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Complications of IBD

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What is meant by the term ‘complications’?

Complication is defined as ‘an event that makes a simple matter more complex.’ In the case of issues relating to health, a complication is defined as ‘a disease that arises as a consequence of another.’

If these definitions are applied to inflammatory bowel disease (IBD), they can best be explained as follows:

In IBD, the main underlying problem is inflammation in parts of the GI tract. Appropriate treatment of the inflammation leads to improvement; inflammatory bowel disease symptoms might lessen or disappear altogether, and the person feels better. That is uncomplicated disease. In some cases, however, there might be a delay in improvement or no improvement at all with treatment, or the disease might advance despite treatment, or there might be signs and symptoms of disease outside the GI tract. That is known as complicated disease.

In general, the complications of IBD can be divided into two main categories:

  • those that involve the intestine, sometimes called local or intra-intestinal complications
  • those that involve parts of the body outside the intestine or the person as a whole, referred to as extra-intestinal or systemic complications, respectively.

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How do I know if I have a complication?

Several of the complications of IBD are internal, often making it difficult for a person to know that something is brewing until something goes wrong. Many of the possible complications are already well known by surgeons through years of experience in treating the condition. This knowledge is complemented by certain investigations that can identify internal abnormalities before they become more serious. Blood and urine tests, bone density scans, etc. all provide vital clues as to what’s going on inside the body. Complications such as skin and eye disorders, or even symptoms of arthritis, can be easy for you to notice yourself should they ever develop.

The key is to act early. If you think something feels not quite right or different from normal, you should discuss your concerns with your clinical team as soon as possible. Early recognition and prompt treatment of complications can lead to better outcomes.

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What are extra-intestinal manifestations?

Although the main site of inflammation in IBD is in the GI tract, the disease can also cause symptoms to appear in other parts of the body. The reasons for these extra-intestinal manifestations are not known, but are thought to relate to a sort of generalised abnormal response of the immune system—in other words, one that is not contained solely within the GI tract. Extra-intestinal manifestations can also be a side effect of medications used to treat IBD and, particularly in Crohn’s disease, can arise because of malabsorption from the small intestine.

The types of extra-intestinal manifestations associated with IBD include:

  • arthritis
  • bone loss
  • eye disorders
  • kidney disorders
  • liver disease
  • skin disorders.

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Inflammation in the joints (arthritis) is the most common extra-intestinal complication of IBD, affecting approximately 25% of those with Crohn’s disease or ulcerative colitis.

Arthritis can occur as:

  • peripheral arthritis which affects the joints in the arms and legs including the elbows, wrists, knees and ankles
  • axial arthritis which affects the lower spine and sacroiliac joints near the base of the spine
  • (rarely) ankylosing spondylitis which is a type of axial arthritis that can also cause inflammation in the eyes, lungs and heart valves.

The development of arthritis among those with IBD can be a sort of chicken-and-egg situation. Is the problem connected with the intestinal condition or is it a separate condition altogether? This is not always easy to tell, especially among those who might have severe joint inflammation and only mild or even no GI symptoms. In most instances though, the presence of diarrhoea or other symptoms of IBD provides important clues towards identifying the cause of the joint problem. Also, the joint inflammation in those with IBD tends to be less severe, with fewer destructive changes in the joints, than in those who have arthritis as their primary condition.

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Bone loss

A lower-than-average bone density is seen in anywhere from 30–60% of those with IBD. The most likely causes of bone loss are long-term use of corticosteroids, inflammation during periods of active disease and, to a lesser extent, vitamin D deficiency (especially among those with Crohn’s disease in the small intestine or those who’ve had part of their small intestine surgically removed).

The bone loss can take the form of osteoporosis (porous bones), osteopaenia (low bone density) or osteomalacia (softening of the bones). Over time, the bones become weakened and might eventually break, most often in the spine and hips. In patients with the risk factors above, especially the long-standing use of corticosteroids, regular bone-mineral density scans are recommended and performed to monitor bone loss.

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Eye disorders

About 10% of those with IBD might experience eye problems. Most of these will not lead to loss of vision if treated early.

The usual types of eye disorders that can occur are:

  • uveitis—painful inflammation of the uvea, the middle layer of the eye wall
  • keratopathy—white deposits at the edge of the cornea
  • episcleritis—inflammation of the outer coating of the white of the eye
  • (very rarely) dry eyes—inflammation of the retina or optic nerve.

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Kidney disorders

Kidney disorders occur more often in those with Crohn’s disease than in those with ulcerative colitis. This is because of the usual location of Crohn’s disease in the small intestine and its potential effects on the absorption of nutrients.

Kidney stones are the most common type of kidney disorder, especially in people who are prone to dehydration. Less common kidney disorders include:

  • hydronephrosis—obstruction of a ureter which connects the kidney to the bladder
  • amyloidosis—deposits of the protein amyloid in the kidneys
  • glomerulonephritis—inflammation of the small blood vessels (glomeruli) in the kidney.

Some medications used to treat IBD (e.g., cyclosporin and, more rarely, compounds containing 5-ASA) can also produce direct effects on the kidney, although these are usually resolved once the drug is discontinued.

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Liver disease

Because the liver and biliary system (gallbladder and pancreas) are so closely connected with the intestine in terms of the breakdown and absorption of food, complications of IBD can also occur in these organs.

The liver can become inflamed during periods of active disease, although this usually resolves if the IBD is treated effectively. A significant complication is primary sclerosing cholangitis (PSC), which is the medical term used to describe severe inflammation and scarring in the bile ducts. PSC impairs the transport of bile and waste from the liver to the small intestine for eventual excretion in the faeces and can lead to serious liver damage. This complication is more common in ulcerative colitis than in Crohn’s disease.

Some might develop gallstones, which occur when the liquid bile stored in the gallbladder hardens into stone-like pieces. These can block the mouth of the gallbladder where it joins the bile duct.

This complication occurs more commonly in Crohn’s disease of the ileum (the last segment of the small intestine) as this is where bile salts are absorbed.

Another complication in this body system is pancreatitis, which is the inflammation of the pancreas. This can occur when a gallstone blocks the bile duct in the area where it joins the pancreas. It can also occur as a side effect of thiopurines (e.g., azathioprine, 6-mercaptopurine) used to treat IBD.

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Skin disorders

Another relatively common type of extra-intestinal manifestation of IBD is skin disorders. In some instances, these can result from medications used to treat the condition. For example, a reaction to sulfasalazine can cause an allergic-type skin rash, and long-term use of corticosteroids can cause thinning of the skin, facial puffiness (moon face), or acne.

The most common skin disorders associated with IBD are:

  • erythema nodosum—tender red bumps that occur on the shins, ankles, and arms
  • pyoderma gangrenosum—deep ulcers oozing pus that occur on the shins, ankles, and arms
  • aphthous stomatitis—canker sores in the mouth.


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How are extra-intestinal manifestations treated?

There is no single answer to describe how extra-intestinal manifestations of IBD are treated. Treatment depends on the type, location, and severity of the complication. For example, eye drops can be used to treat eye inflammations, specific medications might be needed to improve bone strength, surgery might be required to remove gallstones, etc. It is important to note, however, that most extra-intestinal manifestations of IBD respond to treatment that is aimed directly at reducing the primary inflammation of IBD.



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What is meant by ‘systemic complications’?

Systemic complications refer to problems that affect the whole body rather than just the GI tract. The most common systemic complication of IBD is fever, which is the body’s reaction to the presence of inflammation. Any sudden or severe bleeding can cause a rapid heartbeat, drop in blood pressure, and other responses of the circulatory system as it attempts to correct the blood loss. Significant loss of blood over time can lead to anaemia, or a drop in the number of oxygen-carrying red blood cells; this causes feelings of general tiredness and fatigue. Quite often, those with IBD lose their appetite or avoid eating, so as not to make their symptoms worse. This too can cause overall tiredness and fatigue and, over time, can lead to concerning weight loss and malnutrition.

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Are there complications of IBD specific to children and adolescents?

The presence of inflammatory bowel disease in children and adolescents raises a new set of issues that might be related to the condition itself or to its treatment. In children with Crohn’s disease in particular, a lack of adequate nutrition because of poor absorption of essential nutrients from food and/or prolonged treatment with high doses of corticosteroids can lead to delays in growth and the onset of puberty. Identifying which of these causes is mainly responsible for any delayed growth and pubertal development in a younger person with IBD is extremely important, as treatment can often be adjusted to correct any nutritional deficiencies and restore normal growth patterns.

Another issue specific to children and adolescents is that, while the extra-intestinal or systemic manifestations of IBD might be the same as those in adults, for unknown reasons they seem to predominate and even overshadow the intestinal symptoms. This can sometimes make diagnosis more difficult. It also highlights the importance of keeping a close watch on youngsters who are failing to grow or thrive, who frequently feel sick, have fever, and complain of general malaise and weakness, as these may be systemic manifestations of IBD.

Moreover, having a serious chronic illness such as IBD and having to deal with disturbing symptoms such as diarrhoea, bleeding, pain, fever, etc. can most definitely affect anyone with the condition, people are generally less equipped emotionally to cope with all of the issues and will need additional support from family, friends, and their clinical team.

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Does IBD cause cancer?

Among those with long-standing ulcerative colitis (greater than 10 years’ duration) that involves most or all of the colon, the risk of developing colorectal cancer is higher (5–8%) than in the normal population (6%). This is particularly true for those who have developed primary sclerosing cholangitis or have not had regular treatment for their inflammatory bowel disease. Regular screening with colonoscopy is therefore indicated for ulcerative colitis has affected most or all of their colon for more than 10 years. The overall risk of developing colorectal cancer is still relatively low, however, and those at a higher risk can often be identified (e.g., by examination of biopsy samples taken from the colon during colonoscopy) with the close supervision of potential colon cancer symptoms. If the risk of cancer is considered high, surgical removal of the colon might be recommended.

Colorectal cancer is very rare among those with Crohn’s disease, although the risk might be a little higher if the colon is involved.

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Specific complications of Ulcerative Colitis

The majority of those with ulcerative colitis (80–90%) respond well to treatment and never develop any complications. For some, having a complication might simply mean failing to respond in the expected manner to usual medical treatment. Other complications of ulcerative colitis can be more serious and might arise very suddenly, often needing immediate treatment. These include profuse bleeding from deep ulcers in the colon, perforation (rupture) of the colon, and a condition known as toxic megacolon.

Perforation (rupture) of the colon is a potentially life-threatening complication that can occur when the wall of the intestine becomes weakened because of chronic inflammation and ulceration. A hole might develop in the intestinal wall, allowing the contents, which contain a large number of bacteria, to spill out into the abdomen and cause a serious infection known as peritonitis.

In severe ulcerative colitis, the inflammation can eventually penetrate deeper into the layers of the intestinal wall, causing the colon to become very dilated (widened) and swollen. This complication is called fulminant colitis. Initially, a condition called ileus develops where the normal contractions of the intestinal wall stop temporarily and the abdomen becomes distended (bloated). As the condition progresses, the colon gradually loses its muscle tone and begins to expand because of huge amounts of gas trapped inside the paralysed sections of intestine.

Although rare, toxic megacolon is an extreme form of fulminant colitis and is a medical emergency. Toxic megacolon occurs when the dilated colon has virtually lost all its ability to contract properly and move intestinal gas along. Severe abdominal distension results and the person can become suddenly very unwell, with a high white blood cell count, high fever, and pain and tenderness in the abdomen. Immediate medical attention is required to restore any lost fluid, salts, and blood

as well as to decompress the colon in order to prevent rupture. A nasogastric tube might be used to suction out excess air. Surgery might be required if no improvement is noted within 24 hours. If the intestine ruptures, the risk of death is high. With prompt treatment, however, such deaths are rare.

This condition occurs more often in those who have been treated with anti-spasmodic medications, anti-diarrhoeal or narcotic medications, or those who have required prolonged use of corticosteroids. It also occurs more often in the elderly or malnourished.

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Specific complications of Crohn’s Disease

Because Crohn’s disease can affect any part of the GI tract and because, as a rule, it affects the entire thickness of the intestinal wall within a diseased section, a number of complications can arise that are specific to the condition:

  • intestinal obstruction
  • abscesses and skin tags
  • fistulae
  • fissures
  • malabsorption and malnutrition.

Intestinal obstruction (strictures)

The most common complication of Crohn’s disease is obstruction or blockage of the intestine. This occurs when swelling from inflammation and/or scar tissue cause the intestinal wall to thicken, leading to a narrowing of the intestinal passageway. These narrowed areas are called strictures. Symptoms of intestinal obstruction include crampy pain in the abdomen, often accompanied by vomiting and bloating. Medications can relieve the obstruction by reducing the local area of inflammation, but it is preferable that medications are used properly in the first place to prevent this complication from arising. Surgery might be needed if the obstruction is severe, does not respond to medical treatment, or recurs frequently.

Abscesses and skin tags

Abscesses, akin to boils, are localised sacs containing intestinal fluid, bacteria, and pus. They can develop in the intestinal wall, in the abdominal cavity, or on the skin around the anus. Symptoms include swelling, tenderness, pain, and fever. Visible abscesses can be lanced and drained. Antibiotics are usually given to clear up any remaining infection.

Skin tags are swollen lumps or flaps of thickened skin that can occur just outside the anus. Faeces can stick to these tags, causing skin irritation. Good hygiene can help reduce any irritation.


Fissures are ulcerated tears or cracks that can develop in the lining of the anal canal. The cracks can be superficial or deep, and can cause mild to severe rectal pain and bleeding, particularly during bowel movements. Anal fissures are generally treated with topical creams or warm baths.


In Crohn’s disease (and very occasionally in ulcerative colitis), deep sores or ulcers might develop within the intestinal tract, particularly around the anal area. These ulcers can eventually become abnormal channels or fistulae that connect different loops of the intestine to itself, or connect the intestine to other body organs such as the bladder, vagina, or skin. Fistulae leak mucus, pus, and faeces into the connecting organ. Fistulae occur in about 30% of cases of Crohn’s disease, and often become infected. Small fistulae can be treated with antibiotics and other medical treatments, whereas large or multiple fistulae often require surgery.

Malabsorption and malnutrition

The presence of Crohn’s disease in the small intestine can impair the absorption of essential nutrients such as carbohydrates, proteins, fats, and vitamins. This can eventually lead to malnutrition or specific nutritional deficiencies, although these tend to develop mainly if there has been extensive surgery or if the disease is extensive and of long duration. Medical treatments such as vitamin B12 injections and iron supplements can be useful in correcting certain nutritional deficiencies.

In more serious cases of malnutrition, supplements can be given in the form of concentrated nutrient solutions. Hospitalised patients can be given intravenous fluids and sometimes, total parenteral nutrition (TPN) can be given where all nutrients are supplied intravenously.

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When to call the doctor

During the course of your IBD, there might be times when you need or want to consult quickly with your doctor by telephone—for example, if you experience sudden and severe symptoms or you develop a worrisome reaction to a new medication.

Many patients hesitate to call their doctor for fear of bothering a busy professional. But doctors often have dedicated staff such as a nurse or assistant who will serve as the first port of call. It’s worth asking your doctor whom you should contact and under what circumstances you can call (e.g., sudden and unexpected complications arising from your condition).

A call to your doctor is appropriate if you develop any significant—though not potentially life-threatening—symptoms such as nausea, headache, or body rash that you think might be related to your condition or to its treatment. Reporting severe or unusual symptoms early can help prevent a manageable problem from developing into a far more serious situation

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