Disorders of urea cycle metabolism

This code identifies a group of inherited metabolic disorders characterized by defects in the enzymatic pathway responsible for converting ammonia to urea. These defects lead to the accumulation of toxic ammonia in the bloodstream, primarily affecting the brain and liver. The severity can range from life-threatening neonatal presentations to milder, later-onset forms.

Assign this code when documentation specifies a diagnosis of a urea cycle disorder, such as ornithine transcarbamylase (OTC) deficiency, argininosuccinate lyase deficiency, or carbamoyl phosphate synthetase I deficiency. This code is appropriate for patients undergoing diagnostic workups for hyperammonemia of unknown origin or for ongoing management of a confirmed urea cycle defect.

• Always review physician documentation for the specific type of urea cycle disorder, as more specific ICD-10-CM codes are available.
• Consider sequencing this code as a primary diagnosis when the urea cycle disorder is the reason for the encounter.
• Look for associated symptoms like hyperammonemia (276.7), encephalopathy (348.30), or developmental delay (315.9) to code concurrently.