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Abstract: TH-PO382

Renal Replacement Therapy in Treatment of Adult-Onset Ornithine Transcarbamylase Deficiency

Session Information

Category: Fluid, Electrolytes, and Acid-Base Disorders

  • 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical


  • Ritchie, Leanna V., Mayo Foundation for Medical Education and Research, Jacksonville, Florida, United States
  • Mccormick, Benjamin J., Mayo Foundation for Medical Education and Research, Jacksonville, Florida, United States
  • Porter, Ivan E., Mayo Foundation for Medical Education and Research, Jacksonville, Florida, United States

Hyperammonemia is a relatively common disorder that has a spectrum of presentations ranging from confusion to coma. The less common etiology of hyperammonemia is related to urea cycle disorders such as ornithine transcarbamoylase deficiency (OTCD). This X-linked enzymatic disorder results in an accumulation of ornithine, orotic acid and urea with incomplete penetrance. The majority of cases occur as congenital enzyme disorders that may present with severe, development effects and high mortality in the pediatric population. However, the enzyme deficiency may also be inherited with incomplete penetrance such that the disorder is triggered by high protein catabolism states at later life stages.

Case Description

Here presented is a case of a 61 year old female without prior medical history who presented with somnolence after initiation of corticosteroids for acute back pain. No evidence of infection, hemodynamically stable and serum ammonia was 233 mcg/dL.The patient had no hepatic dysfunction and was evaluated for urea cycle disorder. Intermittent hemodialysis (IHD) was used for rapid lowering of serum ammonia levels. Following IHD ammonia improved to 118 mcg/dL. However, within 24h ammonia increased to 223 mcg/dL. The patient received a second session of IHD followed by initiation of CVVH to prevent rebound accumulation. CVVH was continued for approximately 24h to allow for administration of nitrogen scavengers (benzoate and phenylacetate). The patient was initiated on intravenous nitrogen scavengers, low protein/high glucose/high fat diet until mental status improved. Genetic testing identified X-linked hemizygous variant for OTCD.


This case report explores the tandem use of large surface area dialyzer via IHD and continuous veno-venous hemofiltration (CVVH) for rapid ammonia filtration. Rapid withdrawal of IHD prior to maintenance therapy with nitrogen scavengers has been associated with rapid reaccumulation of ammonia if the urea cycle co-factors are not replaced. This is a method that has been previously studied in the pediatric population with limited application to the adult population due to its rarity (1 in 56000 births). However, we applied these principles to an adult with success and improvement in clinical outcome.