CDC guideline on diagnosis and treatment of Botulism
USA: The Centers for Disease Control and Prevention (CDC) has released new guidelines for the diagnosis and treatment of Botulism. The evidence-based guideline, published in the CDC's Morbidity and Mortality Weekly Report, provides health care providers with recommended best practices for diagnosing, monitoring, and treating single cases or outbreaks of foodborne, wound, and inhalational botulism and were developed after a multiyear process involving several systematic reviews and expert input.
Botulism is a rare, neurotoxin-mediated, life-threatening disease characterized by flaccid descending paralysis that begins with cranial nerve palsies and might progress to extremity weakness and respiratory failure. Botulinum neurotoxin, which inhibits acetylcholine release at the neuromuscular junction, is produced by the anaerobic, gram-positive bacterium Clostridium botulinum and, rarely, by related species (C. baratii and C. butyricum).
Exposure to the neurotoxin occurs through ingestion of toxin (foodborne botulism), bacterial colonization of a wound (wound botulism) or the intestines (infant botulism and adult intestinal colonization botulism), and high-concentration cosmetic or therapeutic injections of toxin (iatrogenic botulism). In addition, concerns have been raised about the possibility of a bioterrorism event involving toxin exposure through intentional contamination of food or drink or through aerosolization. Neurologic symptoms are similar regardless of exposure route. Treatment involves supportive care, intubation and mechanical ventilation when necessary, and administration of botulinum antitoxin.
Certain neurological diseases (e.g., myasthenia gravis and Guillain-Barré syndrome) have signs and symptoms that overlap with botulism. Before the publication of these guidelines, no comprehensive clinical care guidelines existed for treating botulism.
Diagnosis of Botulism
- 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.
- Conduct thorough, serial neurologic examinations to detect the neurologic deficits of botulism and their progression.
- If botulism is suspected, immediately contact the local or state health department's emergency on-call staff to arrange an emergency expert clinical consultation and, when indicated, request botulinum antitoxin from CDC.
- When feasible, consider using electrodiagnostic testing to assist in diagnosis of a suspected botulism case. When conducted and interpreted by experts, EMG, RNS, and NCSs can provide useful diagnostic data.
- Clinicians should 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.
- Treat patients with suspected, symptomatic botulism with botulinum antitoxin on the basis of clinical findings; do not await laboratory confirmation because results might take several days, and they can be negative in patients who have botulism.
- Discuss specimen collection with the expert consultant from CDC or the local or state health department.
- Collect specimens for laboratory confirmation of the clinical diagnosis of botulism as soon as possible because toxin levels decrease over time. Obtain serum before BAT is administered.
- Store and transport specimens for botulism testing at refrigeration temperatures (36°F–46°F [2°C–8°C]); do not freeze.
Monitoring Illness Progression in Patients with Botulism
· Conduct frequent, serial neurologic examinations, with an emphasis on cranial nerve palsies, swallowing ability, respiratory status, and extremity strength.
· In settings of contingency and crisis standards of care, in which time is limited, 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. Serial measurements might be more helpful than a single measurement.
· Continuously monitor cardiac rhythm and frequently measure blood pressure.
· Frequently monitor for urinary retention, constipation or ileus, dry mouth, and dry eyes.
· Health care providers who suspect botulism on the basis of clinical symptoms should immediately call the emergency contact number of their local or state health department to arrange for an emergency clinical consultation and, when indicated, shipment of antitoxin.
· Do not routinely perform skin testing for sensitivity before BAT administration.
· Ensure that epinephrine and antihistamine treatments are available for all patients receiving BAT. Caregivers capable of identifying and responding to anaphylaxis should observe patients during antitoxin administration.
· 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 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.
· Patients with suspected botulism should be treated with BAT regardless of underlying medical conditions or age, sex, or other demographic characteristics.
· 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.
· Children suspected of having foodborne botulism and treated with BAT according to the weight-based dose described in the package insert should be monitored closely for worsening paralysis. When confidence in the diagnosis of botulism is substantial, a lack of response to the treatment might indicate that the dose was insufficient, and retreatment should be considered.
· Pregnant women with suspected foodborne botulism should be treated with BAT in the same manner as nonpregnant patients.
· Proactively develop an approach to handle BAT shortages as part of an emergency planning process that incorporates the full range of stakeholders, including local communities.
· Aminoglycosides, magnesium, clindamycin, tetracycline, or calcium should only be administered to patients with botulism after careful consideration and with appropriate monitoring.
"Clinical Guidelines for Diagnosis and Treatment of Botulism, 2021," is published in the CDC's Morbidity and Mortality Weekly Report.