In a 70-year-old with sudden diffuse sternal pain reproducible on palpation, a normal 12-lead electrocardiogram, undetectable high-sensitivity troponin T, negative D-dimer, and normal erythrocyte sedimentation rate, what is the most likely diagnosis and initial management?

Most Likely Diagnosis: Costochondritis

In a 70-year-old with diffuse sternal pain reproducible on palpation, normal ECG, undetectable high-sensitivity troponin T, negative D-dimer, and normal ESR, the most likely diagnosis is costochondritis—a benign musculoskeletal condition that accounts for approximately 43% of chest pain presentations after cardiac causes are excluded. 1

Rationale for Excluding Life-Threatening Causes

Acute Coronary Syndrome (ACS) – Effectively Ruled Out

• Undetectable high-sensitivity troponin T combined with a normal ECG has extremely high negative predictive value for ACS, particularly when measured beyond 3–6 hours from symptom onset. 1
• Pain reproducible on palpation markedly reduces the probability of myocardial ischemia, though it does not completely exclude it (up to 7% of patients with reproducible tenderness may still have ACS). 1, 2
• The absence of radiation to the left arm, jaw, or neck, and the lack of associated diaphoresis, dyspnea, nausea, or syncope further lower the likelihood of ACS. 1

Pulmonary Embolism – Ruled Out

• A negative D-dimer in a patient without high clinical probability effectively excludes pulmonary embolism. 1
• Tachycardia (present in >90% of PE cases) and acute dyspnea with pleuritic pain are absent in this presentation. 1, 2

Aortic Dissection – Unlikely

• The absence of sudden "ripping" or "tearing" pain, pulse differentials between extremities, blood pressure differentials >20 mm Hg between arms, or a new aortic regurgitation murmur makes dissection highly unlikely. 1, 2
• A normal D-dimer further reduces this probability. 2

Pericarditis – Less Likely

• While pericarditis can present with sharp chest pain, the classic positional features (worsening when supine, improving when leaning forward) are not described here. 1, 2
• A normal ESR argues against an inflammatory process, though it does not completely exclude pericarditis. 1
• The absence of a pericardial friction rub and fever further reduces this likelihood. 1, 2

Diagnostic Features Supporting Costochondritis

• Pain reproducible with chest wall palpation is the hallmark of costochondritis, with tenderness typically localized to the costochondral junctions. 1, 2
• Diffuse sternal pain that is affected by palpation, breathing, turning, twisting, or bending strongly suggests a musculoskeletal origin. 1
• The absence of systemic features (fever, weight loss, night sweats) and a normal ESR make inflammatory or infectious causes unlikely. 1

Initial Management Algorithm

1. Confirm Cardiac Exclusion (Already Completed)

• Normal 12-lead ECG ✓
• Undetectable high-sensitivity troponin T ✓
• If troponin was drawn <6 hours from symptom onset, repeat measurement at 6–12 hours to definitively exclude myocardial injury. 1, 3

2. Symptomatic Treatment for Costochondritis

• Prescribe NSAIDs: ibuprofen 600–800 mg three times daily for 1–2 weeks to reduce inflammation and provide pain relief. 2
• Advise temporary avoidance of movements that exacerbate chest wall pain (reaching, lifting, twisting). 2
• Provide reassurance that costochondritis is a benign, self-limited condition. 2

3. Outpatient Cardiac Risk Stratification

• Given the patient's age (70 years), arrange outpatient stress testing or coronary CT angiography within 72 hours to address residual cardiovascular risk, even though acute ACS is excluded. 1, 2
• This step is particularly important if the patient has additional risk factors (hypertension, hyperlipidemia, diabetes, smoking history, family history of coronary disease). 1

4. Safety-Net Instructions

• Return immediately to the emergency department if:
  • Chest pain becomes severe, prolonged (>20 minutes), or occurs at rest
  • New symptoms develop: diaphoresis, dyspnea, nausea, syncope, palpitations
  • Pain changes character or is no longer reproducible with palpation 1

Critical Pitfalls to Avoid

• Do not dismiss the need for outpatient cardiac testing solely because initial troponin and ECG are normal; age ≥70 years warrants objective assessment of coronary disease. 1
• Do not rely on nitroglycerin response to differentiate cardiac from musculoskeletal pain, as esophageal spasm and other non-cardiac conditions may also improve with nitroglycerin. 1, 2
• Do not assume that reproducible chest wall tenderness completely excludes ACS; up to 7% of patients with palpable tenderness still have acute coronary syndrome. 1, 2
• Do not overlook atypical presentations in elderly patients, who may present with minimal or atypical symptoms even with significant coronary disease. 1

Alternative Diagnoses to Consider if Symptoms Persist or Evolve

• Gastroesophageal reflux disease (GERD): burning retrosternal pain related to meals, relieved by antacids; consider empiric proton-pump inhibitor trial. 2
• Esophageal motility disorders: squeezing retrosternal pain with dysphagia; may require upper endoscopy or esophageal manometry. 2
• Herpes zoster: dermatomal pain that may precede the characteristic rash; consider if pain becomes unilateral and burning in quality. 2