KEY-WORDS: Pericarditis and cardiac tamponade

INTRODUCTION
CLINICAL
WORKUP
TREATMENT
MEDICATION
FOLLOW-UP
MISCELLANEOUS
BIBLIOGRAPHY

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INTRODUCTION

Background: Pericarditis and cardiac tamponade are clinical problems involving the potential space surrounding the heart or pericardium. Pericarditis is one cause of fluid accumulation in this potential space while cardiac tamponade is the hemodynamic result of fluid accumulation.

Pathophysiology: The pericardium consists of two layers, an outer fibrous layer and an inner serous layer. The potential space produced by these layers contains approximately 20 cc of fluid with similar electrolyte and protein profiles to plasma. Approximately 120 cc of additional fluid can accumulate in the pericardium without an increase in pressure. Further fluid accumulation can result in marked increases in pericardial pressure resulting in decreased cardiac output and hypotension. The rapidity of fluid accumulation influences the hemodynamic effect.
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.Mortality/Morbidity: The early diagnosis of significant pericardial and cardiac injuries can prevent morbidity and enhance survival.

• Penetrating cardiac injury - Immediate identification of penetrating cardiac injuries via ED echocardiography can improve survival rate and neurologic outcome.
  
• Nontraumatic pericardial effusion - Prompt identification utilizing ED bedside echocardiography streamlines appropriate therapy and disposition.

• Pericarditis

• The most common symptom of acute pericarditis is precordial or retrosternal chest pain, usually described as sharp or stabbing.

• This pain may be of sudden or gradual onset and may radiate to the back (left trapezial ridge), neck, left shoulder, or arm.

• Movement or inspiration may aggravate the pain.

• It can be most severe when the patient is supine and can be relieved when the patient leans forward while sitting.

• Common associated signs and symptoms include a low-grade intermittent fever, dyspnea, and dysphagia.

• Pericardial tamponade

• Patients may present subacutely with symptoms of anxiety, dyspnea, fatigue, or altered mental status.

• Patients may have a history of medical illnesses associated with pericardial involvement, particularly end-stage renal disease (ESRD).

• Traumatic tamponade may present with acute dyspnea or altered mental status.

• The most common and important physical finding is a pericardial friction rub, which is best heard at the lower left sternal border or apex when the patient is sitting forward, or when on hands and knees. It may be transient from one hour to the next.

• Fever

• Cardiac arrhythmias

• Tachypnea

• Distended jugular neck veins (DJV)

• Cyanosis

• Relative or absolute hypotension

• Ewart's sign (dullness and bronchial breathing between the tip of the left scapula and the vertebral column)

• Varying degrees of consciousness

• Pulsus paradoxus (greater than 10 mm Hg decrease in systolic pressure with inspiration)

• Hepatomegaly, ascites

• Cardiac tamponade

• Beck's triad (Jugular venous distention, hypotension, and muffled heart sounds)

• Pulsus paradoxus
  
• Measurement by careful auscultation during the lowering of the pressure in the blood pressure cuff. The first sphygmomanometer reading is recorded at the point when beats are audible during expiration. The second reading is taken when each beat is audible. If the difference between the two readings is greater than 10 mm Hg, pulsus paradoxus is present.

• Serous pericarditis - Usually caused by noninfectious inflammation, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). The fluid will demonstrate few PMNs, lymphocytes, or histiocytes. The usual volume is 50-200 mL and accumulates slowly. Fibrous adhesions rarely occur.

• Fibrous and serofibrinous pericarditis - These two types represent the same basic process and are the most frequent type of pericarditis. Common causes are acute myocardial infarction (AMI), postinfarction (Dressler's syndrome), uremia, radiation, RA, SLE and trauma. Severe infections may also cause a fibrinous reaction, as does routine cardiac surgery.

• Purulent/suppurative pericarditis - Infection is the most common cause. Organisms may arise from direct extension, hematogenous seeding, lymphatic extension, or by direct introduction during cardiotomy. Immunosuppression facilitates this condition. The fluid usually is 400-500 mL in volume and shows a thin to creamy pus. Clinical features include fever, chills, and spiking temperatures. Constrictive pericarditis is a serious potential complication.

• Hemorrhagic pericarditis - Blood mixed with a fibrinous or suppurative effusion most commonly is caused by tuberculosis or direct neoplastic invasion. It also can occur in severe bacterial infections or in patients with a bleeding diathesis. It is common after cardiac surgery and may cause tamponade. The clinical significance is similar to suppurative pericarditis.

• Caseous pericarditis - Until proven otherwise, caseation within the pericardial sac is tuberculous in origin. Untreated, this is the most common antecedent to chronic constrictive, fibrocalcific pericarditis.

• Chronic pericarditis

• Adhesive mediastinopericarditis - This reaction usually follows suppurative or caseous pericarditis, cardiac surgery, or irradiation. It rarely is caused by a simple fibrinous exudate. The pericardial potential space is obliterated and the subsequently there is adhesion of the external surface of the parietal layer to the surrounding structures. Clinically, systolic contraction of the ribcage and diaphragm, and pulsus paradoxus may be observed. The increased workload may cause massive hypertrophy and dilatation, which can mimic an idiopathic cardiomyopathy.

• Constrictive pericarditis - This usually is caused by suppurative, caseous, or hemorrhagic pericarditis. The heart may become encased in a 0.5- 1.0 cm thick layer of scar or calcification (concretio cordis), resembling a plaster mold. Contrary to clinical findings in adhesive mediastinopericarditis, the heart cannot hypertrophy or dilate because of insufficient space.

• Cardiac tamponade

• Penetrating cardiac injuries - Identification of any pericardial fluid in the setting of penetrating injury to the thorax or upper abdomen requires aggressive resuscitation.

• Hemopericardium is the most common feature of penetrating cardiac injuries. In acute massive hemopericardium, there is insufficient time for defibrination to occur. The hemopericardium organizes and may partially clot resulting in a pericardial hematoma. The hematoma may appear echogenic instead of echo-free.

• Iatrogenic causes - Potential sources of perforation include central line placement (CVP), pacemaker insertion, cardiac catheterization, sternal bone marrow biopsies, and pericardiocentesis.

• The right atrium is the most common site of perforation from catheter placement. Perforation as well as direct infusion of fluids through the catheter can cause tamponade.

• Delayed tamponade has occurred secondary to catheter misplacement (hours to days).
  

• Elevated erythrocyte sedimentation rate (ESR)

• Creatinine phosphokinase (CPK) and isoenzymes

• Elevated lactate dehydrogenase (LDH) and serum glutamic-oxaloacetic acid (SGOT)

• Chest radiography

• Not helpful in uncomplicated viral pericarditis. A water-bottle shaped heart can be seen with excessive pericardial fluid accumulation.

• In cardiac tamponade (or large effusions), the chest x-ray may demonstrate an enlarged cardiac silhouette after 200-250 mL of fluid accumulation. This occurs in patients with slow fluid accumulation, compared to a normal cardiac silhouette seen in patients with rapid accumulation and tamponade.

• Limited echocardiography

• In pericarditis, the pericardium may have a normal appearance, without evidence of fluid accumulation.

• If no pericardial effusion is noted, stable patients with presumptive viral pericarditis may be discharged with appropriate instructions and follow-up care.

• The emergency nature of blunt and penetrating trauma often does not allow emergency sonographers to assess pericardial fluid to the same degree as traditional echocardiographers.

• Echocardiographers utilize M-mode to evaluate pericardial fluid and timing during the cardiac cycle.

• Emergency sonographers essentially note the presence or absence of pericardial fluid and may comment on the amount of fluid.

• Very small effusions are located posterior and inferior to the left ventricle.

• Moderate effusions extend toward the apex of the heart and large effusions circumscribe the heart.

• It may be difficult for the emergency sonographer to utilize the classic textbook sonographic findings of tamponade, as the trauma patient is often tachycardic and the exam abbreviated.

• The amount of fluid present is important to note. It should be a large effusion with fluid surrounding the heart.

• A swinging heart may be present. This is characterized as counter-clockwise rotational movement, which occurs in addition to the triangular movement of the heart producing a dance-like motion.

• A dilated inferior vena cava without inspiratory collapse (plethora) is highly suggestive of tamponade.

• Electrocardiography (ECG)

• Electrical alternans is pathognomonic of cardiac tamponade and is characterized by changing levels of ECG voltage of the P wave, QRS complex, and T waves. This is a result of the heart swinging in a large effusion.

• The ECG can be diagnostic in acute pericarditis and evolves in 4 stages. Only 50% of patients with pericarditis experience all 4 stages.
• The first stage is characterized by ST-segment elevation with concave upward ST segments. It can be seen within hours of chest pain and lasting several days. The ST segment changes usually are noted in all leads except V1.
• In the second stage, the ST segments return to baseline with T-wave flattening.
• The third stage is distinguished by T-wave inversion without Q-wave formation.
• The fourth stage is characterized by ECG normalization.
  
• Another important ECG finding is PR segment depression, which has been reported in up to 80% of viral pericarditis cases.

.Procedures:

• Limited echocardiography

• Echocardiography is the diagnostic procedure of choice in patients with large effusions or tamponade.

• Echocardiography is useful in determination of fluid, location, and direction of pericardiocentesis.

• Pericardiocentesis

• The traditional approach is the subxiphoid technique. This technique avoids injury to the coronary arteries.
• The chest is prepared with Betadine and a 16- to 18-gauge catheter is introduced between the xiphoid and the left subcostal margin.
• The catheter is directed toward the inferior tip of the left scapula with slow advancement and with negative pressure.
• If fluid is found, the catheter is advanced and the needle withdrawn. Fluid is removed via the catheter.
• The catheter may be sutured in place for subsequent use.

• Echocardiographically guided pericardiocentesis

• Echocardiographic guided pericardiocentesis has evolved over the past 20 years and is now considered the procedure of choice for removal of pericardial fluid. The technique for echocardiographic guided pericardiocentesis differs from traditional blind pericardiocentesis primarily in the site of needle entry.

• The left chest wall has become the preferred location for needle entry under echo guidance. The intended needle trajectory is investigated with echo to confirm the optimal direction and depth for needle advancement. A 16-gauge needle (with polytef-sheath) is advanced in a straight line without side-to-side manipulation. Needle position can be established via echo while agitated sterile saline is injected.

• The step-by-step approach for echo guided pericardiocentesis includes the following:
• Assess the size, distribution, and ideal needle entry site and trajectory with a 2.5-5 MHz ultrasound transducer placed approximately 3- 5 cm from the parasternal border. Locate the point where the effusion is closest to the transducer as well as an area of maximal, pericardial fluid accumulation.
• Assess or measure the distance from the skin to the pericardial space. The needle trajectory is established by the angle of the transducer. Keep this trajectory in your mind during the procedure.
• Use a sterile skin prep like povidone-iodine and, if readily available, use a transparent sterile plastic sheet (one author recommends a Baxter drape, 1030) to allow imaging and a sterile field.
• Place a sterile 16-gauge catheter on the predetermined location on the chest wall avoiding the inferior rib margin. Advance in the predetermined direction, angle, and depth. Advance 2 mm further once fluid is obtained. Consider leaving the catheter in place after removing the needle. If needed, a guidewire can be advanced through the catheter.

• Central venous pressure (CVP) measurement
  
  • If echocardiography is unavailable, placement of a CVP line may demonstrate increased right-sided pressures. CVP measurements greater than 12- 14 mm Hg usually are found in cardiac tamponade.

• Pericarditis - Routine care as for acute cardiac patients

• Cardiac tamponade

• The initial prehospital care is the same as for any major trauma victim. The diagnosis may be suspected based upon the location of penetrating wounds.

• The possibility of a tension pneumothorax should be a consideration.

• Pericarditis - Ideally, echocardiography should be readily available to determine the presence or absence of a pericardial effusion.

• If a small- to moderately-sized effusion is present, the patient should be admitted for observation and a serial echocardiography. If a large effusion is present, the stable patient may undergo an urgent pericardiocentesis or placement of a pericardial window.

• Cardiad tamponade

• Treatment depends upon stability. Unstable patients require immediate treatment of the increase in pericardial pressure with pericardiocentesis. Removing as little as 30-50 mL may produce dramatic hemodynamic improvement.

• Patients may have subacute tamponade (intermittently decompressing) and may benefit from decompression in the operating room with cardiothoracic care available to treat cardiac injuries.

• Traumatic pericardial injury - trauma or cardiothoracic surgery

• Recurrence of pericarditis

• Noncompressive effusion

• Chronic, constrictive pericarditis

• Cardiac perforation at time of pericardiocentesis

• The prognosis for patients with pericarditis depends upon the etiology of the pericardial infection or inflammation as well as the presence of a pericardial effusion.

• Cardiac tamponade

• For penetrating injuries, the prognosis depends heavily upon the rapid identification of tamponade.

• Favorable factors include minor perforations, isolated right ventricular wounds, systolic blood pressure greater than 50 mm Hg, and the presence of tamponade

Medical/Legal Pitfalls:

• Be careful not to confuse this disease entity with esophageal disorders, costochondritis, or other causes of noncardiac chest pain.

• The potential misdiagnosis of pericarditis for acute myocardial infarction has lead to unfortunate complications when thrombolytic therapy has been given.

• Tension pneumothorax may mimic cardiac tamponade. Trauma ultrasonography has limited this misdiagnosis.

• Elevated CVP may be absent in patients with preexisting hypovolemia.

• Rarely, air can enter the pericardium and obscure the sonographic evaluation.

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