Case report: Abdominal aortic aneurysm mimicking cauda equina syndrome

Spinal cord infarction (SCI) is a rare but critical neurological emergency that can present similarly to cauda equina syndrome (CES). Prompt differentiation between compressive and vascular causes is vital for timely intervention. An 81-year-old Asian male presented with sudden onset bilateral lower limb flaccid paralysis, complete sensory loss, and perianal hypoesthesia, initially suggestive of cauda equina syndrome. MRI of the spine showed only mild to moderate lumbar spinal stenosis without significant cord compression, prompting reconsideration of the diagnosis. A neurologist noted a >40 mmHg inter-arm blood pressure difference, raising suspicion for vascular pathology. A CT aortogram revealed an infrarenal thrombosed abdominal aortic aneurysm with complete occlusion of the bilateral common iliac arteries and distal collateral reconstitution. Despite initiation of anticoagulation, the patient rapidly deteriorated, developing bilateral critical limb ischemia due to progressive thrombosis. Surgical options were deemed unfeasible, and palliative care was initiated. The patient died three days later. This case underscores the importance of considering spinal cord infarction due to vascular causes such as aortic aneurysm in patients presenting with acute lower limb neurological deficits, especially when imaging does not support a compressive etiology. Early recognition and vascular imaging are crucial to improving diagnostic accuracy and informing management decisions in such rapidly progressive conditions.