Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects the spine, causing pain, stiffness, and eventually fusion of the vertebrae. Diagnosing AS can sometimes be challenging as the symptoms can be similar to other conditions. However, there are certain criteria that can help confirm a diagnosis.
One of the key factors in confirming AS is the presence of sacroiliitis, which is inflammation of the sacroiliac joints. These joints are located where the lower spine meets the pelvis. X-rays are commonly used to visualize the sacroiliac joints and detect signs of inflammation. However, it’s important to note that early in the disease, these changes may not be visible on X-rays and other imaging techniques such as MRI or CT scans may be needed for a more accurate diagnosis.
In addition to sacroiliitis, there are other clinical criteria that can support the diagnosis of AS. One of the main symptoms of AS is chronic lower back pain that lasts for at least three months. This pain is typically worse in the morning or after periods of inactivity, and it tends to improve with exercise and physical activity. Resting or lying down often does not provide significant relief from the pain.
It’s important to note that the presence of sacroiliitis alone is not sufficient to diagnose AS. There must also be at least one of the following criteria:
1. Family history: AS has a strong genetic component, so having a close relative with AS increases the likelihood of the diagnosis.
2. HLA-B27 antigen: Around 90% of individuals with AS carry the HLA-B27 gene. However, it’s important to remember that HLA-B27 is not specific to AS and can be found in individuals without the condition as well.
3. Extra-spinal manifestations: AS can also affect other parts of the body, such as the eyes, skin, and joints. These extra-spinal manifestations can include uveitis (inflammation of the eye), psoriasis (a skin condition), or inflammatory bowel disease.
4. Elevated inflammatory markers: Blood tests that measure markers of inflammation, such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), may be elevated in individuals with AS. These tests help assess the level of inflammation in the body.
It’s worth mentioning that the diagnosis of AS is not solely based on these criteria but also relies on the clinical judgment of a healthcare professional. Medical history, physical examination findings, and other relevant factors are taken into account to make an accurate diagnosis.
In my personal experience, I was initially misdiagnosed with mechanical back pain due to the similarity of symptoms. It took several months of persistent symptoms, including morning stiffness, back pain that improved with exercise, and a positive family history of AS, before further investigations were conducted, eventually leading to a diagnosis of AS.
To summarize, the confirmation of ankylosing spondylitis typically involves the presence of sacroiliitis on imaging, along with at least three months of lower back pain that improves with exercise and doesn’t get better with rest. Additional criteria, such as a family history of AS, the presence of HLA-B27 antigen, extra-spinal manifestations, and elevated inflammatory markers, can further support the diagnosis. However, it’s important to consult with a healthcare professional for an accurate diagnosis and to rule out other potential causes of symptoms.