Porphyrias

Question 1

What colour will PCT type 1 show on a Wood’s lamp?

Answer 1

Pink

Question 2

What causes porphyria cutanea tarda type 1?

Answer 2

Chronic liver disease e.g. hep C, alcoholic liver disease, haemochromatosis

Question 3

Caution must be taken when in patients with erythropoietic photoporphyria?

Answer 3

Surgery (due to lots of visible light)

Question 4

What does diagnosis of PCT type 1 involve?

Answer 4

Diagnosis of the porphyria and also the underlying cause

Question 5

What metabolic step cannot occur in erythropoietic photoporphyria?

Answer 5

Photoporphyrin IX to haem

Question 6

What in general terms, are the porphyrias?

Answer 6

A clinically distinct group of disorders, some of which cause cutaneous photosensitivity

Question 7

What should be monitored in erythropoietic photoporphyria?

Answer 7

6 monthly LFTs and RBC porphyrins

Question 8

Acute intermittent porphyria should be considered as a differential to what?

Answer 8

Acute abdomen, Guillain-Barre, psychoses, mononeuritis multiplex

Question 9

If an individual has abnormal cutaneous photosensitivity, what does this mean?

Answer 9

There is an increased reaction to UV and sometimes visible light

Question 10

Erythropoietic photoporphyria affects the production of what? What can this cause?

Answer 10

Haemoglobin, myoglobin, cytochrome: can cause anaemia and pain on exposure to light

Question 11

What enzyme is deficient in acute intermittent porphyria?

Answer 11

PBG deaminase

Question 12

What light is dangerous in erythropoietic photoporphyria?

Answer 12

Visible light (not UV)

Question 13

What are some treatment options for abnormal cutaneous photosensitivity?

Answer 13

Behavioural changes (e.g. clothing and sunscreen use), phototherapy and immunosuppressants

Question 14

Scaling where can often indicate a photosensitive skin problem?

Answer 14

Behind the ears

Question 15

Which types of porphyria can cause yellowing of the teeth?

Answer 15

Severe congenital porphyrias

Question 16

What enzyme is deficient in porphyria cutanea tarda type 1?

Answer 16

Uroporphyrinogen decarboxylase

Question 17

What enzyme is deficient in congenital erythropoietic porphyria?

Answer 17

Uroporphyrinogen III synthase

Question 18

Which porphyria inhibits transition from porphobilinogen to hydroxymethylbilane?

Answer 18

Acute intermittent porphyria

Question 19

What are some treatment options for erythropoietic photoporphyria?

Answer 19

Protection against visible light, phototherapy and anti-oxidants

Question 20

Which porphyria inhibits the progression of uroporphyrinogen III to coproporphyrinogen III?

Answer 20

PCT Type 1

Question 21

Is porphyria cutanea tarda type 1 inherited?

Answer 21

No

Question 22

What can acute intermittent porphyria present as?

Answer 22

Nerve damage (no skin symptoms)

Question 23

What is the most common cause of acute intermittent porphyria?

Answer 23

Medications, especially barbiturates

Question 24

How do you treat PCT type 1?

Answer 24

Treat the underlying condition, supportive treatment for skin involvement

Question 25

From which areas of the electromagnetic spectrum do most skin problems originate from?

Answer 25

Visible and UV light

Question 26

Give an example of a severe congenital porphyria?

Answer 26

Congenital erythropoietic porphyria

Question 27

What enzyme is deficient in erythropoietic photoporphyria?

Answer 27

Ferrochelatase

Question 28

Give an example of a phototoxic skin porphyria?

Answer 28

Erythropoietic porphyria

Question 29

What is the number 1 test for erythropoietic photoporphyria? What other test can be used?

Answer 29

No 1 = Porphyrin plasma scan, Other = quantitative RBC porphyrins

Question 30

Does erythropoietic photoporphria have a genetic component?

Answer 30

Yes

Question 31

What are some presenting features of PCT type 1?

Answer 31

Blistering and fragility, hypertrichosis, hyper pigmentation, solar urticaria, morphoea

Question 32

How can you investigate for PCT Type 1?

Answer 32

Wood's lamp or spectrofluorimeter

Question 33

Do all acute attack porphyrias have skin symptoms? If they do have skin symptoms, what can they be?

Answer 33

Not always, can cause blistering and fragility

Question 34

What differentiates the different types of porphyria?

Answer 34

Depends on where the problem occurs in the normal metabolic cycle

Question 35

What porphyria blocks the transition of hydroxymethylbilane to uroporphyrinogen III?

Answer 35

Congenital erythropoietic porphyria