711 - From Cure to Constriction: Recurrent TIA in a young adult with Radiation-induced Moyamoya Syndrome

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

OA

Omar Awadalla, DO

Resident Physician
NYU Langone Health
New York, New York, United States

Co-Author(s)

CC

Cherie Chen, DO

Resident Physician
NYU Grossman School of Medicine
New York, New York, United States
GA

Gabrielle N. Avancena, MD

Resident Physician
NYU Grossman School of Medicine
Long Island City, New York, United States
RS

Renat Sukhov, MD

Attending
NYU
New York, New York, United States

Submitter(s)

OA

Omar Awadalla, DO

NYU Langone Health
New York, New York, United States

Case Diagnosis: TIA in 20-year-old female with Radiation-induced Moyamoya syndrome (RIMMS)

Case Description: Patient had history of left temporal pilocytic astrocytoma diagnosed at 11 y.o. She underwent neurosurgical and neuroradiological interventions (proton therapy) complicated by acute left hemispheric stroke due to left M1 occlusion (moyamoya) at age 20. While receiving outpatient rehabilitation, she developed worsening right-sided weakness and sensory deficits necessitating transfer for stroke evaluation. She reported stress and insomnia preceding this event. DSA revealed severe stenosis of the left ICA terminus, left A1, and progression to complete LM1 occlusion with collateral circulation from Lt ACA, PCA, MMA to Lt MCA territory. She was monitored in the stroke unit and later discharged home with outpatient therapy recommendation given absent radiographic findings of acute stroke and return to baseline the following day.

Discussions: This case demonstrates brief neurologic dysfunction from focal brain ischemia due to RIMMS. Recent evidence asserts that cases of proton-induced moyamoya typically manifest within the first 2 years of treatment completion. There remains, however, a paucity of evidence referencing secondary prevention of TIAs in young patients with RIMMS. In the background of worsening steno-occlusive disease, it is plausible that dehydration, excessive physical activity, sleep dysregulation, and stress were triggering factors. With this rare case, we highlight the need for secondary TIA prevention and Physiatric interventions geared towards educating young patients with RIMMS on triggers and modifiable risk factors to reduce risk of ischemic events.

Conclusions: RIMMS is an often underrecognized vasculopathic etiology of cerebral ischemic events in young patients who've undergone proton therapy. It is essential for Physiatrists to maintain an appropriate index of suspicion for evolving neurologic dysfunction and educate young patients on modifiable risk factors (hypertension, hypoperfusion/volume depletion, dyslipidemia, smoking, elevated BMI, diabetes). Patients and caregivers with RIMMS should receive lifestyle and activity modification counseling following proton therapy in outpatient rehabilitation settings.