Clinical features of the urge-to-cough in patients with chronic cough.
Hilton E., Marsden P., Thurston A., Kennedy S., Decalmer S., Smith JA.
BACKGROUND: The urge-to-cough is a consciously perceived compulsion, previously investigated in healthy volunteers inhaling irritants. We aimed to characterise the urge-to-cough and associated sensations in a group of chronic cough patients attending a specialist clinic. METHODS: 100 patients with chronic cough [mean age 60 yrs (±11.89), 71 female, median cough duration 7 yrs (IQR 11.13) completed an investigator-led survey describing aggravating and relieving factors for urge-to-cough, associated somatic sensations (quality, location, intensity) and emotions. Subjects rated each using a 5-point Likert scale (strongly disagree to strongly agree) or visual analogue scale (VAS). Cluster analysis identified groups of patients with similar patterns of responses. RESULTS: Subjects rated the severity of urge-to-cough highly (84.5 mm on VAS). The majority always cough in response to the urge-to-cough (91%), but fewer (69%) always experienced an urge-to-cough before coughing. The somatic sensations associated with the urge-to-cough were described as an irritation (86%) or tickle (73%), localised in the neck (75%). The urge-to-cough was triggered by various stimuli including smoky atmospheres (79%), talking (72%), cold temperatures (67%) and dry atmospheres (66%) and relieved by coughing (63%), and drinking (61%); in 42% nothing provided relief. Cluster analysis suggested two distinct patient groups, differing in the factors precipitating the urge-to-cough rather than quality or location of associated sensations. CONCLUSION: The unifying characteristics of patients with chronic cough are a severe urge-to-cough associated with throat irritation, consistent with sensory neuronal dysfunction of vagal afferents. Precipitants of the urge-to-cough vary though, and can be used to classify sub-groups of patients who may share similar underlying pathophysiology.