The Clot Thickens - A case of Limb Ischemia 

PC

A male in his 70s presented to ED with a primary complaint of a very painful left leg. The pain was claudicant in nature. There was no history of trauma. He had a relevant past medical history of diabetes, hypertension, CKD 3 and had a 40 pack year smoking history.

Vital signs

HR 92, BP 183/98, RR 18, T 36.9, SpO2 99% RA

Examination findings

Left leg - pale, cold, painful, loss of sensation in all dermatomes. Loss of dorsalis pedis, posterior tibial, popliteal and femoral pulse. CRT >10 seconds in each toe.

Right leg - normal examination with strong pulses.

There was mild discomfort on deep palptation of the central abdomen which the patient did not mention on history. 

Clinically there was a high suspicion of acute arterial insufficiency in the left leg. However given the abdominal discomfort a bedside US was done.

A curvilinear probe was used to scan the abdomen. The image on the left shows a large central vessel consistent with a dilated abdominal aorta. A closer examination on the right reveals an >8cm abdominal aortic aneurysm (AAA) with a strong suggestion of a mural thrombus:

• There is a central anechoic (black) lumen where blood is flowing.

• Surrounding this, there appears to be echogenic, layered material along the wall - this is characteristic of a mural  thrombus.

• This is very common in large AAAs and not unusual at this size.

A CT aorta and lower limb angiogram was done which confirmed a 9cm abdominal aortic aneurysm with large mural thrombus and evidence of acute left limb ischaemia secondary to a large occlusive thromboembolism proximal to the left Femoral artery. Subsequently the patient was transferred to a vascular centre for ongoing management

Learning points

1. POCUS can identify both the complication and its source — in acute limb ischaemia POCUS is a valuable tool for vascular assessment and extending the scan to the abdominal aorta can reveal underlying aortic syndromes.

2. AAA may present atypically — limb ischaemia can be the first manifestation, even in the absence of abdominal or back pain.

3. Early bedside diagnosis changes management — rapid POCUS detection expedites vascular referral and definitive imaging, improving time-critical care.

Trainee Lead Editor: Dr Amy Knowles, ST5

Checked: Dr Ahmed Abdul-Ghani, Lead Project Consultant