1424 - Capsular Warning Syndrome- a perhaps underappreciated syndrome

Case Diagnosis: capsular warning syndrome

Case Description: A 65-year-old male with hypertension, type 2 diabetes, and hyperlipidemia arrived to the emergency department Day 1 (D1) after a self-limiting episode of severe right-sided upper and lower extremities weakness 8 hours prior. Strength 5/5 throughout CTA revealed 70% stenosis of the left internal carotid artery. He was treated with statin, aspirin, and clopidogrel. During his hospitalization (D3), the patient developed new-onset right-sided weakness 2/5 throughout the right side, slurred speech, right tongue deviation, right facial droop. CT head negative. MRI showed acute infarct in left posterior limb of internal capsule. Patient transferred to acute inpatient rehabilitation AIR (D15) and gradually improved. During rehabilitation stay (D19), patient had acute worsening of slurred speech, lethargy, drooling, and headache. CT head negative for acute hemorrhage and showed infract in left posterior limb of internal capsule. Soon after (D22), the patient's new symptoms resolved, and was back to his AIR baseline (D15).

Discussions: We believe our patient has what is known as capsular warning syndrome (cws) first described by Donnan et all in 1993(neurology 43:957-962). CWS appears to be uncommon and is not widely known about or appreciated. Classically cws is a succession of TIA’s with motor symptoms occurring within 72 hours of each other. Our patient’s case is slightly unusual, but within the scope of cws as he had (1) a TIA (D1), then (2) CVA affecting the internal capsule (D3) and then (3) TIA (D19) during his AIR stay. The waxing and waning nature of the pathology forces the team to adapt its expectations more often than may be expected in classical stroke patients. Repeated head imaging has its own consequences.

Conclusions: CWS should be considered in the differential diagnosis for patients with increased motor symptoms who have been admitted to AIR following a CVA in the internal capsule.