Introduction
Central pontine myelinolysis (CPM) was first defined in 1959 as
demyelination of the pons center due to osmotic imbalance in
malnourished patients (1). It most commonly occurs due to hyponatremia
and its rapid correction (2). Typically, CPM is clinically characterized
by acute quadriparesis, dysphagia, and dysarthria. Cranial nerve
involvement, ocular involvement, sensory changes, and mental impairment
can also be seen. The most common and dramatic symptom is motor
abnormalities.
Among various treatment options, chemodenervation with botulinum
neurotoxin type A (BoNTA) is the preferred method for focal spasticity
management (3). Over the last 30 years, accumulating evidence has proven
the efficacy of BoNTA therapy (4,5), which usually starts on the second
to third day of application, reaching the maximum level within three to
four weeks and lasting for approximately three months (6). BoNTA
injection is considered safe; however, its widespread use and increasing
evidence raise safety concerns (7). Studies have reported local side
effects due to BoNTA injection, such as pain at the injection site,
edema, ecchymosis, hyperesthesia, and headache, which are generally well
tolerated (8,9). Systemic side effects include nausea, weakness and
fatigue, generalized weakness, dysphagia, respiratory distress, rash,
and flu-like symptoms (9). Side effects vary according to the
application and usually depend on the diffusion of the toxin from the
muscle where the drug has been administered to the adjacent muscles
(10). In our case, a systemic side effect was observed far from the
local injection site.
In this paper, we present patient with CPM, a rare disease, who
developed ARDS on the third day after BoNTA application to the spastic
gastrocnemius muscle group-who did not have any past BoNTA
interventions- and required intubation in the intensive care unit due to
this complication. Our main purpose is to warn BoNTA practitioners about
possible post-injection complications and to draw their attention to the
possibility of such an acute and dramatic pulmonary involvement. To our
knowledge, this is the first case reported in the literature to develop
an acute pulmonary complication after BoNTA injection into spastic lower
extremity muscles.