Pericardial effusion is an accumulation of excessive fluid in the space surrounding the heart (pericardial space). It can result from a wide variety of causes and may be present in association with almost all types of pericardial diseases. It is usually seen in inflammatory or infective conditions of the pericardium (pericarditis). The accumulation of fluid in pericardial space to levels that affect the functioning of the heart is called a cardiac tamponade.
Diagnosis of Pericardial Effusion
The medical history, signs and symptoms and certain investigations are useful in diagnosing of pericardial effusion. Small pericardial effusions can be present without any symptoms. The clinical features of pericarditis are discussed further under fluid around the heart.
In patients with larg effusions, symptoms of suggestive of cardiac tamponade can be found. The symptoms of cardiac tamponade are similar to those seen in heart failure. It includes difficulty in breathing (dyspnea) on exertion, breathing difficulty on lying down (orthopnea) and palpitations. The lips and skin may show a bluish tinge (cyanosis). On examination there can be reduced blood pressure (hypotension), increased heart rate (tachycardia), prominent pulsations on neck veins and liver enlargement. The heart sounds are softer or less audible.
Some laboratory investigations may be performed generally in all patients while some investigations are performed only when a particular cause is suspected.
- Routine blood investigations like a complete blood count (CBC)
- Cardiac enzymes
- Serum electrolytes
- Thyroid function
- Specific tests for rheumatoid arthritis
- Tests for rickettsial antibodies
- Tuberculin skin test
- Cancer biomarkers
The most important basic investigation that gives early indication about the pericardial effusion is a chest X-ray. It shows enlargement of the shadow of the heart having a ‘water-bottle’ like appearance. There is also loss of the regular shadows of the cardiac borders. However, a chest x-ray cannot be used a reliable test for confirming the diagnosis.
The diagnostic imaging procedure of choice in evaluation and diagnosis of pericardial effusion is transthoracic (surface) echocardiography. It can provide the accurate size and location of effusion. It also helps in deciding the approaches to be adopted in treatment. Echocardiography can give false (false-positive) results for a pericardial effusion (fluid around the lung). In patients with pleural effusion, thickening of the pericardium, lung collapse (atelectasis) and in patients with excessive fat tissue around the heart.
Computed tomography (CT) scan has the advantage of detecting small quantity effusions. It can detect pericardial effusions as small as 50 ml. It also has a potential to provide vague information about the composition of pericardial fluid. It gives less number of false positive results when compared to echocardiography.
Magnetic resonance imaging (MRI) is more sensitive and can detect effusions as small as 30 ml. MRI scan may be useful in distinguishing hemorrhagic effusions from other effusions. CT scan and MRI scan are of great value in evaluating pericardial effusion resulting from malignancies (cancer).
ECG can show abnormalities in pericardial effusion giving some information about the underlying cause. The ECG changes are prominent in effusions resulting from acute pericarditis and post myocardial infarction effusion (Dressler’s syndrome). The changes in both the conditions are similar but the changes are generalized in acute pericarditis while it is localized in myocardial infarction.
Pericardiocentesis is a procedure to remove fluid from the pericardium using a needle. It may be done for diagnostic purpose or for therapeutic reasons. Diagnostic pericardial fluid aspiration is not done in all patients with pericardial effusion.
The pericardial fluid obtained is then analyzed to determine the cause of the effusion. The pericardial effusion may contain blood in effusions following trauma, myocardial infarction with rupture, or coronary artery rupture during cardiac catheterization. The fluid is milky in appearance when effusion results from rupture of thoracic duct. The fluid is purulent (pus) in bacterial infections and serosanguineous in effusions resulting from tuberculosis, viral infections and neoplastic disease.
Pericardiocentesis can lead to some serious complications. It includes cardiac arryhythmias, rupture of the ventricle and injury to the coronary artery. Pericardiocentesis can also lead to infection if necessary aseptic precautions are not taken during the procedure.
Pericardioscopy is a rarely performed procedure. It allows direct visualization of pericardial space meaning the space can be seen by the physician. It also allows for pericardial biopsies for further examination. This procedure is made use in select patients in whom the cause of pericardial effusion remains inconclusive with other diagnostic procedures.
Pericardial Effusion Treatment
Treatment of pericardial effusion depends on the cause and severity. Some patients with mild asymptomatic pericardial effusions may not require any treatment. A good number of patients with pericardial effusion are managed medically while some patients are managed surgically. Symptomatic effusion in patients with poor general condition may require emergency treatment. An effusion in stable asymptomatic patients may be observed for a couple of days before initiating an active treatment. Some forms of pericardial effusions improve when the primary disease that led to effusion is treated effectively like treatment of hypothyroidism with thyroid hormone supplementation or intensive dialysis of uremic patients.
Patients with small asymptomatic effusions may be observed for a couple of weeks without any active treatment. A follow up echocardiography may be performed after the observation period. If echocardiography shows signs of improvement, then the effusion is likely to resolve without any intervention. Active treatment may be required in patients who become symptomatic during the observation period or if the follow up echocardiography shows increase in the effusion fluid quantity.
- Acute pericardial effusions in most patients arising from viral infections or from unknown causes are usually self-limiting. It responds to treatment with nonsteroidal anti-inflammatory agents (NSAIDs) or aspirin.
- Pericardial effusions caused by autoimmune disease conditions respond well with steroids and NSAIDs.
- Bacterial infections cause purulent effusions that should be drained immediately by catheter drainage or open surgical drainage. This should be closely followed with intravenous antibiotics.
- Antitubercular treatment (tuberculosis) with isoniazid, rifampin, pyrazinamide and ethambutol should be given after drainage for pericardial effusions of tuberculous origin.
- Cancer related pericardial effusions are known to recur. Combination of anticancer treatment with pericardiocentesis is the most effective way of reducing malignant pericardial effusions.
Drainage of pericardial fluid may be done by pericardiocentesis. A catheter is passed over the needle placed in the pericardial space for draining the excess fluid. The pericardiocentesis may be performed under the guidance of echocardiograph or ultrasound to increase the safety and success rate of the procedure. CT-guided pericardial drainage may be done in patients in whom echocardiography guided pericardiocentesis is not possible. CT-guided drainage is of great value in patients who have developed effusion following cardiac surgery or procedures.
Surgical interventions are considered in a selected set of patients in whom pericardiocentesis has failed or is not considered to be effective option.
- Subxiphoid pericardial window or pericardiostomy may be performed to treat some of the patients with pericardial effusion. The procedure can be conducted under local anesthesia. It involves approaching the pericardial space through incision in the area of xiphoid process (sternum). The excess fluid is drained and a chest drain is placed.
- Open chest surgery (thoracotomy) may be considered in patients who fail the other less invasive approaches and in patients with loculated pericardial effusions. The procedure is only performed under general anesthesia. It is associated with more risk for surgical than the subxiphoid pericardiostomy.
- Video-assisted thoracic surgery (VATS) is another option for surgical drainage and exploration of pericardial space. An approach through the sternum (sternotomy) may be required in patients who have developed complications like constrictive pericarditis.
A cardiac tamponade is a medical emergency and management is mainly aimed at maintenance of blood pressure. It is usually done with intravenous fluids. Some critically ill patients may require intravenous cardiac stimulants like dopamine to improve the blood pressure. Catheterization of the right-side of the heart may be done in some of the less severely ill patients to confirm the raised intrapericardial pressure.
Emergency percutaneous pericardiocentesis can be life-saving under critical circumstances in patients with a cardiac tamponade. As much as fluid possible is removed from the pericardial space. The fluid removed is also sent for diagnostic tests if the diagnosis has not been established. A flexible drainage catheter is usually left in the pericardial space for a few days to avoid any immediate reaccumulation of fluid. The catheter is removed after a follow up echocardiography to rule out presence of any additional fluid.