Cough

Introduction

Cough is the explosive expiration that clears the tracheo-bronchial tree of secretions and foreign particles or noxious gaseous materials.
It is a defensive reflex reaction.
It comes to medical attention only when it becomes troublesome, affects life style and/or when there is concern about its cause.

Clinical features

Cough may be:

  • Acute or chronic
  • Seasonal
  • Associated with breathlessness and or wheezing
  • Productive of sputum: note colour,
    smell; haemoptysis
  • Associated with fever
  • Associated with chest pain: note location and character of pain
  • Associated with risk factors, e.g. cigarette smoking
  • Associated with the use of drugs for other illnesses
  • Associated with other constitutional symptoms

Differential diagnoses

Triggers of cough may rise from the upper or lower airways, or lung parenchyma
Upper airways:

  • Inhaled irritants: dust, fumes, smoke
  • Upper airways secretion
  • Gastric reflux

Lower airways:

  • Inflammation
  • Viral bronchitis
  • Bronchiectaesis
  • Bacterial infection
  • Bronchial asthma
  • Endobronchial tuberculosis
  • Bronchial infiltration/compression
  • Parenchymallung disease
  • Pneumonia
  • Lung abscess
  • Interstitial or endobronchial oedema due to heart disease
  • Drugs:
    • ACE inhibitors

Investigations

  • Macroscopic and microscopic examination of sputum
  • Sputum culture
  • Exclude tuberculosis if cough is chronic
  • Sputum cytology for malignant cells
  • Chest radiograph where indicated
  • HIV screen if history and clinical features are suggestive

Treatment objectives

  • Identify and treat the underlying cause(s)
  • Abolish cough

Non-drug measures

  • Adequate rehydration to prevent inspissation
  • Encourage expectoration forbproductivebcough
  • Do not use antitussives unless cough is dry, unproductive and distressing

Drug treatment

  • Appropriate antibiotics for bacterial infections
  • Identify causative/precipitating factors and treated accordingly e.g. CCF, asthma; allergies

Cough suppressants:

  • for dry, unproductive cough
    • Codeine cough linctus: Adult: 5-10 mL 3-4 times daily
    • Dextromethorphan (if codeine is contraindicated) 30 mg tds

Codeine is not recommended in children 

Notable adverse drug reactions, caution

  • Codeine cough linctus: sedation, constipation