Cough

This is a very non-specific symptom and can be described as a forced expulsive manoeuvre usually against a close glottis with an associated characteristic sound (1).

• it can be elicited from the larynx, trachea or bronchi
• helps out in clearing foreign objects and excessive secretions from the airways (1)
• contains
  • inspiratory phase (an inspiratory effort) followed by
  • compressive phase (forced expiratory effort against a closed glottis) followed by
  • expulsive phase (opening of the glottis and rapid expiratory airflow) (2)

Cough is triggered when mechanical or chemical irritants stimulate sensory cough-inducing receptors in the respiratory tract (1). Some common airway irritants include:

• inhaled irritants like smoke, dust, dandruff
• mucous
• infections
• allergens e.g. - animal allergens, pollen
• chemicals (1)

Cough can be categorised according the duration (1):

• acute – less than 3 weeks
• subacute – between 3 to 8 weeks
• chronic – for more than 8 weeks

Note that a persisting acute cough may develop into a subacute or chronic cough (3).

Reference:

• (1) Dicpinigaitis PV et al. Acute cough: a diagnostic and therapeutic challenge. Cough. 2009;5:11
• (2) Widdicombe J, Fontana G. Cough: what's in a name? Eur Respir J. 2006;28(1):10-5
• (3) Pratter MR, et al. An empiric integrative approach to the management of cough: ACCP evidence-based clinical practice guidelines. Chest. 2006;129(1 Suppl):222S-231S