Inborn Errors of Metabolism Flashcards
Why does newborn crash occur in patients with metabolic diseases?
Prior to birth the placenta filters the fetus’ blood
What is the main cause of newborn crash?
Sepsis
A baby presents at 4 days of life with lethargy and decreased p.o. intake. A septic workup is negative. He is noted to have a blood gas with a ph of 7.49. The NH3 is 1200. What is the most likely diagnosis?
A. Ornithine Transcarbamylase deficiency B. Maple Syrup Urine Disease C. MCAD D. Galactosemia E. Phenylketonuria (PKU)
A. Ornithine Transcarbamylase deficiency
What are some of the causes of normal anion gap metabolic acidosis?
- Diarrhea
- Renal tubular acidosis
What group of diseases are the following associated with:
Methylmalonic
Isovaleric
Proprionic
Glutaric acidemia
Organic Acidemias
What is the function of phenylalanine hydroxylase?
Converts phenylalanine to tyrosine
What converts arginine to ornithine?
Arginase
What is the pH of a patient with a urea cycle defect?
Alkalotic (greater than 7.45)
What can agenesis of the corpus collosum indicate?
Nonketoic Hyperglycinemia
What is the inheritance of Maple Syrup Urine disease?
Autosomal Recessive
What group of people is more commonly affected by Maple Syrup Urine disease?
Mennonites
What is the urine smell of tyrosinemia?
Rotten Cabbage
A 6 month old presents to the ER with lethargy. He was diagnosed with a viral illness 3 days prior. He had poor p.o. intake for the past 2 days. Initial laboratory studies showed glucose of 50. Blood gas showed Ph 7.38, CO2 21. The lactic acid was 1.8, NH3 was 80. The urine dip was negative for ketones. The most likely diagnosis:
A. Ornithine Transcarbamylase deficiency B. Maple Syrup Urine Disease C. MCAD D. Galactosemia E. Phenylketonuria (PKU)
C. MCAD
What is Medium-Chain Acyl-Coenzyme A Dehydrogenase Deficiency?
- Classic disorder of fatty acid oxidation
- Most common of the FA oxidation disorders
- Patients cannot break down fat
- Megalencephaly
- MRI abnormalities including lesions to the basal ganglia and subdural hematoma
- Acidemia
Glutaric Acidemia
A newborn begins vomiting after feeding and is severely jaundiced. Treatment for possible sepsis is initiated. A blood screen of galactosemia is positive. Which of the following studies would also be expected?
A. Urine amino acids will show an elevation of phenyalanine
B. Urine organic acids will show elevation of branched chain
amino amino acids
C. Lactic acid will be elevation
D. Urine will be positive for reducing substances
E. Blood culture will indicate Streptococcal sepsis
D. Urine will be positive for reducing substances
What is galactose converted to if it cannot be converted to glucose?
Galactitol
What are the features of galactosemia?
- E. coli sepsis
- Jaundice
- Hepatosplenomegaly
- Cataracts
What is the treatment for galactosemia?
Lactose free diet - no breastfeeding and must use a soy formula
Von Gierke Disease - Glycogen Storage Disease Type I
Cannot convert glucose-6-phosphate to glucose - glucose-6-phosphatase deficiency
McArdle Disease - Glycogen Storage Disease Type V
Deficiency of the enzyme muscle phosphorylase which results in reduced ATP generation by glycogenolysis.
A college student comes into clinic. He recently started a weight lifting program. After a 30 minute work out he experiences severe pain which has not improved over the past week. The day prior he had red colored urine. A urine dip is negative for blood. A CK was noted to be elevated at 600. What is the most likely diagnosis?
A. Beckers Muscular Dystrophy B. MCAD C. Galactosemia D. Pompe Disease E. McArdles Disease
E. McArdles Disease
What color urine can be seen with McArdle disease?
Burgundy colored urine - muscle breakdown NOT blood
