Diagnostic Challenge:
What would you do?

A 22-year-old woman presents in the ER after 48 hours of severe (9/10), aching, diffuse abdominal pain. There are no clear aggravating or alleviating factors. 

Adapted with permission from: Jones BJ, Brzezinski WA, Estrada CA, Rodriguez M, Kraemer RR. A 22-year-old woman with abdominal pain. J Gen Intern Med. 2014:29(7):1074-1078.

Diagnostic Challenge: What would you do?

*Actor Portrayal

Your Patient
A 22-year-old woman presents in the ER after 48 hours of severe (9/10), aching, diffuse abdominal pain.

Patient characteristics and history

Physical exam

Please review all the documents before proceeding.

Step 1 of 6

Patient characteristics and history

  • In past 2 years reports recurrent episodes of severe abdominal pain. Has undergone cholecystectomy, appendectomy, and total abdominal hysterectomy (without salpingo-oophorectomy), all in an attempt to localize and eliminate her recurrent abdominal pain (records and pathological diagnosis not available to ER).
  • Along with episodes of abdominal pain, has nausea (no vomiting) and decreased appetite.
  • Had uncomplicated cystitis 1 week prior and is now completing a course of trimethoprim/sulfamethoxazole.
  • Diagnosed with major depressive disorder 3 years ago.
  • Has received analgesics and opioids from multiple providers over the last 3 years.
  • Takes no medications regularly, no herbal supplements, no OTC drugs.
  • Lives with boyfriend in a monogamous relationship for last 3 years.
  • Unemployed.
  • Drinks 1-2 alcoholic beverages weekly.
  • Has smoked a half a pack of cigarettes daily for last 7 years.
  • Menarche at age 13, never been pregnant, never been treated for STD.
  • Unknown family medical history (she was adopted).

Physical exam

  • BP 112/76 mmHg, heart rate 114 beats/minute, respiratory rate 16 breaths/minute, temperature 98.4˚F.
  • Abdomen soft and nondistended but moderately tender throughout. No succession splash, bowel sounds present but hypoactive, no rebound tenderness or guarding.

Diagnostic Challenge: What would you do?

Based on the patient’s history and physical exam, what diagnoses would you rule out? Check all that apply.



Step 2 of 6

Diagnostic Challenge: What would you do?

All diagnoses are reasonable to include in differential diagnosis. In a young woman with abdominal pain, common maladies, such as cholecystitis, appendicitis, and gynecologic sources, including complications of pregnancy, should be ruled out first. While the patient’s history of abdominal pain leading to multiple surgeries is consistent with acute intermittent porphyria (AIP) and familial Mediterranean fever, both are rare disorders.

Please review the tests below before proceeding.

Laboratory and radiographic tests

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Step 3 of 6

Laboratory and radiographic tests

A number of laboratory and radiographic tests are done, yielding these results:

  • Sodium: 132 mmol/L
  • Potassium: 4.3 mmol/L
  • Chloride: 102 mmol/L
  • Bicoarbonate: 23 mmol/L
  • Urea nitrogen: 22 mg/dL
  • Creatinine: 0.9 mg/dL
  • WBC: 7,900 cells/cm
  • Hemoglobin: 13 g/dL
  • Platelets: 164,000/cm
  • Total protein: 7.5 g/dL
  • Albumin: 3.9 g/dL
  • Total bilirubin: 0.4 mg/dL
  • Aspartate aminotransferase: 18/L
  • Prothrombin and activated partial thromboplastin times: within normal limits
  • Amylase, lipase, and lactic acid: within normal limits
  • Urinalysis: specific gravity 1.030, pH 6.5, 1+ blood, 1+ leukocyte esterase, 1+ nitrate, 10-20 WBC per HPE, 0-2 RBC per HPF, trace bacteria
  • Upright abdominal x-ray shows a normal bowel gas pattern
  • A contrast-enhanced computed tomographic exam of abdomen and pelvis shows no acute process (gallbladder, appendix, and uterus are absent)

Diagnostic Challenge: What would you do?

Based on the patient's history, physical exam, and test results, what diagnoses would you rule out? Check all that apply.



Step 4 of 6

Diagnostic Challenge: What would you do?

All diagnoses are again reasonable to include in differential diagnosis. The initial lab results and imaging appear fairly nonspecific. The serum sodium of 132 mmol/L in a young woman is unusual, but the significance is unclear. Urinalysis is consistent with a possible urinary tract infection (UTI), but she is in the midst of treatment for a UTI and her WBC is normal. Chronic adrenal insufficiency can often present with atypical abdominal pain and hyponatremia, although typically with hyperkalemia and hypoglycemia, which are not seen here. Acute intermittent porphyria should remain high on the differential, given the patient’s demographics, abdominal pain, history, and lack of specific laboratory or radiographic findings.

The patient is hospitalized due to her severe, unrelenting abdominal pain.



Step 5 of 6

Diagnostic Challenge: What would you do?

A 22-year-old woman presents in the ER after 48 hours of severe (9/10), aching, diffuse abdominal pain.

DIAGNOSIS:
Acute intermittent porphyria (AIP)

  • A urinary catheter is inserted (determined after the fact that this could have been dangerous). Later, it's noted that the urine collecting in the bag appears reddish brown.
  • Upon further questioning, the patient says her biological father was a first generation immigrant from Finland.

A urine porphobilinogen (PBG) test is performed

  • Urinary PBG level: 184 mg/L (normal 0-4 mg/L)


Step 6 of 6

Discussion

Key pieces of information that helped to suggest AIP as a diagnostic possibility include:

  • Recurrent, severe abdominal pain
  • Nondiagnostic laparotomies and other surgeries to alleviate the recurrent abdominal pain
  • Hyponatremia
  • Urine turned reddish-brown when exposed to light and air
  • Use of trimethoprim/sulfamethoxazole for a presumed urinary tract infection; this drug is considered very likely to be unsafe for prolonged use by individuals with an acute porphyria, based on consistent evidence
  • Young woman of northern European heritage


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