Citrullinemia refers to a family of autosomal recessive disorders involving the
urea cycle. Three forms exist, which have different implications. Type I
citrullinemia exists in both mild and severe forms. It arises due to mutations with
argininosuccinate synthase leading to accumulation of
ammonia and producing symptoms of
lethargy, poor feeding, and
seizures. Type II
citrullinemia occurs due to
citrin mutations involved in the
urea cycle transport or during neonatal
cholestasis. Management of both conditions requires
low-protein diets along with
arginine,
sodium benzoate, and
sodium phenylacetate. While traditional treatment shows improved outcomes, modifications may be necessary depending on a patient's presentation. We present a unique case of a 19-year-old wheelchair-bound female with a past medical history of heterozygous
type I citrullinemia,
seizures, and
chronic encephalopathy presented to a local children's hospital for evaluation of altered mental status with a lethargic mental state. She was initially found to have an
ammonia level of 329 µmol/L and
choledocholithiasis on admission. Dietary modification with intravenous
dextrose and intralipids with oral
lactulose saw improvement in her labs. However, her
ammonia level increased to 381 µmol/L despite such interventions. Intensive care was required to normalize her serum
ammonia level and clear her for a magnetic resonance cholangiopancreatography (MRCP). We present a unique case of heterozygous
type I citrullinemia with some overlap with type II
citrullinemia features. Further studies are needed to understand better the observed unique presentation and long-term clinical implications associated with the disease.