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Pediatrics- Noelle > Metabolics > Flashcards

Metabolics Flashcards

1
Q

what is the treatment for galactosemia

A 
soy formula (there is no lactose or galactose, it is made of sucrose)
need to remove all galactose- containing foods from the diet along with adequate calcium supplementation
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2
Q

what are the long term problems associated with galactosemia

A

female infertility
ovarian failure with primary or secondary amenorrhea
speech dyspraxia
decreased bone mineral density
cognitive deficits (DD and learning disabilities that increase in severity with age)

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3
Q

what is the classical presentation of galactosemia

A

typically present in the second half of the first week of life
jaundice
hepatomegaly
vomiting
hypoglycemia
seizure
at increased risk for E.coli neonatal sepsis
pseudotumor cerebri can occur and cause a bulging fontanel

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4
Q

what enzyme is deficient in galactosemia

A

galactose-1-phosphate uridyl transferase deficiency

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5
Q

what makes up lactose

A

glucose and galactose

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6
Q

how is galactosemia diagnosed?

A

demonstration of a reducing substance in several urine specimens collected while the patient is on a diet containing lactose
direct enzyme assay using erythrocytes establishes the diagnosis

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7
Q

how is galactoseia inherited?

A

autosomal recessive

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8
Q

what are the 3 key labs to order if you are worried about an IEM

A

glucose (many metabolic conditions have hypoglycemia)
ammonia
some measure of acid base status

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9
Q

what is ammonia

A

the means by which the body clears nitrogen
indicator that you are turning over protein
ammonia serves as an indicator of catabolism and of failure in waste removal

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10
Q

what IEM disorders should you consider if you have a high ammonia

A

urea cycle defects

organic acidemias

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11
Q

how can you distinguish between urea cycle defect and organic acidemia

A

urea cycle infant: high ammonia and ALKALOSIS

organic acidemia: high ammonia and ACIDOSIS

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12
Q

what is Gaucher disease

A

one of the most common lysosomal storage diseases
due to a defect in the glucocerebrosidase gene (part of lipid membrane)
the most prevalent genetic defect among Ashkenazi Jews

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13
Q

what are some features of Gaucher disease

A

thrombocytopenia
splenomegaly **
hepatomegaly
bone pain/disease ** (erlenmeyer flask deformity, lytic lesions)

Pathologic hallmark of Gaucher disease is Gaucher cell in the RES, particularly the bone marrow

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14
Q

what is one feature used to differentiate glycogen storage disease from Gaucher disease on physical exam

A

gaucher- splenomegaly

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15
Q

what is Hurler syndrome

A

MPS-1
infants appear normal at birth but develop coarsening facial features
defect in alpha-iduronidase (an enzyme used to break down mucopolysaccharides)
hepatosplenomegaly
coarse facial features * (heavy brow)
corneal clouding *
large tongue * (protruding tongue, thickened gums)
flat nasal root *
enlarged head circumference
joint stiffness, flexion deformities
short stature
skeletal dysplasia (dysostosis multiplex), clawed hand
hypertrophic cardiomyopathy

Hunter syndrome- similar but x linked (only in boys and no corneal clouding)

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16
Q

what is zellweger syndrome

A

defect in the biogenesis of the peroxisomes

the peroxisomes do not form properly

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17
Q

what are some diagnostic features of zellweger syndrome

A 
very high forehead
extremely large anterior fontanel
jaundice/hepatomegaly *
progressive kidney failure *
severe hypotonia *
narrow set eyes
broad nasal bridge
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18
Q

what are the 3 main metabolic tests

A

plasma amino acids
urine organic acids
plasma acylcarnitine

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19
Q

what is the urea cycle

A

converts ammonia to urea

primarily occurs in the liver

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20
Q

what is the main test for urea cycle defect

A

plasma amino acids

21
Q

what bloodwork results are seen with a urea cycle defect

A

respiratory alkalosis ** huge clue to hyperammonemia
normal electrolytes and anion gap
elevated glutamine +/- Alanine

22
Q

what is the diagnostic test for UCD

A

molecular genetics testing

enzymology

23
Q

what is the treatment for UCD

A 
stop protein
stop catabolism by giving IV glucose
replace Arginine!
provide alternate waste nitrogen pathway (IV NaBenzoate/NaPhenylacetate
dialysis- hemodialysis
24
Q

what is the most common UCD

A

OTC

ornithine transcarbamylase deficiency

25
Q

what lab findings are consistent with OTC

A 
high ammonia
high glutamine
high alanine
low citrulline 
low arginine
low urea
26
Q

how does a patient with OTC present

A

x linked disorder (females primrily asymptomatic)
infant appears normal at birth but becomes symptomatic following introduction of dietary protein
refusal to eat
vomiting
tachypnea
lethargy
seizures are common
hepatomegay
can have increased ICP with bulging fontanelle and dilated pupils

27
Q

how can you differentiate CPS1 from OTC

A

marked increase in urinary orotic acid in patients with OTC deficiency helps differntiate this defect from CPS1 deficiency
CPSI- carbamoyl phosphate synthetase I (another type of urea cycle defect)

28
Q

what is the chronic management for urea cycle defect

A

low protein diet, with adequate calories and trace nutrients
supplementation with urea cycle intermediates (ie arginine or citrulline)
N2 scavengers- NaBenzoate, NaPhenylbutyrate
liver transplant

29
Q

Homocystinuria

A

inborn error of methionine metabolism
homocysteine is a metabolite of methionine (essential amino acid)
methionine- homocysteine- cystathionine- cysteine
caused by cystathionine b-synthase deficiency
they have large amounts of homocysteine in their urine
tx: may respond to high doses of vitamin B6

30
Q

physical features of homocystinuria

A

eye: ectopia lentis, myopia
skeletal abnormalities resembling those of Marfan syndrome
tall with elongated limbs
scoliosis
pectus carinatum or excavatum
high arched palate
crowding of teeth
Vascular: recurrent arterial and venous thrombosis ***
CNS: psychiatric and behavioral disorders, developmental delay

31
Q

what is the main side effect of pyridoxine (vit B6)

A

peripheral neuropathy

32
Q

what is the treatment for homocysteinuria

A

pyridoxine (B6)
protein (methionine) restriction
Betaine (converts homocysteine to methionine)
Aspirin, heparin SC

33
Q

what two AA buildup with homocysteinuria

A

homocysteine and methionine

34
Q

what vitamins are required for homocysteine to make methionine and for conversion of methionine to homocysteine

A

B12 and folate

B6

35
Q

what amino acids build up with propionic/methylmalonic acidemias

A 
VOMIT
V- valine
O- odd chain fatty acids
M- methionine
I- isoleucine
t- threonine

MMA will be high in the urine with methylmalonic acidemia

36
Q

what is the diagnostic test for propionic/methylmalonic acidemias

A

urine organic acids

37
Q

what urea cycle disorders do we screen for on newborn screening

A

citrullinemia and ASA lyase deficiency

NOT: NAGS, CPS and OTC

38
Q

what is adrenoleukodystrophy

A

x-linked disorder
high levels of very long chain fatty acids found in the tissues and body because of impaired b-oxidation in the peroxisomes
present with hyperactivity, inattention, ataxia

39
Q

what is PKU? tx?

A 
phenylalanine hydroxylase deficiency
elevated phenylalanine
low or normal tyrosine
tx: diet restriction of phenylalanine
does not present acutely
40
Q

how does MCAD present? tx?

A

hypoketotic hypoglycemia *
do not tolerate fasting, triggered by minor illness
tx: avoid fasting and catabolism
most common b oxidation disorder

41
Q

what is the treatment for Gaucher disease

A

enzyme replacement, miglustat

42
Q

how do organic Acidemias present

A

acute encephalopathy

anion gap acidosis, hyperammonemia, hypoglycemia

43
Q

how do urea cycle defects present

A

hyperammonemia, NO acidosis, NO hypoglycemia
amino acids may point to the diagnosis
tx: nitrogen scavenger meds Nabenzoate, phenylbutyrate

44
Q

what are the treatment options for MPS/Hurler syndrome

A

enzyme replacement therapy

bone marrow/stem cell transplant

45
Q

what is the best test to diagnose a patient with a mitochondrial disorder

A

muscle biopsy

46
Q 
hypoglycemia + hepatomegaly 
isolated hypoglycemia 
hypoglycemia without ketosis 
hypoglycemia + hyponatremia/hypotension 
hypoglycemia + acidosis/ketosis
A

hypoglycemia + hepatomegaly = GSD
isolated hypoglycemia = hyperinsulinemia
hypoglycemia without ketosis = fatty acid oxidation defect
hypoglycemia + hyponatremia/hypotension = adrenal insufficiency
hypoglycemia + acidosis/ketosis = organic aciduria

47
Q

Fabry disease

A 
x-linked
α-Galactosidase A deficiency
present with recurrent severe pain in hands/ feet (precipitated by hot weather, stress, exercise, fatigue)
angiokeratoma
2 enzyme replacement therapies
48
Q

who to refer to metabolic (8)

A

Recurrent unexplained illness
Unexplained deterioration in clinical status
Liver disease, cholestasis, hepatomegaly (splenomegaly)
Myopathy, Myositis, Rhabdomyolysis
Cardiomyopathy
Unexplained seizures and/or neurological dysfunction
Progressive deterioration in mental status
Children with known or suspected genetic metabolic diseases or a
positive family history

Pediatrics- Noelle (28 decks)

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