Penetrating thoracic injury: the heart is the target

Clinical History

A 16-year-old boy was referred to our emergency department three hours after a fight, with a penetrating stab wound above his left mammillary region. He was anxious, slightly dyspnoeic, but with good pulse and without jugular distension. His blood pressure, heart rate and electrocardiogram (ECG) were unremarkable.

Imaging Findings

Chest radiograph showed a cardiac silhouette with the varying cardiac density sign, abnormal bulge of left cardiac contour and a translucent line delineating the left mediastinal superior border (Fig. 1).

An unenhanced and enhanced non-ECG gated multidetector CT was performed. A small left pneumothorax was seen (Fig. 2). Linear air-bubbles in the third left intercostal space revealed the wound track. A dense heterogeneous effusion (50 HU) in superior pericardial recess was seen, consistent with haemopericardium (Fig. 3). Enhanced CT revealed a linear high density in haemopericardium in front of right ventricular apex suggesting myocardial perforation and contrast extravasation into pericardial sac (Fig. 4).

Transthoracic echocardiogram confirmed a heterogeneous hyperechogenic pericardial effusion suggesting active hemorrhage. Cardiac contractility and function were normal (Fig. 5).

Patient immediately underwent cardiac surgery, which confirmed right ventricular laceration and a blood clot sealing the wound. Rupture of the root of great vessels was excluded, confirming CT findings.

Discussion

Penetrating wound of the chest wall is a relatively frequent type of injury in the emergency situation, usually a non life-threatening one [1]. However, when the heart is injured, less than 20% of patients reach the hospital alive [2] which requires a high index of suspicion [1] to diagnose cardiac perforation on time.

Clinical presentation of cardiac trauma is extremely variable and can range from haemodynamic stability to profound shock, depending on the size and location of the damage [2, 3, 4]. Cardiac perforation can temporarily be sealed by a clot, but if displacement of the clot occurs, pericardial tamponade with exsanguination will seriously compromise cardiac function. If this happens, resuscitation is of limited value and cardiac surgery is the only lifesaving treatment [4].

In the presented case the clinical symptoms were unremarkable and the wound was diagnosed to be only superficial. A more severe situation was suspected based on the admission chest radiograph, which showed a varying cardiac density sign and a translucent line along the upper mediastinal border. Pericardial effusion and pneumothorax were suspected and further investigation was required. CT of the thorax turned out to be critical in order to guide treatment and to plan the surgical procedure. Multidetector thoracic CT, with and without intravenous contrast agent (even without cardiac ECG gating), defined hemorrhagic pericardial effusion and suggested myocardial perforation of the right ventricular apex and contrast extravasation into the pericardial sac. It also excluded involvement of the great vessels in the mediastinum.

This clinical case points out the need for careful inspection of admission chest radiographs even when a superficial thoracic stab wound is thought to be the case. Thoracic CT confirmed the need of a life-saving surgical procedure.

Differential Diagnosis List

Final Diagnosis

Laceration of right ventricular wall after a chest stab injury

URL:	https://www.eurorad.org/case/9496
DOI:	10.1594/EURORAD/CASE.9496
ISSN:	1563-4086