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