Table of contents
Expand All Topics
Botulism
Background
Overview
Definition
Botulism is a rare, life-threatening disease caused by the neurotoxin produced by the bacterium Clostridium botulinum.
1
Pathophysiology
Botulism is caused by the anaerobic, Gram-positive bacterium Clostridium botulinum and, rarely, by related species (Clostridium baratii and Clostridium butyricum). The botulinum neurotoxin inhibits acetylcholine release at the neuromuscular junction, leading to muscle paralysis.
1
Epidemiology
In 2019, the CDC has reported 219 cases of botulism in the US.
2
Risk factors
Risk factors for botulism include ingestion of contaminated food, bacterial colonization of a wound, or the intestines (as in infant botulism and adult intestinal colonization botulism). High-concentration cosmetic or therapeutic injections of toxin can also lead to botulism (iatrogenic botulism).
1
Disease course
Botulism progresses over hours to several days following toxin exposure. Neurologic symptoms typically begin within 12-36 hours but can be delayed up to several days depending on toxin dose and route of exposure. Early signs include blurred vision, diplopia, ptosis, dysarthria, dysphagia, and dry mouth, reflecting cranial nerve involvement. These are followed by progressive, symmetric, descending flaccid paralysis involving the respiratory, axial, and limb muscles. In foodborne botulism, gastrointestinal symptoms such as nausea, vomiting, and abdominal discomfort often precede neurologic deficits by several hours. Vomiting occurs in up to 50% of cases. Infants may present with constipation, hypotonia, weak cry, and poor feeding within 3-30 days of ingesting contaminated food. Proximal muscles are typically affected before distal ones, though exceptions occur. Asymmetric neurologic findings are reported in 6-15% of cases. Respiratory failure typically develops several days after symptom onset and is preceded by bulbar weakness. Rarely, respiratory failure is the initial manifestation. Recovery, often over weeks to months, occurs in reverse order of symptom appearance. Atypical or nonspecific initial presentations, such as gastrointestinal complaints or nonspecific weakness, may delay diagnosis.
3
Prognosis and risk of recurrence
The prognosis of botulism is generally good with appropriate medical care, which includes supportive care, intubation, mechanical ventilation when necessary, and administration of botulinum antitoxin.
1
Guidelines
Key sources
The following summarized guidelines for the evaluation and management of botulism are prepared by our editorial team based on guidelines from the Center for Disease Control (CDC 2021).
1
2
3
Screening and diagnosis
Diagnostic investigations
History and physical examination
As per CDC 2021 guidelines:
Elicit history of possible exposures to well-described sources of botulinum toxin, while keeping in mind that the absence of such exposures does not exclude the possibility of botulism.
E
Perform thorough, serial neurologic examinations to detect neurologic deficits of botulism and assess their progression.
E
More topics in this section
Laboratory testing
Electrodiagnostic studies
Medical management
Contacting local or state health department: as per CDC 2021 guidelines, contact the local or state health department's emergency on-call staff immediately when botulism is suspected to arrange an emergency expert clinical consultation and, when indicated, request botulinum antitoxin.
E
More topics in this section
Antitoxin therapy
Other agents
Supportive care
Inpatient care
Clinical monitoring, neurologic deficits: as per CDC 2021 guidelines, obtain frequent, serial neurologic examinations with an emphasis on cranial nerve palsies, swallowing ability, respiratory status, and extremity strength. Conduct the serial neurologic and other examinations by the same healthcare provider, when possible.
E
Show 2 more
More topics in this section
Clinical monitoring (respiratory compromise)
Clinical monitoring (hemodynamic status)
Clinical monitoring (other complications)
Specific circumstances
Pediatric patients
As per CDC 2021 guidelines:
Obtain close monitoring for worsening paralysis in pediatric patients with suspected foodborne botulism treated with botulinum antitoxin therapy according to the weight-based dose described in the package insert.
E
Consider administering retreatment in patients with a lack of response to the treatment when confidence in the diagnosis of botulism is substantial.
E
More topics in this section
Pregnant patients