In a 49-year-old woman with left sternal border pain at the costochondral junction near the nipple that is aggravated by movement, what is the most likely diagnosis and appropriate initial work‑up and management?

Most Likely Diagnosis: Costochondritis

This is almost certainly costochondritis, and in a 49-year-old woman without cardiac risk factors or concerning features, you can make this diagnosis clinically without imaging and initiate conservative treatment immediately 1.

Diagnostic Approach

Key Clinical Features That Confirm the Diagnosis:

• Pain at the costochondral junction (where sternum meets rib) that is reproducible with palpation over the affected costal cartilages 1
• Pain worsens with movement (characteristic of musculoskeletal origin) 2
• Location at nipple height on left side (typically affects anterior chest wall joints) 2

Critical Cardiac Risk Stratification Required:

You must first exclude cardiac causes before settling on costochondritis 1, 3. In this 49-year-old woman, assess:

• Age >35 years = higher risk threshold - she meets this criterion 1
• History of coronary artery disease or cardiac risk factors (diabetes, hypertension, smoking, family history)
• Any cardiopulmonary symptoms (dyspnea, diaphoresis, radiation to arm/jaw, palpitations)

If she has ANY cardiac risk factors or cardiopulmonary symptoms: obtain ECG immediately 1. Consider chest radiograph as well 1.

If she has NO cardiac risk factors and pain is clearly reproducible on palpation: proceed with clinical diagnosis of costochondritis 1.

Imaging Recommendations:

According to ACR Appropriateness Criteria, most nontraumatic musculoskeletal chest wall pain (42% attributed to costochondritis) does not require diagnostic imaging 2. The diagnosis is made by physical examination alone in the majority of cases 2.

Do NOT order imaging for straightforward costochondritis - it is unnecessary and increases costs without changing management 2, 1.

Management Algorithm

First-Line Treatment:

• Acetaminophen or NSAIDs (where safe and appropriate) 1
• Activity modification: avoid activities producing chest muscle overuse 1
• Reassurance: explain this is self-limited and benign 1

Expected Course:

• Usually self-limited, resolving in several weeks 4
• If symptoms persist >6 months, this becomes "atypical costochondritis" 4

When Conservative Treatment Fails:

If pain persists beyond several weeks to months despite NSAIDs and activity modification, consider physical therapy referral 5. Evidence shows:

• Manual therapy directed at cervicothoracic spine and ribcage 5
• Therapeutic exercise 5
• Rib manipulation and soft tissue mobilization 4
• Mean treatment duration: approximately 5 sessions resulted in clinically meaningful improvement 5

Critical Pitfalls to Avoid

Do not miss cardiac disease: Coronary artery disease is present in 3-6% of adult patients with chest pain AND chest wall tenderness to palpation 1. This is why cardiac risk stratification is mandatory even when costochondritis seems obvious.

Red flags requiring immediate cardiac workup:

• Age >35 with any cardiac risk factors 1
• Pain NOT reproducible with palpation
• Associated dyspnea, diaphoresis, or radiation
• Any ECG abnormalities

Do not order unnecessary imaging: The ACR guidelines emphasize that costochondritis is a clinical diagnosis 2. Imaging is not indicated unless you suspect alternative diagnoses (infection, malignancy, inflammatory arthropathy) or the patient has atypical features.

Infectious costochondritis is rare but serious: If there are signs of infection (fever, erythema, purulent drainage, recent surgery, immunosuppression), this requires urgent evaluation with imaging and possible surgical debridement 6, 7. This is NOT the typical presentation described in this case.