CBRNE - Botulism Guidelines

Updated: Feb 23, 2023
  • Author: Peter P Taillac, MD; Chief Editor: Duane C Caneva, MD, MSc  more...
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Guidelines Summary

In 2021, the Centers for Disease Control and Prevention (CDC) released guidelines for the diagnosis and treatment of botulism. [17]

Cinical Criteria Tool

The CDC guidelines include the following clinical criteria tool for early diagnosis of botulism in crisis and contingency settings [17] :

  • Afebrile (< 100.4°F [< 38°C])§
  • Acute onset of at least one of the following symptoms:
    • Blurred vision
    • Double vision
    • Difficulty speaking, including slurred speech
    • Any change in sound of voice, including hoarseness
    • Dysphagia, pooling of secretions, or drooling
    • Thick tongue
  • At least one of the following signs:
    • Ptosis
    • Extraocular palsy or fatigability (the latter manifested by inability to avert eyes from light shone repeatedly into eye [typically used in infants])
    • Facial paresis (manifested, for example, by loss of facial expression or pooling of secretions and in young children by poor feeding, poor suck on breast or pacifier, or fatigue while eating)
    • Fixed pupils
    • Descending paralysis, beginning with cranial nerves

The CDC recommends clinicians consider botulism when myasthenia gravis or Guillain-Barré syndrome are suspected and in a patient with unexplained symmetric cranial nerve palsies, with or without paresis of other muscles. Thorough, serial neurologic examinations should be conducted to detect the neurologic deficits of botulism and their progression. [17]

Ask patients about possible exposures to well-described sources of botulinum toxin, while keeping in mind that absence of such exposures does not exclude the possibility of botulism. Electrodiagnostic testing should be considered to assist in diagnosis of a suspected botulism case. When conducted and interpreted by experts, EMG, RNS, and NCSs can provide useful diagnostic data. [17]

If botulism is suspected, local or state health department’s emergency on-call staff  must be notified immediately to arrange an emergency expert clinical consultation and, when indicated, request botulinum antitoxin from CDC. Discuss specimen collection with the expert consultant from CDC or the local or state health department. [17]

Collect specimens for laboratory confirmation of the clinical diagnosis of botulism as soon as possible because toxin levels decrease over time. Obtain serum before botulinum antitoxin heptavalent (BAT) is administered. Store and transport specimens for botulism testing at refrigeration temperatures (36°F–46°F [2°C–8°C]); do not freeze. [17]

Monitoring Illness Progression

Because paralysis may result in respiratory compromise from upper airway collapse or respiratory muscle impairment, patients should be closely monitored.  Key CDC recommendations include the following [17] :

  • Frequent, serial neurologic examinations, with an emphasis on cranial nerve palsies, swallowing ability, respiratory status, and extremity strength should be conducted.
  • In settings of contingency and crisis standards of care, focus examinations on signs and symptoms of early onset. Consider brief, focused training in the emergency setting on the neurologic examination.
  • When possible, have the same health care provider conduct the serial neurologic and other examinations.
  • Adjust the frequency of neurologic and other examinations on the basis of signs and symptoms, with very frequent examinations for patients with rapid progression and for patients who have respiratory or bulbar symptoms but have not required intubation.
  • Institute frequent, serial monitoring of respiratory and bulbar function. 
  • Focus the respiratory examination on respiratory rate, lung field auscultation, and work of breathing, including use of accessory muscles of respiration, nasal flaring, and paradoxical breathing.
    • Obtain serial objective data through spirometry, EtCO2 monitoring, blood gas analysis, or other tests. Patients with facial weakness might not achieve an adequate seal around the spirometer mouthpiece and so might require a mask device. If spirometry is not available, consider using the sniff nasal inspiratory pressure or the single breath count test.
    • Consider respiratory status in the context of neurologic status because paralysis can alter signs typically associated with respiratory distress. 
  • Focus bulbar dysfunction examination on dysphagia, dysarthria, nasal voice, drooling, and impaired gag reflex. When feasible, consider assessing the patient’s swallowing ability to help determine whether the patient can safely consume liquids or solids.
  • Continuously monitor cardiac rhythm and frequently measure blood pressure.
  • Frequently monitor for urinary retention, constipation or ileus, dry mouth, and dry eyes.


Administer botulinum antitoxin to patients with suspected botulism as early as possible in the course of illness. The greatest benefit accrues to those who receive it within the first 2 days of illness onset.  Patients with suspected botulism should be treated with BAT regardless of underlying medical conditions or age, sex, or other demographic characteristics. Pregnant women with suspected foodborne botulism should be treated with BAT in the same manner as nonpregnant patients. [17]

The standard adult dose is one vial, administered by intravenous infusion. The pediatric dose is based on weight. Ensure that epinephrine and antihistamine treatments are available for all patients receiving BAT. [17]  

Patients with suspected botulism whose symptoms or signs (e.g., paralysis) are progressing should be treated with BAT regardless of the time that has elapsed since symptom onset.  Patients with suspected botulism whose symptoms and signs are not progressing and who have no remaining voluntary muscle function are less likely to benefit from antitoxin treatment, especially if >7 days have passed since symptom onset, because toxin is infrequently detected beyond this point of illness. [17]

Do not routinely perform skin testing for sensitivity before BAT administration.  Do not give patients with suspected botulism a second dose of BAT unless progression of paralysis clearly continues after the initial dose should have taken effect and suspicion for botulism is high.  If neurologic signs progress for >1 day after administration of one vial of BAT, consider diagnoses other than botulism. [17]