Heme synthesis with reactions occuring in the cytoplasm and some in the mitochondrion (yellow).
  • Inherited and/or acquired disorders in which there are enzyme deficiencies involved in heme biosynthesis, resulting in build up of porphyrins (Porphobilinogen and δ-Aminolevulinic acid [ALA])
  • Heme is a component of many essential hemoproteins, such as hemoglobin, myoglobin and cytochromes, including the cytochrome P450 enzymes
  • Acute intermittent porphyria is most salient to EM
  • The first enzyme in the heme production pathway is ALA synthase (ALAS), which controls the rate of heme synthesis in the liver. This enzyme is down-regulated by heme.
  • The enzyme deficiencies in porphyria limit the capacity of the liver to increase heme synthesis.
  • When drugs, hormones or other factors that induce ALAS and CYPs are given, ALA and porphobilinogen (PBG) are overproduced and accumulate, and a neurovisceral attack may develop


Clinical Features

Urine on the first day (left) compared to urine after three days of sun exposure (right) showing the classic change in color to "port wine-color."

Differential Diagnosis

Diffuse Abdominal pain

Extra-abdominal Sources of Abdominal pain


Consider porphyria in patients with abdominal pain that is unexplained after an initial workup has excluded common causes (appendicitis, cholecystitis, pancreatitis, etc).

  • Spot urinary porphobilinogen (sendout at most hospitals)
    • Normal = 0-4mg/day
    • acute attack, spot urine can be 20-200mg/L
  • Recurrent attacks in a patient with proven acute porphyria are usually similar and can be diagnosed on clinical grounds without biochemical reconfirmation.
  • Hyponatremia has been documented in up to 60% of acute attacks & is attributed to elevated levels of antidiuretic hormone[3]


Decrease heme synthesis

  • Glucose load
    • Decreases porphyrin production
    • E.g. D5NS at 2L/hr x 24h[4]==
    • Avoid D5/D10W due to risk of hyponatremia given significant free water load
  • Hemin (Panhematin®)
    • Decreases porphyrin production, significantly more potent than glucose
    • Recommended for most cases requiring hospitalization, or any with neurologic symptoms
    • 3-4mg/kg IV daily x 4 days
    • Can cause significant infusion site phlebitis - minimize by reconstituting in 25% albumin; consider central venous administration
    • Very expensive - around $8000 per 313mg vial


  • Admission to a monitored bed

See Also

External Links




  1. NR Pimstone, KE. Anderson, B Freilich. (n.d.). Emergency Room Guidelines for Acute Porphyria. American Porphyria Foundation. Retrieved January 11, 2016. From http://www.porphyriafoundation.com/for-healthcare-professionals/emergency-guidelines-for-acute-porphyria#Treatment.
  2. Anderson KE, Bloomer, JR Bonkovsky HL, Kushner JP, Pierach CA, Pimstone NR and Desnick RJ. Recommendations for the Diagnosis and Treatment of the Acute Porphyrias. Ann Intern Med 2005; 142:439-450
  3. Deacon AC, Peters TJ, Identification of acute porphyria: evaluation of a commercial screening test for urinary porphobilinogen. Ann Clin Biochem. 1998;35:726-32
  1. Fredrick, Thomas, M. D., et al. “Turning Purple with Pain.” The New England Journal of Medicine, vol. 385, no. 6, 2021, pp. 549–54, doi:10.1056/NEJMcps2105278.
  2. Fredrick, Thomas, M. D., et al. “Turning Purple with Pain.” The New England Journal of Medicine, vol. 385, no. 6, 2021, pp. 549–54, doi:10.1056/NEJMcps2105278.
  3. Bassett AS, McDonald-McGinn DM, Devriendt K, et al. Practical guidelines for managing patients with 22q11.2 deletion syndrome. J Pediatr. 2011;159(2):332-9.e1. doi:10.1016/j.jpeds.2011.02.039
  4. https://emedicine.medscape.com/article/205220-treatment