Acute limb ischemia presenting as a clinical conundrum: stroke mimic or aortic dissection?

Patients with atrial fibrillation and transthyretin amyloid cardiomyopathy (ATTR-CM) have been found to have a very high incidence of intracardiac thrombus and thromboembolic disease. Acute limb ischemia is a rare, highly morbid condition that may mimic other medical emergencies. An 88-year-old male with ATTR-CM presented with left sided hemiparesis and paraesthesia. Computed tomography scan and magnetic resonance imaging of the head was negative for stroke. Subsequent computed tomography angiography (CTA) of the chest was obtained due to an abnormal interarm blood pressure differential which was negative for acute aortic dissection but revealed simultaneous occlusions of the left axillary and common femoral arteries. These occlusions were presumed to be cardioembolic from a left atrial appendage thrombus concurrently visualized on CTA. This case highlights the importance of avoiding anchoring bias, and systematically reevaluating the differential diagnosis in cases where the initial workup is unrevealing. While an uncommon entity, simultaneous upper and lower acute limb ischemia should be considered in patients with atrial fibrillation and prothrombotic comorbidities, such as ATTR-CM. LEARNING POINTS: Acute limb ischemia can mimic stroke and aortic dissection, requiring a broad differential diagnosis in patients with atrial fibrillation and transthyretin amyloid cardiomyopathy.A systematic vascular-anatomic approach helps identify embolic events when initial stroke imaging is negative.Acute ischemia may be indicated by lactic acidosis without hemodynamic instability, which should lead to additional vascular assessment.