Porphyrias Flashcards
what are porphyrias
a group of disorders that result from the build up of natural chemicals that produce porphyrin in the body
what does the pathology in all porphyrias involve
a problem in the production of haem due to dysfunction of one of the enzymes
how many enzymes are involved in haem production and what does this mean
8 - so there is 8 different porphyrias
what is the most common type of porphyria and dysfunction of what enzyme is the cause
porphyria cutanea tarda
dysfunction of UDP-carboxylase
what is the most common acute porphyria and what enzyme is at fault
acute intermittent porphyria
HMB synthase
why are acute porphyrias more likely to occur in women and what does it present with
due to the effect progesterone has on haem synthesis
presents with abdominal pain
what does the accumulation of haem enzyme ALA lead to
abdominal pain and neurological issues
what does the build up of porphyrin cause
photosensitivity
what are the s/sx of porphyria cutanea tarda (PCT)
- blistering of skin in areas exposed to sunlight
- wine red coloured urine
- onycholysis
how do you treat PCT
you cant- its chronic
avoid alcohol and excess sun exposure, take iron suplements
what is the diagnostic test for PCT and what does it show
woods lamp - shows excess porphyrin pigment
what are the underlying causes of PCT
alcohol 🍺 :(
viral hepatitis
oestrogens
haemochromatosis
what enzyme isn’t functioning in erythropoietic protoporphyria
ferrocheltase
what happens in erythropoietic protoporphyria if you’re in the sun
a few mins = pruritus, erythema, swelling and pain
a bit longer = 2nd degree burns, oedema on hands, face and feet
