Botulism Literature: Commentary by Dr. John G. Bartlett -- April 2007

John G. Bartlett, MD


May 04, 2007

Kongsaengdao S, Samintarapanya K, Rusmeechan S, for Thai Botulism Study Group. An Outbreak of Botulism in Thailand: Clinical Manifestations and Management of Severe Respiratory Failure. Clin Infect Dis 2006;43:1247-1256 . In March, 2006, there was an outbreak of botulism in Northern Thailand that was the biggest that area had seen to date, with 209 victims. The implicated food was home-canned bamboo shoots. Respiratory failure, neuromuscular failure, and autonomic nervous system failure developed in at least 42 patients. Patients with mild illness had only mild dysphagia, dysarthria, diarrhea and/or diplopia without respiratory failure. The patients were treated with standard support and imported botulinum antitoxin. The review here is for 18 patients at one referral center who had severe neuromuscular respiratory failure at 1-65 hours after ingestion of pickled bamboo shoots at a consumption time estimated to be noon on March 14, 2006. The following are important observations in this review:

  • The sequential evolution of symptoms with the frequency of clinical expression in these 18 patients is shown in the Table;

  • Autonomic involvement: This included fluctuation in pulse and blood pressure in all patients and urinary retention in 72%;

  • Classical electrophysiologic findings included low compound muscle action potential (CMAP), abnormal response to repetitive nerve stimulation (RNST) at low level frequency (3 Hz), and fluctuation at high stimulation frequencies (10-50 Hz). The RNST-elicited CMAP showed very low amplitudes at the severe stage of botulism and these improved to normal or nearly normal during the ventilator-weaning stage accompanied by improved overall motor power;

  • Complications included aspiration pneumonia in 83%, pulmonary edema in 11%;

  • There was no significant difference in the rate of respiratory failure in patients given antitoxin at day 4 vs those given in at day 6, but those given this treatment at day 4 had a shorter time to extubation; and

  • In totality, 42 of the 209 patients (20%) required mechanical ventilation, and there were no deaths. The authors concluded that RNST results were useful in guiding the time to wean from mechanical ventilation. They also concluded that their study showed that time of administration of antitoxin provided favorable outcome by reducing the time requiring mechanical ventilation.



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