In order to correctly diagnose arthritis, a careful questioning of the patient (anamnesis) is essential. The doctor asks for information about the type and severity of the symptoms, possible infections or injuries as the cause, as well as previous illnesses and accompanying symptoms. This is followed by a physical examination, during which the extent of the inflammation and movement restriction of the affected joints as well as a possible joint effusion are determined.
Another important part of the diagnosis is the laboratory examination of the blood. All forms of arthritis generally manifest themselves by an increase in inflammatory values, such as the C-reactive protein (CRP), the blood sedimentation rate (BSG) and an increase in white blood cells (leukocytes). In addition, blood tests can provide information about the cause of arthritis: If pathogens are detected in the blood by a blood culture, it is probably septic arthritis, whereas reactive arthritis is a search for antibodies against the pathogens that have already been fought.
Arthritis caused by gout usually manifests itself in blood tests by elevated uric acid levels. In rheumatoid arthritis, the so-called rheumatoid factor – a defence substance produced by the body against the body’s own antibodies – is typically present in the blood. However, since it can also occur in other autoimmune diseases such as systemic lupus erythematosus, the blood is usually additionally tested for so-called CCP antibodies, the presence of which almost certainly proves the presence of rheumatoid arthritis.
If these markers in the blood are negative, however, this does not exclude the presence of arthritis. If an effusion has formed in the inflamed joint, the joint can be punctured as part of the diagnosis. This is particularly useful if infectious arthritis is suspected, as in this case the type of pathogen from the synovial fluid can be identified.
In addition, the number of white blood cells in the synovial fluid is usually increased. If, on the other hand, crystals can be detected during joint puncture, there is a high probability of a crystal arthropathy. Of the imaging procedures, X-rays are the most commonly used to diagnose arthritis.
The X-ray image usually shows characteristic changes, which helps to confirm the diagnosis of arthritis. In addition, the stage of the disease can be determined and any existing consequential damage to the joints can be identified. The X-ray is also indispensable for planning an operation and monitoring the progress of therapy.
MRI shows signs of arthritis at a very early stage, but due to the high costs and the technical effort involved, it is rarely used and only when the diagnosis is unclear. Computer tomography (CT) plays a role above all in the diagnosis of arthritis of the cervical spine. Computer tomography (CT) plays a role above all in the diagnosis of arthritis of the cervical spine.