Chemical Pathology 5 - Metabolic disorders and screening Flashcards
Deficiency of which enzyme causes phenylketouria?
Phenylalanine hydroxylase
What builds up in PKU that causes toxicity?
Tyrosine
What number must you use when requesting a metabolic screen?
OMIM number
What will be the result of not treating PKU shortly after birth?
IQ <50
How is PKU diagnosed?
Based on blood phenylalanine level, as >400 different mutations can cause PKU!
How quickly does PKU treatment need to be initiated in order to be effective?
First 6 weeks of life
What is the test for cystic fibrosis in the neonate?
High immune reactive trypsin
What is MCADD?
Enzyme deficiency that prevents production of acetyl CoA, which permits glucose sparing
Therefore, if you can’t break down fat, you may die of hypoglycaemia
What metabolic defect can cause hyperammonaemia?
Urea cycle defect
How can hyperammonaemia be treated?
Remove ammonia via sodium benzoate or sodium phenyl acetate
Reduce ammonia production (low protein diet)
What is the typical triad of signs for organic aciduria?
Hyperammonaemia
Metabolic acidosis
High anion gap
What unusual odour might be smelt on a patient with isovaleric acidaemia?
Cheesy and sweaty
What are the typical neurological findings in organic acidurias?
Truncal hypotonia and limb hypertonia
What condition causes chronic intermittent organic aciduria?
Reye syndrome
Recall 3 drugs that can precipitate symptoms in Reye syndrome
Salicylates
Anti-emetics
Valporate