What is the differential diagnosis for a patient presenting with cough and a history of hypertension or cardiovascular disease?

Differential Diagnosis for Cough in Patients with Hypertension or Cardiovascular Disease

In patients with hypertension or cardiovascular disease presenting with cough, ACE inhibitor-induced cough must be ruled out first by stopping the medication, followed by systematic evaluation for upper airway cough syndrome, asthma, gastroesophageal reflux disease, and cardiac causes specific to this population. 1

Immediate Priority: ACE Inhibitor Assessment

• Stop ACE inhibitor therapy immediately regardless of temporal relationship between drug initiation and cough onset, as the original cause of cough may have resolved and the persisting cough could be drug-related 1
• Cough resolution typically occurs within a few days to 2 weeks after discontinuation, though the median time is 26 days 1, 2
• ACE inhibitor-induced cough accounts for only 37% of cough cases in patients taking these medications, while 63% of cough cases on ACE inhibitors are attributable to other causes, particularly in heart failure patients where only 29% is truly drug-related 3
• The incidence requiring discontinuation is 4% in hypertensive patients but rises to 18% in congestive heart failure patients 4

Cardiovascular-Specific Causes

• Evaluate for pulmonary edema from cardiac failure, especially in patients aged >65 years with orthopnea, displaced apex beat, or history of myocardial infarction 1, 5
• Beta-adrenergic blocking medications can exacerbate asthma and cause bronchospasm with cough in this population 1
• Aspirin and NSAIDs used for cardiovascular disease can cause bronchospasm with or without cough 1

Common Causes by Cough Duration

Acute Cough (<3 weeks)

• Assess vital signs immediately: fever ≥38°C, heart rate ≥100 bpm, or respiratory rate ≥24 breaths/min suggest pneumonia 2, 5
• Perform focused lung examination for asymmetrical sounds, focal consolidation, rales, egophony, or fremitus 2
• Obtain chest radiography if vital sign abnormalities present, asymmetrical lung sounds detected, or patient appears ill 2
• Common cold with postnasal drip is the most frequent cause in otherwise healthy patients 5

Subacute Cough (3-8 weeks)

• Suspect pertussis when cough lasts ≥2 weeks with paroxysms, post-tussive vomiting, inspiratory whooping, or recent exposure 2
• Obtain nasopharyngeal aspirate for culture and paired sera for fourfold increase in IgG or IgA antibodies to pertussis toxin 2
• Initiate macrolide antibiotic within first few weeks if pertussis confirmed 2
• Postinfectious cough following obvious respiratory infection with no vital sign abnormalities is common, caused by postviral airway inflammation, upper airway cough syndrome, cough-variant asthma, or nonasthmatic eosinophilic bronchitis 2

Chronic Cough (>8 weeks)

• Focus diagnostic approach on upper airway cough syndrome (formerly postnasal drip), asthma, nonasthmatic eosinophilic bronchitis, and GERD—alone or in combination 1
• These four conditions account for the vast majority of chronic cough in nonsmokers with normal chest radiographs not taking ACE inhibitors 1
• Each diagnosis must be considered even when "silent" (no other associated clinical findings besides cough) 1
• Cough characteristics (timing, character, sputum production) lack diagnostic sensitivity and specificity and should not be used to rule in or rule out diagnoses 1

Systematic Evaluation Algorithm

Step 1: Medical History

• Determine cough duration: acute (<3 weeks), subacute (3-8 weeks), or chronic (>8 weeks) 1
• Document all cardiovascular medications, particularly ACE inhibitors and beta-blockers 1
• Assess for systemic signs: fever, sweats, weight loss, hemoptysis 1
• Identify smoking status (chronic bronchitis if current smoker) 1

Step 2: Physical Examination and Initial Testing

• Obtain chest radiograph in all patients with chronic cough 1
• Check vital signs for fever, tachycardia, tachypnea 2, 5
• Perform lung auscultation for asymmetry, consolidation, wheezing 2

Step 3: If ACE Inhibitor Present

• Stop medication immediately 1, 2
• Reassess after 26 days (median resolution time) 1, 2

Step 4: If Normal Chest Radiograph and No ACE Inhibitor

• Treat empirically for upper airway cough syndrome with first-generation antihistamine/decongestant 1, 5
• Evaluate for asthma with spirometry and trial of inhaled corticosteroids/bronchodilators 1
• Consider GERD treatment with proton pump inhibitor and lifestyle modifications 1
• Maintain all partially effective treatments due to possibility of multiple simultaneous causes 1

Step 5: If Cough Persists After Common Causes Addressed

• Perform chest CT scan 1
• Consider bronchoscopic evaluation 1
• Evaluate for uncommon causes before diagnosing idiopathic cough 1

Critical Red Flags Requiring Immediate Investigation

• Obtain chest radiography immediately if: hemoptysis present, significant unintentional weight loss, voice changes, vital sign abnormalities, or asymmetrical lung sounds 2
• Suspect tuberculosis in patients from high TB prevalence areas with systemic symptoms or cough >3 weeks; obtain chest radiograph and sputum smears/cultures for acid-fast bacilli 1, 2
• Consider foreign body aspiration with abrupt onset of cough 1
• Evaluate for endemic fungal or parasitic infections when common causes ruled out in patients from endemic areas 1

Common Pitfalls to Avoid

• Do not assume all cough in patients on ACE inhibitors is drug-induced—63% have other causes, especially in heart failure 3
• Do not rely on cough characteristics alone for diagnosis 1
• Do not diagnose idiopathic cough until thorough evaluation completed and uncommon causes excluded 1
• Do not forget that multiple conditions can coexist simultaneously—maintain all partially effective treatments 1
• Do not overlook cardiac causes in elderly patients with cardiovascular disease 1, 5