What is the best course of action for a patient with a dry cough and exhaustion for weeks, potentially with a history of asthma or chronic obstructive pulmonary disease (COPD)?

Evaluation and Management of Dry Cough with Exhaustion for Weeks

In a patient with dry cough and exhaustion lasting weeks, asthma (including cough-variant asthma) should always be considered as a primary etiology and empiric treatment with inhaled bronchodilators and inhaled corticosteroids should be initiated, particularly if the patient has a history of asthma or COPD. 1

Initial Diagnostic Approach

Key History Elements to Obtain

• Duration and character of cough: Assess whether the cough is paroxysmal, strictly dry, or has any sputum production, and whether it has lasted beyond 8 weeks (defining chronic cough) 2, 3, 4
• Diurnal variation: Determine if cough worsens at night, morning, or after meals, as nocturnal cough suggests asthma or gastroesophageal reflux disease 2
• Associated symptoms: Specifically inquire about wheezing, chest tightness, shortness of breath with exertion, and post-nasal drip 2, 1
• Medication history: Critical to exclude ACE inhibitor use, which causes cough in up to 16% of patients and resolves only with drug cessation (median resolution time 26 days) 5, 1
• Environmental triggers: Ask about exposure to cold air, exercise, pollutants, allergens, and occupational exposures 2, 1

Red Flag Symptoms Requiring Urgent Evaluation

• Hemoptysis (coughing up blood) 2
• Unintentional weight loss or night sweats (suggesting tuberculosis or malignancy) 2, 1
• Recurrent pneumonia 2
• Digital clubbing on examination 2
• Hoarseness persisting with cough 2

Algorithmic Management Strategy

Step 1: Rule Out Common Reversible Causes

If patient is on an ACE inhibitor, discontinue it immediately and switch to an alternative antihypertensive class (such as angiotensin II receptor blocker). Cough may take up to 26 days to resolve, though occasionally up to 40 weeks. 1, 4

Step 2: Evaluate for Asthma/Cough-Variant Asthma (CVA)

Physical examination and spirometry may be entirely normal in CVA, making this a diagnostic challenge. 1

Diagnostic Testing

• Perform spirometry first: If reversible airflow obstruction is demonstrated, empiric asthma therapy is appropriate 1
• If spirometry is normal but asthma suspected: Methacholine inhalation challenge (MIC) testing should be performed to document bronchial hyperresponsiveness 1
• Important caveat: A positive MIC is consistent with but not diagnostic of CVA; definitive diagnosis requires documented resolution of cough with asthma treatment 1
• A negative MIC essentially excludes asthma from the differential diagnosis given its very high negative predictive power 1

Empiric Treatment for Asthma

Initiate standard antiasthmatic regimen with inhaled bronchodilators (such as albuterol) and inhaled corticosteroids. 1

• Partial improvement often occurs after 1 week of inhaled bronchodilator therapy 1
• Complete resolution of cough may require up to 8 weeks of treatment with inhaled corticosteroids 1
• For severe or partially responsive cough, consider oral prednisone 40 mg daily for 1 week, alone or followed by inhaled therapy 1
• Leukotriene receptor antagonists appear particularly effective for asthmatic cough and may be added before escalating to systemic corticosteroids 1

Common Pitfall

Inhaled corticosteroids themselves may induce or exacerbate cough due to aerosol constituents. If cough worsens with inhaled steroids, consider switching formulations (e.g., from beclomethasone to triamcinolone) or evaluate for improper inhaler technique before escalating therapy. 1

Step 3: Consider Post-Viral Cough

Post-viral cough typically presents as persistent dry cough in a previously healthy person where all other URI symptoms resolved weeks earlier. 1

• These patients may have dyspnea, wheezing, reversible airflow obstruction on spirometry, and positive MIC due to transient viral-induced bronchial hyperresponsiveness 1
• This is not asthma but may respond to similar bronchodilator therapy 1

Step 4: Evaluate for Upper Airway Cough Syndrome (UACS)

If asthma evaluation is negative, empiric therapy for UACS with a first-generation antihistamine/decongestant preparation should be prescribed. 1

• Chronic sinusitis may be clinically silent with a relatively nonproductive cough and no typical acute sinusitis findings 1
• If no response to empiric antihistamine/decongestant therapy, sinus imaging should be obtained 1

Step 5: Consider Gastroesophageal Reflux Disease (GERD)

If patient has frequent heartburn or regurgitation, empiric treatment for GERD should be initiated. 1, 3, 4

Step 6: Chest Radiography

Obtain chest X-ray to rule out infectious, inflammatory, and malignant thoracic conditions, particularly if red flag symptoms are present or empiric treatments fail. 3, 4, 6

Management of Exhaustion/Fatigue

The exhaustion likely relates to:

• Sleep disruption from nocturnal cough (common in asthma and GERD) 2
• Increased work of breathing if underlying airway disease is present 2
• Systemic inflammation if chronic respiratory condition is untreated 7

Treating the underlying cause of cough should improve the exhaustion. For nocturnal cough specifically, first-generation sedating antihistamines may provide dual benefit of cough suppression and improved sleep, but only if patient doesn't need to operate machinery. 5

Symptomatic Cough Management

While addressing underlying causes:

• Simple home remedies like honey and lemon mixtures are effective for benign viral cough and should be tried first 5, 8
• If antitussive needed, dextromethorphan 60 mg provides maximum cough reflex suppression (standard OTC doses of 15-30 mg are subtherapeutic) 5, 8
• Avoid codeine or pholcodine: no greater efficacy than dextromethorphan but significantly more adverse effects (drowsiness, nausea, constipation, physical dependence) 5, 8

When to Reassess or Refer

• If cough persists beyond 3 weeks despite initial management, reassessment is mandatory 5, 8
• Cough lasting more than 8 weeks is chronic and requires systematic evaluation for the common triad: upper airway cough syndrome, asthma, and GERD 3, 4, 6
• Consider referral to pulmonologist if diagnosis remains unclear after empiric trials or if advanced testing (high-resolution CT, bronchoscopy) is needed 4, 6

Special Consideration for COPD History

If patient has known COPD, this presentation may represent an acute exacerbation rather than a new problem. 8

• Cough is the most common symptom associated with COPD exacerbations 8
• Adjust chronic disease medications appropriately rather than treating as simple acute bronchitis 8
• Consider chest radiography and spirometry to assess disease progression 8