Pericarditis is an inflammation of the thin, protective sac surrounding the heart. This condition causes sharp chest pain that often improves when sitting forward and worsens when lying down. While it can feel alarming, most cases respond well to treatment, though some people experience recurring episodes that require ongoing care.

Understanding How Common Pericarditis Is

Pericarditis affects approximately 28 people per 100,000 each year, making it the most common condition affecting the pericardium. While anyone can develop this condition, it most often strikes males between the ages of 16 and 65. In emergency departments, around 5% of patients admitted for chest pain unrelated to heart attacks are eventually diagnosed with pericarditis.^[1][13]

The condition doesn’t discriminate by geography, but certain patterns emerge. Men aged 20 to 50 years appear particularly vulnerable, though women and people of other ages can also develop pericarditis. Understanding these patterns helps healthcare providers recognize the condition more quickly and begin appropriate treatment.^[2][3]

What Causes This Heart Condition

The causes of pericarditis are remarkably diverse, though in many cases doctors cannot identify a specific trigger. In North America and Western Europe, the most common causes are either viral infections or unknown (called idiopathic pericarditis, meaning the cause cannot be determined). This uncertainty can be frustrating for patients seeking answers, but it doesn’t necessarily change how the condition is managed.^[1]

When a cause can be identified, infections top the list. Viral infections are the leading infectious cause, including common viruses like influenza, COVID-19, adenoviruses, and HIV. Bacterial infections such as tuberculosis can also trigger pericarditis, though this is less common in developed countries. Fungal and parasitic infections are very rare causes.^[1][11]

Non-infectious causes include injuries to the chest from accidents or surgery. Heart attacks can lead to pericarditis, a complication sometimes called Dressler’s syndrome. Cancer that spreads from other parts of the body, autoimmune conditions like lupus and rheumatoid arthritis, kidney failure (causing uremic pericarditis), and severe underactive thyroid can all inflame the pericardium. Radiation therapy and certain medications can also be culprits.^[1][11]

Sometimes pericarditis develops after heart procedures. Open heart surgery can lead to what’s called postpericardiotomy syndrome. Other cardiac procedures like catheterization or radiofrequency ablation also carry a small risk of triggering pericardial inflammation.^[1][11]

Who Faces Higher Risk

Certain situations dramatically increase the likelihood of developing pericarditis. People who have recently experienced a heart attack face elevated risk, as the damaged heart tissue can trigger inflammation in the surrounding sac. This can occur weeks after the initial heart attack.^[1]

Those who undergo open heart surgery also have higher risk of developing pericarditis afterward. Radiation therapy, particularly when targeted at the chest area, can damage the pericardium and lead to inflammation months or even years after treatment ends. Other cardiac treatments and procedures, including catheterization and certain ablation therapies, carry smaller but still notable risks.^[1][11]

People with autoimmune diseases like lupus, rheumatoid arthritis, or scleroderma face increased vulnerability because their immune systems may mistakenly attack the pericardium. Those with advanced kidney failure are also at heightened risk. Additionally, individuals with compromised immune systems, whether from HIV infection, cancer treatment, or immunosuppressive medications, are more susceptible to bacterial pericarditis.^[6][15]

Recognizing the Symptoms

The hallmark symptom of pericarditis is chest pain, but not just any chest pain. The discomfort is typically sharp and stabbing, though some people experience a dull ache or pressure instead. What makes pericarditis pain distinctive is how it changes with position and breathing. The pain usually feels worse when lying down, coughing, swallowing, or taking deep breaths. Sitting up and leaning forward often brings relief. These specific characteristics help doctors distinguish pericarditis from a heart attack.^[1][2]

The pain is most commonly felt behind the breastbone or on the left side of the chest. It often radiates to the left shoulder, and can spread to the back, neck, or both shoulders. This spreading pattern can initially cause confusion about what’s happening in the body.^[1][2]

Beyond chest pain, pericarditis brings additional symptoms. Many people develop a dry cough that persists and feels irritating. Breathing difficulties may occur, particularly when lying flat, forcing some people to sleep propped up. A racing or irregular heartbeat, called palpitations, can feel frightening. General fatigue washes over many patients, making everyday tasks feel exhausting. A low-grade fever may develop, and some people feel generally unwell with muscle aches.^[1][2]

In severe cases, particularly when fluid builds up around the heart, swelling may appear in the legs, feet, ankles, or abdomen. This indicates a more serious complication requiring immediate medical attention.^[1][2]

Preventing Pericarditis

Because the cause of pericarditis often remains unknown, preventing it entirely can be challenging. However, certain strategies may reduce risk. Maintaining overall heart health through a balanced lifestyle helps protect against many cardiovascular conditions. This includes eating nutritious foods, staying physically active within your capabilities, maintaining a healthy weight, and managing stress through relaxation techniques or meditation.^[15][16]

Avoiding smoking is crucial, as tobacco damages the cardiovascular system in multiple ways. Keeping blood pressure under control through diet, exercise, and medication if needed protects both the heart and surrounding structures. Managing chronic conditions like diabetes, kidney disease, and autoimmune disorders with your healthcare provider helps prevent complications including pericarditis.^[15][16]

For people who have already experienced one episode of pericarditis, taking medications exactly as prescribed is essential for preventing recurrence. This often includes continuing anti-inflammatory medications for the full recommended duration, even after symptoms improve. Some doctors recommend avoiding strenuous physical activity during the acute phase and recovery period, as elevating the heart rate too much may trigger inflammation.^[15][18]

Identifying and avoiding personal triggers can also help. Some people notice that alcohol consumption, excessive heat, high stress levels, or intense exercise precede their pericarditis flares. Keeping track of what happened before symptoms began can reveal patterns worth discussing with your doctor.^[18]

How Pericarditis Changes Normal Heart Function

To understand what happens in pericarditis, it helps to know about the pericardium itself. This structure consists of two thin layers of tissue forming a sac around the heart. The inner layer, called the visceral pericardium, sits directly on the heart surface. The outer layer, the parietal pericardium, forms the outer shell. Between these layers exists a potential space normally containing 15 to 50 milliliters of clear fluid that acts as lubricant, allowing the heart to move smoothly as it beats.^[3]

When inflammation strikes the pericardium, several changes occur. The tissue layers become swollen and irritated. Instead of gliding smoothly past each other, these inflamed layers rub together with each heartbeat, creating friction and causing the characteristic chest pain. Sometimes doctors can actually hear this rubbing through a stethoscope, a sound called a pericardial friction rub that helps confirm the diagnosis.^[1][2]

In some cases, inflammation triggers fluid accumulation in the pericardial space, a condition called pericardial effusion. When fluid builds up gradually, the sac can stretch to accommodate it without immediately affecting heart function. However, rapid fluid accumulation or excessive buildup creates pressure on the heart chambers. This pressure can prevent the heart from filling properly with blood between beats, reducing the amount of blood pumped out with each contraction.^[3][11]

If pressure becomes severe enough, a life-threatening condition called cardiac tamponade develops. The compressed heart cannot fill adequately, causing blood pressure to drop dangerously. This is a medical emergency requiring immediate treatment to drain the excess fluid.^[1][3]

When pericarditis becomes chronic or recurrent, another complication can emerge. The pericardium may develop thick scar tissue that loses its flexibility. This condition, called constrictive pericarditis, creates a stiff cage around the heart. The scarred tissue prevents the heart chambers from expanding fully to receive blood, forcing the heart to work harder and less efficiently. Over time, this can lead to heart failure if not addressed.^[1][6]

The inflammation itself involves the body’s immune system responding to whatever triggered the pericarditis. Immune cells flood the area, releasing chemicals that cause swelling, pain, and heat. In viral pericarditis, this response fights the infection but also damages surrounding tissue. In autoimmune cases, the immune system mistakenly targets healthy pericardial tissue. Understanding these mechanisms helps explain why anti-inflammatory medications form the cornerstone of pericarditis treatment.^[3]