Anatomy Thorax Abdomen · Year 1 · from Anatomy Thorax Abdomen
Case 1: Acute Pericarditis
Clinical Presentation
A 28-year-old male presents to the emergency department with sharp chest pain that began 2 days after recovering from a viral upper respiratory infection. The pain is retrosternal, radiates to the left shoulder and trapezius ridge, and is described as "stabbing." He reports that the pain worsens when lying flat and with deep inspiration, but improves when sitting forward. He denies any exertional component to the pain. Vital signs reveal a low-grade fever of 38.2C, heart rate of 88 beats per minute, and blood pressure of 120/78 mmHg.
On cardiac auscultation, a high-pitched scratchy sound is heard at the left lower sternal border that has three components corresponding to atrial systole, ventricular systole, and early diastole - a characteristic pericardial friction rub. The rub is best heard with the patient leaning forward at end-expiration. ECG shows diffuse ST-segment elevation with PR-segment depression in multiple leads, without reciprocal changes, consistent with acute pericarditis. Echocardiogram shows a small pericardial effusion without signs of tamponade. The patient is treated with colchicine and high-dose aspirin with resolution of symptoms over 2 weeks.
Radiographic Findings
Image: ECG changes in acute pericarditis showing diffuse ST-segment elevation and PR-segment depression. The pattern reflects inflammation of the pericardium affecting the underlying epicardium. Source: Wikimedia Commons, CC BY-SA 4.0.
Key Anatomical Points
- The pericardium consists of an outer fibrous layer and an inner serous layer (with parietal and visceral components)
- The visceral pericardium (epicardium) is intimately adherent to the heart surface and contains the coronary vessels
- The pericardial cavity normally contains 15-50 mL of serous fluid for lubrication
- Inflammation of the pericardium causes the visceral and parietal layers to rub against each other, producing the friction rub
- The phrenic nerve (C3-C5) provides sensory innervation to the pericardium, explaining referred pain to the shoulder
Key Learning Points
- The fibrous pericardium is anchored inferiorly to the central tendon of the diaphragm and anteriorly to the sternum by sternopericardial ligaments
- The transverse pericardial sinus lies behind the ascending aorta and pulmonary trunk, allowing surgical access for clamping these vessels
- The oblique pericardial sinus is a blind cul-de-sac behind the left atrium, bounded by the pulmonary veins and IVC