What are the top differential diagnoses for a 54-year-old female with chronic bronchitis presenting with worsening dyspnea, palpitations, sharp chest pain, and dizziness?

Top Four Differential Diagnoses for JN's Presentation

Based on JN's presentation of palpitations, tachycardia with irregular rhythm, sharp pleuritic chest pain, and dyspnea, the four most critical rule-outs are: (1) Arrhythmia, (2) Pulmonary Embolism, (3) Myocardial Infarction, and (4) Exacerbation of Chronic Bronchitis.

1. Arrhythmia (Most Likely Based on Physical Findings)

The tachycardia (HR 112) with slightly irregular rhythm on examination, combined with palpitations and "fluttering" sensation, makes arrhythmia the most probable diagnosis. 1

• The American College of Cardiology guidelines identify palpitations, dyspnea, and dizziness as common symptoms associated with cardiac arrhythmias 1
• Her age (54 years) and female sex place her at risk for new-onset atrial fibrillation, which commonly presents with irregular tachycardia and palpitations 2
• The symptom relief with breath-holding (vagal maneuver) is characteristic of certain supraventricular arrhythmias 1
• Critical pitfall: Do not dismiss irregular rhythm as anxiety-related without obtaining an ECG, as atrial fibrillation can lead to stroke and hemodynamic compromise 1

2. Pulmonary Embolism (Most Dangerous to Miss)

PE must be ruled out urgently as it can be rapidly fatal and often masquerades as other cardiopulmonary conditions. 3

• The American College of Chest Physicians warns that PE can present with dyspnea, chest pain, tachycardia, and palpitations—all present in this patient 3
• Sharp chest pain that worsens with coughing is consistent with pleuritic pain from PE 1, 4
• Tachycardia and dyspnea occurring together without fever or increased sputum production are concerning features for PE rather than bronchitis exacerbation 3
• Her history of two prior pneumonias and chronic lung disease may predispose to immobility or hypercoagulability 3
• Normal oxygen saturation (98%) does NOT exclude PE, as many patients with PE maintain normal saturations 2

3. Myocardial Infarction (Cannot Be Missed in This Age Group)

The American College of Cardiology mandates that acute coronary syndrome must always be considered in patients over 50 presenting with chest pain and dyspnea. 3

• Women frequently present atypically with dyspnea as the primary symptom of MI rather than classic chest pressure 3
• Her elevated blood pressure (138/72) suggests possible underlying hypertension, a major cardiac risk factor 3
• Dizziness with chest pain can indicate hemodynamic compromise from cardiac ischemia 1
• The tachycardia may represent compensatory response to decreased cardiac output 1
• Critical action: Serial ECGs and cardiac biomarkers are mandatory even with normal initial findings when clinical suspicion exists 1

4. Exacerbation of Chronic Bronchitis (Less Likely but Must Consider)

While chronic bronchitis exacerbation is part of the differential, the clinical features argue AGAINST this diagnosis. 1, 3

• The American College of Chest Physicians defines exacerbation as sudden deterioration with increased cough, sputum production, sputum purulence, and/or dyspnea, often preceded by upper respiratory infection 1
• However, JN has minimal sputum production and her last flare was two months ago, making acute exacerbation unlikely 1, 3
• The absence of fever, increased sputum, or purulent sputum further argues against infectious exacerbation 1, 5, 6
• The pleuritic nature of her chest pain and palpitations are NOT typical features of uncomplicated bronchitis exacerbation 1, 3
• Important distinction: The ACCP guidelines state that absence of cardinal exacerbation features makes alternative diagnoses like PE relatively more likely 3

Why NOT the Other Options

Asthma (Excluded)

• While her sister has asthma, JN has clear lung fields bilaterally with normal oxygen saturation 7
• No wheezing, no response pattern typical of bronchospasm 7
• The irregular cardiac rhythm and palpitations are not explained by asthma 7

Pneumonia (Excluded)

• Temperature is normal (37°C), and lung fields are clear to auscultation 1
• The ACCP guidelines state that absence of fever, tachycardia >100, respiratory rate >24, and clear lung fields with oxygen saturation ≥98% makes pneumonia unlikely 3
• No productive cough or constitutional symptoms 1

Emphysema (Not Acute)

• Emphysema is a chronic structural diagnosis, not an acute presentation 1, 8
• Would not explain the acute palpitations, irregular rhythm, or pleuritic chest pain 8

Immediate Diagnostic Approach

The following tests must be performed urgently:

• ECG immediately to identify arrhythmia, ischemic changes, or signs of right heart strain from PE 1
• Cardiac biomarkers (troponin) to rule out MI 1
• D-dimer if PE probability is low-to-intermediate; CT pulmonary angiography if high probability or positive D-dimer 3, 2
• Chest radiograph to evaluate for alternative diagnoses, though normal CXR does not exclude PE 1