Porphyrias

Question 1

what are porphyrias

Answer 1

inherited blood disorders with problem making haem, due to exposure to sunlight

Question 2

what is the most common type of porphyria and where is the defect

Answer 2

porphyria cutanea tarda

defect in enzyme uroporphyrinogen decarboxylase causing build up of uroporphyrinogen III

Question 3

how does porphyria cutanea tarda present

Answer 3

blistering
skin fragility
hyperpigmentation
increased sensitivity to the sun

Question 4

what are some risk factors for developing porphyria cutanea tarda

Answer 4

increased oestrogens eg COCP and HRT
haemochromatosis
alcohol
hepatitis

Question 5

when examining under a Woods lamp how does porphyria cutanea tarda present

Answer 5

coral pink fluorescence due to increased porphyrins

Question 6

how is porphyria cutanea tarda managed

Answer 6

treat underlying cause

sun protection eg sun block

Question 7

defect in the enzyme ferrochelatase causes what condition

Answer 7

erythropoietic protoporphyria - genetic defect

Question 8

how does erythropoietic protoporphyria present

Answer 8

presents in early childhood with pain, burning and blistering on sun exposed skin
no obvious changes to the skin

Question 9

defect in what enzyme causes acute intermittent porphyria

Answer 9

defect in PBG deaminase - build up of prophobiliogen

Question 10

how does acute intermittent porphyria present

Answer 10

GI upset
urinary retention
psychiatric issues

Question 11

which porphyria has an increased risk of developing hepatocellular carcinoma

Answer 11

acute intermittent porphyria