Welcome to our discussion on pericarditis. Pericarditis is an inflammation of the pericardium, which is the sac-like structure surrounding the heart. The pericardium consists of two main layers: a tough fibrous outer layer called the parietal pericardium, and a thin serous inner layer called the visceral pericardium. Between these layers is a small amount of lubricating fluid. The pericardium serves important functions including protecting the heart, providing lubrication for cardiac movement, and preventing excessive cardiac distention.
Let's discuss the causes and pathophysiology of pericarditis. The most common cause is viral infection, particularly from Coxsackievirus, Echovirus, and Influenza. Less commonly, it can be caused by bacterial, fungal, or parasitic infections. Non-infectious causes include autoimmune conditions like lupus and rheumatoid arthritis, post-myocardial infarction syndrome, uremia from kidney failure, trauma, radiation therapy, malignancy, and idiopathic causes where the trigger is unknown. In the pathophysiology of pericarditis, inflammation of the pericardium leads to increased vascular permeability. This allows fluid and inflammatory cells to accumulate in the pericardial space, creating what we call a pericardial effusion. The inflammation can cause thickening of the pericardium and, in severe cases, may impair the heart's ability to fill properly during diastole.
The hallmark symptom of pericarditis is chest pain, which is typically sharp and pleuritic, meaning it worsens with breathing. The pain is often substernal and may radiate to the neck, shoulders, or back. A characteristic feature is that the pain improves when the patient sits up and leans forward, which reduces pressure on the inflamed pericardium. On physical examination, a pericardial friction rub may be heard. This is a scratchy, high-pitched sound best heard with the diaphragm of the stethoscope at the left sternal border. Other symptoms may include fever, dyspnea, cough, and malaise. For diagnosis, the ECG typically shows diffuse ST segment elevation and PR segment depression. Echocardiography is essential to assess for pericardial effusion and to evaluate cardiac function. Laboratory tests often reveal elevated inflammatory markers like C-reactive protein and erythrocyte sedimentation rate. Troponin may be mildly elevated if there is associated myocarditis. A chest X-ray is usually normal unless there is a large pericardial effusion, which would appear as an enlarged cardiac silhouette.
Let's discuss the treatment and complications of pericarditis. First-line treatment typically involves high-dose NSAIDs such as ibuprofen or indomethacin, which help reduce inflammation and pain. Colchicine is often added to NSAIDs to improve response and reduce the risk of recurrence. For refractory cases or when NSAIDs are contraindicated, corticosteroids may be used, though they're generally avoided as first-line therapy due to their association with increased recurrence rates. For specific causes, targeted treatments are necessary - such as antibiotics for bacterial pericarditis or dialysis for uremic pericarditis. Regarding complications, pericardial effusion is common and may range from mild to severe. A serious complication is cardiac tamponade, which occurs when fluid accumulation in the pericardial space compresses the heart, impeding cardiac filling and reducing cardiac output. This is a life-threatening emergency requiring immediate pericardiocentesis - a procedure where a needle is inserted into the pericardial space to drain the fluid. Another potential complication is constrictive pericarditis, which develops when chronic inflammation leads to scarring and thickening of the pericardium, restricting cardiac filling. Severe cases may require pericardiectomy, a surgical procedure to remove the thickened pericardium.
To summarize what we've learned about pericarditis: It's an inflammation of the pericardium, the protective sac surrounding the heart. While most cases are caused by viral infections, it can also result from autoimmune conditions, post-myocardial infarction syndrome, uremia, or have no identifiable cause. The classic presentation includes sharp, pleuritic chest pain that improves when sitting forward, and a characteristic pericardial friction rub on auscultation. Diagnosis typically involves ECG findings such as diffuse ST elevation and PR depression, echocardiography to assess for effusion, and elevated inflammatory markers. Treatment primarily consists of NSAIDs and colchicine, with corticosteroids reserved for refractory cases. Important complications to watch for include pericardial effusion, cardiac tamponade which requires emergency intervention, and constrictive pericarditis which may necessitate surgical management. Understanding these key aspects of pericarditis is essential for proper diagnosis and management of this condition.