What is Acute Pericarditis?
Acute pericarditis is a condition that involves inflammation of the pericardium, the sac-like membrane that surrounds the heart. This inflammation can cause chest pain, difficulty breathing, and other symptoms.
Acute pericarditis is characterized by inflammation of the pericardium, a double-layered sac that surrounds and protects the heart.
Table of Contents
Structure of the Pericardium and Its Role
The pericardium comprises two layers: the visceral layer, which adheres to the myocardium, and the parietal layer, which lines the fibrous outer sac. Between these layers is a thin layer of serous fluid (15-50 mL), facilitating smooth cardiac motion. The pericardium serves critical roles, including limiting excessive cardiac dilation, reducing friction, and providing a physical barrier against infection.
In acute pericarditis, inflammation disrupts these functions, causing structural and biochemical changes that manifest as clinical symptoms.(alert-success)
Pathophysiology of Acute Pericarditis
The primary mechanisms involve immune-mediated responses, vascular changes, and cellular events that collectively lead to inflammation, pain, and, in some cases, hemodynamic compromise.
A. Inflammatory Cascade in Acute Pericarditis
The hallmark of acute pericarditis is inflammation, triggered by infectious agents (e.g., viruses, bacteria) or non-infectious processes (e.g., autoimmune conditions, trauma).
Regardless of the cause, the following steps typically occur:
1. Triggering Event: Pathogens or endogenous factors like autoimmune antibodies activate immune cells within the pericardium.
Viral infections, the most common cause, directly damage pericardial cells or provoke an immune response.
2. Cytokine Release: Activation of macrophages, dendritic cells, and T-lymphocytes leads to the release of pro-inflammatory cytokines, such as interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6).
These cytokines recruit additional immune cells, amplifying the inflammatory response.
3. Increased Vascular Permeability: Inflammation causes the pericardial capillaries to become more permeable, leading to the exudation of protein-rich fluid, fibrin, and inflammatory cells into the pericardial space.
This can result in pericardial effusion, which may range from mild and asymptomatic to large and hemodynamically significant.
4. Fibrin Deposition: In some cases, particularly with autoimmune or bacterial causes, fibrinogen leaks into the pericardial sac and forms fibrinous strands.
This process can create adhesions between the visceral and parietal layers, contributing to the friction rub heard on auscultation.
5. Pericardial Cell Damage: Persistent inflammation can damage pericardial mesothelial cells, releasing alarmins and danger-associated molecular patterns (DAMPs), which perpetuate the inflammatory cycle.
B. Chest Pain Mechanism in Acute Pericarditis
The characteristic sharp, pleuritic chest pain of acute pericarditis arises from irritation of the pericardial nerve endings, particularly in the parietal pericardium. These nerves are sensitive to stretch and chemical mediators released during inflammation. Pain is often exacerbated by deep inspiration or lying supine, as these positions increase the pericardial stretch while sitting forward alleviates it.
C. Pericardial Effusion and Tamponade in Acute Pericarditis
The inflammation-induced increase in vascular permeability leads to fluid accumulation in the pericardial sac. Small effusions may be asymptomatic, but larger volumes can compress the heart, impairing ventricular filling and reducing cardiac output—a condition known as cardiac tamponade. Tamponade is a critical complication marked by hypotension, jugular venous distension, and muffled heart sounds (Beck’s triad).
D. Electrophysiological Changes in Acute Pericarditis
The inflammatory process can also affect the epicardium, which shares its blood supply with the myocardium. This interaction explains the characteristic diffuse ST-segment elevation and PR-segment depression seen on an electrocardiogram (ECG) in acute pericarditis. These changes reflect inflammation rather than ischemia, distinguishing them from myocardial infarction.
E. Resolution and Potential Chronicity in Acute Pericarditis
In most cases, inflammation resolves as the triggering factors are eliminated, and the immune response subsides. However, in some individuals, especially those with autoimmune diseases or repeated triggers, the inflammation can persist or recur, leading to chronic or recurrent pericarditis. Chronic inflammation may result in fibrosis, pericardial thickening, and constriction, which impair cardiac function.
Causes of Acute Pericarditis
Acute pericarditis can be caused by a variety of factors, ranging from infections to systemic diseases.
The most common cause is viral infection, often due to viruses like coxsackievirus, echovirus, or adenovirus. Bacterial infections, though less common, can also lead to pericarditis, particularly in cases of tuberculosis or after thoracic surgery.
Non-infectious causes include autoimmune diseases such as lupus or rheumatoid arthritis, trauma to the chest, or complications following a myocardial infarction (heart attack), a condition known as Dressler’s syndrome.
Certain medications, such as hydralazine or procainamide, can also trigger pericarditis in rare cases. Risk factors include recent respiratory infections, underlying autoimmune conditions, and cancer, particularly when tumors metastasize to the pericardium.
Symptoms of Acute Pericarditis
Acute pericarditis manifests through a range of symptoms, which primarily result from inflammation of the pericardium and its effect on the surrounding cardiac structures. These symptoms can vary in intensity, and their presentation often depends on the severity of the inflammation, the underlying cause, and whether complications such as pericardial effusion or cardiac tamponade are present.
A. Key Symptoms
1.) Sharp or stabbing chest pain: The most common and characteristic symptom of acute pericarditis is sharp, stabbing chest pain. This pain is usually located in the center or left side of the chest and may radiate to the shoulders, neck, or back. Unlike the chest pain associated with a heart attack, pericarditis pain tends to worsen with deep breathing, coughing, swallowing, or lying flat. Sitting up and leaning forward often provide relief.
2.) Shortness of breath: This symptom can occur due to pain when breathing deeply or, in severe cases, due to fluid accumulation in the pericardial sac (pericardial effusion). Patients may describe difficulty in catching their breath, particularly when lying flat.
3.) Low-grade fever: Low-grade fever often accompanies viral or inflammatory pericarditis. High fever may indicate a bacterial cause or an associated infection.
4.) Fatigue: A general feeling of tiredness or low energy can accompany acute pericarditis, particularly if systemic inflammation is present.
5.) Dry cough: Mild coughing or hoarseness can occur, especially if the inflamed pericardium irritates nearby structures, such as the phrenic nerve.
6.) Swelling in the legs, ankles, or feet: This may occur due to fluid buildup in the body.
7.) Palpitations: Patients may feel an irregular or rapid heartbeat due to the irritation of the heart.
B. Symptoms Related to Complications
If complications like pericardial effusion or cardiac tamponade develop, additional symptoms may appear:
1. Muffled Heart Sounds: Indicate significant fluid accumulation in the pericardial sac. These are detectable through auscultation (listening with a stethoscope).
2. Jugular Vein Distension (JVD): A sign of cardiac tamponade, where the heart is compressed by fluid, reducing its ability to pump effectively.
3. Low Blood Pressure or Shock: A result of impaired cardiac output in severe cases of tamponade.
4. Pericardial Friction Rub: A distinctive scratching or squeaking sound heard during a physical exam with a stethoscope. It is caused by the inflamed pericardial layers rubbing against each other. This sound is most pronounced when the patient leans forward, making it an important diagnostic clue.
C. Pattern of Symptoms
1. Positional Variations: The chest pain is often exacerbated by lying flat and alleviated by sitting up or leaning forward. This positional nature is a hallmark feature of pericarditis-related pain.
2. Duration: Symptoms typically develop over a few hours to days and may persist for weeks, depending on the underlying cause and treatment effectiveness.
It is important to note that not all individuals with acute pericarditis will experience all of these symptoms, and some may experience no symptoms at all. Some of these symptoms can also be caused by other medical conditions, so it is important to seek medical evaluation for an accurate diagnosis.
Complications of Acute Pericarditis
While acute pericarditis is often self-limiting and resolves with appropriate treatment, complications can arise in some cases, particularly if the condition is severe, recurrent, or left untreated. These complications can range from mild to life-threatening, requiring careful monitoring and management.
A. Pericardial Effusion
Pericardial effusion occurs when excess fluid accumulates within the pericardial sac as a result of the inflammatory process in acute pericarditis. The pericardial sac normally contains a small amount of lubricating fluid, but inflammation can increase fluid production, leading to abnormal accumulation. Symptoms of pericardial effusion include shortness of breath, chest pressure, and muffled heart sounds, which are audible during a physical examination. If the fluid accumulates gradually, symptoms may remain mild. However, rapid accumulation increases the risk of more severe complications like cardiac tamponade.
B. Cardiac Tamponade
Cardiac tamponade is a life-threatening condition that occurs when pericardial effusion becomes so significant that it compresses the heart, preventing it from filling and pumping blood effectively. This results in a dramatic drop in cardiac output, leading to symptoms such as low blood pressure, jugular vein distension, and muffled heart sounds—a combination known as Beck's triad. Other signs include pulsus paradoxus (a significant drop in blood pressure during inspiration) and severe shortness of breath. Cardiac tamponade requires immediate medical attention as it can progress rapidly to shock or death.
C. Recurrent Pericarditis
Recurrent pericarditis occurs when symptoms of pericarditis return after an initial episode has resolved. It is estimated to affect 15–30% of patients with acute pericarditis. This condition is often triggered by persistent inflammation or autoimmune responses initiated during the first episode. Symptoms are similar to those of the initial acute episode, including chest pain, fever, and fatigue. Recurrence can significantly impact a patient’s quality of life and may require extended periods of treatment to manage.
D. Constrictive Pericarditis
Constrictive pericarditis is a chronic and severe complication in which the pericardium becomes thickened, scarred, and rigid due to prolonged inflammation. This rigidity restricts the heart’s ability to expand and fill properly during diastole, resulting in reduced cardiac output. Common symptoms include swelling in the legs (peripheral edema), ascites (fluid accumulation in the abdomen), shortness of breath during exertion, and fatigue. A unique sign associated with this condition is Kussmaul’s sign, characterized by a rise in jugular venous pressure during inspiration.
E. Chronic Pericarditis
Chronic pericarditis is defined as inflammation of the pericardium lasting more than three months, either following an acute episode or developing independently. Persistent inflammation can result in ongoing chest pain, fatigue, and mild pericardial effusion. Unlike acute pericarditis, chronic cases may not present with severe symptoms but can subtly impair a patient’s overall health and energy levels over time.
F. Myopericarditis
Myopericarditis occurs when inflammation extends from the pericardium to involve the myocardium, and the heart muscle itself. This condition often arises in viral pericarditis and can compromise heart function. Symptoms of myopericarditis include chest pain similar to that of pericarditis, as well as signs of myocarditis such as arrhythmias (irregular heartbeats), palpitations, and symptoms of heart failure like fatigue and shortness of breath. Elevated cardiac biomarkers, such as troponins, often indicate myocardial involvement in these cases.
G. Effusive-Constrictive Pericarditis
Effusive-constrictive pericarditis is a rare combination of conditions involving both pericardial effusion and constriction. In this scenario, fluid accumulation compresses the heart while the rigid pericardium further restricts cardiac function. Patients may experience symptoms of both complications, including severe fatigue, shortness of breath, and fluid retention, often presenting as swelling in the legs or abdomen.
The complications of acute pericarditis can range from manageable conditions like mild pericardial effusion to life-threatening emergencies such as cardiac tamponade. Early recognition of these complications, based on their distinct symptoms and clinical signs, is essential for timely intervention.(alert-passed)
Diagnosis of Acute Pericarditis
The diagnosis of acute pericarditis relies on a combination of clinical evaluation, physical examination, diagnostic imaging, and laboratory tests. Early and accurate identification is essential to ensure effective treatment and prevent complications. The process involves recognizing characteristic symptoms, identifying specific diagnostic signs, and ruling out other potential causes of chest pain, such as myocardial infarction or pulmonary embolism.
A. Clinical Criteria for Acute Pericarditis Diagnosis
The diagnosis of acute pericarditis is primarily based on clinical criteria. The presence of at least two of the following four features is typically required for diagnosis:
1. Characteristic Chest Pain: Sharp, pleuritic chest pain that worsens with deep breathing, coughing, or lying flat and improves when sitting up or leaning forward.
2. Pericardial Friction Rub: A scratchy or squeaking sound heard during auscultation of the heart, caused by the rubbing of the inflamed pericardial layers. This sound is most noticeable when the patient leans forward.
3. Electrocardiographic (ECG) Changes: Widespread ST-segment elevation and PR-segment depression are hallmark findings in the acute phase.
4. Pericardial Effusion: The accumulation of fluid in the pericardial sac, which can be visualized through echocardiography.
B. Physical Examination in Acute Pericarditis Diagnosis
During the physical exam, a pericardial friction rub is a key diagnostic finding. This rub, audible with a stethoscope, is a hallmark feature of pericarditis and is best heard when the patient is sitting up and leaning forward. The rub has a characteristic scratching or squeaking quality and is usually intermittent. Other physical findings may include signs of pericardial effusion, such as muffled heart sounds or jugular vein distension in severe cases.
C. Electrocardiography (ECG) changes in Acute Pericarditis Diagnosis
ECG plays a crucial role in diagnosing acute pericarditis. The characteristic changes in acute pericarditis include:
1. Diffuse ST-Segment Elevation: This occurs across multiple leads and is often accompanied by PR-segment depression. Unlike in myocardial infarction, these changes are widespread rather than localized to specific regions of the heart.
2. PR-Segment Depression: This finding, which reflects atrial involvement, is another distinguishing feature of pericarditis.
3. T-Wave Inversions: In later stages of pericarditis, T-wave inversions may appear as the condition resolves. These ECG changes evolve in four stages, but not all patients exhibit every stage.
D. Imaging Studies in Acute Pericarditis Diagnosis
Imaging is essential for confirming the diagnosis and assessing complications such as pericardial effusion.
1. Echocardiography: This is the most commonly used imaging modality to evaluate the pericardium. It can detect pericardial effusion, estimate its size, and identify signs of cardiac tamponade. In uncomplicated cases of pericarditis, echocardiography findings may be normal.
2. Chest X-Ray: A chest X-ray is typically normal unless there is a large pericardial effusion, in which case the cardiac silhouette may appear enlarged (a "water bottle" shape).
3. Cardiac Magnetic Resonance Imaging (MRI): MRI is highly sensitive for detecting pericardial inflammation and thickening. It is particularly useful in recurrent or complicated cases.
4. Computed Tomography (CT): CT scans provide detailed visualization of the pericardium and are helpful in identifying thickening, calcification, or masses.
E. Laboratory Tests
Laboratory investigations support the diagnosis by identifying signs of inflammation or ruling out underlying causes.
1. Inflammatory Markers: Elevated levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) are indicative of systemic inflammation. These markers often correlate with the severity of the disease.
2. Cardiac Biomarkers: Troponin levels may be mildly elevated if there is myocardial involvement (myopericarditis). This helps differentiate between isolated pericarditis and conditions affecting the heart muscle.
3. Infectious Workup: In cases of suspected infectious pericarditis, tests may include blood cultures, viral serologies, or tuberculin skin testing to identify the causative pathogen.
4. Autoimmune Markers: If an autoimmune condition is suspected as the underlying cause, tests for antinuclear antibodies (ANA), rheumatoid factor, or anti-double-stranded DNA (anti-dsDNA) may be performed.
F. Pericardial Fluid Analysis
In cases of significant pericardial effusion, fluid may be aspirated using pericardiocentesis. The analysis of this fluid can provide valuable diagnostic information:
1. Appearance: The color and consistency of the fluid can indicate the cause, such as purulent fluid in bacterial infections or bloody fluid in trauma or malignancy.
2. Biochemical Tests: Measuring protein, glucose, and lactate dehydrogenase levels helps classify the fluid as transudative or exudative.
3. Microbiological and Cytological Analysis: Tests for bacteria, viruses, or malignant cells help pinpoint the underlying cause.
G. Differential Diagnosis
To confirm acute pericarditis, it is essential to rule out other conditions that can mimic its presentation, such as:
1. Myocardial Infarction: Chest pain and ECG changes in myocardial infarction are often localized, whereas pericarditis typically causes diffuse ECG changes.
2. Pulmonary Embolism: Sudden chest pain and dyspnea may overlap, but imaging studies and D-dimer tests help differentiate these conditions.
3. Pleuritis: Pain with deep breathing occurs in both conditions, but pleuritis lacks the other systemic or cardiac signs of pericarditis.
The presence of characteristic chest pain, a pericardial friction rub, ECG changes, and evidence of pericardial effusion are the cornerstones of diagnosis. Imaging and laboratory studies further support the identification of underlying causes and complications. Early and accurate diagnosis is essential to ensure timely treatment and prevent progression to severe outcomes.(alert-success)
Treatment of Acute Pericarditis
The treatment of acute pericarditis typically involves addressing the underlying cause of the condition and managing symptoms.
The goal of Management for Acute Pericarditis
1.) Treating the underlying cause: The treatment for acute pericarditis depends on the underlying cause. If the cause is a viral infection, treatment may involve rest, fluids, and over-the-counter pain relievers, such as ibuprofen or aspirin. Antibiotics may be prescribed if the cause is bacterial. If the cause is an autoimmune disorder, such as lupus or rheumatoid arthritis, long-term management with immunosuppressants may be necessary.
2.) Managing symptoms: Acute pericarditis can cause chest pain, shortness of breath, and fever. Pain relievers, such as ibuprofen or aspirin, may be prescribed to manage these symptoms. If the pain is severe or does not respond to over-the-counter pain relievers, stronger pain medications may be prescribed.
3.) Preventing complications: Acute pericarditis can lead to several complications, such as pericardial effusion and cardiac tamponade. To prevent these complications, close monitoring of the patient's condition is necessary. In some cases, the patient may need to be hospitalized for close observation and treatment.
I] Specific Treatment
A. Medications for Acute Pericarditis
The following medications are given for acute Pericarditis:
1.) Nonsteroidal anti-inflammatory drugs (NSAIDs): These medications, such as ibuprofen or aspirin, can help reduce inflammation and relieve pain. If NSAIDs are not effective or well-tolerated, other medications may be prescribed.
2.) Colchicine: This medication may be prescribed to help reduce inflammation and prevent recurrences of acute pericarditis.
3.) Corticosteroids: In some cases, corticosteroids may be prescribed to help reduce inflammation and relieve symptoms.
4.) Antibiotics or antifungal medications: If the cause of acute pericarditis is a bacterial or fungal infection, antibiotics or antifungal medications may be prescribed to treat the infection.
II] Targeted Therapy for Specific Causes
1. Infectious Causes:
a.Viral Pericarditis: Symptomatic treatment with NSAIDs and colchicine suffices in most cases.
b. Bacterial Pericarditis: Requires antibiotics tailored to the causative organism, often combined with pericardiocentesis or surgical drainage for purulent effusion.
c. Tuberculous Pericarditis: Treated with a prolonged course of antituberculous therapy and, occasionally, adjunct corticosteroids to manage inflammation.
d. Post-Myocardial Infarction Pericarditis (Dressler’s Syndrome): Treated with aspirin as the preferred anti-inflammatory agent to avoid interfering with myocardial healing.
e. Autoimmune or Uremic Pericarditis: Immunosuppressive therapy (e.g., corticosteroids or biologics) is used for autoimmune causes. Dialysis or intensive medical management addresses uremic pericarditis in patients with kidney failure.
III] Management of Complications
1. Pericardial Effusion
If the effusion is small and asymptomatic, close monitoring with echocardiography is sufficient. In cases of large or symptomatic effusion, pericardiocentesis (removal of fluid) may be required.
2. Cardiac Tamponade
Cardiac tamponade is a medical emergency requiring immediate pericardiocentesis to relieve pressure on the heart. Ongoing monitoring and repeat imaging may be necessary to ensure no re-accumulation of fluid.
3. Recurrent Pericarditis
Prolonged courses of colchicine (up to 6 months) and NSAIDs are often required to manage recurrences. Immunosuppressive agents (e.g., azathioprine, methotrexate) or biologic therapies (e.g., anakinra) may be used in refractory cases.
IV] Surgical Interventions
In rare cases, surgery may be required to treat acute pericarditis. This may be necessary if there is a large amount of fluid in the pericardial sac, or if there are other complications, such as constrictive pericarditis.
1. Pericardiectomy
Pericardiectomy, the surgical removal of the pericardium, is reserved for cases of constrictive pericarditis or recurrent pericarditis unresponsive to medical therapy.
2. Pericardiotomy
In some cases, particularly in recurrent pericardial effusion, a "pericardial window" may be created surgically to allow continuous drainage of excess fluid.
V] Monitoring and Follow-Up
Rest and avoiding strenuous activity can help reduce symptoms and promote healing. Follow-up appointments with a healthcare provider should be scheduled to monitor progress and adjust treatment if necessary.
If an underlying condition, such as an autoimmune disorder or cancer, is causing pericarditis, managing the condition can help prevent a recurrence.
VI] Patient Education
Patient education is crucial for successful management. Patients should be advised to:
1. Recognize warning signs of complications, such as worsening chest pain, shortness of breath, or signs of tamponade.
2. Adhere to prescribed medications and follow the tapering schedule for NSAIDs or corticosteroids.
3. Avoid strenuous physical activity until cleared by their physician, particularly for athletes.
It's important to note that the treatment for acute pericarditis can vary depending on the cause and severity of the condition, so it's best to consult with a healthcare professional for an individualized treatment plan.
Prognosis of Acute Pericarditis
The prognosis of acute pericarditis is generally good, and most patients with this condition recover completely with proper treatment. The majority of cases of acute pericarditis are caused by a viral infection and typically resolve within a few weeks. In most cases, symptoms will improve within a few days to a week after initiating treatment.
In rare cases, acute pericarditis can lead to complications, such as pericardial effusion or cardiac tamponade, which can be life-threatening if left untreated. However, with prompt diagnosis and appropriate treatment, these complications can often be prevented.
Factors that may affect the prognosis of acute pericarditis include the severity and duration of symptoms, the underlying cause of the inflammation, and the presence of other medical conditions. For example, patients with underlying autoimmune disorders may have a higher risk of recurrent episodes of pericarditis.
In some cases, patients may experience recurrent episodes of acute pericarditis, particularly if the underlying cause is not properly treated or if there is a failure to resolve the underlying inflammation. Recurrence rates vary but are estimated to be around 20-30% within the first year after the initial episode.
With appropriate treatment and close monitoring, most patients with acute pericarditis can expect a good prognosis and a full recovery. Regular follow-up with a healthcare provider is important to monitor for potential complications or recurrence of the condition.(alert-success)
Summary
Acute pericarditis is a relatively common condition that can cause significant discomfort and, in some cases, lead to serious complications. Prompt diagnosis and appropriate treatment are essential for achieving a favorable outcome.
