Cardiac Tamponade as the Cause of Pulmonary Edema: Case Report

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Introduction
Cardiac tamponade is an emergency syndrome that requires fast diagnosis and treatment; otherwise patient follows obstructive shock and cardiac arrest due to pulseless electrical activity or asystole.The Beck's triad, hypotension, jugular venous distention, and muf led heart sounds can be absent in 14% of the patients with cardiac tamponade [1].Manifestations such as pulmonary edema or angina may occur without hypotension [2].Patients with hypovolemia and cardiac tamponade can have hypotension without jugular venous distention [1] .
Cardiac effusion complicated with tamponade can occur in many conditions such as malignant disease in the advanced phase, myocardial infarction, renal failure with uremia, connective tissue disorder, drug-related lupus, cardiovascular surgery or coronary intervention, thoracic trauma, pacemaker lead implantation, central venous catheter insertion, HIV, and tuberculosis [3].
The unique and effective treatment of the cardiac tamponade is drainage of pericardial effusion (pericardiocentesis or pericardial window) [4,5].
We describe a case of cardiac tamponade whose initial diagnosis was respiratory failure due to pulmonary edema, characterized by shortness of breath, hypoxemia, and bilateral pulmonary crackles, in a 70-year-old female.We have the patient's consent for the publication of her case.

Clinical fi ndings
A 70-year-old black female was brought to our emergency department with respiratory distress.On admission, she complained of progressive dyspnea, initially during moderate physical activity, over the past three weeks, associated with orthopnea, paroxysmal nocturnal dyspnea, and edema in her legs.The past medical history includes bipolar disorder and smoking.Upon physical examination, she had tachypnea (respiratory rate of 25 breaths per minute), hypoxemia (SaO 2 https://doi.org/10.29328/journal.jprr.100104689%), jugular venous distention, arterial pressure 220/100 mmHg, heart rate rhythmic of 82 beats per minute, axillary temperature of 36.1 ºC.Diffuse and bilateral crackles on pulmonary auscultation.There was edema in both legs and on abdominal examination there were no signs of peritoneal irritation.Respiratory support was initiated with oxygen, 2 liters per minute, delivered through the nasal catheter.The oxygen saturation increased to 95%.

Diagnosis
A bedside lung ultrasound showed a bilateral B line pattern compatible with pulmonary edema and the echocardiogram demonstrated a large pericardial effusion with signs of tamponade (Figures 1,2).

Treatment
A bedside, subcostal pericardiocentesis, under local anesthesia, was done and approximately 570 ml of hemorrhagic luid was evacuated.After that, the patient's tachypnea decreases.More than 50 ml of hemorrhagic pericardial luid was evacuated and the patient was transferred to the intensive care unit (ICU), hemodynamically stable, without vasopressor, and with SaO 2 95%.

Outcome
At the ICU the echocardiogram was repeated, showing resolution of the cardiac tamponade and a tumor adhered to the lateral wall of the left ventricle.One chest CT was ordered, whose indings were: left lung tumor, measuring 5.5 × 5 cm, on the inferior lobe, in iltrating pericardial sac.A pericardial luid sample sent for cytology analysis was negative for bacteria, fungus, or virus, but positive for malignancy.A pericardium biopsy analyzed by pathology demonstrated undifferentiated carcinoma.Considering the diagnosis, of advanced malignancy, the patient was moved to palliative care.She progressively deteriorated her oxygenation and died due to tumor in iltration in both lungs.

Discussion
Cardiac tamponade diagnosis, in non-traumatic patients requires a high level of suspicion.Respiratory failure, chest pain, and shock, observed in cardiac tamponade, are also present in different diseases such as pulmonary edema, pulmonary embolism, myocardial infarction, and pneumonia [2,6].The most common inding of cardiac tamponade is dyspnea (78% of cases) [2] and the most frequent clinical presentation is dyspnea, tachycardia, and elevated venous jugular pressure [3].Our patient had dyspnea and, on lung ultrasound, was observed an interstitial-alveolar syndrome; it is characterized by bilateral and diffuse B lines and represents pulmonary edema.Pulmonary edema is one of the manifestations of hemodynamic instability, secondary, in cardiac tamponade, to left ventricular diastolic dysfunction due to left ventricular diastolic collapse.After the diagnosis of pulmonary edema, by pulmonary echography, a bedside echocardiogram demonstrated that cardiac tamponade was the pathophysiology related to our case.Echocardiography is a non-invasive tool, with high accuracy for cardiac tamponade diagnosis, and a bedside approach, preventing the risks of patient's transference to the imaging department.We can use an echocardiogram for excluding diagnoses such as cardiomyopathy, constrictive pericarditis, and myocardial infarction in critically ill patients [7].The diagnosis of cardiac tamponade, by echocardiography, is done when observed: a pericardial effusion with right atrial and right ventricular diastolic collapse [3,6].The four most frequent etiologies of cardiac tamponade are cancer (30% -60%), uremia (10% -15%), idiopathic pericarditis (5% -15%), and infectious disease (5% -10%) [3] Table 1 [8].In our patient, the cytology review of the pericardial luid, the sensitivity of 75% [9][10][11] and the pericardium biopsy con irmed malignancy as the etiology of the pericardium effusion and tamponade.In general, malignancy causes pericardium effusion due to direct invasion of the advanced mediastinum or lung tumor [2].An advanced lung cancer invading the pericardium sac was diagnosed in our case.