A doctor will obtain a complete medical history and perform a thorough physical examination, along with laboratory and diagnostic tests, to diagnose Crohn's disease. The examination and other tests are necessary to rule out a number of transient conditions, such as viral, bacterial, or parasitic infection, that cause symptoms similar to Crohn's disease.
In cases of Crohn's disease, patients often experience frequent loose or watery bowel movements. The stool is occasionally accompanied by thick, dark blood (not bright red smears of blood, which usually result from a bleeding hemorrhoid). There is less mucus or pus in the stool than in cases of ulcerative colitis.
Patients may experience crampy, achy, or even sharp pain in the affected area. Most often, patients with Crohn's disease feel pain on the lower right side of the abdomen (lower right quadrant) and just below the bellybutton. This is because the majority of cases of Crohn's disease involve disease in the terminal ileum, where the small intestine meets the large intestine. The terminal ileum crosses from left to right just above the beltline, and joins the large intestine in the lower right quadrant.
The type of pain associated with Crohn's disease depends on what part of the GI tract is affected. Disease in the terminal ileum generally causes sharp pain, while disease in the colon causes more crampy pain, similar to that that of ulcerative colitis. Pain is sometimes relieved (temporarily) after a bowel movement.
Crohn's is an inflammatory disease, and one of the key characteristics of the inflammatory process is fever. (The others are pain, swelling, and redness.) Some individuals with Crohn's disease suffer a high fever, especially during the acute phase of a flare-up. Others run a persistent, low-grade fever. Fever may be accompanied by irritability and fatigue. Sometimes, the fever recurs each day, especially late in the day, then repeatedly breaks during sleep, causing night sweats.
Signs and Symptoms Unrelated To The GI Tract
A number of signs and symptoms that do not involve the gastrointestinal tract can occur with Crohn's disease. These may occur at the same time as the intestinal symptoms, or may be experienced weeks or even months before any intestinal symptoms are noticed. If your doctor suspects inflammatory bowel disease, he or she will ask you detailed questions about whether or not these extra-intestinal symptoms have appeared:
Reddening and inflammation of the eye (iritis)
Joint pain (usually in the large joints of the knees, ankles, elbows, wrists, and shoulders), which sometimes migrates from one joint to another (migrating arthralgia)
Skin lesions, including tender red nodules on the shins or calves (erythema nodosum)