Definition: what is arthritis? Arthritis is an inflammatory condition in the joints. It is known as monoarthritis if only one joint is affected, oligoarthritis if two or three are affected, and polyarthritis when it is more than four. Arthritis must not be confused by arthrosis in which the main difference is the nature of the pain. With arthritis, the pain appears when the person is resting and can reduce slightly with movement. This is the opposite to arthrosis which causes pain when moving. It is mechanical and not inflammatory. Symptoms of arthritis Each type of arthritis has its own symptoms. Nevertheless, they all present clinical characteristic signs of inflammation in the synovial membrane which surrounds the joints: swelling (oedema), redness, warmth and joint pains. This is characterised by morning stiffness, an increase in pain late in the night, causing the sufferer to wake up in the night, and a slight improvement in activity. Forms of arthritis There are various types of arthritis. Aseptic arthritis is a type of arthritis which isn’t caused by infections. The most common types are rheumatoid arthritis, acute articular rheumatism, ankylosing spondylitis, reactive arthritis and psoriatic arthritis. On the contrary, septic arthritis occurs following contamination from a pathogen. It is always found just in one joint, where the infection was. Therefore, it is a type of monoarthritis. Depending on the responsible germ, it can be an infectious arthritis (staphylococcus or streptococcus), a viral arthritis (hepatitis, rubella, aids etc.), juvenile arthritis or Lyme arthritis (due to Lyme disease). Microcrystalline arthritis is caused by a presence of microcrystals in the joint. These are needle-shaped uric acid crystals in the case of gout, and rectangular shape calcium pyrophosphate crystals in the case of articular chondrocalcinosis. Treating arthritis Arthritis treatment must be adapted to the type of arthritis. Medicinal care aims to limit pain and is generally composed of painkillers, non-steroidal anti-inflammatories and corticosteroid infiltrations. Antibiotics can be prescribed in case of bacterial infection. Treatment can be completed by completed by following up with physiotherapy, occupational therapy or physiotherapy sessions. In some cases, a surgical operation can be necessary.