Medical Malpractice Insights: Recurrent belly pain +/- hyponatremia

Recurrent belly pain +/- hyponatremia

How often do you include AIP in your differential?

Facts:

• A 28-year-old female is seen in the ED of Hospital A for recurrent bouts of severe, intermittent abdominal pain. She is admitted for a week and treated for critically low sodium with IV fluids through a central venous line. Workup is otherwise negative including an abdominal CT. She is discharged with oxycodone for pain.
• 5 days later she is seen at Hospital B for similar symptoms. She is again hyponatremic. Workup is otherwise negative. She is treated with IV NS for 3 days and discharged to follow up with her PCP.
• Another 10 days later she is seen at Hospital C, treated a third time for low sodium and discharged, this time with hydromorphone.
• The next day she sees her PCP who sends her back to the ED at Hospital C by EMS for possible appendicitis. Exam shows her clutching her belly and moaning. Abdomen is tender in all 4 quadrants. Differential includes drug seeking and opioid-induced constipation and colic. Her sodium is again critically low. This time an astute emergency physician does a search for “recurrent abdominal pain” in UpToDate online and finds “acute intermittent porphyria (AIP)”, a hereditary disease, listed in the differential. She asks the patient if any family members ever experienced odd attacks like hers that came and went. The patient perks up and says “Oh, yeah, my mother. Something attacked her nerves and blood vessels when she was a teenager.” The patient’s husband is asked to call his mother-in-law who confirms that “porphyria” was the word she recalls from her episode. A urinary porphobilinogen (PBG) is ordered. She is admitted and given IV saline. The PBG test returns strongly positive the next day. She placed on a course of IV hemin (to stop the production of porphyrins) and is discharged 10 days later to follow up with a hematologist.

Result: The ED directors of the first 2 hospitals were informed and the story widely shared for educational purposes. Since damages were limited to delayed diagnosis, no lawsuit was filed and the usual plaintiff and defense arguments are irrelevant.

Takeaways:

• How do you pass up a clue like an ultra-low sodium level? Doctor shopping at 3 different ED’s with the same problem doesn’t help. Giving the same ED and/or physician a second chance is generally the best option. Drug seekers are unlikely to choose the latter.
• Family history can be critical. It’s puzzling that it was not brought up by the patient or family, even if the question was not asked by the physician(s). The answer is almost always in the history: how or if you ask the question.
• According to UTDOL, abdominal pain is the most common symptom of porphyria and is associated with hyponatremia. Interestingly, porphyria is not listed in at least 6 algorithms for evaluation of abdominal pain.
• Porphyria is a disease of faulty hemoglobin production. Half of the 8 varieties are dermatologic, but 4 are primarily neurotoxic and acute; all usually result from a genetic mutation and can be familial.
• Derived from the Greek word for purple, the term porphyria stems from the red or brown color that patients’ urine can turn during an acute attack.
• AIP is the most common acute porphyria, affecting 1 in 20,000 people.
• Although abdominal pain is its hallmark, it can also provoke psychosis, tachycardia, anxiety, muscle weakness, chest pain and/or constipation.
• Triggers of acute attacks include carbohydrate starvation (e.g., the Atkins diet), alcohol, stress and dozens of drugs.
• A patient’s first attack may not occur until well into his or her 30s. Episodes may be years apart and present differently each time. Last year’s anxiety attack and fast heartbeat might share nothing with this year’s abdominal pain and low sodium.
• Hyponatremia is thought to stem from toxic effects on the hypothalamus that regulates water and salt excretion.
• Timely diagnosis isn’t just about pain relief; unchecked, AIP can cause permanent neurological damage or death.

References:
1. Acute Intermittent Porphyria. DeLoughery TG. Medscape eMedicine. Updated Jan 20, 2023.
2. American Porphyria Foundation website.
3. Panhematin (hemin) package insert