Porphyrias: Clinical Classification
Porphyrias are disorders caused by enzyme deficiencies in the heme synthesis pathway. They are broadly divided into acute (neurovisceral) and chronic (cutaneous) presentations.
| Condition | Enzyme Deficiency | Primary Clinical Presentation |
|---|---|---|
| Acute Intermittent Porphyria (AIP) | Porphobilinogen deaminase | Painful abdomen, port-wine colored urine, polyneuropathy, and psychological disturbances. |
| Porphyria Cutanea Tarda (PCT) | Uroporphyrinogen decarboxylase | Blistering cutaneous photosensitivity and hyperpigmentation. Most common porphyria. |
High-Yield Core Realities:
- AIP Triggers: Drugs (especially Cytochrome P450 inducers like barbiturates and sulfonamides), alcohol, and starvation can precipitate acute attacks by inducing ALAS.
- PCT Associations: Strongly associated with Hepatitis C, alcohol consumption, and iron overload (hemochromatosis).
- AIP Management: Treat acute attacks with hemin and glucose to downregulate ALAS.