We reviewed our experience with patients with factitious disorders who presented with renal colic to identify their common characteristics and to quantify the cost burden placed on the health care system as a result.

We retrospectively reviewed the medical records of two Philadelphia area hospitals from 1989 to 1995 to find patients with factitious disorders who presented with renal colic. A control group of patients with nephroureterolithiasis was also identified.

We identified 12 patients who presented with renal colic and had a final diagnosis of Munchausen's syndrome or malingering. The incidence of factitious renal colic was 0.6%. Eighty-three percent of these 12 patients were men, had an average age of 32 years, and made a total of 18 hospital visits. Ninety-two percent claimed an intravenous contrast allergy, 25% claimed an allergy to a specific narcotic, and 39% of the hospital visits ended with the patient voluntarily discharged against medical advice. Thirty-three percent were treated elsewhere for similar complaints. Only the number of intravenous contrast allergies and the number of patients leaving against medical advice were statistically different from the control group. The total cost for all factitious visits was $52,452, with a mean cost per visit of $2914. The average bill of those patients who received retrograde pyleograms was $3046 greater than for those who did not.

Factitious disorders should be considered when evaluating patients with an intravenous contrast allergy and renal colic. These patients are likely to leave against medical advice and place a significant cost burden on hospitals.