Metabolics

Question 1

Name the category of IEM: Metabolic acidosis after fasting with URTI. No ketones. Hypoglycaemia. Mildly raised LFTS

Answer 1

Fatty acid oxidation defects (FAOD)

Question 2

Name 3 categories of illness that can cause an abnormal body odour

Answer 2

1. Metabolic (ie. DKA, inborn errors of metabolism)
2. Infection
3. Intoxication

Question 3

Red flags/ common symptoms of inborn errors of metabolism

Answer 3

poor feeding, FTT, vomiting, lethargy before feeds, unusual dietary preferences. Worse with stressors (illness, fasting, trauma, surgery), developmental delay, recurrent hypoglycemia.
consanguinity, affected siblings/ family members, sibling with SIDS

Question 4

Causes of false negative newborn screen?

Answer 4

sample taken < 24 hours after birth, prematurity, neonatal illness, meds, transfusions, inadequate sample

Question 5

Which IEM is associated with E. Coli sepsis

Answer 5

Galactosemia

Question 6

Causes of hyperammonemia? Name 3 IEM

Answer 6

urea cycle (highest, > 1000), organic acid disorders, FAOD

Question 7

What does MELAS stand for?

Answer 7

mitochondrial encephalopathy, lactic acidosis, stroke-like episodes

Question 8

List 3 categories of IEM that cause dysmorphic features

Answer 8

lysosomal storage, mitochondrial, peroxisomal disorders

Question 9

How to calculate anion gap

Answer 9

AG = Na – (Cl + HCO3)

> 12 is high

Question 10

2 conditions that cause hypoglycemia with low/no ketones?

Answer 10

FAOD or hyperinsulinism

Question 11

Labs for basic metabolic screen?

Answer 11

Blood gas, glucose, electrolytes, ammonia, lactate, urine organic acids, serum amino acids, AC profile, urinalysis (ketones)

Question 12

Which IEM would have hyperammonemia and this blood gas?

7.25/25/bicarb 20, AG 16

Answer 12

Urea cycle (resp alkalosis, little/no gap)

Question 13

Which IEM would have hyperammonemia and this blood gas?

7.0/25/bicarb 5, AG 32

Answer 13

Organic acidemia (metabolic acidosis and big AG)

Question 14

DDx of neonatal hypoglycemia (list 5)?

Answer 14

IEM, hyperinsulinism, prematurity/ SGA, IDM, sepsis, tox (salicylates, ethanol, beta-blockers)

Question 15

Initial treatment of hyperammonemia?

Answer 15

• Decrease catabolism: control fever, IV fluids (D10 ½ NS at 1.5 x maintenance)
• No protein
• May need Dialysis
• Ammonia scavengers: sodium phenylacetate, sodium benzoate (ammunol)
• IV lipids (not if FAOD is a possible diagnosis)