Biochem - Rice Article

Question 1

Fatty acid oxidation disorders - metabolic error

Answer 1

Fat - Defect in beta-oxidation of fatty

acids.

Question 2

Fatty acid oxidation disorders - specific disorders

Answer 2

Medium-chain acyl CoA dehydrogenase, Long-chain 3-hydroxy acyl CoA dehydrogenase, Very long-chain acyl CoA dehydrogenase

Question 3

Fatty acid oxidation disorders - presentation

Answer 3

Hypoketotic Hypoglycemia!

Lethargy, vomiting, sudden infant death syndrome, Reye syndrome

Long-chain disorders have cardiomyopathy and rhabdomyolysis

Question 4

Fatty acid oxidation disorders - laboratory tests

Answer 4

NBS
Plasma acylcarnitines
Hypoglycemia
No or inappropriately low ketones

Question 5

Fatty acid oxidation disorders - acute treatment

Answer 5

Dextrose (10% with salt)
Early use of fluids to prevent hypoglycemia

Question 6

Fatty acid oxidation disorders - chronic management

Answer 6

Low-fat diet
Avoid prolonged fasts
Nighttime feedings when sick
Carnitine
Echocardiography for long-chain fatty acid oxidation disorders

Question 7

Organic acidemias - metabolism error

Answer 7

Protein - Defect in amino acid
breakdown leads to
accumulation of organic
acid byproducts

Question 8

Organic acidemias - disorders

Answer 8

Propionic
Methylmalonic
Isovaleric

Question 9

Organic acidemias - presentation

Answer 9

Metabolic Acidosis With Anion Gap

Neonatal lethargy, vomiting, coma, strokes, death

Question 10

Organic acidemias - lab tests

Answer 10

Newborn Screen
Urine organic acids
Plasma acylcarnitines

Question 11

Organic acidemias - acute treatment

Answer 11

Dextrose (10% with salt) 
Early use of fluids 
No protein 
Intravenous lipid emulsion 
Dialysis may be needed in sick neonate

Question 12

Organic acidemias - chronic management

Answer 12

Low-protein diet
Supplemental medical food
Carnitine
Liver transplantation

Question 13

Aminoacidopathies - metabolism error

Answer 13

Protein

Defect in amino acid breakdown leads to accumulation of certain intact amino acids

Question 14

Aminoacidopathies - disorders

Answer 14

Maple syrup urine
Phenylketonuria
Homocystinuria
Tyrosinemia

Question 15

Aminoacidopathies - lab tests

Answer 15

Newborn Screen

Plasma amino acids

Question 16

Aminoacidopathies - presentation

Answer 16

No Acidosis or Hyperammonemia
Elevations in specific amino acids
(See article for clinical features of specific disorders)

Question 17

Aminoacidopathies - acute treatment

Answer 17

For maple syrup urine disease, similar to organic acidemias

Avoid hyponatremia

Question 18

Aminoacidopathies - chronic management

Answer 18

Restrict offending amino acid
Supplemental food
Monitor plasma amino acids

Question 19

Urea cycle disorders - metabolism error

Answer 19

Protein

Defect in makingurea(blood urea nitrogen) from ammonia that results from amino acid breakdown

Question 20

Urea cycle disorders - disorders

Answer 20

Ornithine transcarbamylase (X-linked)
Citrullinemia
Arginosuccinic aciduria

Question 21

Urea cycle disorders - lab tests

Answer 21

Newborn Screen (not for ornithine transcarbamylase) Hyperammonemia
Plasma amino acids
Urine orotic acid

Question 22

Urea cycle disorders - presentation

Answer 22

Hyperammonemia Without Acidosis

Neonatal lethargy, vomiting, coma, death

Question 23

Urea cycle disorders - acute treatment

Answer 23

Dextrose (10% with salt)
Early use of fluids
Sodium benzoate/ phenylacetate
Arginine Dialysis

Question 24

Urea cycle disorders - chronic management

Answer 24

Low-protein diet
Supplemental food
Phenylbutyrate
Arginine/citrulline
Liver transplantation