Diabetes is not a recognized cause of arthritis or joint inflammation. However, it can be associated with a number of conditions that cause joint pain. These include:
- Neuropathy, including carpal tunnel syndrome -- Symptoms include pain in the forearm, wrist and hand, as well as burning, tingling or numbness that may be due to the compression of the median nerve in the wrist (carpal tunnel syndrome) or diabetic nerve damage (neuropathy).
- Tendonitis and trigger finger -- Inflammation of a tendon (tendonitis) may cause pain near a joint. If the inflammation causes a nodule to form along the tendons in the palm, the nodule may catch in the tube-like sheath surrounding the finger tendons. The finger is then stuck in a bent position. It can be "unstuck" by applying pressure with the other hand, which temporarily frees the finger.
- Frozen shoulder -- Inflammation and scarring around the lining of the shoulder can cause significant shoulder pain and limited motion. When the limitation is in all directions, it's called "adhesive capsulitis" or frozen shoulder. The pain, which can feel very much like arthritis, may subside over time even if the limited motion does not.
- Bursitis -- Inflammation of the bursa, the sac-like structures surrounding large joints, can cause pain in the area and is easily mistaken for arthritis.
- Charcot joint -- Also called neuroarthropathy, this condition is associated with diabetes when significant nerve damage has developed. Joints such as the ankle may become damaged and dislocated because the normal protective mechanisms of pain and the sense of position are impaired. As a result, abnormal stresses are applied to the joints and they are damaged. Despite impaired pain sensation, pain can be prominent early in the course of disease.
People with diabetes who have these conditions may feel they have arthritis because they have pain in their joints. However, while arthritis nearly always causes joint pain, not all joint pain is due to arthritis. None of these conditions are marked primarily by joint inflammation and so they are not considered forms of arthritis.
The reason that people with diabetes are prone to tendonitis, bursitis and frozen shoulder is not clear. Researchers are working on understanding the cause and, more importantly, how to prevent these problems from developing.