porphyria

Question 1

most common types of porphyrias?

Answer 1

• acute intermittent porphyria (AIP)
• porphyria cutanea tarda (PCT)
• erythropoietic protoporphyria (EP)
• variegate porphyria (VP)

Question 2

what is porphyria cutanea tarda?

Answer 2

-a blistering skin condition caused by a deficiency of the haem synthesis enzyme uroporphyrinogen decarboxylase causing a build up in the precursor uroporphyrinogen leading to a build up of caporporphyrinogen iii

Question 3

what is there a deficiency of in porphyria cutanea tarda?

Answer 3

deficiency in the production of the liver enzyme:

UROPORPHYRINOGEN DECARBOXYLASE

Question 4

what is the most common porphyria?

Answer 4

porphyria cutanea tarda (deficiency in uroporphyrinogen decarboxylase)

Question 5

who is porphyria cutanea tarda most common in?

Answer 5

-middle aged, caucasian males

Question 6

in porphyrea cutanea tarda there is a deficiency in the liver enzyme (1)________ leading to a build up in the precursor (2) _____ which forms (3)______

Answer 6

1. deficiency in uroporphyrinogen decarboxylase
2. build up of precursor uroporphyrinogen
3. build up of caproporphynogen iii

Question 7

presentation of porphyria cutanea tarda?

Answer 7

• vesiscles/ bullae/ blisters on sun exposed sites
• skin fragility
• hyperpigmentation
• hypertrichosis (hairy cheeks)
• red coloured urine

Question 8

investigations for porphyria cutanea tarda?

Answer 8

Examine urine under WOOD’S LAMP= pink fluorescence

-porphyrin plasma levels

Question 9

management of porphyria cutanea tarda?

Answer 9

Treat underlying disease

Lifestyle modifications:

• avoid iron, alcohol and oestrogen
• high factor sun cream/ avoidance UV exposure

If still symptomatic:

• chloroquine
• venesection

Question 10

what is erythropoietic protoporphyia?

Answer 10

-a blistering skin condition caused by the insufficienct production of the haem synthesis enzyme ferrochelatase causing a build up of protoporphyin ix

Question 11

what is there a difficiency of in erythropoietic protoporphyria?

Answer 11

deficiency in ferretochelatase

Question 12

what is there a build up of in erythropoietic protoporphyria and why?

Answer 12

• deficiency in ferretochelatase

- this leads to a build up in protoporphyrin IX

Question 13

presentation of erythropoietic protoporphyria?

Answer 13

• child crying in sunlight
• vesicles/ bullae/ blisters
• skin fragility
• solar urticaria and associated pain

due to deficiency in ferrochelatase leasing to a build up of protoporphyrin IX

Question 14

investigations for erythropoietic protoporphyria?

Answer 14

• Flourescence of RBC
• Quantitative RBC porphyrins (raised protoporphyin levels)
• screen/ monitor for associated liver damage

Question 15

what is acute intermittent porphyria?

Answer 15

-a severe form of porphyria resulting from reduced production of porphobilinogen deaminase (PBGD) causing a build up of hydroxymethylbilane

Question 16

presentation of acute