Colitis Indeterminata - A Chronic Disease

According to statistics, 10 to 15 percent of people with chronic inflammatory bowel diseases do not receive a clear diagnosis. 

Although ulcerative colitis or Crohn’s disease can sometimes be diagnosed years later, about one in ten cases remains without a specific diagnosis. Doctors group these cases under the term “colitis indeterminata.”

Colitis indeterminata shares many symptoms with other chronic inflammatory bowel diseases (ulcerative colitis or Crohn’s disease). 

These include, in particular, the following symptoms:

• Diarrhea, sometimes with blood
• Painful bowel movements (tenesmus)
• Extraintestinal symptoms, such as arthritis
• Nonspecific symptoms such as fever or a general feeling of illness

Chronic inflammatory bowel diseases cause inflammation of the intestine @ Sebastian Kaulitzki /AdobeStock

Colitis indeterminata is a diagnosis of exclusion. This means that doctors only make the diagnosis when, despite extensive testing, they cannot identify any other condition.

Other possible conditions include:

• Chronic inflammatory bowel diseases
• Acute infections of the gastrointestinal tract
• Colon cancer 
• Fungal infections
• Autoimmune diseases

A range of modern diagnostic procedures is available for diagnosis:

• Serology (blood test)
• Colonoscopy
• Endoscopy of the esophagus extending into the duodenum
• MRI of the small intestine
• Biopsy followed by pathological examination

If the results suggest a chronic inflammatory bowel disease, doctors can use the findings to distinguish between Crohn’s disease and ulcerative colitis: 

• If inflammatory lesions are found in the small intestine, Crohn’s disease may be present. 
• However, if the inflammation of the intestinal mucosa is limited to the large intestine (colon), it is likely ulcerative colitis. 
• If it is not possible to clearly classify the condition as one of these two diseases, a diagnosis of colitis indeterminata is made.

Since colitis indeterminata is, in a broader sense, an autoimmune disease, doctors treat it with immunosuppressants.

Steroids are frequently used for this purpose. In addition, new medications are available that are also suitable. 

These include:

• Infliximab
• Tacrolimus or
• 6-Thioguanine

Surgical procedures play a minor role in colitis indeterminata and are rarely used. However, experience shows that some patients develop signs of Crohn’s disease or ulcerative colitis even years after their initial diagnosis. This fact makes targeted therapy possible.

The prognosis for this condition is essentially the same as for other chronic inflammatory bowel diseases. Although indeterminate colitis is incurable, there are very effective treatment options available to reduce symptoms.

Like other chronic inflammatory bowel diseases, indeterminate colitis falls within the fields of gastroenterology and visceral surgery. Specialists in indeterminate colitis primarily work at specialized gastroenterology centers.

Please refer to the list above to find a colitis indeterminata specialist near you.

What exactly is colitis indeterminata?

Indeterminate colitis is a chronic inflammatory bowel disease in which a clear distinction between Crohn’s disease and ulcerative colitis cannot be made. The term “indeterminate colitis” is primarily used when, at the time of the initial diagnosis, typical criteria for both conditions are present or when the diagnosis of inflammatory bowel disease cannot be clearly established.

How is colitis indeterminata diagnosed?

The diagnosis of colitis indeterminata is made through comprehensive diagnostic testing. This includes a medical history, physical examination, colonoscopy with biopsy, and imaging studies. Endoscopic and histological findings reveal inflammation of the colon mucosa that cannot be definitively classified. Serological markers such as ASCA or pANCA may provide additional clues but are not decisive on their own.

Is colitis indeterminata different from Crohn’s disease and ulcerative colitis?

Clinically, indeterminate colitis exhibits features of both Crohn’s disease and ulcerative colitis. While Crohn’s disease can also affect the small intestine and has a segmental course, ulcerative colitis is limited to the large intestine. In colitis indeterminata, the location of the inflammation cannot initially be clearly identified. As the disease progresses, it may develop more clearly toward Crohn’s disease or ulcerative colitis.

How is indeterminate colitis treated?

Drug therapy is based on treatment approaches for Crohn’s disease and ulcerative colitis. Treatments include 5-aminosalicylic acid, steroids, immunomodulators, or biologics. In severe cases, surgical procedures such as a colectomy may be necessary. Procedures such as ileoanal pouch creation are also options in visceral surgery.

What role does classification play in indeterminate colitis?

The classification of inflammatory bowel disease (IBD) is crucial for treatment and prognosis. Colitis indeterminata is often considered a diagnosis of exclusion within IBD. International consensus recommendations and scientific studies on the classification of inflammatory bowel disease aid in differentiation. For patients with colitis indeterminata, close follow-up in a gastroenterology setting is important to monitor the course of the disease and tailor treatment decisions to the individual.