Joint Pain and Crohn’s Disease

Issue: August 2016

Q: My Chrohn’s Disease Patient is Complaining of Joint Pain. What should I do?

A Crohn’s disease patient who complains of joint pain should first be queried as to the location, character (presence or absence of inflammatory features), associated musculoskeletal features of a seronegative spondyloarthropathy and correlation of joint pain to the activity of the Crohn’s Disease.

Location

The location of pain is important in creating a differential diagnosis. First, is the patient describing a true articular (joint) process, such as a knee, ankle or wrist process, or is the patient describing a periarticular process, such as a tenosynovitis (rotator cuff tendinitis at the shoulder or extensor tenosynovitis at the wrist)? Ask the patient to point with one finger to the site of maximal discomfort. Joint pain often can be localized, while a periarticular source of pain is often more diffuse and difficult to pinpoint.

Second, identify the affected area of the body. Is the area axial (spine and sacroiliac [SI] joints) or extra-axial (appendages, arms and legs)? The sacroiliac SI joints are located high in the buttocks, toward the midline. Crohn’s disease-associated arthritis may involve the SI joints and asking about discomfort in that region is helpful. Sacroiliitis may be experienced as buttock, low back, thigh or hip pain.

Third, is the involvement monoarticular, oligoarticular (four or fewer joints) or polyarticular? Finally, when there is more than one region or joint affected, is the process symmetric (both sides of the body) or asymmetric?

Character

After the examiner isolates the region/area/structure affected, query the patient on the character of his or her discomfort. Is it acute, chronic or relapsing? What aggravates or alleviates the pain? Periarticular processes, such as a tenosynovitis, are exacerbated by resistance to use. For example, resistance to wrist extension will cause a dorsal forearm tenosynovitis to worsen. Because these are joint based, articular processes usually worsen when using the joint or taking a joint through its normal range of motion.

Are there features of an inflammatory process at work? Inflammatory processes result in some combination of swelling, tenderness and pain. Is there a joint effusion? Is there erythema or warmth overlying a joint? Is the patient holding the joint in a flexed posture? Flexion best accommodates a joint effusion and maximizes pain relief Inflammatory SI joint pain is either unilateral or bilateral and made worse with immobility, such as a night’s sleep, and improves with activity or motion. Sacroiliitis from Crohn’s disease is worse upon awakening, improves with exercise and is felt in the low back, buttocks or even proximally in the legs.

Associated Seronegative Spondyloarthropathies

Arthritis that accompanies inflammatory bowel disease (IBD) is included in the family of seronegative spondylarthritis (SNSA). The rheumatoid-factor negative SNSAs include psoriatic arthritis, reactive arthritis (formerly known as Reiter’s syndrome), ankylosing spondylitis and IBD-associated arthritis (CD or ulcerative colitis). Therefore, it is important to look for the associated features of SNSA in any IBD patient with musculoskeletal complaints. Any of the SNSAs may exhibit stereotypic features such as dactylitis (a swollen toe or finger that extends across several joints), uveitis, psoriasiform palm and foot lesions, enthesitis or sacroiliitis.

Crohn’s Disease Activity

Finally, approach any articular complaint in a CD patient with an eye toward correlating the musculoskeletal complaint with the activity of the CD. In general, CD activity does not correlate with axial (spine/SI joint) involvement but may correlate with peripheral joint involvement. Exceptions occur, but this is a useful general rule.

I find it easier to develop a differential diagnosis after first categorizing the patient’s complaints into a descriptive construct. For example, “This patient has an acute monoarthritis of the knee with inflammatory features” or “This patient has chronic, symmetric, SI region pain.” The description of the process or symptoms allows one to create a differential diagnosis that is more focused than just “this patient has joint pain.” I integrate the structure or location (joint vs. periarticular, axial vs. extra-axial, number of joints/structures affected, and symmetry), presence or absence of inflammatory features, presence or absence of associated SNSA features (uveitis, sacroiliitis and dactylitis) and correlation with CD activity into this description, which helps guide me in best characterizing the musculoskeletal complaints.

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Features that strongly suggest a CD-associated arthritis (enteropathic arthritis) include a mono- or oligo-lower extremity inflammatory arthritis, perhaps with associated sacroiliitis. One should always look for associated dactylitis, enthesitis or other SNSA features.

Pain out of proportion to physical exam findings should always raise concern for avascular necrosis. This is a common enough complication of corticosteroid use and seems especially common in the hip and knee regions. Plain films may not show changes early on in the process, but an MRI is sensitive.

Imaging with plain films might be useful if the symptoms are long-standing (months to years), as this would allow enough time for bony remodeling. Most often, plain films do not show any significant changes, as IBD-associated arthritis is generally nonerosive in the extra-axial skeleton. One useful clue to the presence of CD-associated arthropathy is the presence of sacroiliitis. Sacroiliitis is easily identified on CT imaging. Most CD patients have a past abdominal CT scan available for review. Digital images can be adjusted to bone window and one simply scrolls through the various cuts of the SI joints.

I look for the presence of erosions, sclerosis (increased bony density) or even ankylosis (fusion). In my experience, most radiologists reading abdominal CT scans for IBD do not comment on the SI joints. An abdominal MRI is even more sensitive for sacroiliitis because it shows juxta-articular bone edema and inflammation.

Laboratory evaluation is of limited value for the diagnosis of CD-associated arthritis. Most laboratory tests are nonspecific. A patient may have inflammatory arthritis in the absence of elevated erythrocyte rate or C-reactive protein. Rheumatoid factor and cyclic citrullinated peptide (CCP), a specific serology for rheumatoid arthritis are usually negative. Antinuclear antibodies may be positive but are nonspecific. HLA-B27 testing is a poor screening test for CD-associated arthritis. It is more often found in the setting of axial arthritis than peripheral arthritis and is of limited diagnostic utility.

It should be understood that CD patients and IBD patients at large often have musculoskeletal complaints, but only 10% to 15% will have true CD-associated arthritis. Crohn’s disease patients have the same musculoskeletal issues of the larger population including osteoarthritis, overuse and mechanical injuries. The astute clinician must look for the inflammatory features and location to find the CD-associated arthritis. Crohn’s disease-associated arthritis is frequently monoarticular or pauciarticular, has a predilection for the lower extremity, may be migratory, and may be associated with sacroiliitis or other SNSA features.

References:
Fornaciari G, et al. Can J Gastroenterol. 2001;15(6):399-403.
Inman RD. J Rheumatol. 1987;14(3):406-410.
Gravallese EM, et al. Am J Gastroenterol. 1988;83(7):703-709.
Scarpa R, et al. J Rheumatol. 1992;19(3):373-377.