course and outcome (4)[B]
- Mortality: Overall 7–10%; <5% if infection is treated, but approaches 60% if untreated (6)
- Mortality for patients >60 years is twice that of younger patients
- Full recovery may take months.
- Significant health, functional, and social limitations several years after infection (7)[C]:
- Recovery follows the regeneration of new neuromuscular connections.
- 2–8 weeks of ventilator support may be required in more severe cases.
- Dyspnea with severe ptosis and pupil abnormality has been shown to correlate with severe illness and respiratory failure (8)[C].
- Increased incubation time has been shown to correlate with better outcomes (8)[C].
- Nosocomial infections, including aspiration pneumonia and ventilator-associated pneumonia
- Hypoxic tissue damage
1. Lindström M, Korkeala H. Laboratory diagnostics of botulism. Clin Microbiol Rev. 2006;19:298–314.
2. Fach P, Micheau P, Mazuet C, et al. Development of real-time PCR tests for detecting botulinum neurotoxins A, B, E, F producing Clostridium botulinum, Clostridium baratii and Clostridium butyricum. J Appl Microbiol. 2009;107:465–73.
3. Bayrak A, et al. Electrophysiologic findings in a case of severe botulism. J Neurol Sci. 2006;23:49–53.
4. Dembek ZF, Smith LA, Rusnak JM. Botulism: cause, effects, diagnosis, clinical and laboratory identification, and treatment modalities. Disaster Med Public Health Prep. 2007;1:122–34.
5. Arnon SS, Schechter R, Maslanka SE, et al. Human botulism immune globulin for the treatment of infant botulism. N Engl J Med. 2006;354:462–71.
6. O’Brien KK, Higdon ML, Halverson JJ. Recognition and management of bioterrorism infections. Am Fam Physician. 2003;67:1927–34.
7. Gottlieb SL, Kretsinger K, Tarkhashvili N, et al. Long-term outcomes of 217 botulism cases in the Republic of Georgia. Clin Infect Dis. 2007;45:174–80.
8. Witoonpanich R, Vichayanrat E, Tantisiriwit K, et al. Survival analysis for respiratory failure in patients with food-borne botulism. Clin Toxicol (Phila). 2010;48:177–83.
9. Botulism Facts for Healthcare Providers. Accessed 5/30/2010 at http://emergency.cdc.gov/agent/botulism/hcpfacts.asp.
See Also (Topic, Algorithm, Electronic Media Element)
Food Poisoning, Bacterial
- 005.1 Botulism food poisoning
- 040.42 Wound botulism
- 398565003 Infection due to infection due to clostridium botulinum (disorder)
- 398523009 Foodborne botulism (disorder)
- 398530003 Wound botulism (disorder)
- Botulinum antitoxin should be administered as soon as possible; don’t wait for lab results.
- Medical care providers who suspect botulism in a patient should immediately call their state health department’s emergency 24-hour telephone number.
- A helpful mnemonic to recall progression of symptoms is the “dozen D’s”: Dry mouth, diplopia, dilated pupils, droopy eyes, droopy face, diminished gag reflex, dysphagia, dysarthria, dysphonia, difficulty lifting head, descending paralysis, and diaphragmatic paralysis (9)