The role of the larynx in chronic cough.

Cough lasting more than 8 weeks is considered chronic. If the classic causes of chronic cough have been discarded, vagus nerve sensory disturbances are currently considered the most important etiological cause. Patients with chronic cough of laryngeal origin have associated symptoms such as globus, dysphagia, dysphonia, dyspnoea and/or stridor. These patients are more likely to have paradoxical vocal fold movement. There is a higher cough reflex sensibility and neuropathic laryngeal response, mainly caused by viral infection or reflux. The cough associated with reflux has 2 mechanisms: Exposure to acid in the distal oesophagus (gastroesophageal reflux) and microaspiration of oesophageal contents into the larynx and tracheo-bronchial tree (pharyngo-laryngeal reflux). Laryngeal neuropathy hypersensitivity responds well to speech therapy as a treatment for refractory chronic cough. Because chronic cough is a sign of laryngeal sensory, neuropathy can improve with neuroleptic drugs such as amitriptyline and gabapentin.