Case report of a partially thrombosed ACoA aneurysm presenting with bilateral foot drop

Foot drop is defined as a weakness in the ankle and foot dorsiflexors. A disruption of the neural pathway starting from the mesial frontal cortex and ending in the peroneal nerve can lead to foot drop. Unilateral foot drop due to lower motor neuron injury is well documented. However, bilateral foot drop due to a central cause is very rare.

A 29-year-old male presenting with bilateral lower extremity weakness in addition to rigidity. The patient is known to have bipolar disorder and an Anterior communicating artery aneurysm (ACoA) for which he has not followed up. A CTA showed a partially thrombosed 5 mm × 6 mm ACoA aneurysm. The patient underwent placement of flow diverter PED.

Central causes of acute bilateral foot drop are rare but should be considered in the differential diagnosis. Thrombo-embolism due to a partially thrombosed aneurysm is a well known phenomenon, all treatment options should be considered keeping in mind the risks associated with the different techniques due to the intra saccular thrombus.