What are the possible diagnosis and next steps for a 74-year-old male (M) with a 1-week history of cough, recent endoscopy due to cholecystitis (inflammation of the gallbladder) with jaundice, 25 pack-year smoking history, partial thyroidectomy (surgical removal of part of the thyroid gland) in the early 2000s, and current symptoms of dry cough, nocturnal (night-time) cough, and snoring noise with vibration on the lungs and chest wall, more predominant on the right anterior lungs?

Differential Diagnosis and Management of Post-Procedural Cough in a High-Risk Patient

This 74-year-old male with significant smoking history (25 pack-years) and new-onset cough following endoscopy requires urgent chest imaging with CT scan to exclude malignancy, aspiration complications, and structural airway abnormalities, given the concerning physical examination findings of inspiratory snoring with palpable chest wall vibration.

Most Likely Diagnoses (in order of priority)

1. Aspiration-Related Complications from Endoscopy

• The temporal relationship between endoscopy and cough onset is highly suspicious for procedure-related aspiration 1
• GERD-related aspiration can cause hemorrhagic tracheobronchitis, subglottic stenosis, and erythema of subsegmental bronchi visible on bronchoscopy 1
• The inspiratory snoring noise with palpable vibration suggests large airway involvement or partial obstruction 1
• Aspiration syndromes associated with GERD include chemical pneumonitis, bacterial pneumonia, diffuse aspiration bronchiolitis, and tracheobronchitis 1

2. Occult Lung Malignancy (High Priority Given Risk Factors)

• 25 pack-year smoking history places him at elevated lung cancer risk 1
• Cough is present in 57% of lung cancer patients, and malignancy was diagnosed in 1-2% of chronic cough case series 1
• Normal chest X-ray does NOT exclude malignancy: in retrospective analysis, 2 of 266 patients with chronic cough and normal chest radiographs had malignancy 1
• Chest radiography has low sensitivity (69-71%) compared to CT for detecting airway lesions 1

3. Large Airway Disorder (Tracheobronchomalacia or Stenosis)

• The inspiratory snoring with palpable vibration is a red flag for large airway pathology 1
• Flow-volume curves and direct bronchoscopy are more helpful than imaging for detecting large airway disorders 1
• Uncommon causes including tracheobronchomalacia, airway stenosis, and tracheobronchial masses should be considered when common causes are excluded 1

4. Post-Infectious/Post-Viral Cough

• Household contacts had recent upper respiratory infections 2
• However, the abnormal physical examination findings (inspiratory snoring with vibration) make simple post-viral cough unlikely 2
• Post-viral cough typically presents with clear lung examination and normal vital signs 2

5. Thyroid-Related Airway Compression

• History of partial thyroidectomy in early 2000s raises possibility of thyroid goiter or recurrent thyroid pathology causing airway compression 1
• Thyroid disorders are listed as uncommon causes of chronic cough when they cause airway compression 1

Immediate Next Steps (Algorithmic Approach)

Step 1: Urgent Chest CT (NOT just chest X-ray)

• CT chest is mandatory given: (1) 25 pack-year smoking history, (2) abnormal lung examination with inspiratory snoring/vibration, (3) recent instrumentation with aspiration risk 1
• Chest radiography has inadequate sensitivity (64% negative predictive value) for excluding relevant pathology in chronic cough 1
• CT is superior for detecting bronchiectasis, bronchial wall thickening, mediastinal masses, early malignancy, and aspiration-related changes 1

Step 2: Pulmonary Function Tests with Flow-Volume Loops

• Flow-volume curves are essential for detecting large airway disorders that may not show on imaging 1
• The inspiratory snoring with palpable vibration suggests possible variable extrathoracic obstruction (flattening of inspiratory loop) or fixed obstruction (flattening of both loops) 1, 3

Step 3: Direct Laryngoscopy and Flexible Bronchoscopy

• Indicated if CT shows concerning findings OR if flow-volume loops suggest large airway pathology 1
• Can visualize aspiration-related changes (hemorrhagic tracheobronchitis, erythema, subglottic stenosis) 1
• Can assess for airway stenosis, tracheobronchomalacia, masses, or foreign bodies 1
• Can evaluate vocal cord function and laryngeal pathology 1

Step 4: Neck CT or Ultrasound

• Assess thyroid bed for recurrent goiter or mass effect on trachea given history of partial thyroidectomy 1

Red Flags Present in This Case

• Abnormal lung examination: inspiratory snoring with palpable chest wall vibration is NOT consistent with simple post-viral cough 1, 2
• Significant smoking history (25 pack-years) elevates lung cancer risk 1
• Recent instrumentation (endoscopy) with temporal relationship to cough onset suggests aspiration 1
• Age 74 years increases malignancy risk 1

What NOT to Do (Common Pitfalls)

• Do NOT rely on chest X-ray alone in this high-risk patient with abnormal examination 1
• Do NOT assume post-viral cough when physical examination is abnormal (inspiratory snoring/vibration is NOT normal) 2
• Do NOT empirically treat for GERD, asthma, or upper airway cough syndrome without first excluding structural/malignant pathology given red flags 1, 4
• Do NOT delay imaging while attempting therapeutic trials in a patient with this risk profile 1

If Initial Workup (CT, PFTs, Bronchoscopy) is Normal

Only then consider common causes of chronic cough in systematic fashion:

• Upper airway cough syndrome (postnasal drip): trial of first-generation antihistamine plus decongestant 4, 5
• Asthma/cough-variant asthma: bronchoprovocation testing if baseline PFTs normal, trial of inhaled bronchodilators/corticosteroids 4, 5
• GERD: 24-hour esophageal pH monitoring or empiric trial of intensive acid suppression (may take 2-3 months to see improvement) 1, 6

The abnormal physical examination findings in this case mandate structural evaluation before empiric treatment trials.