706 - OTC Deficient Metabolic Encephalopathy uncovered by Surgical Intervention: A Case Report

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

RK

Ryan B. Keller, DO

Resident Physician
Northwestern Medicine (Shirley Ryan Ability Lab / Lurie Children's Hospital)
Chicago, Illinois, United States

Co-Author(s)

TG

Tanya Goyal, BS

Co-Author
Texas College of Osteopathic Medicine
Fort Worth, Texas, United States
JP

Jessica Pryor, MD

Assistant Professor
University of Texas Southwestern Medical Center (UTSW), Department of Pediatrics
Frisco, Texas, United States

Submitter(s)

RK

Ryan B. Keller, DO

Northwestern (SRAL/Lurie Children's)
Chicago, Illinois, United States

Case Diagnosis: OTC Deficient Metabolic Encephalopathy uncovered by Surgical Intervention: a Case Report

Case Description:
A 10-year-old female with past medical history of ADHD, behavioral concerns, self-restricting protein diet, and cyclic vomiting was admitted after a recent supracondylar fracture s/p closed reduction with acute altered mental status, poor sleep, intermittent slurred speech, and respiratory alkalosis found to have hyperammonemia. Neurologic investigation via rMRI and EEG revealed white matter track diffusion abnormalities and diffuse slowing, respectively, consistent with metabolic encephalopathy. With genetic consultation, a de novo heterozygous pathogenic variant was identified in her Ornithine Transcarbamylase sequence. To balance behavioral restriction and uncontrolled ammonia levels, this patient required ammonia scavengers, genetic and dietitian services, and placement of a G-tube. Her care was complicated by deconditioning due to a prolonged hospital stay and functional dysarthria, requiring intensive PT/OT/SLP.

Discussions: Ornithine Transcarbamylase Deficiencies are estimated in 1 in 14,000 to 1 in 80,000 births per year. Though often identified on newborn screening, late-onset OTC deficiency is characteristically uncovered by the emergence of neuropsychiatric symptoms. As a manifestation of underlying encephalopathy, these brain injuries are typically symmetric in nature, with involvement of the white matter in the insular and cingulate cortices. Due to these areas’ advanced metabolism, rapid sequelae of injury can result in cognitive and behavioral disturbances.

Conclusions: This case describes a progressive brain injury resulting from a metabolic deficiency. While the evolution of traumatic brain injury is a focus of current research, transient states of encephalopathy represented by diffusion abnormalities are underdefined. Cases like this better outline the process for early detection, treatment, and recovery--key components to preventing long-term neurocognitive deficits and fatal outcomes in OTCD populations. In collaboration between specialties, pediatric physiatrists often care for patients with both late-onset and neonatal onset OTCD, due to chronic complications like developmental delay, intellectual disability, and cerebral palsy.