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Chronic Cough

Basics

  • Defined as cough >8 weeks in adults; >4 weeks in children.
  • Subacute cough: 3 to 8 weeks duration.
  • Common reasons for medical attention include fear of serious illness, annoyance, and hoarseness.
  • Affects gastrointestinal and pulmonary systems.

Epidemiology

  • Occurs in all age groups.
  • Equal male/female prevalence, but females more likely to seek care.
  • Up to 10% of patients have persistent unexplained cough; chronic cough common in primary care.

Etiology & Pathophysiology

  • Often multifactorial; bronchial irritation predominant.
  • Frequent causes (>90% in nonsmokers):
  • Upper airway cough syndrome (UACS), including allergic and vasomotor rhinitis
  • Postnasal drip
  • Postviral cough
  • Asthma
  • Gastroesophageal reflux disease (GERD)
  • Other causes:
  • ACE inhibitors
  • Smoking, smoke exposure, pollutants
  • Aspiration
  • Bronchiectasis, infections (pertussis, tuberculosis)
  • Nonasthmatic eosinophilic bronchitis (NAEB)
  • Cystic fibrosis
  • Sleep apnea
  • Restrictive lung disease
  • Neoplasms (bronchogenic, laryngeal)
  • Psychogenic (habit cough)
  • Cough hypersensitivity syndrome: cough with characteristic triggers not explained by other conditions.
  • Pediatric causes differ: asthma, protracted bacterial bronchitis, UACS.

Risk Factors

  • Smoking and pulmonary diseases are major contributors.

Associated Conditions

  • Chronic cough may be sole symptom in UACS, asthma, GERD.

Diagnosis

History

  • Assess age, symptoms, medical and medication history (esp. ACE inhibitors), exposures, aspiration risk, smoking.
  • Cough character or sputum quality usually not predictive.
  • Cough diaries have limited diagnostic value.
  • Hemoptysis or systemic illness signs warrant further evaluation.

Physical Exam

  • Usually nonproductive cough without other signs.
  • Look for signs of UACS, sinusitis, GERD, heart failure, stress.
  • Absence of additional signs does not exclude diagnosis.

Diagnostic Tests

  • Initial empiric therapy plus chest X-ray (CXR).
  • Extensive testing guided by history and physical.
  • Children with persistent cough unresponsive to Ξ²-agonists may need spirometry and foreign body evaluation.
  • Further testing as indicated:
  • Spirometry for COPD, asthma, restrictive lung disease.
  • Sweat chloride for cystic fibrosis.
  • Sputum eosinophils/cytology for hypereosinophilia, TB, malignancy.
  • Chest CT if abnormal CXR or suspicion of pulmonary disease.
  • Pulmonary consult or specialist cough clinic.
  • GI consult and endoscopy if reflux suspected.
  • Diagnostic procedures may include:
  • Pulmonary function tests, PPD, allergen testing.
  • 24-hour esophageal pH monitoring.
  • Bronchoscopy (if hemoptysis or normal CXR with risk factors).
  • Sinus CT.
  • Ambulatory cough monitoring.
  • Echocardiography.

Treatment

General Measures

  • Empiric treatment directed at common causes (UACS, asthma, GERD).
  • Nasal steroids and/or antihistamines for allergic symptoms/postnasal drip.
  • GERD therapy if typical symptoms present.
  • Nonsedating antihistamines not effective for common cold-related cough.
  • Smoking cessation resolves many cases.
  • Switch ACE inhibitors if cough intolerable; resolution may take weeks.
  • Avoid empiric PPIs without GERD diagnosis.
  • Speech therapy may improve cough severity in some adults.
  • Treat likely cause maximally for several weeks before investigating other etiologies.

Medications

  • Directed by underlying cause: nasal steroids, antihistamines, antacids, bronchodilators, inhaled corticosteroids, PPIs, antibiotics.
  • Trial of PPI may be considered if GERD suspected.
  • OTC cough/cold meds not recommended in children <2 years; contraindication for codeine in <12 years.
  • Leukotriene receptor antagonists lack evidence for chronic cough in children.
  • First-line: nasal steroids (e.g., fluticasone, budesonide).
  • Second-line: benzonatate (age >10 years), gabapentin for refractory cough (risk-benefit at 6 months).
  • Limited evidence supports opioids or nonanesthetic antitussives.

Referral

  • Pulmonology, gastroenterology, ENT, allergy specialists.
  • Specialist cough clinic.

Surgery/Procedures

  • Fundoplication may help refractory GERD-related cough.

Ongoing Care

  • Consider stepwise withdrawal of medications post-cough resolution.
  • Frequent follow-up to monitor treatment efficacy.

Diet

  • GERD patients may benefit from avoiding ethanol, caffeine, nicotine, citrus, tomatoes, chocolate, fatty foods.

Patient Education

  • Reassure most chronic coughs are not life-threatening.
  • Treatment may take weeks to months.
  • Prepare for multiple diagnostic and therapeutic trials due to empirical nature.

Prognosis

  • 80% diagnosed and treated effectively with systematic approach.

  • Resolution depends on successful treatment of underlying cause.

Complications

  • Cardiovascular: arrhythmias, syncope.
  • Stress urinary incontinence.
  • Abdominal/intercostal muscle strain.
  • GI: emesis, hemorrhage, herniation.
  • Neurologic: dizziness, headache, seizures.
  • Respiratory: pneumothorax, airway trauma.
  • Skin: petechiae, purpura, wound disruption.
  • Medication side effects.
  • Negative impact on quality of life.

Clinical Pearls: - Chronic cough persists >8 weeks in adults. - Common causes include smoking, asthma, UACS, GERD. - OTC cough meds contraindicated in young children; codeine contraindicated <12 years.