Case Report: Acute Intermittent Porphyria
A 34-year-old pregnant woman presented for evaluation of severe, persistent abdominal pain.
Treatment
Treatment targets runaway heme precursor synthesis at its start and finish (Figure). Glucose-loading suppresses the initial enzyme, ALA synthase. Since the absence of normal end-product (heme) drives the enzymatic cascade, addition of IV hemin provides the substrate—and negative feedback—to stop it.
Conclusion
This case represents an example of AIP in which a patient presented with the characteristic abdominal pain and hyponatremia, complicated by the fact that she was pregnant and her urine was not red.
Intractable abdominal pain with negative imaging must prompt a search for red urine, neurological symptoms, porphyria medication triggers, and a family history of porphyria. Any constellation of findings should prompt immediate urine PBG testing.
In the appropriate clinical setting, it may be prudent to glucose-load a patient while waiting for confirmatory testing (which can take 1-2 days). Hemin therapy is best instituted by the hematology service after high urine PBG levels are confirmed.
