Abstract WP333: Reversible Anterior Cerebral Artery Vasoconstriction Presenting as Limb-Shaking Transient Ischemic Attack

Background: Limb-shaking transient ischemic attack (LS-TIA) is an uncommon manifestation of cerebral hypoperfusion, often linked to in situ large-vessel stenosis. Involvement of the anterior cerebral artery (ACA) is rare. Reversible cerebral vasoconstriction syndrome (RCVS) presents with multifocal arterial narrowing that resolves within weeks to months and often presents with thunderclap headache. The combination of LS-TIA and RCVS is unusual and highlights the importance of considering dynamic vasospasm in the differential diagnosis. Case: A 48-year-old woman with a history of migraine and a 30-pack-year smoking history presented with right lower extremity weakness and shaking lasting 2–3 minutes, with spontaneous resolution, followed by bifrontal and bioccipital headaches. She experienced three similar episodes on the same day. Neurological examination was normal, with NIHSS 0. MRI of the brain and EEGs were unremarkable. CTA of the head and neck showed multifocal severe narrowing of the left ACA, a hypoplastic right ACA, and mild basilar narrowing. Echocardiogram was normal. She was started on dual antiplatelet therapy and a high-intensity statin, counseled on smoking cessation, and advised on hydration. At 2-month follow-up, CTA demonstrated complete resolution of ACA narrowing, consistent with RCVS. Discussion: Dynamic vasospasm in RCVS can mimic fixed stenosis, especially with poor collateral supply, and trigger LS-TIA through transient hypoperfusion. Follow-up vascular imaging is essential to confirm reversibility, avoid misdiagnosis, and prevent unnecessary prolonged therapy. Modifiable triggers such as smoking, dehydration, and emotional stress should be addressed, and a course of calcium channel blockers may be considered in symptomatic patients. This case expands the clinical spectrum of both LS-TIA and RCVS, suggesting vasospasm-induced LS-TIA may be underrecognized. Conclusion: This case represents an atypical presentation of LS-TIA due to reversible ACA vasoconstriction in RCVS. RCVS should be considered in cases of LS-TIA associated with headache and multifocal narrowing. Early recognition and serial imaging are essential for accurate diagnosis, optimal management, and prevention of triggers.