Continuous left hemidiaphragm sign revisited: a case of spontaneous pneumopericardium and literature review

Abstract

In pneumopericardium, a rare but potentially life threatening differential diagnosis of chest pain with a broad variety of causes, rapid diagnosis and adequate treatment are crucial. In upright posteroanterior chest radiography, the apical limit of a radiolucent rim, outlining both the left ventricle and the right atrium, lies at the level of the pulmonary artery and ascending aorta, reflecting the anatomical limits of the pericardium. The band of gas surrounding the heart may outline the normally invisible parts of the diaphragm, producing the continuous left hemidiaphragm sign in an upright lateral chest radiograph. If haemodynamic conditions are stable, the underlying condition should be treated and the patient should be monitored closely. Acute haemodynamic deterioration should prompt rapid further investigation and cardiac tamponade must be actively ruled out. Spontaneous pneumopericardium in a 20 year old man is presented, and its pathophysiology described.

Cardiac Tamponade by Iatrogenic Pneumopericardium

“…10) Mill-wheel murmur produced by churning movement of the heart in a pericardial cavity is a pathognomic finding on auscultation.…”

“…Chest X-ray may show air separating pericardium from the heart or "continuous diaphragm sign" that indicates the presence of air within pericardium making normally invisible parts of central diaphragm visible in continuation with both hemidiaphragms. 10) Computed tomography can offer confirmation of the diagnosis in obscure cases and additional information about associated lesions. 9) As ultrasound beam can not easily pass through air, echocardiography is not routinely used for diagnosis of pneumopericardium.…”

Pneumopericardium and Deep Sulcus Sign After Blunt Chest Trauma

“…For diagnosis, CXR and CT could be used. The "continuous left hemidiaphragm sign" can be observed at CXR that indicates the presence of air within pericardium, which makes normally invisible parts of the central diaphragm visible in continuation with both hemidiaphragms [4]. At CXR, the characteristic sign is the presence of air around the cardiac silhouette.…”

“…In tension pneumopericardium, rapid fluid resuscitation and emergent pericardiocentesis with echocardiographic guidance and haemodynamic monitoring, followed by pericardial fenestration and pericardial drainage, should be performed [6]. With stable haemodynamic conditions and absent tamponade, the underlying condition should be treated and the patient should be monitored closely [4]. In our case, mechanical ventilation was not required.…”

“…In addition, the electrocardiogram changes, such as ST elevation/ depression, could be seen. None of these findings, however, are specific [4]. For diagnosis, CXR and CT could be used.…”