Recurrent Abdominal Pain/discomfort With Disordered Bowel Habit

A 32 year old businesswoman is referred to a gastroenterologist because of recurrent episodes of abdominal pain associated with a disordered bowel habit (Box1, Fig 1). The symptoms have been present intermittently for about five years, but have become more frequent and severe over the past four months. The pain occurs every two or three weeks, and lasts for several days at a time. It is usually situated in the left iliac fossa or periumbilical region and is often brought on by eating and relieved by a bowel movement. Her stools usually become looser and more frequent at the onset of the pain. She may have up to four loose mushy stools within a period of two hours in the morning. At other times she may not have a bowel movement for three or four days, and the stool is then hard and lumpy. She experiences urgency accompanying the loose bowel movements, straining with the hard bowel movements and often experiences a sensation of incomplete evacuation. She also has an uncomfortable sensation of bloating and her abdomen is often visibly distended, especially in the afternoon and evening (Box 2). There are no alarm features, with no blood or mucus in her stools, no weight loss, nor any pain during the night (Box 3). She has no nausea, vomiting or anorexia, but feels tired for much of the time. Her periods are heavy, often lasting six or more days. She has no significant past medical history apart from longstanding migraine. There is no family history of gastrointestinal disease (Box 3).

The patient is a non-smoker and eats a balanced diet with no known food intolerances. Her milk intake is less than 240ml per day. Caffeine, fiber, and fructose intake are not excessive. Her only medications are the oral contraceptive pill and infrequent sumatriptan tablets for migraine headaches. She has not taken antibiotics recently. She has tried a number of herbal preparations for her symptoms with no improvement. Physical examination is negative with no pallor or abdominal mass. She demonstrates the location of her pain with both hands spread open over the umbilicus. Perianal and rectal examination are normal (Boxes 2, 3). Given her tiredness and heavy periods the gastroenterologist arranges a complete blood count (CBC); he also suggests checking celiac serology (Box7). The CBC is normal (Hb 11.7 gm/dl, MCV 88 fl) and tissue transglutaminase is negative (Box 8).

The gastroenterologist makes a diagnosis of irritable bowel syndrome (IBS) (Box 9). He discusses the diagnosis of IBS, including the possible causes and how the symptoms may occur, and reassures her that IBS does not lead to more serious disease. He uses the Bristol Stool Form Scale (BSFS) to help the patient describe her usual pattern of stool consistency (without laxatives or anti-diarrheal preparations) (Box 10). This discussion confirms that her stool form, according to the BSFS, varies from Type 1 or 2 (hard/lumpy) to Type 6 or 7 (mushy/watery) in approximately equal proportions of time (at least 25% of the time for each pattern). On this basis a diagnosis of mixed IBS (IBS-M) is made (Box 12).