A 26-year-old woman is evaluated for intermittent abdominal pain occurring over the last several years. The pain is crampy without radiation and graded 6/10 in intensity. She also has fluctuating diarrhea but has not seen blood in the stool. The patient has no nausea, vomiting, constipation, urinary frequency, dysuria, or vaginal symptoms. Her last menstrual period was 2 weeks ago. She does not use tobacco or alcohol. Temperature is 37.2 C (99 F), blood pressure is 115/70 mm Hg, and pulse is 90/min. On examination, the abdomen is tender without guarding or rebound. There is a draining fistula near her coccyx. Which of the following is the most likely diagnosis?
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This patient likely has Crohn disease (CD) complicated by a perianal fistula. CD can involve the gastrointestinal tract anywhere from the mouth to the anus but often spares the rectum. Patients typically present insidiously (over the course of years) with bouts of crampy abdominal pain, diarrhea, and constitutional symptoms (eg, fatigue, weight loss, fever). Fecal occult blood testing is often positive; however, grossly bloody stool is less commonly seen unless the colon is involved.
Patients are prone to developing fistulas and abscesses due to the transmural inflammation that occurs in CD. Fistulas are abnormal connections between 2 epithelial-lined organs. They are usually formed between the bowel and nearby structures that include the skin (enterocutaneous), urinary bladder (enterovesical), vagina (enterovaginal), or bowel (enteroenteric). Perianal disease other than fistulas is also common and may include skin tags and fissures.
(Choice B) Diverticulitis is characterized by inflammation of saclike protrusions (diverticula) that typically form in the sigmoid colon of older patients. It can present with left lower quadrant abdominal pain, diarrhea or constipation, low-grade fever, and fistulas; however, this patient's young age makes the diagnosis less likely.
(Choice C) Intergluteal pilonidal disease is a common skin condition involving the upper natal cleft of the buttocks. Although patients may present with draining sinus tracts in the intergluteal region, abdominal pain/tenderness and diarrhea are not characteristic.
(Choice D) Irritable bowel syndrome (IBS) is characterized by chronic abdominal pain associated with altered bowel habits (eg, diarrhea and/or constipation). Pain is often relieved with bowel movements. IBS is not an inflammatory condition and does not cause fistulas.
(Choice E) Ulcerative colitis is an inflammatory disease of the colonic mucosa that almost always affects the rectum and often presents with grossly bloody stool. Fistulas are not commonly seen as inflammation does not involve the full thickness of the bowel wall.
Educational objective:
Crohn disease typically presents with the insidious onset of abdominal pain, diarrhea, and constitutional symptoms (eg, weight loss, fever). Patients are prone to developing fistulas/abscesses as the lesions affect the entire thickness of the bowel wall. Perianal disease (eg, skin tags, fissures) is also common.