Pericarditis

The hearts sits in the center of the chest and is surrounded by a sac called the pericardium. This sac has two layers, one that fits tightly onto the heart muscle and another looser layer surrounding the inner layer. Inflammation of these tissue layers surrounding the heart is referred to as pericarditis.

causes

There are many causes of pericarditis. Most often the cause is unknown. Causes of pericarditis are listed below:

Idiopathic

• The cause of the illness is not identified (although often it's the result of a minor viral illness or "cold")

Mechanical injury to the heart

• Heart attack (myocardial infarction) and Dressler's syndrome
• Heart surgery and post pericardiotomy syndrome
• Trauma

Infection Bacterial

• Viral
• Fungal
• HIV

Tumors or cancer

• Primary (rare)
• Metastatic

Connective Tissue Disease

• Rheumatoid arthritis
• Systemic Lupus Erythematosus (SLE)
• Sarcoidosis
• Scleroderma

Metabolic diseases

• Uremia (kidney failure)
• Hypothyroidism

Medication Reactions

• Side effects of certain medications can cause an immune response causing an inflammation of the pericardial sac and pericarditis. Medicines that have been implicated include phenytoin (Dilantin), hydralazine (Apresoline) and procainamide (Pronestyl, Procan-SR, Procanbid).

Classification

Pericarditis can be classified according to the composition of the inflammatory exudate.^[1]

Types include:

• serous
• purulent
• fibrinous
• caseous
• hemorrhagic

Pericardiocentesis can be performed to permit analysis of the pericardial fluid.

Acute vs. chronic

Acute pericarditis is more common than chronic pericarditis, and can occur as a complication of infections, immunologic conditions, or heart attack.

One form of chronic pericarditis is constrictive pericarditis.

• Clinically: Acute (<6 weeks), Subacute (6 weeks to 6 months) and Chronic (>6 months)

Clinical presentation

Chest pain is the most common symptom of pericarditis.

• The pain is usually sharp and stabbing.
• It can arise slowly or suddenly and can radiate directly to the back, to the neck or to the arm.
• If there is associated irritation of the diaphragm (the flat muscle that separates the chest from the abdomen), the pain can radiate to the shoulder blade.
• The pain can be made worse with deep breaths (pleuritic).
• The pain is frequently positional and made worse when lying flat and better when leaning forward.

These pain characteristics may help the doctor distinguish between pain from pericardial inflammation around the heart and angina (the pain from heart muscle that doesn't get enough blood supply because of narrowed blood vessels).

The heart sits is the mediastinum, a space that exists in the middle of the chest between the lungs. The trachea, the breathing tube from the mouth to the lungs and the esophagus, the swallowing tube from the mouth to the stomach are also located in the mediastinum. Some symptoms may depend upon where the inflammation may be in the heart lining.

• There may be pain with deep breaths and shortness of breath because of that pain, if there is inflammation in the pericardium near lung tissue.
• Pain may occur with swallowing if the inflammation is near the esophagus.
• Other symptoms depend upon the specific cause of the pericarditis. For example, infections may present with fever, chills and other non-specific symptoms such as muscle aches and general malaise.

Since the mid-19th Century, retrospective diagnosis of pericarditis has been made upon the finding of adhesions of the pericardium.^[2] When pericarditis is diagnosed clinically, the underlying cause is often never known; it may be discovered in only 16^[3] to 22^[4] percent of patients with acute pericarditis.

Physical Evaluation

The doctor will assess:

• the quality of pain,
• what brings it on,
• what makes it better, and
• where it came on gradually or quickly and what other symptoms may be present.

The history gives direction as to what may be the cause of chest pain when the symptoms described above are noted.

The most common physical finding that almost always confirms the diagnosis is a pericardial friction rub. Fluid and inflammation in the pericardial sac causes a noise that can be heard with a stethoscope over the lower border of the sternum (the breastbone). It is sometimes better heard when the patient leans forward, which causes the heart to shift to the front of the chest. The rub may not always be present and may come and go from hour to hour.

Diagnostic Testing

The electrocardiogram (EKG or ECG) shows electrical activity of the heart. In pericarditis, there are often abnormalities that sometimes can help with the diagnosis. Unfortunately, many normal variants can mimic the changes in pericarditis or the EKG may be normal.

A chest x-ray may suggest enlargement of heart tissue and can be used to rule out other problems within the chest.

Echocardiography or ultrasound of the heart is often used to confirm the diagnosis. The cardiologist looks for the presence of fluid in the pericardial sac, although in many mild cases of acute pericarditis, there is no pericardial fluid seen with echocardiography.

Blood testing can be used to look for specific causes of pericarditis like infection, leukemia, kidney failure, connective tissue diseases or thyroid abnormalities.

Pathophysiology

Complications

Most cases of acute idiopathic pericarditis resolve without complications or recurrence. Complications may include:

• Pericardial effusion
• Constrictive pericarditis
• Cardiac tamponade [2]

Treatment

Medicines that reduce inflammation are the primary treatment for pericarditis. Nonsteroidal anti-inflammatory drugs, such as ibuprofen, are used to decrease the inflammation and fluid accumulation in the pericardial sac. Occasionally, a short course of narcotic pain medication [codeine, hydrocodone (Vicodin) or oxycodone (OxyContin, Roxicodone)] will be needed. In recurrent cases, especially in immunologically-mediated causes, corticosteroids are often very effective. Treatment of the underlying cause of pericarditis is essential and will be based on the disease process.

Pericardiocentesis, a procedure where a thin needle is inserted through the chest wall into the pericardial sac, may be considered if too much fluid is present (see cardiac tamponade below), or to aid in establishing the cause of the pericarditis (for example, infection, cancer, etc.) by analyzing the fluid that is removed. Pericardotomy (cutting a hole in the pericardial sac) or pericardectomy (removing the sac completely) may be needed for recurrent pericarditis of scarring within the pericardial sac.

complications

Cardiac tamponade

If there is enough fluid in the pericardia sac, there may be enough pressure on the outside of the heart to prevent it from beating adequately to push blood to the body and lungs. The pressure within the sac itself needs to be higher than the pressure within the heart chambers, but symptoms gradually progress as the heart function is compromised. This can be a true medical emergency.

The symptoms tend to be nonspecific but can include shortness of breath and difficulty with exercise or doing daily activities. Additional complaints may be due to the illness or disease that caused the effusion to accumulate in the first place.

Upon physical examination the following signs may be present:

• blood pressure may be low;
• veins in the neck can dilate (jugular venous distention);
• fluid can accumulate in parts of the body that are below the heart due to gravity (edema);
• heart sounds can be muffled because the fluid in the pericardial sac blocks normal heart sounds from being heard with a stethoscope;
• lung examination may reveal fluid back up as well.

Testing likely will include an urgent EKG, chest x-ray and echocardiogram.

Cardiac tamponade may be a true emergency that is treated by pericardiocentesis, a procedure where a long needle is inserted through the chest wall into the pericardial sac and fluid is removed. This relieves the pressure within the sac and temporarily resolves the acute emergency. A plastic tube or catheter may be left in the chest until the underlying illness that cause the tamponade is addressed and further accumulation of fluid in the pericardium is prevented. Admission to the hospital is usually required.

Constrictive pericarditis

If the heart or the pericardial sac is damaged because of trauma, or disease invades the space, then there can be scarring of the space. This scarring can prevent the heart from expanding to collect blood from the body. This limits the ability of the heart to function because it cannot collect blood and pump it to the lungs and then back to the body. The heart is constricted and cannot dilate normally. There may or may not be fluid detectable around the heart.

Bleeding into the pericardium from trauma or from a heart operation is the most common cause of constrictive pericarditis, but tumors, or infections like tuberculosis or fungus can also be the cause.

The constriction occurs slowly over time and will cause shortness of breath on exertion and decreased ability to exercise. Swelling in the legs and the abdomen may exist because it is difficult for blood to return to the heart and fluid leaks out into the tissues.

Diagnosis is made again by history, physical examination, EKG, echocardiography and sometimes computerized tomography (CT) of the chest.

If there is significant scarring of the pericardial sac, pericardotomy, an operation to split open the pericardium to free up the constriction around the heart may be required to improve function.

The treatment in viral or idiopathic pericarditis is with non-steroidal anti-inflammatory drugs. Severe cases may require:

• pericardiocentesis
• antibiotics
• steroids
• colchicine
• in rare cases, surgery