210 - Intersecting Crises: Thyroid Storm and Encephalopathy in Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL)

42-year-old female with CADASIL, prior ischemic strokes with residual left-hemiparesis, seizure disorder, and migraines presented after a fall with head strike. Initial CT head showed no acute abnormality and trauma workup was negative. While awaiting transfer, she developed fever, tachycardia, hypertension, and encephalopathy. Labs revealed TSH < 0.01 and free T4 3.68, consistent with thyroid storm (Burch-Wartofsky score >70). Thyroid ultrasound demonstrated diffuse enlargement without nodules. She was treated with propranolol, methimazole, iodine, and corticosteroids. Repeat CT Head revealed chronic microvascular ischemic changes in periventricular white matter and remote infarcts in the basal ganglia, thalamus and cerebellum. MRI brain demonstrated chronic changes. During acute inpatient rehabilitation, impaired mobility, difficulty with ADLs, and cognitive deficits in the setting of confusion and agitation were addressed with PT, OT, and SLP. She progressed from moderate/maximum-assistance to supervision/independent with mobility and self-care. On discharge, she continued with outpatient therapy.

Discussions: Thyroid storm is a rare but life-threatening endocrine emergency, most often precipitated by systemic illness or neurologic stressors. In this patient, seizures and underlying CADASIL with prior ischemic stroke may have contributed to her decompensation. CADASIL is a hereditary small vessel vasculopathy associated with recurrent strokes, migraine, and cognitive decline, which complicates recovery from acute metabolic insults. Differentiating encephalopathy due to thyroid storm from other etiologies such as seizure, infection, or vascular injury is clinically challenging. Rehabilitation management emphasized safety awareness, cognitive retraining, energy conservation, and motor recovery.

Conclusions:

This case illustrates that the encephalopathy was likely primarily attributable to thyroid storm with underlying CADASIL as a compounding factor. Prompt recognition and treatment of thyroid storm stabilized her condition, while targeted inpatient rehabilitation supported functional gains. Multidisciplinary coordination between endocrinology, neurology, and rehabilitation was essential to optimize recovery in the setting of overlapping metabolic and neurologic disease.