Hi, this is Tom, and in this episode I'm going to be going through Porphyria, and you can find notes at 0.0.2finals.com slash porphyria, and in the second edition of the 0.0 to Finals pediatrics book, which is out later this year. And you can find flashcards and questions at

members.0.0.0.com. So let's jump straight in. Porphyria is a group of disorders caused by

defects in the heem synthesis pathway. So the pathway that creates heem that goes into the hemoglobin molecule.

When there's defects in this pathway,

it leads to a build-up of porphyrens or their precursors,

which are upstream in the creation of the hemoglobin molecule.

This group of conditions are broadly divided into acute porphyrias,

which mainly cause neurovisceral symptoms,

meaning affecting the nervous system and the gastrointestinal system,

and cutaneous porphyrias,

which mainly cause photosensitivity and skin problems.

The two key types to remember are acute intermittent porphyria, which is the most common acute porphyria,

and Porphyria-cutania-T Tarda, which is the most common overall.

Porphyrias are often inherited, although some forms, for example, porphyria-cutania Tarda,

may be acquired or have non-genetic contributing factors.

Acute attacks are often triggered by medications, for example,

rifampasin, carbamazepine and oral contraceptives, alcohol, fasting, or going a long time without

food, infections, smoking, stress or hormonal changes during the menstrual

cycle. A top tip for you, in your exam, look out for a patient with severe recurrent abdominal

pain, psychiatric symptoms, peripheral neuropathy, or red, dark urine, particularly after taking a

triggering medication or during fasting. The underlying diagnosis might be acute intermittent porphyria.

Alternatively, look out for a patient with photosensitive, blistering skin lesions who may have

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