Sacroiliitis: what is it, symptoms. treatment, prognosis

What is sacroiliitis?

Sacroiliitis Is an inflammation of the sacroiliac joint, usually accompanied by pain. This is often a diagnosis of exclusion. The sacroiliac joint is one of the largest joints in the body and is a common source of pain in the buttocks and lower back. It connects the bones of the ilium to the sacrum. Sacroiliitis can be especially difficult to diagnose because its symptoms are similar to many other common sources of back pain. It is often overlooked as a source of back or buttock pain. Pain from this condition is often due to chronic degenerative causes, but is relatively rare. Sacroiliitis can be secondary to rheumatic, infectious, medicinal or oncological sources. Some specific examples of non-degenerative conditions that can lead to sacroiliitis include ankylosing spondylitis, psoriatic arthritis, Behcet's disease, hyperparathyroidism, and various pyogenic sources.

Causes and risk factors

Various conditions can lead to inflammation of the sacroiliac joint, causing severe pain. Osteoarthritis can cause joint degeneration, leading to abnormal articulations and movements leading to this condition. By themselves, spondyloarthropathies can cause significant inflammation of the joint itself. Pregnancy is another cause of inflammation due to the hormone relaxin, which leads to relaxation, stretching and possible expansion of the joint (s). Weight gain during pregnancy also puts additional mechanical stress on the joint, leading to further wear and tear. Trauma can cause direct or indirect stress and damage to the sacroiliac joint. Pyogenic sacroiliitis is the most common cause of acute sacroiliitis. Pain can come from the synovial joint, but also from the posterior sacral ligaments.

Signs and symptoms

Sacroiliitis is manifested by pain. Reports on the prevalence of sacroiliac pain vary widely. Some studies report a prevalence of 10% to 25% of patients with low back pain. In patients with a confirmed diagnosis, pain manifested itself at the level of the ipsilateral buttocks (94% of cases) and the midline of the lower lumbar region (74%). As mentioned earlier, the presentation may vary. Up to 50% of cases experience pain in the lower limb: 6% in the upper lumbar region, 4% in the groin and 2% in the lower abdomen.

Epidemiology

Medicine does not know exactly how many people live with sacroiliitis. However, it is estimated that 10 to 25 percent of people reporting low back pain may have sacroiliitis.

Pathophysiology

The sacrum articulates with the ilium, which helps to distribute body weight to the pelvis. The sacroiliac joint capsule is relatively thin and often has defects that allow fluid, such as joint effusion or pus, to drain into surrounding structures. When exposed to the surrounding muscles and structures, pain can have different manifestations, since these structures innervate different nerve roots. The common pain distribution is dermatomes L4-L5, but the distribution can certainly be present in dermatomes up to L2 and up to S3. Asymmetric pelvic movement can cause mechanical dysfunction, leading to degeneration and severe pain. Differential diagnosis includes leg length mismatch, one-sided limb or gluteus weakness, tight surrounding muscle structures, or hip osteoarthritis.

Histopathology

General degenerative changes show destruction and fibrosis of the cartilage, as well as destruction, erosion and ossification of the subchondral bone. Also common is synovitis, which reveals hyperplasia of the lining cells with infiltration of inflammatory cells. Inflammatory cells are also found in degenerative enthesitis. The infectious etiology of sacroiliitis reveals lymphocytes, plasma cells and fibrosis. It is noteworthy that in some patients, histopathological changes are not found.

Diagnostic procedures

- History and physics.

Sacroiliitis usually presents with back pain. Pain manifestations vary greatly, and patients may describe pain in one or both buttocks, in the thigh, or even more distant. Patients may report that their pain is worse after prolonged sitting or rotating movements. The characteristics of pain also vary widely and are usually described as sharp and stabbing, but can also be described as dull and aching. It is important to find out more than just the timing and description of the pain. The VP will ask about the history of the inflammatory conditions discussed earlier. In addition, a careful assessment of systemic symptoms such as fever, chills, night sweats, and weight loss should be obtained. These symptoms indicate a more serious process, indicating a probable systemic illness.

Although not always obvious, examination can reveal asymmetry in the pelvis. Measurement of the limbs can eliminate leg length discrepancies. The spine is examined for any abnormal curvatures or abnormalities in rotation. Generally, range of motion, neurological, and strength studies are unremarkable, although some of these tests are painful.

- Analyzes.

As discussed earlier, various inflammatory conditions can cause or contribute to pain in the sacroiliac joints. If there is a suspicion of an inflammatory condition, the possibility of ordering a complete blood cell count is considered, erythrocyte sedimentation rate, C-reactive protein, antinuclear antibodies, human leukocyte antigen (HLA-B27) and rheumatoid factor. Although cancer is a much less common cause of sacroiliitis, if a malignant process is suspected, ordering an analysis to evaluate malignancy is considered.

In most clinical trials, general laboratory findings under aseptic conditions include:

• White blood cell count is usually normal (elevated with infection / septic manifestation).
• ESR - increased.
• CRP - increased.
• HLA-B27 - approximately 50% to 92% of patients with ankylosing spondylitis will be HLA-B27 positive.
• Rheumatoid factor (RF) is negative in true ankylosing spondylitis.

If trauma or inflammatory causes are not suspected, radiographs are usually not required as there is usually no correlation between pain and radiographic images. If radiographs are taken, an anteroposterior view of the pelvis / lumbar spine should be ordered. These images can show sclerosis or other degenerative changes in the sacroiliac joint. Specific sacroiliac views can also be obtained at an angle of 25 to 30 degrees to help delineate enlargement or sclerotic changes at the edges of the joints. CT scans can also show sclerotic changes and reveal a reactive spur or subluxation. Previously noted imaging results are usually later changes. An MRI scan can show subchondral edema, which is the earliest sign of sacroiliitis. PET scans can be ordered to evaluate metastatic bone lesions.

The most informative test for the diagnosis of sacroiliitis is an injection of a local anesthetic and a steroid into the sacroiliac joint. If this procedure relieves the pain, it is likely that inflammation in the area was causing the pain. Potentially, a single injection or a series of injections can completely relieve pain. If the injection provided very significant pain relief, even if over a short period, then chronic pain is likely to be associated with sacroiliitis. In such cases, surgery should be considered because the injections have localized pain in the iliac joint (s). There should be no more than three injections per year.

Treatment

If the pain is caused by hypermobility, physical therapy can be very helpful. Therapy can help stabilize and strengthen the lumbar-pelvic muscles. If the pain is caused by stiffness, physical therapy can help increase the mobilization of the sacroiliac joint. Non-steroidal anti-inflammatory drugs and muscle relaxants may be prescribed during the acute phase of presentation. They are less effective as cases become more chronic. For diagnostic and therapeutic benefit, intra-articular anesthetic / steroid injections can be performed under real-time visual guidance. If previous treatment has not provided adequate relief, some doctors will consider radiofrequency ablation. Surgery is usually used as a last resort for patients with chronic pain.

Forecast

The outcome of the disease in most patients with sacroiliitis is excellent. However, recovery can take 2-4 weeks. Relapses are common if patients do not change their lifestyle. In some series, a relapse rate of more than 30% is reported.

Complications

Complications of sacroiliitis include:

• chronic back and hip pain;
• muscle atrophy.