Complications of crohn’s disease

Potential Long-Term Complications from Crohn’s

Crohn’s disease can involve any part of your intestinal tract. Inflammation from Crohn’s disease commonly causes abdominal pain and diarrhea. This inflammation can affect all layers of tissue in the lining of the intestine and can lead to a variety of complications.

Here are some of the most likely complications:

Intestinal blockage

This is the most common complication of Crohn’s disease. Swelling and scarring can narrow the passage through your intestines, causing a bowel obstruction. This can cause nausea, vomiting, bloating, constipation, and abdominal pain.


Chronic inflammation of the lining of the intestine can cause internal sores called ulcers to develop. Ulcers may occur anywhere in your digestive tract, including your mouth and anus. They can also occur in the genital area.


Ulcers can penetrate deeply into the tissue of the intestinal wall. They may even form a tunnel all the way through the wall of the intestine. This is called a fistula.

Fistulas create abnormal connections between different parts of your intestine, your intestine and your skin, or your intestine and other structures, such as the bladder, the vagina, or the aorta.

There are five types of fistulas:

  • Aortoenteric fistula: This occurs when a tract is formed between the bowel and the aorta. It’s a serious and potentially life-threatening condition, since massive amounts of blood can be lost in a short period of time.
  • Entero-vesical fistula: A fistula between the intestine and the bladder is called an entero-vesical fistula. This can cause frequent urinary tract infections. It may also cause you to pass gas and feces during urination.
  • Entero-cutaneous fistula: A fistula between the intestine and the skin is called an entero-cutaneous fistula. This can cause an opening on the skin of the abdomen. Pus, bowel contents, and mucus may discharge from this opening.
  • Colo-vaginal fistula: A fistula between the colon and the vagina is called a colo-vaginal fistula. This can cause gas and feces to pass through the vagina.
  • Anal fistula: A fistula from the anus to the skin is called an anal fistula. Mucus, pus, and stool may discharge from the anus through the fistula to the skin.

Another related complication is an abdominal abscess. This occurs when a hole or perforation occurs in the intestine and drains intestinal contents directly into the abdominal cavity. Severe pain and infection will soon set in. This is a serious condition that can result in sepsis and death.


Malabsorption is common with Crohn’s disease. It can lead to nutritional deficiencies, as scarred and damaged tissues fail to absorb nutrients properly. If you have chronic diarrhea, your intestines may not have time to absorb nutrients. Malabsorption can also lead to anemia and malnutrition.


Osteoporosis is a weakening of the bones caused by a loss of calcium. This is especially common if your treatment plan has included corticosteroids.

Increased risk of cancer

Crohn’s disease increases your risk of developing colon cancer. Regular screenings are recommended.

Complications in children

Children with Crohn’s disease may have impaired growth and delayed sexual development due to malnutrition and vitamin or mineral deficiencies.

Other common complications

Other complications of Crohn’s disease include:

  • arthritis
  • skin problems
  • inflammation of the eyes or mouth
  • kidney stones
  • gallstones
  • impaired liver function

Long-term outlook

Most people with Crohn’s disease experience periods of remission and flare-up. Up to 75 percent of patients will eventually require surgery, and some people will require multiple surgeries.

Crohn’s disease is a life-altering condition. While some people with Crohn’s disease may have very few symptoms with proper medical treatment, many others will continue to struggle with medical complications and pain.

If you’re diagnosed with Crohn’s disease, it’s important to find a gastroenterologist with whom you are comfortable and can develop a good working relationship so that your treatment plan can be tailored to your needs. Some people with Crohn’s disease also benefit from becoming involved in support groups with others who have been diagnosed with Crohn’s disease.

Definition & Facts for Crohn’s Disease

In this section:

  • What is Crohn’s disease?
  • How common is Crohn’s disease?
  • Who is more likely to develop Crohn’s disease?
  • What are the complications of Crohn’s disease?
  • What other health problems do people with Crohn’s disease have?

What is Crohn’s disease?

Crohn’s disease is a chronic disease that causes inflammation and irritation in your digestive tract. Most commonly, Crohn’s affects your small intestine and the beginning of your large intestine. However, the disease can affect any part of your digestive tract, from your mouth to your anus. Learn more about your digestive system and how it works.

Crohn’s disease is an inflammatory bowel disease (IBD). Ulcerative colitis and microscopic colitis are other common types of IBD.

Crohn’s disease most often begins gradually and can become worse over time. You may have periods of remission that can last for weeks or years.

How common is Crohn’s disease?

Researchers estimate that more than half a million people in the United States have Crohn’s disease.1 Studies show that, over time, Crohn’s disease has become more common in the United States and other parts of the world.1,2 Experts do not know the reason for this increase.

Who is more likely to develop Crohn’s disease?

Crohn’s disease can develop in people of any age and is more likely to develop in people

  • between the ages of 20 and 292
  • who have a family member, most often a sibling or parent, with IBD
  • who smoke cigarettes

What are the complications of Crohn’s disease?

Complications of Crohn’s disease can include the following:

  • Intestinal obstruction. Crohn’s disease can thicken the wall of your intestines. Over time, the thickened areas of your intestines can narrow, which can block your intestines. A partial or complete intestinal obstruction, also called a bowel blockage, can block the movement of food or stool through your intestines.
  • Fistulas. In Crohn’s disease, inflammation can go through the wall of your intestines and create tunnels, or fistulas. Fistulas are abnormal passages between two organs, or between an organ and the outside of your body. Fistulas may become infected.
  • Abscesses. Inflammation that goes through the wall of your intestines can also lead to abscesses. Abscesses are painful, swollen, pus-filled pockets of infection.
  • Anal fissures. Anal fissures are small tears in your anus that may cause itching, pain, or bleeding.
  • Ulcers. Inflammation anywhere along your digestive tract can lead to ulcers or open sores in your mouth, intestines, anus, or perineum.
  • Malnutrition. Malnutrition develops when your body does not get the right amount of vitamins, minerals, and nutrients it needs to maintain healthy tissues and organ function.
  • Inflammation in other areas of your body. You may have inflammation in your joints, eyes, and skin.

What other health problems do people with Crohn’s disease have?

If you have Crohn’s disease in your large intestine, you may be more likely to develop colon cancer. If you receive ongoing treatment for Crohn’s disease and stay in remission, you may reduce your chances of developing colon cancer.3

Talk with your doctor about how often you should get screened for colon cancer. Screening is testing for diseases when you have no symptoms. Screening for colon cancer can include colonoscopy with biopsies. Although screening does not reduce your chances of developing colon cancer, it may help to find cancer at an early stage and improve the chance of curing the cancer.

Crohn’s disease

Reducing symptoms

If you have Crohn’s disease and it’s causing moderate or severe symptoms, this is known as an “active disease”. Treatment for active Crohn’s disease usually involves medication, but surgery is sometimes the best option.

Initial treatment

In most cases, the first treatment offered is steroid medication (corticosteroids) to reduce the inflammation. Examples of corticosteroids used for Crohn’s disease include prednisolone tablets or hydrocortisone injections.

These medications are often effective in reducing the symptoms of Crohn’s disease, but they can have significant side effects, such as:

  • weight gain
  • swelling of the face
  • increased vulnerability to infections
  • thinning and weakening of the bones (osteopenia and osteoporosis)

Because of these possible side effects, your dose will be gradually reduced when your symptoms start to improve.

If you prefer, you may be able to choose to have a milder steroid called budesonide, or a type of medication called a 5-aminosalicylate (such as mesalazine), as an alternative initial treatment. These medications have fewer side effects, but they’re less effective.

In children or young people, where there are concerns about growth and development, a special liquid diet may be recommended as an initial treatment. This is known as an elemental or polymeric diet, and it can reduce inflammation by allowing your digestive system to recover while ensuring you get all the nutrients you need.

Additional treatment

If your symptoms flare up twice or more during 12 months, or return when your steroid dose is reduced, further treatment may be necessary.

In these cases, medicines to suppress your immune system (immunosuppressants) may be combined with your initial medication. Medicines called azathioprine or mercaptopurine are most commonly used.

These medicines aren’t suitable for everyone, so a blood test should be carried out to check if you can use them. If they’re not suitable, an alternative immunosuppressant medication called methotrexate may be used.

Side effects of these immunosuppressants can include:

  • nausea and vomiting
  • increased vulnerability to infection
  • pancreatitis
  • feeling tired, breathless and weak, which is caused by anaemia
  • liver problems

During the course of medication, you’ll have regular blood tests to check for serious side effects.

The immunosuppressants azathioprine and mercaptopurine are considered safe in pregnancy and breastfeeding. Women can continue to use these drugs when trying to start a family and during pregnancy.

However, methotrexate must not be taken for at least 6 months before trying for a baby, as this drug is known to cause birth defects. This applies to both men and women. It must also be avoided while you’re breastfeeding.

It’s important to speak to your doctor if you’re planning a pregnancy or if you become pregnant during your course of treatment for Crohn’s disease.

Severe Crohn’s disease

For people in poor general health with severe symptoms of Crohn’s disease, medicines called biological therapies may be used to reduce your symptoms if corticosteroids and immunosuppressants are unsuitable or ineffective.

Biological therapies are a type of powerful immunosuppressant medication created using naturally occurring biological substances, such as antibodies and enzymes.

The 2 medicines used to treat Crohn’s disease in the UK are called infliximab and adalimumab. They work by targeting a protein called tumour necrosis factor-alpha (TNF-alpha), which is believed to be responsible for the inflammation associated with Crohn’s disease. Infliximab can be used for children over 6 years old and adults, but adalimumab should only be used by adults.

Infliximab is given as a drip into a vein in your arm (known as an infusion) in hospital. Adalimumab is given as an injection, and it may be possible for you, a family member or a friend to be taught how to give it, so you don’t need to visit hospital for every treatment.

Treatment usually lasts at least 12 months, unless these drugs stop being effective sooner than this. After this time, your condition will be assessed to determine if further treatment is necessary.

There’s a risk of these medicines causing an allergic reaction, which can cause symptoms such as:

  • itchy skin
  • a high temperature
  • joint and muscle pain
  • swelling of the hands or lips
  • problems swallowing

You should seek immediate medical assistance if you experience these symptoms. Reactions can occur immediately after treatment, although they have been known to occur months later, even after treatment stops.


Surgery may be recommended to reduce your symptoms if your healthcare team feel the benefits outweigh the risks.

In many cases, a type of surgery called a resection is used. This involves removing the inflamed area of the intestine and stitching the healthy sections together.

In some cases, your doctor may recommend a procedure called an ileostomy to temporarily divert digestive waste away from the inflamed colon (large intestine) to give it a chance to heal.

During this operation, the end of the small intestine (the ileum) is disconnected from the colon and re-routed through a hole made in the abdomen, which is known as a stoma. An external bag is attached to the opening to collect waste products.

Once the colon has sufficiently recovered – usually after several months – a second operation will be needed to close the stoma and re-attach the small intestine to the colon.

Maintaining remission

Remission is a period when you don’t have any symptoms or your symptoms are mild. During these periods, you can choose whether or not to use medication to help maintain this.

If you decide not to have further treatment, you should be advised about attending regular follow-up appointments and which symptoms to look out for. These symptoms include unintended weight loss, abdominal pain and diarrhoea.

If you choose to have treatment, this will usually involve immunosuppressants. Corticosteroids aren’t recommended for maintaining remission.


If you develop complications of Crohn’s disease, such as anal fistulas or intestinal narrowing (stricture), these will also need to be treated. Surgery is necessary in most of these cases.

See complications of Crohn’s disease for more information.

Diet and smoking

Although there’s no evidence to suggest diet plays a role in Crohn’s disease, some people have found certain foods aggravate their symptoms. It may be useful to keep a food diary to make a note of the foods you eat and to record the effects they have on your symptoms.

If you notice certain foods make your symptoms worse, avoiding these may reduce your symptoms. However, the total elimination of entire food types, such as grains or sugars, isn’t usually recommended.

Some people find that eating 6 smaller meals a day, rather than three larger meals, improves their symptoms.

If you smoke, stopping can also reduce your symptoms and maintain remission.

Read about treatments to help you quit smoking.

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