Case 4

A 20 yo college sophomore schedules an appointment at the health plan because of intermittent pain in the left lower abdomen that began about 3 months ago. The pain, which is crampy and lasts for about an hour, occurs once or twice daily, and occasionally awakens her from sleep. It is sometimes relieved by lying prone but not by bowel movements. She has had diarrhea about 2 hours hours after a meal once or twice per week. Other than these infrequent bouts, there have been no changes in the form or frequency of her stool. Prior to the onset she had been in good health and takes no medication. She is an anthropology major who 6 months ago returned from  rural Malawi in southeast Africa where she had lived for a semester studying local agriculture. On review of systems she has lost about 2 pounds and has had irregular menstrual periods (LMP 2 weeks ago) for the past year. The initial physical examination shows normal vital signs including temp 98.2 degrees. There is mild tenderness in the left lower quadrant. The remainder of the abdominal exam is normal. 

Which of the following is the least likely diagnosis. 

A.  Lactose intolerance

B. Irritable bowel syndrome

C. Ovarian cyst

D. Gluten enteropathy

E. Inflammatory bowel disease