Bilateral lower-extremity paresis as an atypical presentation of subarachnoid hemorrhage: A case report.

Background: Subarachnoid hemorrhage (SAH) is a neurological emergency typically presenting with a sudden, severe headache. Focal neurological deficits are generally unilateral and correspond to the location of the aneurysm or hematoma. Bilateral lower limb paresis as an initial manifestation is extremely rare and may delay diagnosis. This report highlights a unique case and explores potential mechanisms underlying this atypical presentation. Case Description: A 62-year-old woman presented with acute bilateral leg weakness and headache. Imaging revealed diffuse SAH from a ruptured aneurysm at the right internal carotid-posterior communicating artery junction, without mass effect . Magnetic resonance imaging revealed acute infarcts in the bilateral medial frontal lobes and the splenium of the corpus callosum, consistent with an infarction in the anterior cerebral artery territory. Angiography revealed no vasospasm, and spinal pathology was excluded. The aneurysm was successfully treated with coil embolization. The patient's leg strength gradually improved over the 1st month. Conclusion: This case underscores the importance of including SAH in the differential diagnosis of acute paraparesis, even in the absence of classic signs. Bilateral infarcts may result from early microthrombosis or transient cerebral hypoperfusion following a sudden increase in intracranial pressure. Recognizing such mechanisms is essential for timely diagnosis and management.