Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IBI Test 3 > B3-092 Porphyria > Flashcards

B3-092 Porphyria Flashcards

1
Q

porphyria is caused by

A

partial deficiency of heme biosynthesis enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

porphyria results in the accumulation of _____________ in tissues

A

heme precursors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

all autosomal dominant porphyrias have

A

low clinical penetrance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Heme is necessary for [3 functions]

A

oxygen binding
oxygen metabolism
electron transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

most heme is synthesized by _________ cells in bone marrow and ____________ in the liver

A

erythroid; hepatocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

4 pyrrole rings linked by methenyl bridges

A

ferrous iron (Fe2+) and protoporphyrin IX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

porphyrias can be classified into two main groups based on predominant clinical manifestations

A

causing acute neurovisceral attacks
porphyrias causing chronic cutaneous photosensitivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

ALA dehydratase deficiency affects which enzyme?

A

ALAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Does ALA dehydratase deficiency have neurovisceral or skin manifestations?

A

neurovisceral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

inheritance pattern: ALA dehydratase deficiency

A

autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Acute intermittent porphyria affects which enzyme?

A

HMBS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

does Acute intermittent porphyria cause neurovisceral or skin manifestations?

A

neurovisceral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

inheritance pattern: Acute intermittent porphyria

A

autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

hereditary coproporphyria affects which enzyme?

A

CPO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

does hereditary coproporphyria cause neurovisceral or skin manifestations?

A

both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

inheritance pattern: hereditary coproporphyria

A

autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Variegate affects which enzyme?

A

PPOX

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

does variegate cause neurovisceral or skin manifestations?

A

both

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

inheritance pattern: variegate

A

autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

congenital erythropoietic porphyria affects which enzyme?

A

UROS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

does congenital erythropoietic porphyria cause neurovisceral or skin manifestations?

A

skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

inheritance pattern: congenital erythropoietic porphyria

A

autosomal recessive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

porphyria cutanea tarda affects which enzyme?

A

UROD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

does porphyria cutanea tarda exhibit neurovisceral or skin manifestations?

A

skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

inheritance pattern: porphyria cutanea tarda

A

complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

which enzyme does erythropoietic protoporphyria affect?

A

FECH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

does erythropoietic protoporphyria cause neurovisceral or skin manifestations?

A

skin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

inheritance pattern: erythropoietic protoporphyria

A

autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

enzyme defects up to _________ cause acute neurologic porphyria

A

HMBS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

enzyme defects up to HMBS cause

A

acute neurologic porphyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

enzyme defects after HMBS are ______________ and cause cutaneous porphyria

A

less soluble

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

enzyme defects after HMBS are less soluble and cause

A

cutaneous porphyria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

VP and HCP ____________ PBG production

A

increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

increased PBG production interferes with _____________ causing neurovisceral attacks

A

GABA signaling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

increased PBG production interferes with GABA signaling causing

A

neurovisceral attacks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

enzyme deficiency, combined with _________________ causes an imbalance in the heme pathway

A

environmental or physiologic trigger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

overproduction of porphyrins and porphyrin precursors into blood causes

A

skin lesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

overproduction of porphyrins and porphyrin precursors into the liver cause

A

acute neurologic symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

overproduction of porphyrins and porphyrin precursors into bone marrow cause

A

acute neurologic symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

common triggers that induce ALA synthase

A

alcohol use
smoking
medications
hormone replacement
sunlight exposure
stress
dieting and fasting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

symptoms of cutaneous porphyrias

A

oversensitivity to sunlight
blisters on sun exposed skin
skin fragility
scarring
hyper or hypo pigmentation
hypertrichosis/alopecia
urticaria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

porphyrins deposited in skin absorb energy in the visible light spectrum causing

A

oxidative damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

porphyrins deposited in skin absorb energy in the _____________ causing oxidative damage

A

visible light spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

most common porphyria

A

porphyria cutanea tarda

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

porphyria cutanea tarda onsets in which stage of life?

A

adulthood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

porphyria cutanea tarda is more common in women or men?

A

men

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

______% of porphyria cutanea tarda causes are acquired

A

75

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

causes of acquired porphyria cutanea tarda

A

hep C
hemochromatosis
alcohol abuse
smoking
estrogen rx
polychlorinated cyclic hydrocarbon exposure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

in porphyria cutanea tarda ________ accumulates in skin

A

uroporphyrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

porphyria cutanea tarda is symptomatic when enzyme is

A

<20% of normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

porphyria cutanea tarda causes the inability to convert uroporphyrinogen to

A

coproporphyrinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

porphyria cutanea tarda causes the inability to convert _______________ to coproporphyrinogen

A

uroporphyrinogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

in porphyria cutanea tarda, LFTs are

A

abnormal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

porphyrins in the liver down regulate

A

hepcidin

55
Q

down regulation of hepcidin causes

A

iron overload and formation of ROS

56
Q

treatment of porphyria cutanea tarda

A

avoid sunlight
discontinue. risk factors
treat comorbid conditions
phlebotomy

57
Q

congenital erythropoietic porphyria is caused by a deficiency in

A

uroporphyrinogen III synthase

58
Q

erythropoietic protoporphyria is caused by a deficiency of

A

ferrochelatase

59
Q

most common early childhood porphyria

A

erythropoietic protoporphyria

60
Q

causes acute photosensitivity without skin fragility and blisterin

A

erythropoietic protoporphyria

61
Q

erythropoietic protoporphyria is caused by a deficiency of

A

ferrochelatase

62
Q

erythropoietic protoporphyria increases the risk of

A

hemolytic anemia
gallstones
liver disease (may require transplant)

63
Q

erythropoietic protoporphyria treatment

A

avoid sunlight
melanocyte stimulating hormone to darken skin and reduce photosensitivity
narrowband UVB to darken skin
cholestyramine to absorb protoporphyrin
stem cell transplant

**liver transplant if liver failure

64
Q

in erythropoietic protoporphyria, excess protoporphyrin accumulates in

A

RBCs

diffuses into plasma, enters skin, cleared by liver and secreted into bil

65
Q

associated with vampire folklore

A

congenital erythropoietic porphyria

66
Q

onset soon after birth

A

congenital erythropoietic porphyria

67
Q

severe photosensitivity with scarring, erythrodontia, hemolytic anemia, and gallstone

A

congenital erythropoietic porphyria

68
Q

porphyrin laden erythrocytes in congenital erythropoietic porphyria cause

A

hemolysis, splenomegaly, gallstones
photolysis in dermal capillaries

69
Q

caused by enzyme defect in bone marrow erythroid cells

A

congenital erythropoietic porphyria

70
Q

congenital erythropoietic porphyria treatment

A

avoid sunlight
transfusion for anemia
stem cell transplant

71
Q

chronic cutaneous manifestations may lead to misdiagnosis

A

variegate porphyria

72
Q

chronic cutaneous manifestations with abdominal pain, neuropathy, and psychiatric

A

variegate porphyria

73
Q

rarest forms of porphyria

A

hereditary coproporphyria

74
Q

usually provoked by cholestasis from some other cause

A

hereditary coproporphyria

75
Q

increased coproporphyria in urine and feces

A

hereditary coproporphyria

**similar to VP

76
Q

coproporphyrin III:I ratio of 10-20 with no increase in protoporphyrin

A

hereditary coproporphyria

77
Q

symptoms of acute neurologic porphyrias

A

severe abdominal pain
psychiatric distress
hypertensions, tachycardia
seizures
parasthesia
fever
weakness progressing to paralysis

78
Q

acute neurologic porphyrias can be provoked by

A

barbituates
sulfonamide antibiotics
anticonvulsants
antihistamines
chemicals
smoking
alcohol
caloric restriction

79
Q

in ALAD and AIP, tetrapyrrole intermediates

A

do not accumulate

80
Q

ALAD and AIP do not cause

A

photosensitivity

81
Q

VP and HCP increase ___________ & do cause photosensitivity

A

tetrapyrrole

82
Q

VP and HCP increase tetrapyrrole and cause

A

photosensitivity

83
Q

onset between 15-35 years

A

acute porphyria

**rare before puberty

84
Q

acute porphyria is more common in women or men?

A

women

85
Q

characterized by acute neurovisceral attacks

A

acute porphyria

86
Q

recurrence of acute porphyria may be related to the __________________ in women

A

menstrual cycle

87
Q

acute porphyria is difficult to diagnose because

A

symptoms are non specific and variable
family history often missing or incomplete

88
Q

PBG is almost always increased in

A

AIP, VP, and HCP

89
Q

most common acute porphyria

A

AIP

90
Q

higher incidence in northern europe

A

AIP

91
Q

sequence of symptoms, AIP

A

abdominal pain –> psychiatric –> peripheral neuropathy

92
Q

GI symptoms of AIP

A

constipation
colicky abdominal pain
vomiting
diarrhea

93
Q

psychiatric symptoms of AIP

A

psychotic episodes
depression
anxiety

94
Q

in AIP, excess PBG and ALA are

A

neurotoxic

95
Q

ALA interferes with

A

GABA signaling

96
Q

heme deficiency inhibits cytochromes and causes

A

neurodegeneration

97
Q

heme deficiency decreases hepatic tryptophan pyrrolase activity resulting in

A

increased serotonin and cognitive changes

98
Q

port wine urine

A

AIP

99
Q

in AIP, excess porphobilinogen and aminolevulinic acid are excreted in

A

urine

100
Q

extremely rare acute neurologic porphyria

A

ALAD

101
Q

only acute porphyria to begin in childhood

A

ALAD

102
Q

ALAD has _________ levels of urine porphobilinogen

A

normal

103
Q

ALAD has ______________ aminolevuliniv acid

A

significantly elevated

**rule out lead poisoning

104
Q

treatment: acute porphyrias

A

treat symptoms and try to correct heme pathway deficiency

105
Q

therapeutic options for acute porphyrias

A

remove exacerbating factors
IV fluid with dextrose
opiate pain control
nausea control
hematin IV therapy

106
Q

panhematin is infused IV and taken up by

A

hepatocytes –> enters heme pool

107
Q

panhematin inhibits synthesis of

A

ALA synthase

**rate limiting enzyme of heme pathway

108
Q

ultimately, panhematin reduces production of

A

porphyrin precursors

109
Q

RNA interference drug targeting Aminolevulinic acid synthase

A

givlaari

110
Q

alternative to hemin infusions for patients with frequent acute porphyria attacks

A

givlaari

111
Q

best initial test to diagnose porphyrias

A

urine porphyring analysis + porphobilinogen

**erythrocyte protoporphyrin if EPP suspected

112
Q

Confirmatory PCT testing:

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay:yes
Urine elevations: uroheptacarboxyl
Feces elevations: isocopro heptacarboxyl
Erythrocyte elevations: none
plasma elevations: uroheptacarboxyl

113
Q

confirmatory EPP testing:

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: no
Urine elevations: no
Feces elevations: proto
Erythrocyte elevations: proto
plasma elevations: proto

114
Q

confirmatory CEP testing:

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: yes
Urine elevations: Uro I, Copro I
Feces elevations: Copro I
Erythrocyte elevations: Uro I, Copro I
plasma elevations: Uro I, Copro I

115
Q

confirmatory AIP testing:

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: yes
Urine elevations: ALA, PBG, Uro, Copro
Feces elevations: Uro
Erythrocyte elevations: no
plasma elevations: Uro

116
Q

confirmatory VP testing

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: no
Urine elevations: ALA, PBG, Copro
Feces elevations: proto>copro, copro III/I
Erythrocyte elevations: no
plasma elevations: copro, proto

117
Q

confirmatory HCP testing

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: no
Urine elevations: ALA & PBG, copro
Feces elevations: copro III/I
Erythrocyte elevations: no
plasma elevations: copro

118
Q

confirmatory testing ALAD

Enzyme Assay:
Urine elevations:
Feces elevations:
Erythrocyte elevations:
plasma elevations:

A

Enzyme Assay: yes
Urine elevations: ALA copro
Feces elevations: no
Erythrocyte elevations: zinc
plasma elevations: n/a

119
Q

only order __________ after biochemical diagnosis has been made to confirm diagnosis

A

molecular test

120
Q

molecular testing for at risk family members

A

test for mutation identified in family

counsel to avoid exacerbating factors

121
Q

heme pathway

A
122
Q

3 most common porphyrias in US

A

Acute intermittent
erythropoietic protop.
cutanea tarda

123
Q

most common porphyria in US

A

cutanea tarda

124
Q

second most common porphyria in US

A

AIP

125
Q

third most common porphyria in US

A

erythropoietic protoporhyria

126
Q

presents with acutely painful skin lesions

A

erythropoietic protoporphyria

127
Q

presents with acute neurovisceral symptoms

A

AIP

128
Q

presents with chronic blistering skin lesions

A

porphyria cutanea tarda

129
Q

the intermittent symptoms of porphyrias is due to

A

partial deficiencies in the heme pathway

130
Q

cutanea tarda is caused by

A

uroporphyrinogen decarboxylase deficiency

131
Q

erythropoietic protoporphyria is caused by

A

ferrochelatase deficiency

132
Q

congenital erythropoietic porphyria is caused by

A

UROS

133
Q

congenital erythropoietic porphyria is inherited in an

A

autosomal recessive pattern

IBI Test 3 (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions