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

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3
Q

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

A

Urea cycle defect

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4
Q

Normal ammonia
Normal AG.
What type of metabolic dx?

A

Aminoacidopathy 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 diagnose organ acidemia?

A

Urine Organic Acid

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7
Q

How do you tx an organic acidemia?

A

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

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8
Q

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

A

True.

  • neutropenia
  • thrombocytopenia
  • pancytopenia

… due to bone marrow suppression

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9
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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10
Q

What is galactosemia?

A

Deficiency in galactose- 1 - phosphate uridyl transferase

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11
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

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12
Q

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

A

E coli.

Neonatal Sepsis

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13
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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14
Q

How do you tx galactosemia?

A

Non lactose containing milk substitute

= casein hydrolysate, soy bean based formula

+ Ca2+ supp

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15
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.

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16
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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17
Q

Hyper ammonia child. List 3 steps in management:

A

“Hydrate+ Substrate- Med- Dialysis”

  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
    * > Na phenyl acetate
  4. dialysis if tx above fails
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18
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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19
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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20
Q

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

A

Urea cycle defect

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21
Q

Name one organic acidemia:

A

Methamelonic Acid

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22
Q

Name one urea cycle defect:

A

Weird Names…

CPS1= Carbamyl Phosphatase synthetase

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23
Q

Name one aminoacidopathy:

A
  • Maple Syrup Urine Disease

- PKU

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24
Q

IEM: Musty or mousy order.

A

PKU

Phenylketonuria

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25
IEM: Maple Syrup smell
Maple Syrup Urine dx
26
What do you do if your newborn screen is (+) for PKU?
Order quantitive BLOOD phenylalanine level. Don't repeat screen; CONFIRM!
27
Phenylketonuria is inherited?
AR. Carrier are unaffected.
28
What type of inborn error of metabolism is PKU?
Aminoacidopathy. | Meaning ammonia, pH, AG all normal.
29
List three traits of PKU:
1. Fair skin + blue eyes. 2. Microcephaly 3. Musty odour (breath, skin odour) 4. Growth retardation 5. Intellectual impairment.
30
How do you confirm dx of PKU?
Quantitive Blood phenylalanine level. If > 120= Dx OR altered phenylalanine/ tyrosine ratio in untreated state.
31
How do you treat PKU?
Phenylalanine limited diet (PKU formula, diet modification, avoid aspartame) + Supplement tyrosine
32
List 3 complications of maternal PKU:
1. IUGR 2. Intellectual impairment. 3. DD 4. Microcephaly 5. CHD
33
Screening BW for kid in shock with suspicion for IEM?
- Lactate, ammonia VBG. | - Acetylcarnitine profile help dx f.a. oxidation defect
34
6 mo. old w/ DD brought in shock. Now stable. Help with dx via: - CT - lactate, carnitine, ammonia - serum organic acid - urine a.a.
Lactate Carnitine Ammonia
35
Which protein metabolism in IEM present as shock? What else is on DDX?
Organic Academia - High AG metabolic acidosis. DDX: urea cycle defect, aminoacidopathy, galactosemia DDX: infection, trauma, CNS anomaly
36
What is the most common f.a. oxidation disorder?
MCAD Deficiency = Medium chain acyl-CoA dehydrogenase deficiency
37
T or F: MCAD typically has non ketotic hypoglycaemia AND no acidosis.
true.
38
Abetalipoproteinemia causes all EXCEPT: - ataxia - hyperlipidemia - acanthocytosis - retinitis pigments - diarrhea + FTT
NO Hyperlipid. Abeta-lipoproteinemia: - 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, night blindness (pigmented retinopathy)
39
Distal RTA. How do you remember it?
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
40
AG calculation:
Na- Cl- bicarb Normal: 8-12
41
Xray with VERY WHITE bones. Think of marble bones dx. Name?
Osteopetrosis. ``` = bone do not reabsorb (osteoclast issue) = BW normal except +/- pan cytopenia Can # XR: thick dense bone ```
42
6 mo. old pale. irritable. XR show very white bone. Dx?
Osteopetrosis
43
Cardiomegaly and hypoglycaemia. Like etiology: - cardiac lesion - sepsis - IEM
Inborn error of metabolism (IEM) Think Pompe!
44
What is Pompe disease?
Glycogen storage disease. - AR
45
Classic ppt of Pompe:
Hypoglycaemia Poor Tone Feeding Issue Big Liver Hypertrophic cardiomyopathy
46
Lethargic. Poor feed. Big liver. Normal ammonia, pH, lactate. Likely dx? - Maple Syrup - Propionic acidemia - Urea cycle defect - Galactosemia
Galactosemia Propionic acid= organic acid= high ammonia + AG met acid Urea cycle: high hmm + N pH or resp alk Maple Syrup= Aminoacidopathy - poor feed, lethargic, athetoid (fence, cycling), spastic, sz - N pH + amm but ketoaciduria w/ high plasma a.a. - no hepatomegaly noted Galactosemia - carb metab issue - jaundice - hepatomegaly - low BG - lethargic, sz, irritable - normal BW except liver problem, ++ plasma a.a. - dx via RBC GALT deficient or gene mutation Tx: non lactose containing milk substitute
47
T or F: decreased LOC (encephalopathy) prior to focal neuro deficit or feature suggest inborn error of metabolism.
True.
48
T or F: if suspect IEM and unsure of definitive dx it is fair game to give thiamine to prevent further sequelae?
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)
49
Which coFactors can you give to prevent sequelae while waiting IEM dx?
- Carnitine - B12 - B6 (neo sz) - Biotine (neo sz)
50
T or F: liver dysfunction is long term complication of MCAD (lipid metabolism defect).
True.
51
Lang delay and inferior ectopia lentis. Dx?
Homocystinuria "Downward IQ= Downward Lens"
52
How do you dx homocystinuria?
Plasma a.a. | = elevated methionine or homocysteine in body fluid (urine or blood)
53
What is downward lens= down IQ. Dx?
Homocystinuria. Versus marfan = upward dislocation= normal IQ.
54
List 3 diff between marfan + homocysteinuria.
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
55
How do you decide which diseases to create screening test?
1. Disease (natural hx allow tx, cure or halt complications if caught early) 2. Test known 3. Treatment (effective, $) 4. Societal implications
56
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
Sibling died of unknown cause > consanguinity.
57
What inheritance pattern suggest mitochondrial disease?
Maternal inherit i.e. mom and her mom have hearing loss + DM NOTE: Boy + Girl affected But boy can't pass it on.
58
T or F: lactate is usually UP in mitochondrial dx?
True
59
T or F: poor response to glucagon hallmark of hyperinsulinemia?
False. Exaggerated response key (i.e. 1.8 to 4)
60
Workup for DD?
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
61
Metabolic crisis approach:
>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
62
7 mon. VLCAD. Gastro. Mild dehydration. What do you start?
D10NS x 1.5 maintenance ** never give lipids to f.a. oxidation disorder.
63
7 mon. VLCAD. What BW:
``` Lytes Glucose BUN Cr **CK (Rhabdo) ```
64
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?
Microarray Urine mucopolysaccharide screen = MPS= Enzyme replacement therapy + Bone marrow/stem cell transplant
65
MCAD. Vomit and diarrhea. Next?
Stat BG | Start IV fluid w/ D10W