Inherited metabolic diseases in Peds

Question 1

In which patients should a metabolic disorder be considered?

Answer 1

All neonates with unexplained, overwhelming or progressive disease after a normal pregnancy

All children with acute deterioration of general condition, esp when preceded by illness

All children with S and S of Acidosis or Hypoglycemia

Question 2

What are the common Clinical features of Metabolic Errors?

Answer 2

Hypoglycemia
Metabolic/Lactic Acidosis Ketosis
Hyperammonemia
Seizures

Question 3

What are the signs of possible Hyperammonemia?

Answer 3

Lethargy, somnolence, vomiting, grunting respirations, seizures
Caused by errors in urea cycle enzymes, severe liver failure

Question 4

What is the function of Screening for inborn errors of metabolism?

Answer 4

Detect disorders that can cause serious consequences if not diagnosed and CAN be treated.
PKU, hemoglobinopathies, congenital adrenal hyperplasia, galactosemia

Question 5

What enzyme is Defective in PKU?

Answer 5

Phenylalanine hydroxylaze can’t convert Phenylalanine to Tyrosine
Phenylalanine builds up and is converted to Phenylketones

Question 6

How is PKU diagnosed?

Answer 6

Plasma Phe > 20 mg/dl

Question 7

What is the Tx of PKU?

Answer 7

Restriction of Phe intake

Lofenalac

Question 8

What is unique about MALIGNANT HyperPHEemia?

Answer 8

Defective Coenzyme for phe hydroxylase

Diet restriction does not prevent neuro consequences

Question 9

What are the dangers of PKU in pregnancy?

Answer 9

Mom must keep low PHE >360

Causes: microcephaly, low birth weight, mental retardation, malformations in infants of mom’s with poorly controlled PKU

Question 10

What is the defect in Galactosemia?

Answer 10

GALT enzyme defective
Galactose 1 Phos not converted to Glucose 1 Phos

Galactose builds up and converted to Galactitiol

Question 11

What are the Clinical Manifetations of Galactosemia?

Answer 11

Normal at birth
Delayed presentation
Vomiting, diarrhea, HSM, jaundice, anemia, cataracts,
Gram Negative Sepsis

Question 12

WHat is MCAD?

Answer 12

Medium chain acyl-CoA Dehydrogenase Deficiency

Question 13

What are the features of MCAD?

Answer 13

Disorder of Fatty acid oxidation 
NO FASTING
Lethargy leads to coma
Newborn screening
Autosomal Recessive

Question 14

What is the difference between Organic Acidemias and Urea Cycle Disorder?

Answer 14

Org. Acidemia: pH, pCO2, HCO3 low

UCD: HIGH PH, pCO2 and HCO3 Low