Complications of IBD can occur especially when the disease is active and can result in problems inside (local) as well as outside of the digestive system (systemic).
Inside the bowel (local)
Perforation (hole in the intestine)
In severe inflammation, the wall of the intestine can become so thin that it breaks. If this happens, the contents from your intestines can leak into the surrounding area leading to an infection called peritonitis. This is potentially life-threatening and requires specialist medical care.
Strictures (Crohn’s disease only)
This is the most common complication of Crohn’s disease. If there is prolonged inflammation you may get scar formation in the area. This can narrow the intestines leading to what is known as a stricture. Strictures can result in the contents of the intestines getting stuck like a plug (ileus).
Abscesses (Crohn’s disease only)
Abscesses (boils) are pockets of pus that develop as a result of a bacterial infection. An abscess is red, tender and warm, and most often occur near to the anus (the opening of the rectum) but also inside the intestine. This is treated by emptying the abscess surgically.
Fistulas (Crohn’s disease only)
May affect about 30% of people with Crohn’s disease. Deep sores or ulcers within the intestine may turn into tracts, called fistulas. These may tunnel into either other parts of the intestine (most often near the anus) or less commonly, the surrounding tissues of the bladder, vagina, or skin. These can become infected causing discomfort.
Small painful cracks or tears in the skin around the anus. They can cause bleeding and very painful bowel movements. Can result in fistula formation. These occur most often in Crohn’s disease and can cause mild-to-severe rectal pain and bleeding, particularly during bowel movements.
A rare condition where the colon becomes dilated and swollen and a condition called ileus can develop. The normal contractions of the intestinal wall stop temporarily, and the stomach area can become distended or swollen. As the condition progresses, the colon loses muscle tone and begins to expand and gas becomes trapped inside.
This is the most severe (and potentially life-threatening) complication of IBD. The colon loses its ability to contract properly and move gas along. The stomach area can become severely swollen or distended. There is high fever and pain and tenderness in the stomach area/abdomen. Immediate medical attention is essential.
Small intestinal bacterial overgrowths (SIBO)
Excessive amounts of bacteria can develop in the small intestine leading to gas, abdominal pain, bloating and diarrhoea.
Other parts of the body (systemic)
Anaemia (lack of iron)
Loss of blood in the stool can result in anaemia. Inflammation can also inhibit the ability of the bone marrow cells to produce red blood cells, which can also result in anaemia. This can lead to fatigue and generally feeling run down.
Joint inflammation with swelling, redness and tenderness of one or more joints, most often the large joints. This is seen when the disease is active.
Joint pain without swelling, most often in the small joints of the hands and feet. This is seen often in people with IBD. These arthralgias can occur at any stage of the condition.
There is a small increased risk for cancer of the intestines especially in patients with ulcerative colitis. Some medical studies suggest that 5-aminosalicylic acid (5-ASA) may have a protective effect, but this is still unconfirmed.
Erythema nodosum is a type of skin rash that is made up of large (0.5 to 2 cm) blue-red, tender nodules. These are especially common on the shin and forearm.
Uveitis (inflammation of the iris)
Uveitis is an inflammation of the inner muscles of the eye. The symptoms include pain in the eye (particularly in bright light), blurry vision, headache and redness in the white part of the eye. Should be treated promptly.
Effects on the liver
Quite rare. Inflammation can result in narrowing of the bile ducts in the liver. Results in itchy skin and tiredness. It is generally detected through blood tests.
Malabsorption and malnutrition (Crohn’s disease mostly)
Crohn’s disease usually affects the small intestine, which is the part of the gut that absorbs most nutrients. Malabsorption and malnutrition (of proteins, vitamins, and fats) can develop in severe cases.