How to follow the evolution of rheumatoid arthritis?
19 Jun 2019 • 3 comments
Rheumatoid arthritis is a disease that progresses by flare-ups in unpredictable ways. Gradually, if the disease is not treated, it tends to affect other joints. This is why it is essential to monitor the evolution of the disease in order to limit complications. Follow our explanatory guide.
The first year after the diagnosis of the disease, a monthly assessment (at each consultation) is carried out. When the disease is controlled (remission or low activity) the assessment takes place every 3 months.
Assessing disease progression: the DAS score
DAS, the measurement of disease activity
Disease activity is assessed according to certain clinical and biological parameters. These parameters allow the calculation of the DAS 28 score, DAS stands for Disease Activity Score.
It is an index of rheumatoid arthritis activity that combines several aspects of the disease into a single data set, expressed as a number. We speak of DAS 28 because this score is calculated on 28 joint sites.
Quatre valeurs pour calculer le DAS
1 & 2. The joints
The number of swollen joints (NAG) and the number of painful joints (NAD) are the first two criteria to be taken into account.
3. Patient evaluation
The patient is also asked to assess the activity of his or her rheumatoid arthritis in a global way. It is measured using a visual analogue scale graduated from 0 to 10. The principle is the same as for pain assessment: 0 = no manifestation of the disease; 10 = maximum severity that the patient can imagine.
4. Measure inflammation: the CRP value and the VS value
When the body detects substances that seem foreign to it, it sets up a defense strategy to recognise, destroy and eliminate them: this is the inflammatory reaction. The causes of inflammation are multiple: they can be of external origin (bacteria, viruses, skin lesions, blows...) or internal (autoimmune diseases such as rheumatoid arthritis, cancers...).
- C-Reactive Protein (CRP) is an inflammatory protein, synthesised by the liver, which increases its blood concentration within a few hours in the event of inflammation. CRP plays an important role in mobilising and activating the immune defences (white blood cells) and stimulating the destruction process of cells considered as foreign (phagocytosis). The higher the CRP value, the more important the inflammatory response.
To determine the sedimentation rate, a technician places the red blood cells in a test tube and determines the distance until they fall within a given time (usually one hour). In the event of an inflammatory reaction, the blood level of the inflammation proteins (including fibrinogen) increases and leads to the formation of red blood cell clusters. The higher the value of the sedimentation rate, the heavier the aggregates are and the faster they fall to the bottom of the tube. The inflammation is therefore more important.
Monitor treatment reactions
Follow-up examinations also measure the response to treatment, i.e. its efficacy, but also the follow-up of the tolerance of the prescribed treatment, in accordance with the summaries of the product characteristics and the patient's clinical context (including other pathologies of the patient).
Prevent possible complications
The monitoring of rheumatoid arthritis also involves looking for extra-articular symptoms of the disease. These symptoms may be caused by the progression of the disease. These symptoms include tenosynovitis, rheumatoid nodules, vasculitis, dry syndrome, or Raynaud's syndrome.
The radiological progression of the disease
The imaging assessment will allow us to look for signs of erosion or joint pinching, which are characteristic signs of rheumatoid arthritis. X-rays will be taken of all symptomatic joints. At the very beginning of the disease, x-rays will be normal.
Thereafter, when the signs appear, these radiological examinations will have a double benefit: they will confirm the diagnosis and serve as a basis for comparison with subsequent radiological examinations (the evolution of the disease will therefore be better monitored). Ultrasound or MRI can also be used as part of an imaging assessment.
As part of the follow-up of the evolution of your rheumatoid arthritis, the medical imaging check-up is carried out every 6 months in the first year and at least every year for the first 3 to 5 years and in the event of a change in therapeutic strategy. Radiological examinations are then spaced apart once the disease is more stable.
Do you have any questions about rheumatoid arthritis follow-up? How did your doctor explain these tests to you?