The best method of diagnosing ulcerative colitis is endoscopy. Usually a flexible sigmoidoscopy is enough to support the diagnosis; however, if the picture is unclear, a full colonoscopy can be performed. The scope of the procedure can be limited in order to prevent perforation if the physician encounters a severe form of colitis. Endoscopic signs of ulcerative colitis include:


  • Erythema and friability of the mucous layer – the inner lining of colon becomes red, while the tissues of the mucous layer tear very easily which can result in bleeding or even perforation.
  • Loss of the colon’s vascular appearance – the inner walls of colon are usually lined with vessels which can easily be seen during colonoscopy. As a result of ulcerative colitis these vessels are no longer seen during colonoscopy.
  • Superficial ulceration – the ulcers that appear as a result of ulcerative colitis are usually superficial, which means that they don’t damage the inner layers of the intestinal walls, which is why these ulcers every rarely cause perforation.
  • Pseudopolyps – are a mass of scar tissue that develops as time after time the tissues of the colon become inflamed and then heal. These tissues do not have any malignant potential and can be safely removed using surgery.

Ulcerative colitis almost always involves the rectum, and as the disease progresses, more and more parts of the colon are involved.

When diagnosing ulcerative colitis other tests and examinations include:

    • A complete blood count – since ulcerative colitis often leads to bleeding from the gastrointestinal tract, it is important to know if the patient has developed an anemia. Additionally, people with ulcerative colitis occasionally have thrombocytosis.
    • Electrolyte studies and renal function tests – are performed since continuous diarrhea may lead to hypomagnesemia, hypokalemia, and pre-renal failure.
      • Hypomagnesemia is characterized by muscle cramps, weakness, cardiac arrhythmia, tremors, nystagmus, and jerking. In severe cases, it may lead to confusion, hallucinations, disorientation, epileptic fits, tachycardia, hypertension, and tetany.
      • Hypokalemia – in mild cases may lead to a slightly higher blood pressure and sometimes trigger cardiac arrhythmias. Moderate hypokalemia may cause myalgia (muscle pain), muscle weakness, and constipation (all this happens as a result of disturbed function of skeletal and smooth muscles). Rhabdomyolysis can occur in severe cases of hypokalemia, possibly leading to renal failure and disseminated intravascular coagulation.
    • Liver function tests - are done in order to spot primary sclerosing cholangitis, a condition which frequently accompanies ulcerative colitis and leads to liver failure and cirrhosis. These tests include levels of liver transaminases (AST and ALT), direct and indirect bilirubin. These tests allow to detect and evaluate the damage to liver cells.
    • Biopsy of the mucous layer – is performed in order to differentiate between Crohn’s disease and ulcerative colitis. It is important to differentiate between the two as they are managed differently. Ulcerative colitis is characterized by cryptitis (inflammation of crypts), frank crypt abscesses, and inflammatory cells and hemorrhage in the lamina propria (the deeper layer of the mucosa).

x-ray colitis

  • X-ray – can sometimes detect signs of bowel wall inflammation:
    • Mucosal thickening (also known as thumbprinting) – the haustral folds become very thick and distance between the bowel’s loops is increased, since the bowel walls swell due to inflammation.
    • Lead pipe colon – is usually seen in patient that have a longstanding ulcerative colitis. During this condition the X-ray shows loss of haustral markings which are normally present. In the majority of cases the distal part of the colon is also involved in the process; however, this can often be overlooked on the X-ray.
    • Toxic megacolon – is a very significant dilation of the colon without any obstruction. This is a life-threatening condition which causes acute abdominal pain and sepsis. Patients with fulminant ulcerative colitis are in danger of developing this condition.
  • Stool culture – is used to detect infectious diseases and parasites, which could be the cause of chronic inflammation. This test has to be done in order to exclude the possibility of parasite- or infection-caused colitis, in which case it can be treated very easily using antibiotics.
  • Erythrocyte sedimentation rate (ESR) and C-reactive protein – an increase of those two factors can be a sign of an inflammatory process.

Despite the fact that the cause of ulcerative colitis is unknown, an inquiry should still be made about the usual factors that are believed to trigger this disease:

  • Recent cessation of smoking tobacco
  • Recent administration of vitamin B6 and iron
  • Enemas using a solution of hydrogen peroxide