What are the top differential diagnoses for a patient with chronic bronchitis presenting with worsening dyspnea, palpitations, sharp chest pain, and dizziness?

Top Four Differential Diagnoses

Based on this patient's presentation of palpitations, tachycardia with irregular rhythm, sharp pleuritic chest pain, and dizziness, the four most critical rule-outs are: (1) Arrhythmia, (2) Pulmonary embolus, (3) Myocardial infarction, and (4) Exacerbation of chronic bronchitis.

Primary Concern: Arrhythmia

The most immediately evident diagnosis is cardiac arrhythmia, given the documented tachycardia (HR 112), irregular rhythm on examination, palpitations with "fluttering" sensation, and associated dizziness. 1

• The combination of palpitations, dizziness, and irregular tachycardia strongly suggests a supraventricular arrhythmia, which can present with heart rates of 150-250 beats/min in paroxysmal forms, though this patient's rate is currently 112 1
• Her symptom relief with breath-holding (vagal maneuver) further supports an arrhythmic etiology, as vagal maneuvers can terminate certain supraventricular tachycardias 1
• Arrhythmias represent an immediate threat requiring ECG confirmation and potential cardioversion if unstable 1

Life-Threatening Consideration: Pulmonary Embolus

Pulmonary embolism must be ruled out as it can mimic acute exacerbation of chronic bronchitis and presents with dyspnea, chest pain, tachycardia, and can be rapidly fatal. 2

• The ACCP guidelines explicitly warn that pulmonary embolism can masquerade as chronic bronchitis exacerbation, making it a critical differential 2
• Her sharp, pleuritic chest pain (worse with coughing) is characteristic of PE 3
• Tachycardia and dyspnea without fever or sputum production are concerning for PE rather than infectious exacerbation 2
• The absence of typical exacerbation features (minimal sputum, last flare 2 months ago) makes PE relatively more likely 2

Cardiac Emergency: Myocardial Infarction

Myocardial infarction requires urgent exclusion given her age (54), chest pain, dyspnea, and cardiovascular risk factors (hypertension suggested by BP 138/72). 2

• Acute coronary syndrome must always be considered in patients over 50 presenting with chest pain and dyspnea, particularly with concurrent tachycardia 2
• The combination of chest pain, palpitations, and dizziness can represent cardiac ischemia 1
• Women may present atypically with dyspnea as a primary symptom of MI 2
• Her elevated blood pressure (138/72) suggests possible underlying hypertension, a risk factor for cardiac disease 2

Pulmonary Consideration: Exacerbation of Chronic Bronchitis

While less likely given the clinical picture, acute exacerbation of chronic bronchitis remains in the differential but ranks lower due to atypical features. 2

• ACCP guidelines define exacerbation as sudden deterioration with increased cough, sputum production, sputum purulence, and/or dyspnea, often preceded by upper respiratory infection symptoms 2
• This patient has minimal sputum production and her last exacerbation was 2 months ago, making active exacerbation less likely 2
• She lacks fever (temp 37°C), has clear lung fields bilaterally, and normal oxygen saturation (98%), all arguing against acute infectious exacerbation 2, 4
• However, exacerbations can present with dyspnea and chest discomfort, and other serious conditions (heart failure, PE) must be excluded before diagnosing exacerbation 2

Diagnoses NOT in Top Four

Pneumonia is excluded because she lacks the cardinal features: no fever (temp 37°C), heart rate <100, respiratory rate <24, clear lung fields on auscultation, and oxygen saturation 98% 2, 4. The ACCP guidelines state that absence of these findings eliminates the need for chest radiograph for pneumonia 2, 4.

Asthma is unlikely despite her sister's history, as she has no documented history of asthma, no wheezing on examination, normal oxygen saturation, and her symptoms don't fit the typical asthma exacerbation pattern 4, 5. While approximately 65% of recurrent "bronchitis" may be mild asthma, her presentation with palpitations and irregular rhythm points elsewhere 4.

Emphysema is not an acute diagnosis but rather a chronic structural condition; it would not explain her acute presentation with palpitations and irregular cardiac rhythm 2.

Critical Clinical Pitfall

The most dangerous error would be attributing her symptoms to anxiety or chronic bronchitis exacerbation without obtaining an ECG and ruling out life-threatening cardiac and thromboembolic causes. 2, 1 Her irregular tachycardia demands immediate electrocardiographic evaluation, and the constellation of dyspnea, chest pain, and tachycardia requires exclusion of PE and MI before considering less urgent diagnoses 2, 1.