Undesirable distant effects following botulinum toxin type a injection.
OBJECTIVE
To study the incidence of clinical signs linked to botulinum toxin type A (BoNTA) spread from the injection site.


METHODS
Single-center, retrospective, cohort study. All patients who received BoNTA injections for spasticity treatment were assessed 1 month postinjection. Adverse effects indicative of BoNTA treatment were systematically sought. Any patient with adverse effects possibly due to BoNTA spread underwent further clinical examination and single-fiber electromyography. One patient underwent neuromuscular biopsy.


RESULTS
Between January and September 2005, 266 BoNTA injection sessions (187 patients) were performed (233 BOTOX, 33 Dysport). Five patients presented with clinical signs of toxin spread. Four of these underwent single-fiber electromyography, which showed increased jitter. Neuromuscular biopsy detected signs of recent denervation without signs of reinnervation.


CONCLUSIONS
Diffusion diagnosis of BoNTA from the injection site depends on clinical, temporal, and electromyographic factors. Clinical expression of spread varies widely, with mechanisms remaining largely unknown, and further prospective, randomized clinical trials are required.
Roche
Nicolas
N
Service de Physiologie d'Explorations Fonctionnelles, Faculty of Medicine Paris Ile-de-France Ouest, University of Versailles-Saint Quentin, Garches, France. roche.nicolas@rpc.aphp.fr
Schnitzler
Alexis
A
Genêt F
François
F
Durand
Marie-Christine
MC
Bensmail
Djamel
D
D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000009:adverse effects*; D015331:Cohort Studies; D004576:Electromyography / Q000379:methods; D005221:Fatigue / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009128:Muscle Spasticity / Q000188:drug therapy / Q000503:physiopathology; D018908:Muscle Weakness / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology; D012189:Retrospective Studies
D019274:Botulinum Toxins, Type A