Mechanism - Voluntary or Psychogenic

Reflex Stimulation

• Cough receptors:
  • extrathoracic: nose, oropharynx, larynx, upper trachea
  • intrathoracic: rapidly adapting irritant receptors in epithelium of lower trachea and large central bronchi
  • other locations: tympanic membrane, diaphragm, stomach
• Afferent nerves: trigeminal, glossopharyngeal, superior laryngeal, vagus
• Efferent nerves: recurrent laryngeal nerves, vagus, corticospinal tract and peripheral nerves
• Reflex begins with deep inspiration, followed by glottic closure, diaphragmatic relaxation, and thoracic and abdominal expiratory muscle contraction. Posterior wall of airway invaginates and causes shearing of mucus.
• Positive pleural pressure generated up to 100-300 mm Hg; peak flows of 12 L/sec

Productive Cough

• "Normal" quantity unknown; usually cleared by mucociliary action alone
• Accumulate secretions because of:
  • excessive production
  • altered physical properties
  • deficient clearance

Nonproductive Cough: Irritative Phenomenon

• May be mechanical, chemical, thermal, or inflammatory
• Alteration of surface epithelium of major airways exposes irritant receptors which become sensitized and cause cough

Complications

• Provokes more coughing
• Paroxysms may stimulate vomiting
• Syncope/dizziness
• Utter exhaustion
• Rib fractures
• Muscle tears
• Vertebral compression fractures
• Pneumoperivarices
• Headache
• Rupture spleen
• Esophageal variceal bleeding
• Stress incontinence