Inflammatory Bowel Disease: Diagnosis

Crohn’s disease and ulcerative colitis have many common symptoms, ranging from mild to severe, which may develop rapidly or gradually. These include:

Persistent diarrhea, which may be bloody and lead to dehydration.

Abdominal pain.

Loss of appetite and subsequent weight loss. Children with IBD often fail to develop and grow properly.

Fever, which is a common sign in severe IBD cases.

Chronic inflammation, which may result in fissures, ulcers, fistulas, scarring, and strictures. 

In severe cases, toxic megacolon may result, with an increased danger of colon perforation.

Extraintestinal manifestations include arthritis (more common in Crohn’s disease); eye inflammations (conjunctivitis/uveitis); skin lesions (eg, erythema nodosum, pyoderma gangrenosum, and aphthous stomatitis), which occur more often in Crohn’s; anemia (primarily due to rectal bleeding); and liver disorders (mainly primary sclerosing cholangitis).

Diagnostic Tests

The following methods are often used to diagnose or evaluate IBD. Test selection depends on the type and severity of symptoms and previous test results. Invasive testing increases perforation risk and is not appropriate for patients with severe disease.

Endoscopic procedures, with or without biopsy, are recommended depending on the area of the digestive tract affected. Sigmoidoscopy, colonoscopy, esophagogastroduodenoscopy (EGD), endoscopic retrograde cholangiopancreatography (ERCP), and capsule “minicamera” endoscopy can be used to diagnose and observe the extent of IBD. These tests can also rule out other diseases that may mimic IBD, such as cancer and hemorrhoids.

Radiologic tests provide important information that cannot be obtained through endoscopy alone. Plain abdominal x–ray can detect small bowel obstruction in Crohn’s disease or toxic megacolon in ulcerative colitis. Barium swallow or enema can reveal strictures or intestinal fistula. However, neither one should be performed in cases of recent obstruction or severe inflammation.

CT scan may rule out complications of IBD (eg, intra–abdominal abscess, stricture, small bowel obstruction, fistula, and bowel perforation), narrow the differential, and aid in abscess drainage.

Laboratory Tests

Complete blood count is used to check for anemia.

Tests for electrolytes, serum albumin, and carotenoid concentrations assess the possible consequences of malabsorption.

In 10% to 15% of patients, indeterminate colitis may be diagnosed through the perinuclear antineutrophil cytoplasmic antibody (P–ANCA) identified in ulcerative colitis, and the anti–Saccharomyces cervisiae antibody which typically indicates Crohn’s disease.

Stool culture may be useful, because treatable bacterial infections can trigger an IBD flare.