Porphyrias Flashcards

1
Q

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

A

Pink

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2
Q

What causes porphyria cutanea tarda type 1?

A

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

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3
Q

Caution must be taken when in patients with erythropoietic photoporphyria?

A

Surgery (due to lots of visible light)

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4
Q

What does diagnosis of PCT type 1 involve?

A

Diagnosis of the porphyria and also the underlying cause

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5
Q

What metabolic step cannot occur in erythropoietic photoporphyria?

A

Photoporphyrin IX to haem

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6
Q

What in general terms, are the porphyrias?

A

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

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7
Q

What should be monitored in erythropoietic photoporphyria?

A

6 monthly LFTs and RBC porphyrins

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8
Q

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

A

Acute abdomen, Guillain-Barre, psychoses, mononeuritis multiplex

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9
Q

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

A

There is an increased reaction to UV and sometimes visible light

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10
Q

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

A

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

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11
Q

What enzyme is deficient in acute intermittent porphyria?

A

PBG deaminase

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12
Q

What light is dangerous in erythropoietic photoporphyria?

A

Visible light (not UV)

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13
Q

What are some treatment options for abnormal cutaneous photosensitivity?

A

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

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14
Q

Scaling where can often indicate a photosensitive skin problem?

A

Behind the ears

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15
Q

Which types of porphyria can cause yellowing of the teeth?

A

Severe congenital porphyrias

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16
Q

What enzyme is deficient in porphyria cutanea tarda type 1?

A

Uroporphyrinogen decarboxylase

17
Q

What enzyme is deficient in congenital erythropoietic porphyria?

A

Uroporphyrinogen III synthase

18
Q

Which porphyria inhibits transition from porphobilinogen to hydroxymethylbilane?

A

Acute intermittent porphyria

19
Q

What are some treatment options for erythropoietic photoporphyria?

A

Protection against visible light, phototherapy and anti-oxidants

20
Q

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

A

PCT Type 1

21
Q

Is porphyria cutanea tarda type 1 inherited?

A

No

22
Q

What can acute intermittent porphyria present as?

A

Nerve damage (no skin symptoms)

23
Q

What is the most common cause of acute intermittent porphyria?

A

Medications, especially barbiturates

24
Q

How do you treat PCT type 1?

A

Treat the underlying condition, supportive treatment for skin involvement

25
Q

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

A

Visible and UV light

26
Q

Give an example of a severe congenital porphyria?

A

Congenital erythropoietic porphyria

27
Q

What enzyme is deficient in erythropoietic photoporphyria?

A

Ferrochelatase

28
Q

Give an example of a phototoxic skin porphyria?

A

Erythropoietic porphyria

29
Q

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

A

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

30
Q

Does erythropoietic photoporphria have a genetic component?

A

Yes

31
Q

What are some presenting features of PCT type 1?

A

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

32
Q

How can you investigate for PCT Type 1?

A

Wood’s lamp or spectrofluorimeter

33
Q

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

A

Not always, can cause blistering and fragility

34
Q

What differentiates the different types of porphyria?

A

Depends on where the problem occurs in the normal metabolic cycle

35
Q

What porphyria blocks the transition of hydroxymethylbilane to uroporphyrinogen III?

A

Congenital erythropoietic porphyria