TOACS FCPS Station · Chest X‑ray: Pneumopericardium

📷 Chest X‑ray (PA view)

Chest X-ray showing air in pericardial sac – pneumopericardium

Figure 1 · PA chest radiograph · Pneumopericardium

🔍 Key radiographic features:

✓ Air density within the pericardial sac – lucent line surrounding the heart
✓ Heart silhouette outlined by air – visible pericardial margin
✓ Air does NOT extend above the pericardial reflection (differentiates from pneumothorax)
✓ Heart size – normal or enlarged (if effusion)
✓ No mediastinal shift (unless tension physiology)

📋 Clinical scenario (examiner prompt)

A 3‑week‑old neonate with respiratory distress syndrome on mechanical ventilation develops sudden hypotension, muffled heart sounds, and jugular venous distension. The chest X‑ray (AP view) is shown.

Mechanical ventilation Air around the heart Hypotension Muffled heart sounds

🧑‍⚕️ Examiner tasks · TOACS

1. Identify the diagnosis from the X‑ray and clinical context.

2. Describe the X‑ray findings (air outlining the pericardial sac).

3. Explain the pathophysiology (air in pericardial sac → tamponade).

4. Discuss management (pericardiocentesis, chest tube, treat underlying).

⚠️ Key concept: Pneumopericardium is air within the pericardial sac. It can cause cardiac tamponade (Beck's triad: hypotension, muffled heart sounds, JVD). In neonates, it is often iatrogenic from mechanical ventilation (barotrauma). Emergent pericardiocentesis is required if hemodynamically significant.

🎯 Expected answers (for examiners)

• Diagnosis: Pneumopericardium (with signs of cardiac tamponade)
• X‑ray findings: Air density outlining the pericardial sac, visible pericardial margin
• Pathophysiology: Air in pericardial sac → impaired diastolic filling → tamponade
• Management: Emergent pericardiocentesis (if tamponade), pericardial drain, reduce airway pressures, treat underlying cause

⚡ Quick FCPS‑style MCQ

A neonate on mechanical ventilation develops sudden hypotension, muffled heart sounds, and JVD. CXR shows air outlining the pericardium. The next immediate step is:

A. Pericardiocentesis B. Chest tube insertion C. Increase ventilator settings D. Echocardiogram

📌 Topic summary ·

Definition
Air in the pericardial sac

Beck's triad
Hypotension, muffled heart sounds, JVD

Common causes
Ventilation (barotrauma), trauma, surgery

X‑ray finding
Air outlining the pericardium

Differential
Pneumothorax (air above pericardial reflection)

Treatment
Pericardiocentesis (if tamponade)

Feature	Pneumopericardium	Pneumothorax
Air location	Pericardial sac	Pleural space
Air extends above heart	No (limited by pericardial reflection)	Yes (apical)
Visceral pleural line	Absent	Present
Tamponade	Common	Rare (unless tension)
Treatment	Pericardiocentesis	Chest tube

🩻 TOACS FCPS Station · Chest X‑ray: Pneumopericardium

📷 Chest X‑ray (PA view)

🧑‍⚕️ Examiner tasks · TOACS

📌 Topic summary ·