Metabolic disorders Flashcards
Overflow vs renal disorders
Overflow: disruption of pathway. Inborn error of metabolism
Renal disorder: malfunction in tubular reabsorption mechanism
Abnormal metabolic constituents
Color
Homogentistic acid
Melanin
Indican
porphyrins
abnormal metabolic constituents
Odor
Phenylketonuria
MSUD
isovaleric academia
cystinuria
cystinosis
homocystinuria
Abnormal metabolic constituents
crystals
cystine
leucine
tyrosine
lesch-nyhan disease (uric acid)
Amino acid disorders
Phenylalanine Tyrosine disorders
Branch chain amino acid disorder
tryptophan disorders
cystine disorders
Phenylketonuria
Mousy odor urine
Increase keto acids in urine
can’t code for phenylalanine hydroxylase
Decrease in melanin
Phenylketonuria treatment
newborns/babies: specialized formula
No food with phenylalanine/aspartame
can alter diet slightly with age
Phenylketonuria blood testing
Blood is tested for phenylalanine
screen for PKU
Detectable after drinking milk for 24 hours
Guthrie test
Phenylalanine Urine testing
Follow up procedure
screening for known PKU to monitor
ferric chloride test: permanent blue-green color
Tyrosyluria
excess tyrosine
most common: transitory in premature infants
Insufficient liver development
or live doesn’t make enzymes
Tyrosyluria urine testing
tyrosine and leucine crystals (if liver disorder)
ferric chloride test (green fades rapidly)
Nitroso napthol: orange color, non-specific
Melanuria
Increased melanin -> dark urine
after exposure to air
overprolifertion of melanocytes
Melanuria condition
Malignant melanoma
Melanuria tests
Ferric chloride (grey or black precipitate)
Sodium nitroprusside (red color)
Ehrlich’s reagent (red color)
alkaptonuria
Alkali lover
darker after standing at room temp
homogenistic acid oxydase missing
alkaptonuria condition
Homogenistic acid accumulates
children: brown, black stained diapers
Adults: brown pigments in body tissues, arthritis
alkaptonuria testing
Ferric chloride (blue)
clinitest: yellow precipitate
Alkali additive to fresh urine -> dark color
Branch chained amino acid (BCAA)
Type 1: Accumulation Early break down products (MSUD)
Type 2: Organic acidemia (acids made further in pathway
MSUD
Inborn error of metabolism
Inability to metabolize keto acids
Leucine, isoleucine, valine
keto acids accumulate in blood/urine
MSUD condition
Failure to thrive 1 wk after birth
UA findings: sweet odor, ketone +
Testing: MS/MS, DNPH (yellow precip), AA chromotography
Organic acidemias
Symptoms: ketonuria, increase serum ammonia
Disorders: isovaleric acidemia, propionic acidemia
Testing: no UA test
Tryptophan disorders
Indican
5-HIAA
Indicanuria
Increased tryptophan conversion to indole
Hartnup disease
indole converted to indican -> blood -> urine
Indicanuria indications
Indican oxidizes to blue
Blue diaper syndrome
Hartnup disease
Inherited metabolic disease
abnormalities in renal tubes (Fanconi’s)
dry red scaley rash
muscular incoordination
Cystine disorders
Cystinuria: transport of amino acids
Cystinosis: error of metabolism
Cystinuria
Cystine in urine
renal disorder
inability of tubuals to reabsorb cyctine
cystinuria findings
Cystine crystals
cystine kidney stones (most common in kids)
cyanide-nitroprusside test: red-purple color
Cystinosis
Overflow disorder
incomplete metabolism of cystine
defect in lysosomal membrane
cystine deposits in body (cornea)
cystinosis findings
polyuria
aminoaciduria
homocystinuria
increased homocystine
failure to thrive, mental deficits, death
homocystinuria findings
screening: pos cyanide-nitroprusside: red
Confirm: silver-nitroprusside: red
Porphyrin disorders screening
Ehrlich’s reaction/Howesch test
fluorescence: 550-600 nm range
(extract w/ glacial acetic acid, blue = negative, purple,pink,red = pos)
Hurler’s syndrome
Mucopolysacchride disorder
Gargoyalism
usually fatal in childhood
Hunter’s syndrome
Mucopolysacchride disorder
skeletal deformaty
usually fatal in childhood
Sanfilippo’s syndrome
mucopolysaccharide disorder
mental deficiencies
most common, least detrimental
mucopolysacchride screening tests
CTAB (white turbidity)
Acid-albumin turbidity (white turbidity)
metachromic staining (blue spot)
Lesch-Nyhan disease
failure to inherit, causing large excretion of uric acid crystals
Lesch-Nyhan symptoms
Gout, self destruction, renal stones, mental dysfunction
Orange particles in diapers
Carbohydrate disorders
Melituria: increased urinary sugar
inherited disorder
galactosuria
Major concern
can’t convert galactose to glucose
GALT or G-1-PUT enzyme
Galactosemia
Toxic intermediate conversion products
Failure to thrive
liver disorder
cataracts
galactosemia testing
Clinitest (not done anymore)
positive while strip test negative
treat w/ removal of lactose from diet
