Early forms of SMN1-related proximal spinal muscular atrophy are very often accompanied by swallowing disorders and salivary stasis. Canadian clinicians report the case of a 17-month-old child with SMA type I who received several injections into the submaxillary and parotid glands to combat chronic hypersialorrhoea:
- the child experienced increased hypotonia and regression of modest motor skills shortly after the injections,
- swallowing disorders were more severe, to the point of requiring gastrostomy feeding,
- the imputability of the observed disorders to the toxin treatment was delayed,
- the patient took several months to recover his previous state.
The authors rightly point out that the neuromuscular junction is often dysfunctional in SMA, thus potentiating the adverse effects of botulinum toxin.
