The most frequent disorders are inflammatory episodes called sacroiliitis that may be due to infections (brucellosis) or appear in the course of other systematic diseases (ankylosing spondylitis). Dislocations and subluxations also occur due to very serious blows or injuries, such as those due to motorcycle accidents or high-altitude falls, sometimes accompanied by fractures of other bones of the pelvis and hip.
Ankylosing spondylitis is a progressive inflammatory condition of the spine of unknown origin, which causes stiffness in the back and sometimes in the main joints of the limbs. It usually appears in young people, between 16 and 25 years old. It starts in the sacroiliac joints, at the base of the spine, and usually progresses upward, sometimes also affecting the hips, shoulders or neck. In many cases, the deformity of the back is maintained once the disease has stopped progressing.
The first symptoms are lower back pain and increased stiffness; subsequently, the pain extends upward, which can reduce chest movements. It is common for the pain to also extend downward, to one or both legs. Sometimes the knees or hips are also affected.
Although the cause of the disease remains unidentified, it is believed that there is a genetic predisposition to contract the disease. The incidence is higher in populations carrying the human leukocyte antigen HLA-B27, which is present in almost 90% of cases. That antigen is found on the surface of white blood cells or leukocytes and belongs to a series of antigens inherited from parents. It is associated with susceptibility to certain diseases, such as some autoimmune.
This condition usually stops progressing after 10 or 15 years, leaving behind several levels of permanent stiffness, due to bone growth (ossification) or fusion of the joints, which can cause a deformity in the back. The progress of the disease can be controlled by anti-inflammatories, intensive rehabilitation and radiotherapy. In cases of severe deformity in the back, interventions can be performed to remove part of the bone and thus improve posture and relieve symptoms.
Sacroiliitis is the inflammation of the sacroiliac joint. This disease can manifest itself in different ways. In general, the patient suffers from sudden attacks of fever, weight loss, pain and a decrease in the extent of movements.
The conditions that cause sacroiliitis can be injuries, pregnancy, skin infections, osteomyelitis, urinary system infection, endocarditis or drug use.
In medical exams, this disease is usually confused with appendicitis, herniated disc, sciatica, pyelonephritis, an abscess of psoas. Semi-acute sacroiliitis is difficult to diagnose and delay in diagnosis and proper treatment can lead to an increase in joint destruction, potential rupture and abscess formation.
For an accurate and rapid diagnosis of the disease, clinical and physical laboratory tests are essential. In many cases the condition is diagnosed through a blood test. Many times a biopsy and culture are required to establish the diagnosis and identify the infectious agent.