Emergency Preparedness

Kern Medical Bioterrorism Response Guide Section 2-A-3 – Botulism

from myasthenia. The cerebrospinal fluid in botulism is normal and the paralysis is generally symmetrical, which distinguishes it from enteroviral myelitis. Mental status changes are generally seen in viral encephalitis but not generally with botulinum intoxication. Other diseases to consider would be stroke, chemical intoxication (e.g., carbon monoxide, barium carbonate, methyl chloride, organic phosphorus compound or atropine), mushroom poisoning, medication reactions (e.g., neomycin, streptomycin, kanamycin and gentamicin), and poliomyelitis. Diagnosis Routine laboratory studies are of little diagnostic value. The occurrence of several afebrile patients with progressing symmetrical descending flaccid paralysis strongly suggests botulism. Foodborne outbreaks tend to occur in small clusters. An unusual number of cases within a defined geographical area should alert hospital emergency department and the infection control personnel that a bioterrorist event could be evolving. Serum specimens should be drawn and sent to the laboratory capable of performing a mouse neutralization bioassay. Currently in California only the CDHS Microbial Diseases Laboratory (MDL) and the Los Angeles County Health Department Public Health Laboratory perform botulism bioassays. However, the decision to treat (see below) should not await laboratory confirmation, which takes 2 days or more to complete. Tests to rule other diseases include spinal fluid protein, Tensilon® test, electromyography and computerized tomographic scans. Treatment Respiratory failure due to paralysis of the respiratory muscles is the most serious complication of botulinum intoxication and is generally the cause of death. Prolonged ventilator assistance is almost always required for survival. Intensive and prolonged nursing care is required for most patients. Without administration of antitoxin, it may be as long as three months before there are any signs of improvement, and up to one year for complete resolution of symptoms. In the recent epidemic of wound botulism in California mild cases have occurred not requiring ventilation or antitoxin administration. Early administration of botulinum antitoxin can be critical to survival. Antitoxin neutralizes circulating toxin, but not toxin that has already effected cholinergic synapses. Antitoxin will minimize subsequent nerve damage and severity of disease but will not reverse existent paralysis. Therefore, antitoxin should be administered to patients upon initial diagnosis or in patients with symptoms that continue to progress. The decision to treat is based upon clinical diagnosis and should not await laboratory confirmation. When sympto m progression ceases, no circulating toxin remains and the antitoxin is no longer effective. Antitoxin may be withheld only if a patient has been clearly improving from point of maximal paralysis, or if clearly stable with no respiratory impairment. Antitoxin may be effective in foodborne cases where presumably toxin continues to be absorbed through the gut wall, and in wound botulism cases where

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