TABLE 13.2: Intoxication Disorders

Intoxication Disorders^{1, 2, 3, 4, 5, 6}

Disorders With Selected Examples	Etiology, Clinical Presentation	Acute Management^a	Chronic Management^a	Diagnostic Testing^a
Urea Cycle Disorders OTC Deficiency CPS I Deficiency Citrullinemia	Unable to metabolize proteins to energy Acute intoxication episodes of hyperammonemia, ± respiratory alkalosis	Reversal of Catabolism Bolus if dehydration D10 + ¼ NS to NS at 1.5–2× maintenance Stop Intake of Offending Agents Stop protein intake (NPO). Resume within 24–48 hr to prevent deficiencies of essential nutrients Toxin Removal Removal of ammonia via sodium benzoate + sodium phenylacetate (Ammonul) with arginine IV or dialysis as indicated for ammonia >250 μmol/L	Protein-restricted diet Ammonia scavengers (e.g., sodium phenylbutyrate) Arginine supplementation (dependent on defect)	PAA Urine orotic acid Molecular testing OTC deficiency (most common, X-linked) and CPS I deficiency are not picked up on newborn screening
Organic Acidemias Propionic acidemia Methylmalonic acidemia Isovaleric acidemia	Unable to metabolize certain amino acids and fats Acute intoxication episodes of hyperammonemia with metabolic acidosis Bone marrow suppression, cardiomyopathy	Reversal of Catabolism, as above Stop Intake of Offending Agents, as above Toxin Removal Carnitine in propionic, methylmalonic, and isovaleric acidemia Glycine in isovaleric acidemia Bicarbonate if pH <7.1	Formula that restricts certain amino acids Carnitine	Acylcarnitine profile Quantitative (free and total) carnitine PAA UOA Molecular testing
Maple syrup urine disease	Unable to metabolize branched-chain amino acids (BCAAs) Acute intoxication with high leucine leads to intracranial edema and coma Inappropriate urinary ketones	Reversal of Catabolism, as above Stop Intake of Offending Agents Stop protein from food and continue BCAA-free formula, valine, and isoleucine Toxin Removal Dialysis in extreme situations	Diet and formula that restricts BCAAs Supplementation with isoleucine and valine	PAA UOA Molecular testing
Aminoacidopathies Phenylketonuria (PKU) Tyrosinemia (HT)	Unable to metabolize phenylalanine (PKU) or phenylalanine and tyrosine (HT) PKU: intellectual disability if untreated HT: liver failure, vomiting, pain crisis, hyponatremia, Fanconi syndrome	Supportive. Dextrose-based fluids are safe for use HT: Pain control and hydration during pain crisis	PKU: Phenylalanine-restricted diet; sapropterin effective in some HT: Tyrosine- and phenylalanine-restricted diet; Nitisinone	PAA HT: UOA for succinylacetone Molecular testing
Carbohydrate Disorders GalactosemiaHereditary fructose intolerance (HFI)	Unable to metabolize galactose (galactosemia) or fructose (HFI) Vomiting, diarrhea, liver failure, renal failure Galactosemia: risk of Escherichia coli sepsis	Supportive. Dextrose-based fluids are safe for use	Galactosemia: Avoidance of galactose (and lactose); soy-based formulas HFI: Avoidance of fructose (and sucrose)	Urine reducing substances Galactosemia: erythrocyte gal-1-phosphate, galactose-1-phosphate uridyltransferase activity Molecular testing
Metal Disorders Menkes Wilson disease hemochromatosis	Defects in the uptake or excretion of metals Liver disease + neurologic involvement (Menkes, Wilson) + cardiomyopathy (hemochromatosis)	Chelation therapy	Wilson: Copper avoidance, copper chelation Menkes: Copper supplementation Hemochromatosis: Phlebotomy, iron chelation	Serum copper Ceruloplasmin Iron Ferritin Transferrin Molecular testing

CPS, Carbamoyl phosphate synthetase; D10, dextrose 10%; IV, intravenous; NPO, nil per os; NS, normal saline; OTC, ornithine transcarbamylase; PAA, plasma amino acids; UOA, urine organic acids.
a Management and testing should be in partnership with a genetics physician, as comprehensive details are beyond the scope of this resource.

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TABLE 13.2: Intoxication Disorders

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