Giant left atrium mimicking right pleural effusion

Manuscript type : Case Report | Article Date : 2015/03/18

  • Autors

    1. Soltani Mohammad Hosein
    2. Namayandeh Seyedeh Mahdieh
  • Abstract

    Giant left atrium is a rare condition normally resulting from mitral valve disease, especially Rheumatic heart disease. Several definitions have been presented for giant left atrium, but this condition is usually termed giant left atrium when the left atrial diameter exceeds 80 or and 65 mm. Giant left atrium is the end product of severe and prolonged pressure and volume overload, occurring mainly during mitral insufficiency, stenosis, and rarely in mitral valve prolapse alone4This condition may predispose the patient to atrial arrhythmia, atrial thrombosis and systemic embolization. It may also compress adjacent structures or mimic pleural effusion. It is defined left atria larger than 6 cm in diameter as giant left atrium. In this case report, we present a 75-year-old woman with giant left atrium, which was mistaken for right pleural effusion.
  • Description

    INTRODUCTION

    Giant left atrium is a rare condition normally resulting from mitral valve disease, especially Rheumatic heart disease. This condition may predispose the patient to atrial arrhythmia, atrial thrombosis and systemic embolization.(1) It may also compress adjacent structures or mimic pleural effusion. There are different definitions for giant left atrium. Piccoli and colleagues defined the giant left atrium as a cardio-thoracic ratio of >0.7 on chest radiography combined with a left atrial anterior-posterior diameter of >8 cm on transthoracic echocardiography.(2) Isomura and co-workers defined left atria larger than 6 cm in diameter as giant left atrium. Giant left atrium may mimic pleural effusion and causes inappropriate pleural tap. In this case report, we present a patient with giant left atrium, which was mistaken for right pleural effusion.(3)

    CASE REPORT

    A 75-year-old woman was admitted to our hospital with severe dyspnea and cough lasting for one week. The patient was operated for mitral valve replacement 5 years before her admission and had remained nearly stable afterwards. On admission, clinical examination revealed an irregular heart rate of 90 beats/min, a blood pressure of 125/75 mmHg, and a respiratory rate of 35/min. Jugular pressure was about 12 mmHg at sitting position. Heart sound was irregular and with loud S1 and no significant murmur. There was absence of lung sound in lower right hemi thorax with dullness over it. ECG showed atrial fibrillation with ventricular rate of 95 beats/min and no signs of cardiac ischemia. An echocardiography was done showing normal left ventricular size and function. Left atrium was severely enlarged (anteroposterior diameter=11 cm) with no clots. Mitral prosthetic valve had normal function. The right ventricle was mildly enlarged with mild systolic dysfunction and a moderate tricuspid regurgitation was seen and systolic pulmonary pressure was estimated to be about 50 mmHg. Arterial blood gas showed respiratory acidosis with PaCO2 of about 64 mmHg and oxygen saturation of 75%. Chest radiography is shown in figure 1. Right lung ultrasonography showed right pleural effusion with high density fluid. We treated the patient with supplemental oxygen and antibiotics for possible lung infection and moderate doses of furosemide. There were no signs of improvement in the patient"s clinical condition and blood gases in the following two days. Therefore, we aspirated the possible pleural effusion with and angiocath (No 14) for better evaluation. The fluid was aspirated easily and it was like whole blood. By moving the angiocath, blood was easily aspirated again. Due to the risk of puncturing a blood containing chambers, we injected some contrast agent under fluoroscopic guidance and noticed that the angiocath was in the left atrium. Consulting the surgeon, we removed the catheter with ease. It was obvious that the left atrium was attached firmly to the pleural membrane. Because of continuous hypercapnia, the patient was admitted to the intensive care unit, and underwent mechanical ventilation with concomitant treatment with wide spectrum antibiotics and systemic steroids. She recovered after 8 days and was discharged from the hospital with good condition. Written consent from the patient was performed.

    DISCUSSION

    Several definitions have been presented for giant left atrium, but this condition is usually termed giant left atrium when the left atrial diameter exceeds 80 or and 65 mm. (3, 4) Giant left atrium is the end product of severe and prolonged pressure and volume overload, occurring mainly during mitral insufficiency, stenosis, and rarely in mitral valve prolapse alone.(4) With our patient, the size of the left atrium was about 11 cm in the anteroposterior view and was extended to the right side of the thorax and attached to the right pleural membrane. In chest radiography, it looked like right pleural effusion. Giant left atrium may mimic left or right pleural effusion, and can be inadvertently punctured as pleural fluid. (5-7) Our case was also inadvertently punctured as a right pleural effusion. Thereafter however, with careful evaluation of the chest radiography, it was clear that right costopherenic angle was free of fluid and we might evaluate the patient with more imaging modality. Left atrial puncture may lead to tamponade, but in our case, there was no tamponade or bleeding due to adhesion of the left atrium to the right pleural membrane.

    CONCLUSION

    Giant left atrium may mimic right pleural effusion and in suspected patients with possible left atrial enlargement, careful attention to past medical history, imaging data such as costopherenic angle in chest radiography and more imaging modality is needed to differentiate these conditions.
  • Reference

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