In the past week, three suspected cases of “iatrogenic botulism” have emerged in Hong Kong, with patients experiencing weakness, dizziness, slurred speech, difficulty breathing and swallowing after receiving botulinum toxin injections in mainland China. These cases have sparked widespread discussion and raised concerns about the safety of botulinum toxin.
The three female patients sought medical attention three to ten days after the injections and were diagnosed with iatrogenic botulism, but were stable enough to be discharged from the hospital. What they have in common is the injection being administered in mainland China, although the source and injection details of the botulinum toxin used (including dosage, dilution, injection technique, and whether it was administered by a doctor) are unclear. So, what are the risks associated with botulinum toxin injections?
Like all medications, botulinum toxin carries the potential for side effects. Typically, side effects are mild and include redness, bruising, and pain at the injection site. Depending on the injection site, there is also a chance of headaches, drooping eyelids, double vision, and asymmetry. Systemic side effects such as weakness, dizziness, slurred speech, difficulty breathing, and swallowing have also been reported in medical literature. However, the chance of systemic side effects is actually very low and I have never encountered a case myself. According to medical literature, systemic side effects typically occur with the administration of 600 units or equivalent of Botox (unit conversion varies between different manufacturers) and with repeated injections (every three months or less). In general, cosmetic injections are not given in such large doses, even when administered to the calf, where only 200 units of Botox would be used.
The strange thing about this event is the emergence of three rare cases in a short period of time, with all injections given in mainland China and the source of botulinum toxin remaining unknown. At present, the cause of the event remains unclear, and we must wait for the results of the investigation. For those seeking botulinum toxin injections, it is best to find a registered doctor and ensure that the source of the botulinum toxin is legitimate. In Hong Kong, quality assurance is always a top priority!
*Beth E. Crowner, PT, DPT, Diego Torres-Russotto, M.D., Alexandre R. Carter, M.D., PhD, andBrad A. Racette, M.D. Systemic Weakness After Therapeutic Injections of Botulinum Toxin A: A Case Series and Review of the Literature. Clin Neuropharmacol. 2010 Sep-Oct; 33(5): 243–247.