A male patient in his 20s presented to the ED with complaints of light-headedness. The patient reported a history of sustaining a stab wound on the anterior aspect of his left thigh 1-day prior. His leg x-ray was normal, and he was discharged after receiving 2 subcutaneous sutures. The following day, the patient presented to the ED after experiencing a syncopal event post-micturition followed by persistent light-headedness.
His presenting blood pressure was 97/48 mmHg with a heart rate of 112 beats per minute, oxygen saturation of 97%, and a respiratory rate of 25 breaths per minute. The patient appeared pale, with clear breath sounds, and regular upper and lower limb pulses. His abdominal examination was unremarkable, his Glasgow Coma Scale was 14/15 (E3 V5 M6) with equal 3mm reactive pupils and he had a glucose level of 210 mg/dl.
The patient’s blood pressure failed to respond to an initial 1-liter of normal saline fluid bolus, and his oxygen saturation dropped to 92% on room air. This was accompanied by a sudden onset of bilateral chest pain. He was subsequently administered oxygen via a nasal cannula at a flow rate of 6L/min. However, despite this intervention, his oxygen saturation continued to decline, reaching a critical level of 74%.
The patient’s clinical examination continued to remain unremarkable with clear lung fields, lack of murmurs on auscultation, no evidence of distended neck veins or tracheal deviation. Examination of his lower limbs revealed equal pulses in the dorsalis pedis and posterior tibial along with no clear signs of edema or skin color changes. The previously injured left thigh had a 1-cm sutured wound with mild localized tenderness, no swelling, ecchymosis nor active bleeding. No other injuries were noted during the examination.
The case was recognized as undifferentiated shock and a bedside US with the utilization of the RUSH protocol was performed. This revealed a strained and dilated right ventricle with akinesia of the free wall along with apical sparing, features suggestive of an increased pulmonary artery pressure5. The inferior vena cava was dilated, while the lung and abdominal ultrasound displayed normal findings. The vasculature of the lower limbs was also assessed revealing a deep vein thrombosis (DVT) in the left femoral and popliteal veins. In a span of 8 minutes, a provisional diagnosis of obstructive shock by a DVT-induced PE had been made. The patient’s electrocardiogram (ECG) had a positive S1Q3T3 sign with T-wave inversions in the anterior and inferior leads, features further suggestive of PE (Fig. 1).
The patient underwent computed tomography pulmonary angiography (CTPA), revealing a thrombotic occlusion in the right pulmonary artery bifurcation (Fig. 2), extending into the right upper, middle, and lower lobar branches, as well as segmental branches. Additionally, a small pulmonary embolus was noted in the left lingula and lower lobar branches. The imaging also revealed a significantly increased right-to-left ventricular ratio (RV/LV) of 2.1 with a dilated pulmonary artery (Fig. 3). A final diagnosis of massive PE was made, and the cardiology team was promptly notified for the initiation of the tissue plasminogen activator (tPA) treatment.
CT angiogram of the lower limb revealed an active intramuscular vascular leak, resulting in a large hematoma at the left mid-thigh. This was caused by an arterial pseudoaneurysm originating from a smaller branch of the left superficial femoral artery (SFA) (Fig. 4). The pseudoaneurysm was likely a consequence of what was initially thought to be a superficial stabbing injury. This exerted an external compression on the patient's deep veins, leading to a clot formation. The dislodgement of the clot subsequently resulted in the development of the patient’s PE. The vascular team stented the pseudoaneurysm the following day, and the patient was discharged in a clinically and hemodynamically stable condition after 10 days of admission.