Acute Pericarditis

Overview
  • Acute Pericarditis refers inflammation of the pericardium. Although acute pericarditis can be caused by a number of distinct etiological processes, disease manifests with a common set of clinical consequences. Importantly, acute pericarditis represents the most common disease process afflicting the pericardial layers.
Etiologies
  • Overview
    • Pericarditis can be caused by both infectious and noninfectious etiologies. In most cases, the proximate cause of pericardial inflammation is unknown and thus is termed "Idiopathic Pericarditis" although a viral etiology is usually suspected.
  • Infectious Etiologies:
    • Many classes of microbes, including viruses, bacteria, or fungi, can infect the pericardium
    • Viral Pericarditis: Typically caused by Group B Coxsackie Viruses and often occurs in the context of viral Myocarditis
    • Tuberculous Pericarditis: May be observed in immunocompromised patients and often caused by local extension of Mycobacterium tuberculosis from adjacent foci of pulmonary or mediastinal node infection
    • Purulent Pericarditis: Caused by infection with pyogenic bacteria in those with severe mediastinal trauma/surgery or heavily immunocompromised patients
  • Noninfectious Etiologies:
    • Post-Myocardial Infarction Pericarditis: Myocardial inflammation developing soon after a MI can locally extend into the pericardium
    • Neoplastic Pericarditis: Neoplastic metastases to the pericardium can result in significant pericardial inflammation
    • Radiation-induced Pericarditis: Radiation injury due to mediastinal radiation therapy can cause significant pericardial inflammation
    • Uremic Pericarditis: Uremia associated with Chronic Renal Failure can cause pericarditis through a poorly-understood mechanism
    • Collagen Vascular Disease Pericarditis: Pericardial inflammation is associated with certain collagen vascular diseases such as SLE and Rheumatoid Arthritis
Morphology
Clinical Consequences
  • Symptomology
    • The prototypical symptom of acute pericarditis is retrosternal chest pain which may also refer to the back and shoulders. The chest pain is typically "pleuritic" meaning that it is sharp in nature and aggravated by coughing or inspiration. Consequently, patients often develop dyspnea because of discomfort associated with breathing. In many cases pericardial pain is difficult to distinguish from angina associated with MI; however, pericardial pain is classically relieved by sitting up or leaning forward.
  • Signs
    • The typical auscultory finding of pericarditis is the "Pericardial Friction Rub" which is observed as a high-pitched, scratching sound likely caused by the inflamed pericardial layers rubbing against one another.
  • EKG Features
    • The EKG hallmark of pericarditis is diffuse ST-segment elevation across all leads as well as PR-segment depression.
  • Complications