Hyperammonemia-Associated Stroke-Like Episodes and Acute Liver Failure in an 11-Month-Old Infant With Probable Ornithine Transcarbamylase Deficiency: Diagnostic and Therapeutic Challenges in a Resource-Limited Setting

Hyperammonemia outside the neonatal period is a time-critical emergency and may reveal a late-onset urea cycle disorder, including ornithine transcarbamylase deficiency (OTCD), which can be particularly challenging to recognize in females. We report the case of an 11-month-old female who presented with seizures and transient focal neurological deficits in the context of recurrent vomiting and acute hepatic dysfunction, with respiratory alkalosis and marked hyperammonemia accompanied by biochemical features compatible with a proximal urea cycle defect. Brain imaging showed stroke-like changes that were not consistent with a vascular territory, supporting a metabolic mechanism rather than primary ischemia. In a resource-limited setting where standard nitrogen-scavenging therapy and extracorporeal ammonia removal were not accessible, prompt catabolic control using strict protein restriction and high-calorie hydration was associated with biochemical recovery and clinical improvement, although mild residual weakness remained. This report highlights that early suspicion and immediate supportive management can be lifesaving when advanced diagnostics and targeted therapies are unavailable.