A 14‐year‐old African American girl with no medical history presented to the emergency room (ER) with acute diffuse abdominal pain associated with nausea and vomiting. The workup included basic laboratory evaluation and abdominal radiography, which were all negative. She improved with ondansetron and was discharged from the ER. Approximately 1 week after the onset of abdominal pain, the patient was admitted to the hospital with acute onset of paranoia, auditory hallucinations, and inappropriate laughter. On physical examination, the patient was alert and in no distress but had a severely delayed verbal response with blunt affect and was unable to relay the details of her history. The abdomen was diffusely tender, without guarding or rebound. Laboratory analysis, including comprehensive drug screen, rapid plasma reagin, thyroid‐stimulating hormone, lead level, liver function tests, amylase, lipase, urine human chorionic gonadotropin, electrolytes, HIV, and urine analysis, was unremarkable. The patient was transferred to inpatient psychiatry for further treatment. When she failed to improve, a urine sample was sent that showed increased porphobilinogen, suggesting a diagnosis of acute porphyria. Further testing revealed her to have a low porphobilinogen deaminase activity level (4.6 nmol/L/s), consistent with the diagnosis of acute intermittent porphyria (AIP). Hemin and carbohydrate loading therapy were initiated, and the patient's psychotic symptoms began to improve.
The differential diagnosis for acute‐onset psychosis in children is broad and includes drug effects, central nervous system lesions, metabolic conditions, and psychiatric causes. The diagnosis of AIP was delayed because the initial treatment team did not consider AIP in the workup of her psychosis or link her original abdominal pain with her new psychotic features. AIP is an inborn error in heme metabolism resulting from a deficiency in porphobilinogen deaminase. It presents most commonly with abdominal pain, vomiting, constipation, and tachycardia. Hallucinations and other psychiatric symptoms are less common presenting symptoms but do occur in 40%–58% of patients. A diagnosis of acute porphyria can be made promptly by finding increased porphobilinogen in a single‐void urine. Secondary testing can be done to differentiate AIP from coproporphyria and variegate porphyria, but treatment should not be delayed while awaiting the results. Treatment of an acute attack is based on inhibiting ALA synthase, the rate controlling enzyme in heme synthesis, often with hemin and carbohydrate loading.
Although a rare disorder, AIP often presents in early adulthood but may present in adolescence. Acute porphyria can be quickly diagnosed by sending porphobilinogen levels on a single‐void urine. Hospitalists should consider acute porphyria early in the evaluation when a patient presents with unexplained abdominal pain or mental status changes.
K. Tartaglia ‐ none; B. Betz ‐ none
To cite this abstract:Tartaglia K, Betz B. Okham's Razor Revisited. Abstract published at Hospital Medicine 2011, May 10-13, Dallas, Texas. Abstract 414. Journal of Hospital Medicine. 2011; 6 (suppl 2). https://www.shmabstracts.com/abstract/okhams-razor-revisited/. Accessed January 18, 2020.