Ornithine Transcarbamylase (OTC) Deficiency Treatment & Management

Updated: Jan 07, 2019
  • Author: Karl S Roth, MD; Chief Editor: Luis O Rohena, MD, MS, FAAP, FACMG  more...
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Treatment

Medical Care

Immediate temporary discontinuation of protein intake in a symptomatic individual with ornithine transcarbamylase (OTC) deficiency is mandatory, with compensatory increases in carbohydrates and lipids in order to offset any catabolic tendency to draw on muscle amino acids for energy.

In a patient who is comatose with extremely high blood ammonia levels (in some cases exceeding 2000 mg/dL), rapid reduction can be achieved with hemodialysis.

Intravenous administration of sodium benzoate, arginine, and sodium phenylacetate is important; however, only administer these drugs in a large medical facility setting with close laboratory monitoring available. Intravenous sodium benzoate and phenylacetate (Ammonul) was approved in the United States in February 2005.

Glycerol phenylbutyrate is a pre-prodrug that undergoes metabolism to form phenylacetate. Results of a phase 3 study comparing ammonia control in adults showed glycerol phenylbutyrate was noninferior to sodium phenylbutyrate. [11] In a separate study involving young children ages 2 months through 5 years, glycerol phenylbutyrate resulted in a more evenly distributed urinary output of phenylacetylglutamine (PAGN) over 24 hours and accounted for fewer symptoms from accumulation of phenylacetate. [12]

A biochemical geneticist and a highly trained nutritionist should administer long-term outpatient care in a large facility setting with laboratory monitoring available.

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Consultations

Consultations include the following:

  • Medical geneticist

  • Metabolic disease specialist

  • Dietitian

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Diet

Immediate temporary discontinuation of protein intake in a symptomatic individual is mandatory, with compensatory increases in carbohydrates and lipids in order to offset any catabolic tendency to draw on muscle amino acids for energy.

A highly trained nutritionist should administer long-term outpatient care in a large facility setting with laboratory monitoring available.

Scrupulous adherence to the dietary and medication recommendations is mandatory for survival.

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Further Outpatient Care

A biochemical geneticist must oversee patient care because the metabolic integrity of such individuals with ornithine transcarbamylase (OTC) deficiency is very tenuously poised.

Proper nutrition does not follow the usual nutritional rules, and any variations from what is appropriate may result in disaster. This is true throughout life but mostly in the growing infant and adolescent child in whom requirements may fluctuate weekly and must be closely monitored.

Scrupulous adherence to the dietary and medication recommendations is mandatory for survival. Under no circumstances should this be undertaken by a general physician without close guidance from an expert in the care of patients with inherited metabolic diseases.

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