Inflammatory bowel diseases develop due to chronic inflammation in some part of the digestive tract or gut. The two most common types of inflammatory bowel diseases are:
- Crohn’s disease. Patients with Crohn’s disease have inflammation in the lining of the digestive tract that affect various regions in the small and/or the large intestine.
- Ulcerative colitis. Patients with ulcerative colitis have constant inflammation and sores that affect the inner lining of the colon and rectum.
Patients with inflammatory bowel disease can develop two different types of joint problems:
- Arthralgia, which refers to pain of joints without inflammation. Arthralgia is the more common joint problem among patients with inflammatory bowel disease. It develops in 40 to 50 percent of patients.
- Arthritis. Arthritis simply refers to inflammation of joints. In some patients, the development of Inflammatory bowel disease is associated with a type of arthritis known as enteropathic arthritis (sometimes also known as inflammatory bowel disease-associated arthritis). Enteropathic arthritis is an inflammatory arthritis that commonly affects the spine and other joints. Enteropathic arthritis is more common in Crohn’s disease compared to ulcerative colitis. Arthritis strikes between 15 and 20 percent of Crohn’s disease patients as well as in around 10 percent of patients with ulcerative colitis.
Cause of inflammatory bowel disease and enteropathic arthritis
At this point, researchers are not sure of the exact cause that leads to the development of inflammatory bowel disease and enteropathic arthritis. However, it is known that these are both autoimmune diseases, in which the body’s immune system, which is responsible for attacking foreign pathogens, turns on the body’s own healthy tissue instead.
Researchers speculate that one of the causes of the development of enteropathic arthritis is that inflammation of the gastrointestinal tract (which is prevalent in patients with inflammatory bowel disease) provokes the immune system, which causes an inflammatory response in other parts of the body such as the joints. Another theory regarding the cause of enteropathic arthritis is that it is triggered by an infection, which leads to an aberrant response of the immune system.
There is also a genetic component which makes people with inflammatory arthritis more susceptible to the development of arthritis. Patients with inflammatory bowel disease that have peripheral arthritis are more likely to have a gene called HLA-B27.
Furthermore, there is actually an even stronger association between the presence of a rare gene called HLA-DR103 and the development of arthritis in patients with inflammatory bowel disease. HLA-D103 is present in approximately 35 percent of patients who present with large joint arthritis and in approximately 65 percent of patients with more than one episode of large joint arthritis. In comparison, HLA-DR103 is only present in around one to three percent of the normal population.
While researchers are unsure how this gene contributes to the development of arthritis, some researchers believe that bouts of arthritis are actually triggered by a leaky, inflamed gut (which is found in inflammatory bowel disease). This leaky gut is likely caused by the presence of these HLA genes that patients inherit. Thus, patients with genetic susceptibility have a leaky gut that causes bacteria in the gut to escape and cause an inflammatory reaction in the joints.
Symptoms of inflammatory bowel disease and enteropathic arthritis
There are several symptoms associated with Crohn’s disease and ulcerative colitis including:
- Severe diarrhea
- Stomach pain
- Weight loss
These are the symptoms that develop in patients with enteropathic arthritis of the spine:
- Subtle low back pain (particularly in younger patients)
- Stiffness of the back in the morning, which becomes worse with prolonged sitting or standing time and improves with activity.
If enteropathic arthritis occurs in other joints besides the spine, it usually doesn’t cause any deformities or damage to the joints. Symptoms tend to occur at the same time as symptoms of the inflammatory bowel disease. There are two types of enteropathic arthritis:
- Type 1 or peripheral arthritis. In type 1 arthritis, less than five joints tend to be affected which typically involve the larger joints such as the knees, hips and shoulders. Type 1 arthritis flares last less than 10 weeks and acute attacks are strongly associated with activity of inflammatory bowel disease. The flares most commonly occur during bouts of severe ulcerative colitis. Approximately 60-70 percent of patients with enteropathic arthritis have peripheral arthritis.
- Type 2. In type 2 arthritis, the patient has disease involvement of more than five joints. This type of arthritis can last months to years. The joint involvement tends to be symmetric so it affects both sides of the body equally. It is present in the small joints of the hands, and is independent of bowel disease. Patients also have enthesitis, which refers to inflammation of regions whether tendons and ligaments attach to bone. Enthesitis affects the heel, knee, butt, and foot.
Patients can also develop reactive arthritis, which is a painful type of inflammatory arthritis that develops in response to infection by certain bacteria. Hence, it can occur in people with inflammatory bowel disease. Reactive arthritis normally involves the knees and/or ankles and tends to be asymmetric. It can develop up to several weeks affect the initial gut infection.
Finally, anywhere between one to six percent of patients with inflammatory bowel disease will develop ankylosing spondylitis, which is a progressive inflammatory disease that affects the sacroiliac joints and the spine. Patients with ankylosing spondylitis develop progressive fusion of the spine over a period of time.