What is arthritis?
The term ‘arthritis‘ (Latin arthros = joint, itis = inflammation) means inflammation of a joint. For ages, we have always linked arthritis to old age. Though an elderly person is more likely to get arthritis, after the years of wear and tear in the joint. However, certain people are predisposed to get arthritis at a much younger age. There are also some juvenile types of arthritis which occur exclusively in childhood. Thus, it is necessary to broaden our views about arthritis, rather than just considering it as a ‘disease of the old’.
A joint (Picture 1) can be considered as an interaction between two or more bones. The surface of the bones in a joint are covered by cartilage smooth movement at the joint. This is called the articular cartilage. The joint is covered by a membrane called synovium, which makes it a closed space and secretes the synovial fluid. This fluid acts like oil to lubricate the bony surfaces and reduce friction during joint movement. It also provides nutrition to the cartilage, because the cartilage is not supplied by blood.The synovial membrane is covered by the joint capsule which seperates it from the muscles surrounding the joint and prevents it from injury during muscle movement.
A joint affected by arthritis (Picture 2) loses its ability to provide smooth movement between the bones. This is because of the following changes taking place gradually over a period of time
- decrease in the amount of synovial fluid
- wear and tear of the articular cartilage
- thickness and stiffness of synovium
- stiffness and of the joint capsule
These changes can occur due to several reasons like ageing, autoimmune disorders (immune system destroys our own body), genetic disorders, traumatic incident (accident, fall, or blunt injury), infection, and so on. The arthritic changes are generally permanent and cannot be reversed after a period of time. Hence, early recognition and treatment is the only way to prevent more damage.
Different Types of Arthritis
Based on the causes of arthritic changes, several forms of arthritis can be named. A particular type of arthritis occurs in a particular age group and in a particular joint (see table).
|Osteoarthritis||Elderly||Knee, lower back, fingers|
|Juvenile Rheumatoid Arthritis||Childhood||Knee, hip|
|Septic Arthritis||Childhood||Knee, hip|
|Rheumatoid Arthritis||Young adults||Hip, knuckles, knee|
|Ankylosing Spondylitis||Young adults||Lower back, chest|
|Psoriatic Arthritis||Young adults||Knee|
|Traumatic Arthritis||Any||Any (commonly knee, hip, ankle)|
|Gout||Young adults||Big toe, knee|
The different types of arthritis are often confusing for a layman. Even though the word “arthritis”, is frequently associated with stiff and painful joints. Some arthritis can have much more disastrous and disabling consequences. Some other arthritis are a part of major diseases elsewhere in the body, like gout, ankylosing spondylitis, and so on. Each type of arthritis has an affinity for some particular joints and some peculiar features, which distinguish it from the other types.
Osteoarthritis is a disease of the elderly. It generally occurs in females after their menopause. The small joints of the fingers (Picture 1) and large joints like knees are commonly affected.
Picture 1: Osteoarthritis of fingers
The backbone can also be affected with osteoarthritis causing low back pain and leg pain. The swelling that is seen, is typically hard (bony), and is because of friction between the bony surfaces, due to loss of the intervening articular cartilage. This bony swelling also reduces the mobility of the joint making it stiff. If untreated the joint develops typical deformities, like bow-legs, knock knees, bunion, and so on.
Rheumatoid arthritis (RA) is an inflammatory process, which originates in the immune system. It occurs in middle aged people between 20-30 yrs of age. These people have episodic pain, swelling, and stiffness of joints. The joints of the knuckles (Picture 2), wrist, knee, and ankle are commonly involved.
Picture 2: Rheumatoid arthritis (knuckles)
The stiffness is mainly in the morning, and disappears after 1-2 hours of light activity (morning stiffness). The joint swelling is soft and gives the feeling of water on knee (effusion). Untreated rheumatoid arthritis can lead to significant disfiguring of the joint (Picture 2), with complete loss of movement. The joints on both sides of the body are simultaneously affected (symmetric involvement), i.e. both knees, or both wrists, and so on.
Juvenile Rheumatoid Arthritis
Juvenile rheumatoid arthritis is a group of arthritis, which occur in childhood. They commonly occur in the lower limb and lead to inability to walk or abnormal gait. The pain is severe, which makes the child resist the movement, and later results in deformation of the joint. There are several types of this disease, some affecting multiple joints, some affecting single joint (knee), some affecting the vertebral column, and so on.
Ankylosing spondylitis is a dreadful disease, which results in a gradually increasing stiffness of all joints of the body. The end result is stiffness of the chest joints, making a person unable to breath, and ultimately leading to death (at around 30-40 years of age). This form of arthritis begins with lower back pain with stiffness, which improves with activity. The joints of the vertebral column are commonly affected, which eventually fuse together giving a “bamboo stick” like appearance on x-ray (bamboo spine)(Picture 3).
Picture 3: Ankylosing Spondylitis Bamboo Spine
A person also gets chest pain and respiratory infections, because of the ongoing inflammatory changes, but they are transient and episodic. The movements of all joints decrease with time and if proper treatment is not taken, it results in early death.
Gout is a disease which affects joints indirectly. It generally affects a single joint, especially the big toe of the foot or the knee joint. Most of the time, the disease is rooted in the kidneys, which are unable to excrete uric acid from the body. This uric acid accumulates in the joints in the form of crystals which precipitate and cause friction between the joint cartilage. There are episodes of pain, swelling, and itching, which resolve in a week without any treatment. It is the frequent recurrence of these episodes, that is disabling and distressing. During later stages, an ulcer may develop on the skin over a joint, which discharges chalky white material (Picture 4).
Picture 4: Knee Gout Ulcer
The treatment for the primary kidney disorder can also give rise to an episode of arthritis. So one has to be aware of it, and continue it, in the right faith, for the better good of the body.
Traumatic arthritis occurs because of bony injuries that occur near a joint. Improper union of a fractured bone near a joint causes the joint surface to become uneven. This increases the friction between the bones, as well as, leads to restriction of movement. The symptoms are similar to osteoarthritis, but are seen in a much younger person.
The treatment for fractures of the bone like using a plaster cast, also makes the joint stiff by keeping it in the same position (immobilized) for a long period (few weeks to a month). Thus, after a bony injury near a joint, it is very important to get physical therapy to improve the joint mobility and keep it active while the bone heals.
Septic arthritis is due to an infection of a joint. This condition is mainly seen in children, sometimes after a trivial fall or injury. Under normal conditions, it is very unlikely for an infection to reach a joint. This is because of the joint capsule and synovium forming a barrier around it. However, children have a poorly developed joint capsule, which makes them prone to get joint infections.
Psoriatic arthritis is a part of the skin disease psoriasis, which affects skin, nails, and joints. It is an allergic disorder arising from an abnormality in the immune system. The joints of the foot and ankle are commonly affected. The toes are swollen like sausages (sausage toes)(Picture 5) with joint stiffness and discoloration of nails.
Picture 5: Psoriatic Arthritis
The skin develops red, scaly, patches over the back, hands, and neck. There are different types of psoriatic arthritis, depending on the region in which they occur, like only toes, only vertebral column, on both feet, and so on.
Other Types of Arthritis
Reiter’s disease, inflammatory bowel disease, and lyme’s disease, are known to cause rare forms of arthritis, which are similar to rheumatoid arthritis. Their origin lies in the abnormalities of the immune system, which causes destruction of the joint and early wear and tear of the joint cartilage.
The variety of symptoms caused by arthritis can many times mask the important ones, which actually help to differentiate them. A treatment plan for arthritis can only be initiated if the root of the problem is properly identified. There are numerous investigations, like x-rays, blood tests, MRI, CT Scan, and so on. However, a proper account of the symptoms, does much more than that, in unmasking the type of arthritis.