A pericardial effusion is an abnormal accumulation of fluid in the

pericardial cavity The pericardium (: pericardia), also called pericardial sac, is a double-walled sac containing the heart and the roots of the great vessels. It has two layers, an outer layer made of strong inelastic connective tissue (fibrous pericardium), a ...

. The pericardium is a two-part membrane surrounding the heart: the outer fibrous connective membrane and an inner two-layered

serous membrane The serous membrane (or serosa) is a smooth epithelial membrane of mesothelium lining the contents and inner walls of body cavity, body cavities, which secrete serous fluid to allow lubricated sliding (motion), sliding movements between opposing ...

. The two layers of the serous membrane enclose the pericardial cavity (the

potential space In anatomy, a potential space is a space between two adjacent structures that are normally pressed together (directly apposed). Many anatomic spaces are potential spaces, which means that they are potential rather than realized (with their realiz ...

) between them. This pericardial space contains a small amount of

pericardial fluid Pericardial fluid is the serous fluid secreted by the Serous membrane, serous layer of the pericardium into the pericardial cavity. The pericardium consists of two layers, an outer fibrous layer and the inner serous layer. This serous layer has t ...

, normally 15-50 mL in volume. The pericardium, specifically the pericardial fluid provides lubrication, maintains the anatomic position of the heart in the chest ( levocardia), and also serves as a barrier to protect the heart from infection and inflammation in adjacent tissues and organs. By definition, a pericardial effusion occurs when the volume of fluid in the cavity exceeds the normal limit. If large enough, it can compress the heart, causing cardiac tamponade and

obstructive shock Obstructive shock is one of the four types of shock, caused by a physical obstruction in the flow of blood. Obstruction can occur at the level of the great vessels or the heart itself. Causes include pulmonary embolism, cardiac tamponade, and ten ...

. Some of the presenting symptoms are

shortness of breath Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that con ...

, chest pressure/pain, and

malaise In medicine, malaise is a feeling of general discomfort, uneasiness or lack of wellbeing and often the first sign of an infection or other disease. It is considered a vague termdescribing the state of simply not feeling well. The word has exist ...

. Important etiologies of pericardial effusions are inflammatory and infectious (

pericarditis Pericarditis () is inflammation of the pericardium, the fibrous sac surrounding the heart. Symptoms typically include sudden onset of sharp chest pain, which may also be felt in the shoulders, neck, or back. The pain is typically less severe whe ...

neoplastic A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

, traumatic, and metabolic causes.

Echocardiogram Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an echo ...

, CT and

MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and rad ...

are the most common methods of diagnosis, although

chest X-ray A chest radiograph, chest X-ray (CXR), or chest film is a Projectional radiography, projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common fi ...

and EKG are also often performed.

Pericardiocentesis Pericardiocentesis (PCC), also called pericardial tap, is a medical procedure where fluid is aspirated from the pericardium (the sac enveloping the heart). Anatomy and physiology The pericardium is a fibrous sac surrounding the heart composed o ...

may be diagnostic as well as therapeutic (form of treatment).

Signs and symptoms

Pericardial effusion presentation varies from person to person depending on the size, acuity and underlying cause of the effusion. Some people may be asymptomatic and the effusion may be an incidental finding on an examination. Others with larger effusions may present with

chest The thorax (: thoraces or thoraxes) or chest is a part of the anatomy of mammals and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main di ...

pressure or pain,

dyspnea Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that ...

, and

(a general feeling of discomfort or illness). Yet others with cardiac tamponade, a life-threatening complication, may present with dyspnea, low

blood pressure Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...

, weakness, restlessness, hyperventilation (rapid breathing), discomfort with lying flat, dizziness, syncope or even loss of consciousness. This causes a type of shock, called obstructive shock, which can lead to organ damage. Non-cardiac symptoms may also present due to the enlarging pericardial effusion compressing nearby structures. Some examples are nausea and abdominal fullness,

dysphagia Dysphagia is difficulty in swallowing. Although classified under " symptoms and signs" in ICD-10, in some contexts it is classified as a condition in its own right. It may be a sensation that suggests difficulty in the passage of solids or l ...

and hiccups, due to compression of stomach, esophagus, and phrenic nerve respectively.

Causes

Any process that leads to injury or inflammation of the pericardium or inhibits appropriate lymphatic drainage of the fluid from the pericardial cavity leads to fluid accumulation. Pericardial effusions can be found in all populations worldwide but the predominant etiology has changed over time, varying depending on the age, location, and comorbidities of the population in question. Out of all the numerous causes of pericardial effusion, some of the leading causes are inflammatory, infectious, neoplastic and traumatic. These causes can be categorized into various classes, but an easy way to understand them is dividing them into inflammatory versus non-inflammatory. PericardialeffusionUS

Inflammatory

# Infectious: #* Viral: coxsackie A and B viruses,

HIV The human immunodeficiency viruses (HIV) are two species of '' Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the im ...

(seen in 5-43% of HIV patients), hepatitis viruses, parvovirus B19 #* Bacterial: Mycobacterium (

tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

), gram positive cocci (Streptococcus, Staphylococcus), Mycoplasma, Neisseria (meningitides, gonorrhea), Coxiella burnetii. Tuberculosis is the leading cause of pericardial effusion in the developing world, with the mortality rate ranging from 17 to 40%. #* Fungal: Histoplasma, Candida #* Protozoal: Echinococcus,

Trichinosis Trichinosis, also known as trichinellosis, is a parasitic disease caused by roundworms of the '' Trichinella'' genus. During the initial infection, invasion of the intestines can result in diarrhea, abdominal pain, and vomiting. Migration of ...

, Toxoplasma # Cardiac injury syndromes: Heart surgery ( postpericardiotomy syndrome), post-myocardial infarction ( Dressler's syndrome), coronary interventions such as drug eluting stents. Post-cardiac surgery pericardial effusions contribute to 54% of total effusions in the pediatric population. # Cardiac inflammation: idiopathic pericarditis is the most common inflammatory cause of pericardial effusion in the United States.Imazio M, Gaita F, LeWinter M
Evaluation and Treatment of Pericarditis
A Systematic Review. ''JAMA.'' 2015;314(14):1498–1506. doi:10.1001/jama.2015.12763 # Autoimmune:

lupus Lupus, formally called systemic lupus erythematosus (SLE), is an autoimmune disease in which the body's immune system mistakenly attacks healthy tissue in many parts of the body. Symptoms vary among people and may be mild to severe. Common ...

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

, Sjögren syndrome, scleroderma, Dressler's syndrome, sarcoidosis # Drug hypersensitivity/ side effects: Chemotherapy drugs (doxorubicin and cyclophosphamide),

Minoxidil Minoxidil is a medication used for the treatment of high blood pressure and pattern hair loss. It is an antihypertensive and a vasodilator. It is available as a generic medication by prescription in oral administration, oral tablet (pharmacy), ...

# Others: kidney failure, uremia

Non-Inflammatory

# Neoplastic: pericardial effusions may present as primary manifestations of underlying

malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

. #*

Primary tumor A primary tumor is a tumor growing at the anatomical site where tumor progression began and proceeded to yield a cancerous mass. Most solid cancers develop at their primary site but may then go on to metastasize or spread to other parts of the b ...

: the most common primary pericardial tumor is

mesothelioma Mesothelioma is a type of cancer that develops from the thin layer of tissue that covers many of the internal organs (known as the mesothelium). The area most commonly affected is the lining of the lungs and chest wall. Less commonly the lini ...

. Various imaging appearances such as solid and cystic components could be encountered on CT scan on those with mesothelioma. Other less common primary tumors are sarcoma, lymphoma, and primitive neuroectodermal tumour. #* Secondary

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

s: that have spread to the pericardium such as breast and lung cancer. Pericardial irregular thickening and/or nodularity, focal, or diffuse FDG uptake on PET scan and lack of preserved fat plane with an adjacent tumor are strongly suggestive of cancer spread from other parts of the body. # Metabolic:

hypothyroidism Hypothyroidism is an endocrine disease in which the thyroid gland does not produce enough thyroid hormones. It can cause a number of symptoms, such as cold intolerance, poor ability to tolerate cold, fatigue, extreme fatigue, muscle aches, co ...

(myxedema coma), severe protein deficiency # Traumatic: penetrating or blunt chest trauma, aortic dissection # Reduced lymphatic drainage: congestive heart failure, nephrotic syndrome

Pathophysiology

Pericarditis can progress to pericardial effusion and eventually cardiac tamponade

How much fluid is stored in the pericardial sac at one particular time is based on the balance between production and reabsorption. Studies have shown that much of the fluid that accumulates in the pericardial sac is from plasma filtration of the epicardial capillaries and a small amount from the myocardium, while the fluid that is drained is mostly via the parietal lymphatic capillaries. Pericardial effusion usually results from a disturbed equilibrium between these two processes or from a structural abnormality that allows excess fluid to enter the pericardial cavity. Because of the limited amount of anatomic space in the pericardial cavity and the limited elasticity of the pericardium, fluid accumulation beyond the normal amount leads to an increased intrapericardial pressure which can negatively affect

heart The heart is a muscular Organ (biology), organ found in humans and other animals. This organ pumps blood through the blood vessels. The heart and blood vessels together make the circulatory system. The pumped blood carries oxygen and nutrie ...

function. A pericardial effusion with enough pressure to adversely affect heart function is called

cardiac tamponade Cardiac tamponade, also known as pericardial tamponade (), is a compression of the heart due to pericardial effusion (the build-up of pericardial fluid in the pericardium, sac around the heart). Onset may be rapid or gradual. Symptoms typically i ...

. Pericardial effusions can cause cardiac tamponade in acute settings with fluid as little as 150mL. In chronic settings, however, fluid can accumulate anywhere up to 2L before an effusion causes cardiac tamponade. The reason behind this is the elasticity of the pericardium. When fluid fills the cavity rapidly, the pericardium cannot stretch rapidly, but in chronic effusions, the gradual fluid collection provides the pericardium enough time to accommodate and stretch with the increasing fluid levels.

Diagnosis

Patients with pericardial effusion may have unremarkable physical exams but often present with

tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...

, distant heart sounds and

tachypnea Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing. In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea b ...

. A physical finding specific to pericardial effusion is dullness to percussion, bronchial breath sounds and egophony over the inferior angle of the left scapula. This phenomenon is known as Ewart's sign and is due to compression of the left lung base. Patients with concern for cardiac tamponade may present with abnormal vitals and what's classically known as the Beck's triad, which consists of hypotension (low blood pressure), jugular venous distension and distant heart sounds. Though these are the classical findings; all three occur simultaneously in only a minority of patients. Patients presenting with cardiac tamponade may also be evaluated for pulsus paradoxus. Pulsus paradoxus is a phenomenon in which systolic blood pressure drops by 10 mmHg or more during inspiration. In cardiac tamponade, the pressure within the pericardium is significantly higher, hence decreasing the compliance of the chambers (the capacity to expand/ conform to volume changes). During inspiration, right ventricle filling in increased, which causes the

Interventricular septum The interventricular septum (IVS, or ventricular septum, or during development septum inferius) is the stout wall separating the ventricle (heart), ventricles, the lower chambers of the heart, from one another. The interventricular septum is di ...

to bulge into the left ventricle, hence leading to reduced left ventricular filling and consequently reduced stroke volume and low systolic blood pressure.

Exams

Some patients with pericardial effusions may present with no symptoms and the diagnosis can be an incidental finding due to imaging of other illnesses. Patients who present with dyspnea or chest pain have a broad

differential diagnosis In healthcare, a differential diagnosis (DDx) is a method of analysis that distinguishes a particular disease or condition from others that present with similar clinical features. Differential diagnostic procedures are used by clinicians to di ...

and it may be necessary to rule out other causes like

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...

pulmonary embolism Pulmonary embolism (PE) is a blockage of an pulmonary artery, artery in the lungs by a substance that has moved from elsewhere in the body through the bloodstream (embolism). Symptoms of a PE may include dyspnea, shortness of breath, chest pain ...

pneumothorax A pneumothorax is collection of air in the pleural space between the lung and the chest wall. Symptoms typically include sudden onset of sharp, one-sided chest pain and dyspnea, shortness of breath. In a minority of cases, a one-way valve is ...

, acute pericarditis, pneumonia, and esophageal rupture. Initial tests include

electrocardiography Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of t ...

(ECG) and chest x-ray. Chest x-ray: is non-specific and may not help identify a pericardial effusion but a very large, chronic effusion can present as "water-bottle sign" on an x-ray, which occurs when the cardiopericardial silhouette is enlarged and assumes the shape of a flask or water bottle. Chest radiograph is also helpful in ruling out pneumothorax, pneumonia, and esophageal rupture. ECG: may present with

sinus tachycardia Sinus tachycardia is a sinus rhythm of the heart, with an increased rate of electrical discharge from the sinoatrial node, resulting in a tachycardia, a heart rate that is higher than the upper limit of normal (90–100 beats per minute for adu ...

, low voltage QRS as well as electrical alternans. Due to the fluid accumulation around the heart, the heart is further away from the chest leads, which leads to the low voltage QRS. Electrical alternans signifies the up-and-down change of the QRS amplitude with every beat due to the heart swinging in the fluid (as displayed in the ultrasound image in the introduction) . These three findings together should raise suspicion for impending hemodynamic instability associated with cardiac tamponade. Echocardiogram (ultrasound): when pericardial effusion is suspected, echocardiography usually confirms the diagnosis and allows assessment of the size, location and signs of hemodynamic instability. A

transthoracic echocardiogram A transthoracic echocardiogram (TTE) is the most common type of Echocardiography, echocardiogram, which is a still or moving image of the internal parts of the heart using ultrasound. In this case, the probe (or ultrasonic transducer) is placed on ...

(TTE) is usually sufficient to evaluate pericardial effusion and it may also help distinguish pericardial effusion from pleural effusion and MI. Most pericardial effusions appear as an anechoic area (black or without an echo) between the visceral and the parietal membrane. Complex or malignant effusions are more heterogeneous in appearance, meaning they may have variations in echo on ultrasound. TTE can also differentiate pericardial effusion based on the size. Although it's difficult to define size classifications because they vary with institutions, most commonly they are as follows: small <10, moderate 10–20, large >20. An echocardiogram is urgently needed for evaluation when there is concern for hemodynamic compromise, a rapidly developing effusion or history of recent cardiac surgery/procedures. Cardiac CT and MRI scans: cross-sectional imaging with computed tomography (CT) can help localize and quantify the effusion, especially in a loculated effusion (an effusion contained to one area). CT imaging also helps assess for pericardial pathology (pericardial thickening, constrictive pericarditis, malignancy-associated pericarditis). Whereas cardiac MRI is reserved for patients with poor echocardiogram findings and for assessing pericardial inflammation, especially for patients with continued inflammation despite treatment. CT and MRI imaging can also be used for continued follow up on patients.

: is a procedure in which fluid is aspirated from the pericardial cavity with a needle and catheter. This procedure can be used to analyze the fluid but more importantly can also provide symptomatic relief, especially in patients with hemodynamic compromise. Pericardiocentesis is usually guided by an echocardiogram to determine the exact location of the effusion and the optimal location of puncture site to minimize risk of complications. After the procedure, the aspirated fluid is analyzed for gross appearance (color, consistency, bloody), cell count, and concentration of glucose, protein, and other cellular components (for example

lactate dehydrogenase Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of pyruvic acid, pyruvate to lactic acid, lactate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that t ...

). Fluid may be also sent for gram stain, acid fast stain, or culture if high suspicion of infectious cause. Bloody fluids may also be evaluated for malignant cells. Fluid analysis may result in: * ''transudative effusion: due to non-inflammatory causes (''

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF typically pr ...

, myxoedema,

nephrotic syndrome Nephrotic syndrome is a collection of symptoms due to kidney damage. This includes proteinuria, protein in the urine, hypoalbuminemia, low blood albumin levels, hyperlipidemia, high blood lipids, and significant edema, swelling. Other symptoms ...

) * ''exudative'' effusion: inflammatory or malignant causes (

, spread from empyema,

metastasis Metastasis is a pathogenic agent's spreading from an initial or primary site to a different or secondary site within the host's body; the term is typically used when referring to metastasis by a cancerous tumor. The newly pathological sites, ...

) * ''hemorrhagic'' effusion: high blood concentration (trauma, rupture of aneurysms, malignant effusion) File:PericaridaleffusionCT.png, A CT scan showing a pericardial effusion File:Hemorragic effusion.jpg, A large anechoic (black) pericardial effusion as seen on ultrasound. Closed arrow: the heart, open arrow: the effusion File:Tamponade.PNG, Pericardial effusion due to malignancy. Note bulbous heart and primary lung cancer in right upper lobe. File:Pericardiocentesis.jpg, Pericardiocentesis: fluid aspiration of hemorrhagic effusion

Treatment

Treatment depends on the underlying cause and the severity of the heart impairment. For example, pericardial effusion from autoimmune etiologies may benefit from anti-inflammatory medications. Pericardial effusion due to a viral infection usually resolves within a few weeks without any treatment. Small pericardial effusions without any symptoms don't require treatment and may be watched with serial ultrasounds. If the effusion is compromising heart function and causing cardiac tamponade, it will need to be drained. Fluid can be drained via needle pericardiocentesis as discussed above or surgical procedures, such as a pericardial window. The intervention used depends on the cause of pericardial effusion and the clinical status of the patient. Pericardiocentesis is the choice of treatment in unstable patients: it can be performed at the bedside and in a timely manner. A drainage tube is often left in place for 24 hours or more for assessment of re-accumulation of fluid and also for continued drainage. Patients with cardiac tamponade are also given IV fluids and/or

vasopressors An antihypotensive, also known as a vasopressor, is an agent that raises blood pressure by constricting blood vessels, thereby increasing systemic vascular resistance. This is different from inotropes which increase the force of cardiac contra ...

to increase systemic blood pressure and cardiac output. But in localized or malignant effusions, surgical drainage may be required instead. This is most often done by cutting through the pericardium and creating a pericardial window This window provides a path for the fluid to be drained directly into the chest cavity, which prevents future development of cardiac tamponade. In localized effusions, it might be difficult to get safe access for pericardiocentesis, hence a surgical procedure is preferred. In case of malignant effusions, the high likelihood of recurrence of fluid accumulation is the main reason for a surgical procedure. Pericardiocentesis is not preferred for chronic treatment options due to risk of infection.

References

External links

{{Authority control Disorders of fascia Pericardial disorders