What is the differential diagnosis for sudden right posterior rib pain radiating anteriorly accompanied by dyspnea?

Differential Diagnosis for Sudden Right Posterior Rib Pain Radiating Anteriorly with Dyspnea

Pulmonary embolism is the most critical diagnosis to exclude immediately in any patient presenting with sudden pleuritic chest pain and dyspnea, as it accounts for the majority of life-threatening causes in this presentation pattern. 1, 2

Immediate Life-Threatening Causes (Rule Out First)

Pulmonary Embolism

• Tachycardia occurs in >90% of PE patients, and dyspnea with pleuritic chest pain is the hallmark presentation. 3, 1, 2
• Pleuritic chest pain is present in approximately 52% of confirmed PE cases and results from pleural irritation due to distal emboli causing alveolar hemorrhage (pulmonary infarction). 2, 4
• Tachypnea >20 breaths/min occurs in approximately 70% of PE patients. 3, 1
• Use the Wells score or revised Geneva score to estimate pre-test probability before ordering D-dimer or CT pulmonary angiography. 3, 1, 2
• A pleural effusion develops in approximately 46% of PE cases and is frequently hemorrhagic, contributing to ongoing pleuritic discomfort. 4

Pneumothorax

• The classic triad consists of dyspnea, sharp pleuritic pain on inspiration, and unilateral absence or marked reduction of breath sounds with hyperresonant percussion. 1, 2, 4
• Right-sided presentation with sudden onset strongly suggests spontaneous pneumothorax, particularly in tall, thin individuals or those with underlying lung disease. 1, 2

Acute Coronary Syndrome

• Approximately 13% of ACS patients present with pleuritic-type chest pain, so sharp pain does not exclude myocardial ischemia. 1, 2, 4
• Radiation of pain to the left arm, jaw, or neck increases ACS likelihood even when other features appear atypical. 1
• A completely normal physical examination does not exclude uncomplicated myocardial infarction. 1

Aortic Dissection

• Sudden "ripping" or "tearing" chest or back pain that is maximal at onset and radiates to the upper or lower back is characteristic. 1, 2
• Pulse differentials between extremities occur in approximately 30% of patients; a systolic blood pressure difference >20 mmHg between arms strongly suggests dissection. 1

Serious Pulmonary Causes

Pneumonia with Pleuritis

• Fever with localized, often pleuritic chest pain suggests pneumonia; examination may reveal regional dullness to percussion, egophony, or a pleural friction rub (biphasic sound heard during both inspiration and expiration). 1, 2, 4
• Elderly patients may lack typical symptoms despite having pneumonia on imaging. 4

Pleural Effusion

• Dyspnea is the most common presenting symptom, along with pleuritic chest pain that is typically localized to the affected side and described as sharp. 4
• Unilateral decreased breath sounds suggest pneumothorax or large pleural effusion. 2

Cardiac Causes (Non-ACS)

Pericarditis

• Sharp, pleuritic chest pain that worsens when lying supine and improves when sitting forward or leaning forward is pathognomonic for pericarditis. 3, 1, 2
• A pericardial friction rub may be audible on auscultation (absence does not exclude disease), and fever commonly accompanies the presentation. 3, 1
• ECG typically shows diffuse concave ST-segment elevation with PR-segment depression. 1, 2

Musculoskeletal Causes

Costochondritis/Tietze Syndrome

• Palpable tenderness over costochondral joints is characteristic; pain is reproducible with direct pressure and is influenced by breathing, turning, twisting, or bending of the torso. 1, 2
• When cardiac causes are excluded, costochondritis accounts for approximately 43% of chest-pain presentations in primary care. 1, 2
• Critical pitfall: Up to 7% of patients with reproducible chest-wall tenderness still have acute coronary syndrome, so palpable tenderness does not completely exclude serious pathology. 1, 2

Immediate Diagnostic Algorithm (First 10 Minutes)

1. Obtain a 12-lead ECG within 10 minutes to identify ST-elevation myocardial infarction, new ischemic changes, or pericarditis patterns (diffuse ST-elevation with PR-depression). 1, 2

2. Measure high-sensitivity cardiac troponin immediately in every patient with acute chest pain because it is the most sensitive biomarker for myocardial injury. 1, 2

3. Assess vital signs immediately: heart rate, respiratory rate, oxygen saturation, and bilateral arm blood pressures to detect tachycardia (>90% of PE), tachypnea (70% of PE), or pulse/BP differentials suggestive of aortic dissection. 3, 1, 2

4. Perform focused cardiovascular and pulmonary examination for:

   • Unilateral absent or decreased breath sounds (pneumothorax, pleural effusion) 1, 2
   • Pericardial friction rub (pericarditis) 1, 2
   • Pleural friction rub—biphasic, creaking leather sound during both inspiration and expiration (pleuritis, pneumonia with pleural involvement) 2, 4
   • Pulse differentials between extremities (aortic dissection) 1

5. Obtain PA and lateral chest radiograph to screen for pneumothorax, pneumonia, pleural effusion, or mediastinal widening. 1, 2

   • Important caveat: A normal chest X-ray does not exclude pulmonary embolism or other serious conditions. 2

Risk Stratification for Pulmonary Embolism

• Apply the Wells criteria or revised Geneva score to categorize pre-test probability. 3, 1, 2
• Critical risk factors to assess include: immobilization in the past 4 weeks, history of DVT/PE, active malignancy, recent surgery, prolonged travel, unilateral lower limb pain or edema, and age >65 years. 3, 4
• In low-to-intermediate probability patients, obtain a D-dimer using age- and sex-specific cutoffs; a negative D-dimer effectively rules out PE. 1, 2
• If probability is high or D-dimer is positive, proceed directly to CT pulmonary angiography (CTPA). 1, 2

Disposition and Management

• If ECG shows ST-elevation, new ischemic changes, or the patient exhibits hemodynamic instability, diaphoresis, dyspnea, nausea, or syncope, activate emergency medical services immediately for transport to the emergency department. 1

• If high clinical suspicion for PE, pneumothorax, or aortic dissection exists, do not delay transfer for additional testing in office settings; transport urgently by EMS. 1, 2

• If cardiac testing (ECG and troponin) is normal and pain is reproducible with palpation, diagnose costochondritis and treat with NSAIDs (ibuprofen 600-800 mg three times daily for 1-2 weeks), but arrange outpatient stress testing or coronary CT angiography within 72 hours if cardiovascular risk factors are present. 1

• If pericarditis is confirmed (positional pain, friction rub, ECG changes), initiate high-dose aspirin (500 mg–1 g every 6–8 hours) plus colchicine (0.5–0.6 mg once or twice daily for approximately 3 months) and arrange cardiology consultation. 2

Critical Pitfalls to Avoid

• Do not dismiss ACS solely because chest pain is pleuritic or reproducible on palpation; approximately 13% of patients with pleuritic pain have acute myocardial ischemia, and 7% of those with reproducible tenderness still have ACS. 1, 2, 4

• Do not rely on nitroglycerin response to differentiate cardiac from non-cardiac chest pain, as esophageal spasm and other conditions may also improve. 1, 2

• Do not assume a normal physical examination excludes ACS; uncomplicated myocardial infarction can present with entirely normal findings. 1, 2

• Do not assume a normal chest X-ray excludes pulmonary embolism; proceed with risk stratification and appropriate imaging based on clinical probability. 2