Diagnosis: Pericardial Effusion and Cardiac Tamponade

Review of the patient's abdominal series revealed a severely enlarged cardiac silhouette interpreted as a large pericardial effusion and/or structural enlargement of the heart.

Based on these findings and echocardiogram was obtained and showed a large pericardial effusion with impending tamponade. An arterial pressure waveform revealed evidence of pulsus paradoxus with a respiratory variation of pressure greater than 10 mmHg. The initial right atrial pressure was 24 mmHg and the initial pericardial pressure was 18 mmHg. 

The patient subsequently underwent pericardiocentesis with a total of 1,720 ml of serosanginous pericardial fluid removed. Following the procedure the right atrial pressure decreased to 18 mmHg and the pericardial pressure to 3-5 mmHg with normal left ventricular systolic function (ejection fraction 60%). 

Inpatient work-up revealed no laboratory abnormalities including a normal troponin level. The patient was placed on a bowel regimen of colace and senna with subsequent bowel movement. He was discharged in stable condition the following day with cardiology follow-up.

Pericardial Effusion and Cardiac Tamponade Rapid Fire

Most common causes of pericardial effusion:

1. viral
2. idiopathic
3. malignancy
4. uremia
5. trauma
6. radiation therapy 

Pericardial effusion can produce an enlarged cardiac silhouette on CXR

• 200-250 ml pericardial fluid necessary to produce cardiomegaly 
• echocardiogram = study of choice for differentiating pericardial effusion from enlarged cardiac chamber size

Treatment of choice for pericardial effusion = pericardiocentesis

• diagnostic and therapeutic 
• guided by echocardiography
• typical studies: protein, glucose, spec grav, cell count, gram stain, culture
• complications: dysrhythmias, pneumothorax, myocardial perforation, coronary artery and/or liver laceration 

Cardiac tamponade = compression of myocardium by contents in pericardium

3 stages necessary for tamponade:

1. fluid filling parietal pericardium 
2. fluid accumulating faster than rate of parietal pericardium's ability to stretch
3. accumulation exceeds body's ability to increase blood volume to support RV filling pressure = decreased cardiac output = badness :( 

When to suspect tamponade:

• Beck's Triad = hypotension, distended neck veins, muffled heart sounds
• any penetrating chest wound
• uremic pericarditis
• progressive or severe chest pain, cough, dyspnea
• Pulsus paradoxus = exaggeration of normal inspiratory decrease in systolic BP 
• inspiration leads to >12 mmHg drop in systolic BP 

10% of all patients with cancer develop cardiac tamponade

ECG = decreased voltage and electrical alternans 

Diagnosis confirmed by echocardiogram

• pericardial effusion + paradoxical systolic wall motion

Management of non-traumatic cardiac tamponade

• volume --> IVF to augment RV filling pressure to overcome pericardial constriction
• pericardiocentesis or pericardial window
• patient may require repeated pericardiocentesis or eventual pericardiectomy
• traumatic cardiac tamponade is better severed by a surgical procedure 
• thoracotomy, sternotomy --> better access, more definitive management
• pericardial blood often clots and fails to drain with pericardiocentesis

Cardiac tamponade = high mortality --> rapidity of diagnosis and treatment matters! 

References: 

Jouriles NJ, Rosen's Emergency Medicine Concepts and Clinical Practice, 8th Ed, 2014, Chapter 82: Pericardial and Myocardial Disease

Eckstein M, Henderson SO, Rosen's Emergency Medicine Concepts and Clinical Practice, 8th Ed, 2014, Chapter 45: Thoracic Trauma

Ugras-Rey SS, Rosen's Emergency Medicine Concepts and Clinical Practice, 8th Ed, 2014, Chapter 123: Selected Oncologic Emergencies

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