A pericardial effusion is an abnormal accumulation of fluid in the

pericardial cavity The pericardium, 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 connective tissue (fibrous pericardium), and an inner layer made of ...

. The pericardium is a two-part membrane surrounding the heart: the outer fibrous connective membrane and an inner two-layered serous membrane. 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.Phelan, D., Collier, P., Grimm, R.
Pericardial Disease
'. Cleveland Clinic. July 2015. Retrieved Nov 2020. This pericardial space contains a small amount of

pericardial fluid Pericardial fluid is the serous fluid secreted by the 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 two membranes which ...

. The fluid is normally 15-50 mL in volume. The pericardium, specifically the pericardial fluid provides lubrication, maintains the anatomic position of the heart in the chest, and also serves as a barrier to protect the heart from infection and inflammation in adjacent tissues and organs.Vogiatzidis, Konstantinos et al.
Physiology of pericardial fluid production and drainage
" ''Frontiers in physiology'' vol. 6 62. 18 Mar. 2015, doi:10.3389/fphys.2015.00062 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. Some of the presenting symptoms are

shortness of breath Shortness of breath (SOB), also medically 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 disc ...

, chest pressure/pain, and malaise. Important etiologies of pericardial effusions are inflammatory and infectious ( pericarditis), neoplastic, traumatic, and metabolic causes.

Echocardiogram An echocardiography, echocardiogram, cardiac echo or simply an echo, is an ultrasound of the heart. It is a type of medical imaging of the heart, using standard ultrasound or Doppler ultrasound. Echocardiography has become routinely used in th ...

, CT and

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

are the most common methods of diagnosis, although

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

and

EKG Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

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 or chest is a part of the anatomy of humans, 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 divisions of the crea ...

pressure or pain,

dyspnea Shortness of breath (SOB), also medically 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 di ...

, and malaise (a general feeling of discomfort or illness). Yet others with cardiac tamponade, a life-threatening complication, may present with dyspnea, low blood pressure, weakness, restlessness, hyperventilation (rapid breathing), discomfort with laying 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 liq ...

and hiccups, due to compression of stomach, esophagus, and phrenic nerve respectively.Vakamudi, Sneha et al
"''Pericardial Effusions: Causes, Diagnosis, and Management''.
''Progress in cardiovascular diseases'' vol. 59,4 (2017): 380-388. doi:10.1016/j.pcad.2016.12.009

Causes

Any process that leads to injury or inflammation of the pericardium and/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 immune ...

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

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

), 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'' type. During the initial infection, invasion of the intestines can result in diarrhea, abdominal pain, and vomiting. Migration of ...

, Toxoplasma # Cardiac injury syndromes:

Heart surgery Cardiac surgery, or cardiovascular surgery, is surgery on the heart or great vessels performed by cardiac surgeons. It is often used to treat complications of ischemic heart disease (for example, with coronary artery bypass grafting); to corr ...

(

postpericardiotomy syndrome Postpericardiotomy syndrome (PPS) is a medical syndrome referring to an immune phenomenon that occurs days to months (usually 1–6 weeks) after surgical incision of the pericardium (membranes encapsulating the human heart). PPS can also be caused ...

), post-myocardial infarction (

Dressler's syndrome Dressler syndrome is a secondary form of pericarditis that occurs in the setting of injury to the heart or the pericardium (the outer lining of the heart). It consists of fever, pleuritic pain, pericarditis and/or a pericardial effusion. Dressle ...

), 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, technically known as 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. Comm ...

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

, Sjögren syndrome, scleroderma,

, sarcoidosis # Drug hypersensitivity/ side effects: Chemotherapy drugs (doxorubicin and cyclophosphamide),

Minoxidil Minoxidil, sold under the brand name Rogaine among others, is a medication used for the treatment of high blood pressure and pattern hair loss. It is an antihypertensive vasodilator. It is available as a generic medication by prescription in or ...

# 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. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

. #*

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 cancers develop at their primary site but then go on to metastasize or spread to other parts of the body. These fur ...

: 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 most common area affected is the lining of the lungs and chest wall. Less commonly the lining ...

. Various imaging appearances such as solid and cystic components could be encountered on CT scan on those with

. Other less common primary tumors are sarcoma, lymphoma, and primitive neuroectodermal tumour. #* Secondary

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

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 (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 in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...

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

cardiac tamponade Cardiac tamponade, also known as pericardial tamponade (), is the buildup of fluid in the pericardium (the sac around the heart), resulting in compression of the heart. Onset may be rapid or gradual. Symptoms typically include those of obstructi ...

. 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 Egophony (British English, aegophony) is an increased resonance of voice sounds heard when auscultating the lungs, often caused by lung consolidation and fibrosis. It is due to enhanced transmission of high-frequency sound across fluid, such as in ...

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, also paradoxic pulse or paradoxical pulse, is an abnormally large decrease in stroke volume, systolic blood pressure and pulse wave amplitude during inspiration. The normal fall in pressure is less than 10 mmHg. When the drop ...

. 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 ventricles, the lower chambers of the heart, from one another. The ventricular septum is directed obliquely backwar ...

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 (abbreviated DDx) is a method of analysis of a patient's history and physical examination to arrive at the correct diagnosis. It involves distinguishing a particular disease or condition from others that p ...

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 blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...

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 p ...

pneumothorax A pneumothorax is an abnormal 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 shortness of breath. In a minority of cases, a one-way valve i ...

, acute pericarditis, pneumonia, and esophageal rupture. Initial tests include electrocardiography (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 an elevated sinus rhythm characterized by an increase in the rate of electrical impulses arising from the sinoatrial node. In adults, sinus tachycardia is defined as a heart rate greater than 100 beats per minute (bpm). The ...

, low voltage QRS as well as

electrical alternans Electrical alternans is an electrocardiographic phenomenon of alternation of QRS complex amplitude or axis between beats and a possible wandering base-line. It is seen in cardiac tamponade and severe pericardial effusion and is thought to be relat ...

. 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 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 the chest or abdo ...

(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 lactate to pyruvate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from on ...

).Kopcinovic, Lara Milevoj, and Jelena Culej.
Pleural, peritoneal and pericardial effusions - a biochemical approach
" ''Biochemia medica'' vol. 24,1 123-37. 15 Feb. 2014, doi:10.11613/BM.2014.014 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, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

myxoedema Myxedema is a term used synonymously with severe hypothyroidism. However, the term is also used to describe a dermatological change that can occur in hyperthyroidism and (rare) paradoxical cases of hypothyroidism. In this latter sense, myxed ...

, nephrotic syndrome ) * ''exudative'' effusion: inflammatory or malignant causes (

, spread from

empyema An empyema () is a collection or gathering of pus within a naturally existing anatomical cavity. For example, pleural empyema is empyema of the pleural cavity. It must be differentiated from an abscess, which is a collection of pus in a newly fo ...

metastasis Metastasis is a pathogenic agent's spread 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, then, ...

) * ''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 A pericardial window is a cardiac surgical procedure to create a fistula – or "window" – from the pericardial space to the pleural cavity. The purpose of the window is to allow a pericardial effusion or cardiac tamponade to drain from the sp ...

. 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 agent, also known as a vasopressor agent or simply vasopressor, or pressor, is any substance, whether endogenous or a medication, that tends to raise low blood pressure. Some antihypotensive drugs act as vasoconstrictors to in ...

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

{{Circulatory system pathology Disorders of fascia Pericardial disorders