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Flashcards in Porphyrias Deck (65):
1

What usually causes porphyrias?

Enzyme deficiencies in heme biosynthesis

2

Porphyrias result in the ______ and ________ of precursors in heme biosynthesis

overproduction and excretion

3

These are chemical intermediates in the synthesis of hemoglobin, myoglobin, and respiratory pigments

porphyrins

4

These are colorless and unstable metabolites of porphyrins

porphyrinogens

5

_______ is found in the urine of those with acute porphyria

Porphobilinogen

6

Urine with porphobilinogen is ______ when fresh, but then turns _______

normal
red/wine colored
(turns black if heated to 100 C w/ dilute HCl)

7

What are disorders of heme synthesis?

Porphyrias

8

Qualitative heme disorders are:

Hemoglobinopathies. Structural changes in globin molecule.

9

Quantitative heme disorders are:

Thalassemias

10

What are porphrins?

Stable colored compounds. Usually red-violet to red-brown.

11

Porphrins fluoresce at ________

400 nm

12

Protoporphyrin is...

Porphyrin found in feces

13

Coporporphyrin is...

porphyrin in urine and feces

14

Uroporphyrin is...

porphyrin in urine

15

Porphyrinogens are readily ______ to porphyrins upon exposure to ______ or ________

oxidized
light or oxygen

16

3 chemically altered hemoglobins:

1. methemoglobin
2. carboxyhemoglobin
3. sulfhemoglobin

17

T/F Most porphyrias are due to complete lack of enzymes

False- most are just deficiencies of enzymes

18

Inheritance pattern of porphyrias

Autosomal dominant (with one exception)

19

Porphyrias can be ______ or _______

inherited or aqcuired

20

What is the inheritance pattern of Congenital Erythropoietic Porphyria (CEP)?

Autosomal recessive

21

Which porphyria is acquired?

Porphyria Cutanea Tarda

22

Where are the 2 main places heme precursors build up?

Bone marrow and liver

23

Erythropoietic porphyria is...

Heme precursors build up in marrow

24

Hepatic porphyria is...

Build up of precursors in liver

25

Acquired porphyrias can be differentiated from true porphyrias by measuring what?

Urinary ALA and PBG

26

Excess of early heme precursors leads to _______ porphyria

Neuropsychiatric

27

Excess of late heme precursors causes _______ porphyria

cutaneous

28

What are 2 examples of early heme precursors?

ALA
Porphobilinogen

29

What are examples of late heme precursors?

Uroporphyrin, Coproporphyrin, Protoporphyrin

30

Regulation of this enzyme controls the rate of heme synthesis in the liver:

ALA synthase

31

The main purpose of porphyrias in the body is...

to contribute to the synthesis of heme

32

Disease states corresponding to enzyme deficiencies have been linked to every step of heme synthesis except:

ALAS

33

The diagnosis of porphyrias is made by a combo of ________ , _______ , and ________ findings

history, physical, laboratory

34

_________ is usually the presenting symptom of cutaneous porphyrias

Photosensitivity

35

ALAD porphyria is a _____ ________ disorder

rare genetic

36

What is the deficiency in ADP?

ALA dehydratase (ALAD)

37

What is precursor is measured in ADP?

ALA in urine

38

CEP stand for ______ and is a(n) ______ porphyria

Congenital erythropoietic porphyria; erythropoietic

39

AIP stands for __________ and is a(n) ________ porphyria

Acute intermittent hepatic porphyria; hepatic

40

HCP stands for ________ and is a(n) _______ porphyria

hereditary coproporphyria; hepatic

41

EPP stands for _______ and is a(n) ______ porphyria

erythropoetic protoporphyria; hepatic

42

mixed porphyrias as also known as...

Variegated porphyria (VP)

43

Accumulation of uroporphyrinogen & coproporphyrinogen in the body tissues lead to...

Excretion of these metabolites in urine & feces
Light sensitivity (tissues mutilate when exposed)

44

Most common of hepatic porphyrias is:

PCT (porphyria cutanea tarda). However, is classified as erythropoietic due to skin manifestations

45

PCT is mostly ______

acquired; few may be auto-dominant

46

what is deficient in PCT?

Uroporphyrinogen decarboxylase

47

Decrease in Uroporphyrinogen decarboxylase leads to increased production of:

Uroporphyrinogen

48

Some degree of _____ damage is seem in all PCT patients

liver

49

AIP is an ________ porphyria with a _______ _______ inheritance pattern and is due to an deficiency in _______ ______.

acute
autosomal dominant
PBG deaminase

50

What builds up in AIP?

porphobilinogen & ALA

51

Manifestation of AIP is mostly ________ symptoms

Neurological

52

HCP is due to a deficiency of which enzyme?

This leads to build up of what metabolites?

Coproporphyrinogen oxidase

Coproporphyrinogen (III) PBG & ALA

53

What is deficient in EPP?

What builds up?

Ferrochelatase

Protoporphyrins in plasma and feces; possibly Coproporphyrinogen

54

This is the second most common porphyria

EPP

55

EEP leads to lifelong accumulation of protoporphyrins in _____

skin
(light sensitivity seen)

56

What is the most severe complication of EEP?

Progressive hepatic failure due to accumulation of protoporphyrins in liver

57

What enzyme is deficient in VP?

Protoporphyrinogen oxidase

58

How do we distinguish VP from EPP?

RBCs will fluoresce red in EPP

RBCs in VP have normal protoporphyrin levels- no fluorescence

59

What is secondary porphyria and how is it distinguished from primary?

Secondary: Mild to moderate increase in porphyrins in urine. Not due to enzyme deficiency, but due to drugs, toxins, or other disorders.

In secondary, urinary ALA will be increased but PBG normal

60

What are the 2 most common screening tests for urinary porphobilinogen?

Hoesch test
Watson-Schwartz test

61

What is the principle of the Hoesch test?

Urine + Hoesch reagent
--> if PBG present, red color is formed

62

What's the principle of the Watson-Schwartz test?

Ehrlich reagent + sodium acetate + urine
--> If PBG present, pink pigment formed with reagent

63

Generally, the cutaneous manifestations of ___ are less severe than those of ___, ___ or ___

EPP
PCT, VP, HCP

64

These three porphyrias have neurological manifestations:

AIP, VP, HCP

65

These porphyrias have cutaneous manifestations:

PCT, VP, HCP, EPP