(743) Brain MRI Findings in Children With Paroxysmal Sympathetic Hyperactivity After Acute Brain Injury

Introduction: Paroxysmal sympathetic hyperactivity (PSH), seen in survivors of severe brain injury, is defined as paroxysmal, transient increases in sympathetic and motor activity. Causes of PSH include traumatic brain injury, anoxic brain injury, intracranial hemorrhage, and CNS infection. PSH is associated with longer hospital stay and worse functional outcomes. The pathophysiology of PSH is poorly understood, and the literature suggests an association between symptoms and brain imaging findings such as white matter damage or focal lesions. The aim of this study was to describe MRI brain findings and clinical course of pediatric patients with new PSH.

Methods: This single site retrospective study included patients ≤ 18 years with acute severe brain injury between January 1, 2019, and December 31, 2023, with PSH symptoms and a full MRI brain completed during PICU admission. Demographics, primary diagnosis, hospital timeline, MRI findings, clinical symptoms, PSH maintenance and rescue medications were abstracted from the medical record.

Results: Of the 49 patients, median age was 11 (IQR 3, 16) years, 63% were male. Primary diagnoses were TBI (45%), cardiac arrest (16%), CNS infection (10%), and intracranial bleed (8%). The median initial GCS was 3 (IQR 3, 7), hospital length of stay 42 (IQR 30, 57) days, and PICU length of stay 17 (IQR 11, 25) days. MRI brain reports revealed diffusion restriction (69%), edema (61%), microhemorrhage (39%), diffuse axonal injury (33%), subdural hematoma (27%), contusion (20%), subarachnoid hemorrhage (14%), and extradural hematoma (8%). Median MRI report-based score (calculated as sum of these findings = Yes) was 2 (IQR 1, 4). Maintenance medications prescribed included Clonidine (86%), Propranolol (71%), Bromocriptine (59%), Baclofen (39%), Gabapentin (37%), and Dexmedetomidine (4%), and median number of maintenance medications was 3 (IQR 2, 4). Analysis of the relationship between MRI scores and severity of PSH is in process.

Conclusions: Preliminary analysis indicates that most children with PSH after acute severe brain injury will have multiple abnormal MRI findings and require several maintenance medications with PRN doses during treatment.