Botulism is a rare but serious and potentially fatal paralytic disease. It is caused by a potent neurotoxin called botulinum toxin (BTX), which is excreted by an anaerobic and spore-forming bacterium, Clostridium botulinum (C. botulinum) found in the environment, soil and contaminated food.

Hong Kong/CIA
Hong Kong/CIA

Botulism has been a notifiable infectious disease in Hong Kong under the Prevention and Control of Disease Ordinance (Cap. 599) since July 14, 2008. In May 2016, as suspected botulism cases related to injection of BTX were reported to the Centre for Health Protection (CHP) of the Department of Health, the clinical criteria of botulism were revised and adopted, in which, iatrogenic botulism was included as one of the categories of botulism besides foodborne, infant, wound and other botulism.

Iatrogenic botulism was defined as “the spread of BTX beyond injection site following injection of BTX for therapeutic or cosmetic purposes, and the patient develops symptoms of botulism such as generalized weakness, dysphagia, aspiration pneumonia, flaccid paralysis, respiratory muscle paralysis, and autonomic neuropathy etc”.

So far, 11 probable cases of iatrogenic botulism were reported from May 27 to August 4, 2016 to CHP, affecting 11 women aged from 21 to 47 years (median = 39 years). The duration of symptoms onset ranged from two to 31 days after injections (median = 3 days) and the presenting symptoms ranged from neck weakness and dysphagia to generalized muscle weakness and breathing difficulty.

Antitoxin was administered to three patients as they developed generalized weakness and had difficulty in breathing or swallowing to prevent further deterioration. All of them were in stable condition. Nine required hospitalization in Hong Kong and all have been discharged. None of the cases required mechanical ventilation.

Investigation revealed that nine of them had history of BTX injection in different beauty centres in the Mainland, while two claimed that they had received injection in Hong Kong at a commercial premise in Mong Kok and at home, respectively. Both cases receiving injection in Hong Kong had been referred to the Police for necessary action and investigation.

The latter case was found to have the injection in Shenzhen after investigation by the Police and thus 10 imported cases were recorded. For the cases receiving injection in the Mainland, relevant information was provided to the Mainland health authority for their follow-up investigations and measures.