Considerations in the difficult-to-manage urea cycle disorder patient.

Today, patients with urea cycle disorder (UCD) may survive well beyond infancy. The goal of keeping them in consistent nitrogen balance can be undermined by changing metabolic needs throughout various stages of life, resulting in hyperammonemia in the short term, and poor growth and development in the long term. The specific UCD genotype can affect the risk of metabolic destabilization and management difficulties, as can variable protein tolerance secondary to changing growth demands, biochemical complications, and environmental influences. Preventing catabolic stress is as important as controlling dietary protein intake for avoiding metabolic decompensation. Optimal treatment, specifically pharmacologic therapy, possible branched chain amino acid (BCAA) supplementation, accurate laboratory monitoring, and psychosocial support, requires thorough understanding and careful application of each component.