Urine Screening for Metabolic Disorders Flashcards
1
Q
Disorders resulting from disruption of a normal metabolic pathway that causes increased plasma concentrations of the nonmetabolized substances
A
Overflow disorders
2
Q
Overflow disorders are frequently associated with
A
Inborn error of metabolism (IEM), or by organ malfunction from disease or toxic reactions
3
Q
Abnormal accumulations of the renal type caused by malfunctions in the tubular reabsorption mechanism
A
Renal disorders
4
Q
Gold Standard test for newborn screening
A
Tandem mass spectrophotometry (MS/MS)
5
Q
The most well-known of the aminoacidurias
A
Phenylketonuria
6
Q
Urine odor of patient with phenylketonuria
A
Mousy
7
Q
Enzyme deficient in cases of phenylketonuria
A
Phenylalanine hydroxylase
8
Q
Urinalysis result of patient with phenylketonuria shows increased amounts of
A
Keto acids, including phenylpyruvate
9
Q
How does phenylketonuria produce fair complexion in children?
A
Normal conversion of phenylalanine to tyrosine is disrupted; leading to decreased production of tyrosine and its pigmentation metabolite melanin
10
Q
In phenylketonuria, gene is inherited as an autosomal dominant trait. True or False?
A
False; recessive
11
Q
How to manage phenylketonuria?
A
Dietary changes that eliminate phenylalanine
12
Q
Positive result of ferric chloride test for phenylketonuria
A
Permanent blue-green color
13
Q
Describe the principle and process of guthrie blood test for PKU
A
Principle: same as culture sensitivity testing
- Media containing beta-2-thieneylalanine, an inhibitor of Bacillus subtilis, is streaked with the bacteria
- Blood impregnated discs placed on the agar; phenylalanine counteracts the inhibitor, and bacteria grow around the disc
NOTE: bacterial growth indicates presence of phenylalanine; patient has PKU
Bacterial growth is due to phenylalanine countering the effect of the beta-2-thienylalanine
14
Q
In tyrosinemia, the urine may contain excess tyrosine or its degradation products, _____ and _____
A
p-hydroxyphenylpyruvic acid
p-hydroxyphenyllactic acid
15
Q
Urine odor of patient with tyrosinemia
A
Rancid butter odor
16
Q
Metabolic classification of tyrosinemia
A
Transitory tyrosinemia
Acquired severe liver disease
17
Q
Tyrosinemia seen in premature infants, which is caused by underdevelopment of the liver function required to produce the enzymes necessary to complete the tyrosine metabolism
A
Transitory tyrosinemia
18
Q
Tyrosinemia that produces tyrosyluria resembling that of the transitory newborn and is more serious
A
Acquired severe liver disease
19
Q
In Transitory tyrosinemia and Acquired severe liver disease, tyrosine and leucine crystals are frequently seen. True or False?
A
False; rarely seen
20
Q
Hereditary classification of tyrosinemia
A
Type 1 tyrosinemia
Type 2 tyrosinemia
Type 3 tyrosinemia
21
Q
Deficient enzyme in Type 1 tyrosinemia
A
Fumarylacetoacetate hydrolase (FAH)
22
Q
Deficient enzyme in Type 2 tyrosinemia
A
Tyrosine aminotransferase
23
Q
Deficient enzyme in Type 3 tyrosinemia
A
p-hydroxyphenylpyruvic acid dioxygenase
24
Q
Tyrosinemia with generalized renal tubular disorder and progressive liver failure in infants soon after birth
A
Type 1 tyrosinemia
25
Tyrosinemia with corneal erosion and lesions on the palms, fingers, and soles of the feet believed to be caused by crystallization of tyrosine in the cells
Type 2 tyrosinemia
26
Tyrosinemia leading to mental retardation if dietary restrictions of phenylalanine and tyrosine are not implemented
Type 3 tyrosinemia
27
Positive result of ferric chloride test for tyrosinemia
Transient green color
28
Positive result of Nitroso-Naphthol Test for Tyrosine
Orange-red color
29
Byproducts of the second metabolic pathway for tyrosine
Thyroxine
Epinephrine
Melanin
Protein
Tyrosine sulfate
30
Responsible for the dark color of hair, skin, and eyes
Melanin
31
Deficient production of melanin leads to
Albinism
32
Elevated urinary melanin indicates
Proliferation of the normal melanin-producing cells (melanocytes), producing a malignant melanoma
33
Describe the production of dark urine due to melanin
Tumors (malignant melanoma) secrete a colorless precursor of melanin, 5,6-dihydroxyindole, which oxidizes to melanogen and then to melanin, producing the characteristic dark urine
34
Positive result of Ferric Chloride Tube Test for melanuria
Black /gray precipitate
35
Positive result of Sodium Nitroprusside Test for melanuria
Purple color
36
Positive result of Ehrlich Test for melanuria
Red color
37
Observed in urine that has darkened after becoming alkaline from standing at room temperature
Alkaptonuria
38
Alkaptonuria also means
“Alkali lover”
39
Third major defect in the phenylalanine-tyrosine pathway
Alkaptonuria
40
Enzyme deficient in cases of alkaptonuria
Homogentisic acid oxidase
41
Deposits of homogentisic acid in the cartilage leads to
Arthritis
42
Positive result of Ferric Chloride Tube Test for alkaptonuria
Transient deep blue color
43
Positive result of Clinitest for alkaptonuria
Yellow precipitate
44
Positive result of Ammonium Hydroxide and Silver Nitrate Test for Homogentisic Acid
Black/ darkening color
45
Quantitation method of homogentisic acid
Paper and Thin Layer Chromatography
46
Branched chain amino acids disorders
MSUD
Organic acidemias
47
Accumulation of one or more of the early amino acid degradation products
MSUD
48
Accumulation of organic acids further down in the amino acid metabolic pathway
Organic acidemias
49
A significant laboratory finding in branched-chain amino acid disorders
Ketonuria
50
Amino acids involved in MSUD
Leucine
Isoleucine
Valine
51
Urine odor of patient with MSUD
Caramelized sugar/burnt sugar/curry odor/maple syrup odor
52
Maple syrup odor of urine is due to
Accumulation of keto acids
53
Positive result of 2,4-Dinitrophenylhydrazine (DNPH) Test for MSUD
Yellow precipitate
54
The three most frequently encountered organic acidemia disorders
Isovaleric acidemia
Propionic acidemia
Methylmalonic acidemia
55
Urine odor of patient with isovaleric acidemia
“Sweaty feet”
56
Sweaty feet odor of urine is due to
Accumulation of isovalerylglycine
57
Deficient enzyme in cases of isovaleric acidemia
Isovaleryl coenzyme A
58
Cause of propionic and methylmalonic acidemias
Errors in the metabolic pathway converting isoleucine, valine, threonine, and methionine to succinyl coenzyme A
59
The presence of isovaleric, propionic, and methylmalonic acidemias can be detected by newborn screening programs using
MS/MS
60
Positive result of p-Nitroaniline Test for organic acidemias
Emerald green color
61
The major concern of the urinalysis laboratory in the metabolism of tryptophan
Indicanuria
5-hydroxyindoleacetic acid (5-HIAA)
62
Two usual causes of tryptophan disorders
Intestinal infection
Malignant tumors
63
Color of urine exhibiting indicanuria
Colorless until oxidized to the dye indigo blue by exposure to air
64
Intestinal disorder causing increased amounts of tryptophan converted to indole
Hartnup disease
65
Cause of blue diaper syndrome
Hartnup disease
66
Hartnup disease causes Fanconi syndrome. True or False?
True
67
Substance given to patients with Hartnup disease
Niacin
68
Positive result of Ferric Chloride Test for indicanuria
Blue or violet color
69
Serotonin is produced from tryptophan by the
Argentaffin cells
70
Serotonin is carried through the body primarily by
Platelets
71
Cause of urinary 5-HIAA
Carcinoid tumors involving the argentaffin (enterochromaffin) cells producing excess amounts of serotonin
72
Adding nitrous acid and 1-nitroso-2-naphthol to urine that contains 5-HIAA causes the urine to turn
Purple to black
73
Normal excretion of 5-HIAA
2-8 mg/day
74
Excretion >25 mg 5-HIAA/24 hour indicates
Argentaffin cell tumors
75
Patient instruction for 5-HIAA test
No bananas, pineapples, tomatoes, phenothiazines, and acetanilids for 72 hours
76
Two distinct disorders of cystine metabolism
Cystinuria
Cystinosis
77
Cystine disorder caused by defect in the renal tubular transport of amino acids
Cystinuria
78
Cystine disorder caused by inborn error of metabolism
Cystinosis
79
Urine odor of people with cystine metabolism disorders
Sulfur odor
80
Inherited disorder marked by elevated amounts of the amino acid cystine in the urine
Cystinuria
81
Cause of cystinuria
Inability of the renal tubules to reabsorb cystine filtered by the glomerulus
82
Two modes of inheritance of Cystinuria
Cystine, lysine, arginine, and ornithine are not reabsorbed
Only cystine and lysine are not reabsorbed
83
A chemical screening test for urinary cystine
Cyanide-nitroprusside
84
Positive result of Cyanide-nitroprusside test for cystinuria
Red-purple color
85
Regarded as a genuine IEM
Cystinosis
86
Three variations of cystinosis
Nonnephropathic Cystinosis
Infantile Nephropathic Cystinosis
Late-Onset Nephropathic Cystinosis
87
Cystinosis that is relatively benign but may cause some ocular disorders
Nonnephropathic Cystinosis
88
Cystinosis with rapid progression to renal failure
Infantile Nephropathic Cystinosis
89
Cystinosis gradual progression to total renal failure
Late-Onset Nephropathic Cystinosis
90
Cause of cystinosis
A defect in the lysosomal membranes prevents the release of cystine into the cellular cytoplasm for metabolism resulting to crystalline deposits of cystine in many areas of the body
91
Remedies to prevent the buildup of cystine in tissues
Renal transplants
Cystine-depleting medication
92
Defects in the metabolism of the amino acid methionine, producing an increased amount of homocystine throughout the body
Homocystinuria
93
Diet change to alleviate metabolic problems in homocystinuria
Exclude foods high in methionine
94
Positive result of Cyanide-nitroprusside test for homocystinuria
Red-purple color
95
Positive result of Silver-nitroprusside test for homocystinuria
Red-purple color
96
Disorders of porphyrin metabolism are collectively termed
“Porphyrias”
97
Three primary porphyrins
Uroporphyrin
Coproporphyrin
Protoporphyrin
98
Porphyrin precursors
α-aminolevulinic acid [ALA] and porphobilinogen
99
The solubility of the porphyrin compounds varies with their structure. True or False?
True
100
Porphyrin that is most soluble and readily appear in the urine
Uroporphyrin
101
Coproporphyrin is less soluble but is found in the urine, whereas protoporphyrin is not seen in the urine. True or False?
True
102
Method to detect coproporphyrin and protoporphyrin
Fecal analysis
Bile is a more acceptable specimen to avoid false-positive
103
An indication of the possible presence of porphyrinuria
Red or port wine color of urine after exposure to air
103
Porphyria may also exhibit red discoloration of an infant’s diapers; and staining of the teeth. True or False?
True
104
Test used only for the detection of ALA and porphobilinogen
Ehrlich reaction
105
Test used for the other porphyrins
Fluorescent technique
106
Positive result of Fluorescent technique for porphyrins
Violet, pink, or red fluorescence
107
Negative result of Fluorescent technique for porphyrins
Faint blue fluorescence
108
Test that rules out porphobilinogen and ALA
Fluorescent technique
109
Test for the differentiation between the presence of urobilinogen and porphobilinogen
Watson-Schwartz Test
110
Testing for the presence of porphobilinogen
Hoesch test
111
Common porphyrias
Acute intermittent porphyria
Porphyria cutanea tarda
Congenital erythropoietic porphyria
Variegate porphyria
Erythropoietic protoporphyria
Lead poisoning
112
Products most frequently found in the urine of patients with mucopolysaccharide disorders
Dermatan sulfate
Keratan sulfate
Heparan sulfate
113
Mucopolysacchariddoses resulting to abnormal skeletal structure, severe mental retardation, and corneal damage
Hurler Syndrome
114
Mucopolysacchariddoses resulting to abnormal skeletal structure, severe mental retardation, inherited as a sex-linked recessive, rare in females
Hunter Syndrome
115
Mucopolysacchariddoses in which the only abnormality is mental retardation
Sanfilippo Syndrome
116
Most promising treatments for mucopolysaccharide disorders
Bone marrow transplants
Gene replacement therapy
117
Positive result of Acid-albumin and Cetyltrimethylammonium Bromide (CTAB) Turbidity Tests for mucopolysaccharide disorders
Thick, white turbidity formation
118
Reading time of Acid-albumin test
30 minutes
119
Reading time of CTAB test
5 minutes
120
Positive result of Metachromatic Staining Spot Tests for mucopolysaccharide disorders
Blue spot that cannot be washed away with dilute acidified methanol
121
Lesch-Nyhan disease is caused by
Disorder of purine metabolism
122
Lesch-Nyhan disease is characterized by
Massive excretion of urinary uric acid crystals
123
Deficient enzyme in cases of Lesch-Nyhan disease
Hypoxanthine guanine phosphoribosyltransferase
124
The first sign of this disease is often uric acid crystals resembling orange sand in diapers
Lesch-Nyhan disease
125
The presence of increased urinary sugar
Melituria
126
Most meliturias cause no disturbance to body metabolism except for _____
Galactosuria
127
Inability to properly metabolize galactose to glucose
Galactosuria
128
Galactosuria can be caused by a deficiency in any of three enzymes:
Galactose-1-phosphate uridyltransferase (GALT)
Galactokinase
UDP-galactose-4-epimerase
129
Deficient enzyme in cases of galactosuria that causes severe, possibly fatal symptoms associated with galactosemia
Galactose-1-phosphate uridyltransferase (GALT)
130
Deficient enzyme in cases of galactosuria that causes cataracts in adulthood
Galactokinase
131
Deficient enzyme in cases of galactosuria that may be asymptomatic or produce mild symptoms
UDP-galactose-4-epimerase
132
Diet change for the management of galactosuria
Removal of lactose
133
Carbohydrate disorder seen during pregnancy and lactation
Lactosuria
134
Carbohydrate disorder associated with parenteral feeding
Fructosuria
135
Carbohydrate disorder associated ingestion of large amounts of fruit
Pentosuria
