Porphyrias

Question 1

What does porphyria refer to?

Answer 1

Group of metabolic disorders that result from a build up of natural chemicals that produce porphyrin in your body. Porphyrins are essential for the function of haemoglobin. All porphyrias are usually due to some sort of damage in the haem pathway.

Question 2

Describe porphyria cutanea tarda

Answer 2

This is associated with liver disease, usually precipitated by alcohol excess, HCV infection and 20% of cases have underlying haemochromatosis

Question 3

How does porphyria cutanea tarda present?

Answer 3

Sun induced blisters, skin fragility, scarring, milia (small bump like cysts) especially on the dorsal hands and hypertrichosis (abnormal amount of hair growth).

Question 4

Management of porphyria cutanea tarda?

Answer 4

Treat underlying cause and relieve the skin disease.

Question 5

What is the cause of erythropoietic photoporphyria? How does it often present?

Answer 5

Genetic condition. Often presents with a child screaming when exposed to light but there is little to see on examination.

Question 6

Investigation and management for erythropoietic photoporphyria?

Answer 6

Can take quantitative RBC porphyrins.

Treatment- visible light photo protection

Question 7

Describe acute intermittent porphyria

Answer 7

Often triggered by something. Severe abdo pain, constipation, diarrhoea, nausea, vomiting, mental changes. No skin symptoms.

Question 8

What is the molecular cause of erthyropoietic protoporphyria?

Answer 8

Build up of protoporphyrin 1X due to lack of Ferrochelatase enzyme

Question 9

What is the molecular cause of acute intermittent porphyria?

Answer 9

Impaired function of porphobilogen deaminase (PBG deaminase)