A patient who is 4 days post–coronary artery bypass surgery reports she is having new chest pain that is “different from my angina pain.” The pain’s onset was 5 or 6 hours ago upon first waking up in the morning. The patient has a new pericardial friction rub and a low-grade fever of 100.5°F. The patient is diagnosed with acute pericarditis.

Introduction

Acute pericarditis is a condition characterized by inflammation of the pericardium, which is the thin sac that surrounds the heart. It can have various causes and commonly presents with chest pain, fever, and pericardial friction rub. This paper will discuss the clinical presentation, pathophysiology, diagnosis, and treatment of acute pericarditis in a patient who is 4 days post-coronary artery bypass surgery.

Clinical Presentation

The patient in question reports having new chest pain that is different from her angina pain. This pain has been present for approximately 5 or 6 hours and started upon waking up in the morning. Additionally, the patient exhibits a new pericardial friction rub and a low-grade fever of 100.5°F. These findings are consistent with acute pericarditis.

Chest pain is the cardinal symptom of acute pericarditis and is typically sharp, pleuritic in nature, and worsens with inspiration and lying down. It often radiates to the trapezius ridge, neck, shoulders, or arms. The pain can be mistaken for myocardial ischemia or myocardial infarction, as in this case where the patient describes it as different from her angina pain. The character and radiation of the pain, as well as the presence of a pericardial friction rub, aid in distinguishing acute pericarditis from other causes of chest pain. The low-grade fever is another typical feature of acute pericarditis, as inflammation is the underlying mechanism of this condition.

Pathophysiology

The exact cause of acute pericarditis in this patient is unclear; however, it can be related to the recent coronary artery bypass surgery. Acute pericarditis can occur as a result of various etiologies, including viral infections, autoimmune disorders, postoperative complications, and certain medications. In this case, the recent surgery may have led to an inflammatory response in the pericardium, resulting in acute pericarditis.

Acute pericarditis is characterized by inflammation of the pericardium, which is composed of two layers: the outer fibrous layer and the inner serous layer. The serous layer is further divided into the visceral and parietal layers, with a potential space called the pericardial cavity in between. Inflammation can involve any or all of these layers, leading to the classic clinical presentation.

The etiology of acute pericarditis determines its pathophysiology. In infectious pericarditis, viruses or bacteria invade the pericardium, leading to an inflammatory response and subsequent symptoms. Autoimmune disorders such as systemic lupus erythematosus can result in immune-mediated inflammation of the pericardium. Postoperative pericarditis, as in this case, may be due to trauma to the pericardium during surgery, leading to an inflammatory response.

Diagnosis

Diagnosing acute pericarditis involves a combination of clinical history, physical examination, and additional tests. In this case, the history of recent coronary artery bypass surgery, characteristic chest pain, pericardial friction rub, and low-grade fever are suggestive of acute pericarditis. However, further investigations may be required to confirm the diagnosis and rule out other causes of chest pain.

An electrocardiogram (ECG) is a key diagnostic tool in acute pericarditis. It often shows specific changes, known as the ECG findings of pericarditis. These include diffuse ST-segment elevations in the precordial leads (V1-V6) and the limb leads (I, II, III, aVF, aVL, aVR), as well as PR-segment depressions. These changes are typically widespread and involve multiple leads. The ECG findings in acute pericarditis are different from those seen in myocardial infarction, which typically show ST-segment elevations limited to one or two contiguous leads corresponding to the area of myocardial ischemia.

Additional tests such as cardiac enzymes, complete blood count, and inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate may be ordered to evaluate the extent of inflammation and rule out other causes of chest pain. Imaging studies such as echocardiography or cardiac magnetic resonance imaging may be required in some cases to assess the pericardium and its function.