Ptosis as a remote effect of therapeutic botulinum toxin B injection

The authors report a patient with cervical dystonia, previously treated with botulinum toxin A (BTX-A), who developed bilateral ptosis and difficulty with accommodation only after botulinum toxin B (BTX-B). High-frequency repetitive nerve stimulation of the abductor digiti minimi demonstrated a 34% increment in compound muscle action potential. No increment in 20 people injected with BTX-A and no cases of ptosis in a chart review of 1,606 BTX-A injections for cervical dystonia were found. The authors conclude that systemic spread of BTX-B can cause symptomatic involvement of autonomic neurons.