cough

Introduction

see chronic cough if > 2 months duration

Etiology

• generally a reflex response to stimuli that irritate the larynx, trachea or large bronchi
  • external stimuli* including asthma
    • dust
    • foreign body
    • hot or cold air
    • smoke
  • internal stimuli
    • inflammation of the respiratory mucosa
      • bronchitis (acute bronchitis, chronic bronchitis)
      • pneumonia
      • upper respiratory tract infection
    • compression of the airway
      • tumor
      • enlarged peribronchial lymph node
    • post-nasal drip*
    • gastroesophageal reflux disease*
• left-sided heart failure
• pharmacologic agents:
  • ACE inhibitors*
  • inhaled drugs
  • mycophenolate
  • propofol
  • aspirin, NSAIDs
  • beta-blockers
  • antibiotics
    • amphotericin B
    • erythromycin
    • sulfonamides
    • aminoglyocosides
  • chemotherapeutic agents
• respiratory tract infection
  • pertussis (coughing spasms)
• elderly
  • oropharyngeal dysphagia with meal-time cough in elderly may be due to stroke
  • pocketing of food in severe dementia
• cough may be intentional action to illicit a vagal maneuver

* common causes of chronic cough

Epidemiology

• most common complaint in outpatient medicine

Pathology

• afferent arm of cough reflex
  • trigeminal nerve
  • glossopharyngeal nerve
  • superior laryngeal nerve
  • vagus nerve
• efferent arm of cough reflex
  • recurrent laryngeal nerve
  • spinal nerves
• lesions in the nose, ears, pharynx, larynx, bronchi, lungs, pleura & abdominal viscera may cause cough

History

• duration, rate of onset, fever/chills, sputum (quality), dyspnea, pleuritic chest pain, orthopnea, sore throat, rhinorrhea, headache, stiff neck, ear pain, nausea/vomiting, diarrhea, arthralgia, myalgia, smoking, recent antibiotics, exposure to tuberculosis or asbestos, travel, ill contacts, pneumococcal & influenza vaccination

Clinical manifestations

• cough due to upper respiratory tract infection may persist from weeks to several months
  • generally resolves within 10 days in 50% of children & within 25 days in 90%
• persistent severe, paroxysmal coughing suggests pertussis
• cough with exposure to cold air suggests asthma
• see chronic cough for cough > 2 months duration

Laboratory

• sputum examination for eosinophilia
• Bordetella pertussis antigen in body fluid (if indicated)

Diagnostic procedures

• provocation inhalation testing with methacholine for suspected asthma
• see chronic cough for cough > 2 months duration

Radiology

• chest X-ray
  • generally of low yield
  • indications:
    • fever, constitutional symptoms,
    • abnormal physical examination
    • altered mental status

Complications

• cough syncope
  • increased intrathoracic pressure
  • decreased cardiac output & cerebral perfusion
• rib fractures
• pneumothorax

• disease interaction(s) of cough with stress urinary incontinence

Management

• antihistamine (1st generation)/decongestants, i.e. (brompheniramine/pseudoephedrine) 1st line agent for cough due to common cold
  • may be useful for cough due to post-nasal drip
• intranasal glucocorticoids for cough due to allergic rhinitis & post-nasal drip (upper airway cough syndrome)
• opiates (i.e. codeine) have proven antitussive effects
  • codeine not recommended for children with cough due to upper respiratory tract infection
• inhaled ipratropium for cough with wheezing that persists > 1 week after upper respiratory tract infection
• inhaled glucocorticoids if ipratropium fails
• dextromethorphan has mild antitussive effects (avoid coadministration with SSRI)
• sugar, honey, cough drops can relieve cough by increasing saliva which coats the larynx & relieves irritation
• haloperidol is an effective antitussive agent
• cough due to GERD may respond to omeprazole
• NSAIDs may be useful by reducing inflammation
• little evidence that other agents have antitussive effects
  • guaifenesin, terpin hypdrate, benzonatate, cough drops
• placebo before bedtime of benefit in treatment of cough, congestion, & rhinorrhea due to common cold in children
• treatment of asthma
• antibiotics
  • not recommended without a clear bacterial cause
  • azithromycin if pertussis suspected
    • persistent severe, paroxysmal coughing suggests pertussis
• unexplained chronic cough
  • speech therapy may be benefit
  • antitussives may be of benefit
  • gabapentin may be effective

More general terms

• sign/symptom

More specific terms

• chronic cough
• coughing spasm; paroxysmal coughing
• postinfectious cough