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2019 RC Specialties > Metabolic > Flashcards

Metabolic Flashcards

1
Q

What basic bloodwork do you do for metabolic conditions?

A 
Gas
Lytes
Glucose
Ammonia
Lactate

note: hamilton 3 acute test: plasma a.a., plasma acylcarnitine, urine organic acid

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2
Q

Metabolic disorder= Lactic Metabolic acidosis (AG acid) + Normal or high ammonia. What type of metabolic dx?

A

Organic acidemia (proprionic acidemia, methylmalonic acidemia or glutaric acidemia)

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3
Q

++ Ammonia and normal gas. What type of metabolic dx?

A

Urea cycle defect (OTC, Citriulinemia, Arginosuccinic acidemia)

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4
Q

Normal ammonia
Normal AG.
What type of metabolic dx?

A

Aminoacidopathy (MSUD, PKU, Homocystinuria) or Galactosemia

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5
Q

How can you tell the diff between organic academia vs. urea cycle defect vs. amino acidopathy:

A

Organic Acid:
= AG Met Acid

Urea Cycle
= HI ammonia
Normal AG

A.A. or Galact
= Normal everything.

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6
Q

How do you tx an organic acidemia?

A 
Acute:
STOP Protein intake
IV Dextrose 10% with NaCl
Correct metabolic acidosis
IV lipid emulsion
\+/- Dialysis

Longterm: Low protein diet from food (w/ food that don’t have certain a.a) BUT min. protein for growth

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7
Q

T or F: there are CBC changes with organic acidemia?

A 
True.
Nelson's talks about this re: proprionic acidemia
- neutropenia
- thrombocytopenia
- pancytopenia

… due to bone marrow suppression

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8
Q

what is the diff in urea cycle versus organic academia BW?

A

Organic academia:
AG + severe metabolic acidosis

Both can have ammonia +

Urea cycle:
normal AG. normal or alkalotic pH +/- Tachypnea w/ resp alkalosis. ICP.

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9
Q

What is galactosemia?

A

Deficiency in galactose- 1 - phosphate uridyl transferase

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10
Q

When does galactosemia usually present?

A

DOL 3-7 (once exposure to lactose containing milk)

CC: jaundice, big liver, vomit, low BG, FTT, sz, lethargy, nuclear cataracts

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11
Q

What type of sepsis are kids with galactosemia at higher risk for?

A

E coli.

Neonatal Sepsis

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12
Q

What is screen and the dx test for galactosemia?

A

Prelim dx
= reducing substance in urine

Dx
= RBC enzyme assay looking for galactose 1 phosphate uridyl transferase deficiency
= DNA mutation in GALT gene

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13
Q

How do you tx galactosemia?

A

Non lactose containing milk substitute

= casein hydrolysate, soy bean based formula

+ Ca2+ supp

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14
Q

All long term risk are reversed with galactosemia tx?

A

False.

Still long term risk= ovarian failure, lower bone mineral density, DD, LD.

BUT you do reverse liver, renal and growth issue and cataracts

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15
Q

10 d with FTT, jaundice, hepatomegaly. BCX E coli. What disorder may child have? What test to confirm?

A

Galactosemia

Confirm:

  • erythrocyte GALT (galactose-1-phosphate-uridyl transferase activity) deficiency
  • DNA testing for GALT gene mutation
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16
Q

Hyperammonia child. List 3 steps in management:

A

“Hydrate+ Substrate- Med- Dialysis”
STOP PROTEIN

  1. Rehydrate
    = stop protein catabolism in tissue
  2. Give Substrate=
    Fluid, Fat, Lytes
    = D10W, NaCL, lipids
    w/ min. amt of essential a.a.
  3. Priming doses then infusion of: “ABP”
    * > Arginine HCL
    * > Na benzoate/phenylacetat (ammonia scavengers)
  4. dialysis if tx above fails
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17
Q

T or F: VPA is drug of choice in kids with hyperammonemia if seizing:

A

False.

  • Increase ammonia
  • decrease urea cycle f’n
    = DO NOT USE.
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18
Q

Baby with hypoglycaemia. No ketones. 2 DDX:

A
  1. Hyperinsulinism
  2. F.a. Oxidation Defect (high f.a. on BW)
  3. Other (panhypopit, SGA, birth asphyxia)
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19
Q

3 day old. Lethargic. Worsening LOC. Coma. Intracranial HTN. Resp Alkalosis. Dx?

A

Urea cycle defect

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20
Q

Name one organic acidemia:

A 
Methamelonic Acidemia, proprionic acidemia, 
glutaric acidemia (the hard to Dx one with macrocephaly and mvmt d/o when unwell, subdural hematoma)
Previously Well child, presents with weakness, lethargy, coma
Classic Lab Findings:
Metabolic Acidosis with high AG
Mild - Moderate Ammonia elevation
High Ketones
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21
Q

Name one urea cycle defect:

A

Ornithine Transcarbamylase deficiency (OTC)
Citrulinemia
Arginosuccinic aciduria

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22
Q

Name one aminoacidopathy:

A
  • Maple Syrup Urine Disease
  • PKU
  • Homocystinuria (Marfanoid-like, thrombosis problems)
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23
Q

IEM: Musty or mousy order.

A

PKU = Phenylketonuria

Autosomal Recessive
Normal Ammonia. Normal pH.
Presentation : 
Fair skin and hair
Eczema
Light Sensitivity
Hair Loss
Untreated - Mousy Odor, Epilepsy, Eye abnormalities (hypopigmentation), SEVERE ID
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24
Q

IEM: Maple Syrup smell

A

Maple Syrup Urine Disease

Autosomal Recessive
Presentation: Baby 3-5 days with poor feeding, irregular respirations, hard to arouse, coma, death

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25
Q

What do you do if your newborn screen is (+) for PKU?

A

Order quantitive BLOOD phenylalanine level.

Don’t repeat screen; CONFIRM!

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26
Q

Phenylketonuria is inherited?

A

AR.

Carrier are unaffected.

27
Q

What type of inborn error of metabolism is PKU?

A

Aminoacidopathy.

Meaning ammonia, pH, AG all normal.

28
Q

List three traits of PKU:

A
  1. Fair skin + blue eyes.
  2. Microcephaly
  3. Musty odour (breath, skin odour)
  4. Growth retardation
  5. Intellectual impairment.
  6. Eczema
  7. Light sensitivity
  8. Hair loss
29
Q

How do you confirm dx of PKU?

A

Quantitive Blood phenylalanine level.

If > 120= Dx

OR altered phenylalanine/ tyrosine ratio in untreated state.

30
Q

How do you treat PKU?

A

Phenylalanine limited diet (PKU formula, diet modification, avoid aspartame)
+ Supplement tyrosine

31
Q

List 3 complications of maternal PKU:

A
  1. IUGR
  2. Intellectual impairment.
  3. Developmental delay
  4. Microcephaly
  5. CHD
32
Q

Screening BW for kid in shock with suspicion for IEM?

A
  • Lactate, ammonia, VBG, glucose, electrolytes

- Acetylcarnitine profile help dx f.a. oxidation defect

33
Q

6 mo. old w/ DD brought in shock. Now stable. Help with dx via:

a. CT
b. lactate, carnitine, ammonia
c. serum organic acid
d. urine a.a.

A

Lactate
Carnitine
Ammonia

34
Q

Which protein metabolism in IEM present as shock? What else is on DDX?

A 
Organic Academia (proprionic, glutaric, methylmalonic, etc)
- High AG metabolic acidosis.

DDX: urea cycle defect, aminoacidopathy, galactosemia
DDX: infection, trauma, CNS anomaly

35
Q

What is the most common f.a. oxidation disorder?

A

MCAD Deficiency

= Medium chain acyl-CoA dehydrogenase deficiency

36
Q

T or F: MCAD typically has non ketotic hypoglycaemia AND no acidosis.

A

true.

37
Q

Abetalipoproteinemia causes all EXCEPT:

  • ataxia
  • hyperlipidemia
  • acanthocytosis
  • retinitis pigments
  • diarrhea + FTT
A

NO Hyperlipid.
—> think A … (as in missing)… lipo…..
Abetalipoproteinemia:
- severe fat malabsorption
- can’t make lipoprotein
- intestinal bx show ++ lipid in enterocyte (fat stuck in wall)
- low cholesterol, TG, ADEK
- acanthocytosis (Spiked RBC smear), ataxia, loss of DTR (secondary to Vitamin E deficiency), night blindness (pigmented retinopathy)

38
Q

Distal RTA. How do you remember it?

A

D1stal= Type 1= H+ is one letter
= collecting duct can’t excrete H+
= high urine pH
= low K, Ca2+ kidney stones

versus. Proximal= type 2= bicarb reabsorption lacking
= link w/ low phosphate rickets

39
Q

AG calculation:

A

(Na+) - (Cl-) - (HCO3-)

Normal: 8-12

40
Q

Xray with VERY WHITE bones. Think of marble bones dx. Name?

A

OsteoPETROSIS

= bone do not reabsorb (osteoclast issue) / remodel
ANEMIA with extra medullary hematopoiesis in liver and spleen = hepatosplenomegaly
Optic and facial nerve problems b/c bone no change = deafness and blindness
Can #

41
Q

6 mo. old pale. irritable. XR show very white bone. Dx?

A

Osteopetrosis

42
Q

Cardiomegaly and hypoglycaemia. Like etiology:

  • cardiac lesion
  • sepsis
  • IEM
A

Inborn error of metabolism (IEM)

Think Pompe!

43
Q

What is Pompe disease?

A

Glycogen storage disease.

- AR

44
Q

Classic ppt of Pompe:

A 
Poor Tone
Feeding Issue
Big Liver
Hypertrophic cardiomyopathy
High CK
NO hypoglycaemia, no aciduria.
45
Q

Lethargic. Poor feed. Big liver. Normal ammonia, pH, lactate. Likely dx?

  • Maple Syrup
  • Propionic acidemia
  • Urea cycle defect
  • Galactosemia
A

Galactosemia
- galactose-1-phosphate uridyltransferase
- jaundice
- hepatomegaly
- low BG
- lethargic, sz, irritable
- coagulopathy
- normal BW except liver problem, ++ plasma a.a.
- dx via RBC GALT deficient or gene mutation
Tx: non lactose containing milk substitute

Maple Syrup= Aminoacidopathy

  • poor feed, lethargic, athetoid (fence, cycling), spastic, sz
  • N pH + amm but ketoaciduria w/ high plasma a.a.
  • no hepatomegaly noted

Propionic acid= organic acid= high ammonia + AG met acid
Urea cycle: high hmm + N pH or resp alk

46
Q

T or F: decreased LOC (encephalopathy) prior to focal neuro deficit or feature suggest inborn error of metabolism.

A

True.

47
Q

T or F: if suspect IEM and unsure of definitive dx it is fair game to give thiamine to prevent further sequelae?

A

False.

Give cofactors that may be missing in IEM
> Carnitine (organic academia, f.a., caritine def)
> B12 (cobalamin; organic acid)
> B6 (pyridoxine; for neo sz)
> Biotin (for neo recurrent sz for carboxylase def)

48
Q

Which coFactors can you give to prevent sequelae while waiting IEM dx?

A
  • Carnitine
  • B12
  • B6 (neo sz)
  • Biotine (neo sz)
49
Q

T or F: liver dysfunction is long term complication of MCAD (lipid metabolism defect).

A

True.

50
Q

Lang delay and inferior ectopia lentis. Dx?

A

Homocystinuria

“Downward IQ= Downward Lens”

51
Q

How do you dx homocystinuria?

A

Plasma a.a.

= elevated methionine or homocysteine in body fluid (urine or blood)

52
Q

What is downward lens= down IQ. Dx?

A

Homocystinuria.

Versus marfan
= upward dislocation= normal IQ.

53
Q

List 3 diff between marfan + homocysteinuria.

A

Marfan: AD
Homo: AR

Marfan: upward lens
Homo: downward (inferior ectopia lentis)

Marfan: normal IQ
Homo: low

Marfan: joint laxity
Homo: rigid

Marfan: Ao root dilation.
Homo: thromboembolism predisposition

Homo: tx w/ vitamin B6

54
Q

How do you decide which diseases to create screening test?

A
  1. Disease (natural hx allow tx, cure or halt complications if caught early)
  2. Test known
  3. Treatment (effective, $)
  4. Societal implications
55
Q

Which is best clue to probable genetic dx?

  • sibling died of unknown cause
  • fhx dementia
  • child adopted
  • hx cancer in distant relatives
  • parents first cousin
A

Sibling died of unknown cause > consanguinity.

56
Q

What inheritance pattern suggest mitochondrial disease?

A

Maternal inherit

i.e. mom and her mom have hearing loss + DM

NOTE: Boy + Girl affected
But boy can’t pass it on.

57
Q

T or F: lactate is usually UP in mitochondrial dx?

A

True

58
Q

T or F: poor response to glucagon hallmark of hyperinsulinemia?

A

False.

Exaggerated response key (i.e. 1.8 to 4)

59
Q

Workup for DD?

A
  1. Chromosomal Microarray
  2. Fragile X
  3. Hearing
  4. Metabolic: Lytes, gas, ammonia, BG, lactate, CK, LFT, CBC, a.a. serum, urine organic acid, acylcarnitine profile
  5. MRI if macro, microcephaly or neuro signs
60
Q

Metabolic crisis approach:

A

> Rehydrate
- ABC, resus, no dehydration

> Substrate

  • 2X D10NS + 20K
  • protein restrict
  • caloric restriction
  • megavitamins

> Meds

  • if known (ammonia ABP- arginine, Na benzoate, Na phenylactate)
  • Carnitine
  • B12 (met acidosis)
  • B6 or Biotin if neo sz

> Dialysis

61
Q

7 mon. VLCAD. Gastro. Mild dehydration. What do you start?

A

D10NS x 1.5 maintenance

** never give lipids to f.a. oxidation disorder.

62
Q

7 mon. VLCAD. What BW:

A 
Lytes
Glucose
BUN
Cr
**CK
(Rhabdo)
63
Q

2 y.o. developmental delay. ? liver enlargement. Which investigations FIRST:

  • Urine MPS
  • plasma MPS screen
  • Microarray
  • Plasma a.a
  • Plasma acylcarnitine profile.

If that’s normal- 2nd test?

A

Microarray

Urine mucopolysaccharide screen

= MPS= Enzyme replacement therapy
+ Bone marrow/stem cell transplant

64
Q

MCAD. Vomit and diarrhea. Next?

A

Stat BG

Start IV fluid w/ D10W

2019 RC Specialties (31 decks)

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