The porphyrias.

The porphyrias are a group of disorders involving enzymatic defects in heme synthesis. The porphyrias classically manifest neuro-visceral or photocutaneous symptoms based on which enzyme in the heme metabolic pathway is deficient. Although rare, the porphyrias would most likely be encountered in the emergency department in patients presenting with chronic unspecified abdominal or musculoskeletal pain and those with new onset of psychiatric complaints.