Unusual cause of chronic abdominal pain

The Case

It is a busy day in the clinic. You enter your next exam room and meet a friendly 11-year-old white girl and her mother who recently moved to the area. The child explains that she has a long history of chronic, sharp abdominal pain without radiation to her flanks, back, or groin that lasts 2 to 3 days at least twice a month. It typically begins 15 to 30 minutes after eating breakfast and waxes and wanes throughout the day, improving by evening.

Because the girl's pain seems to worsen with eating, she refuses to eat during these episodes. The pain improves with defecation. Although she normally has 1 bowel movement daily, she currently is having a bowel movement every 3 days. Her mother brought her to your clinic because this current episode has lasted 5 weeks. She is very concerned, especially because her daughter is refusing to eat and is losing weight.

History and examination

The girl's past medical history is significant for constipation and seasonal allergies. Her only medication is the once-daily PEG. She is not taking any herbal remedies or other supplements. She has had a tonsillectomy and adenoidectomy. Her birth and development history are normal. Her family history is unremarkable, except for maternal asthma.

She states that she is adjusting well to her new school. During a private interview, she states that she is "fine" with her weight and denies intentional weight loss and alcohol, tobacco, or drug use.

You observe that she is a talkative and friendly, well-developed, well-nourished girl. Her temperature is 36.1°C; heart rate, 75 beats per minute; respiratory rate, 20 breaths per minute; and blood pressure, 110 mm Hg/70 mm Hg. Of note, her anthropometrics are: weight, 38.3 kg (50th percentile); height, 149 cm (60th percentile); and body mass index (BMI) of 17.3 (40th percentile). The mother informs you that her daughter weighed 45 kg a couple of months ago-a possible 7 kg weight loss.

Physical examination reveals "allergic shiners" during HEENT exam. Her cardiovascular, pulmonary, thyroid, dermatologic, and neurologic examinations are normal. Her abdomen is soft, nontender, nondistended, without hepatosplenomegaly or mass. She does not manifest a Murphy sign. She has normally active bowel sounds. A rectal exam with occult blood screening is normal.

You review her emergency department record and note that she weighed 42 kg. All her recorded laboratory studies were normal: complete blood count (CBC), complete metabolic panel (CMP), amylase, lipase, and urinalysis. Her abdominal CT is noted as normal, too.