Does botulinum toxin alter laryngeal secretions and mucociliary transport?

Localized botulinum toxin injection disrupts cholinergic transmission and has potential to cause focal dysautonomia. Mucociliary transport and laryngeal secretions are thought to be mediated in part by autonomic, cholinergic transmission. We questioned whether patients who receive Botox injection for adductor spasmodic dysphonia (ADSD) report postinjection symptoms possibly related to altered mucociliary clearance or laryngeal secretions. Medical histories, audiotaped interviews, and symptom ratings were retrospectively examined for 29 patients with ADSD who were followed after one or more Botox injections. Patients had received bilateral, percutaneous Botox injections of 2.5 units using an EMG-guided approach. One or more weeks after injection, four patients reported either burning, tickling, or irritation of the larynx/throat, excessive thick secretions, or dryness. Symptoms recurred with subsequent injections in two patients and were not associated with swallowing difficulty. These symptoms are consistent with, but not diagnostic of, the known effects of botulinum toxin on cholinergic, autonomic transmission.