Understanding Arthritis - Part 1

The term arthritis literally means 'inflammation of the joint/s'. There are around 206 bones in our body and each of them forms a joint with another bone. So a joint is made up of two articulating bone surfaces which are covered with a cartilage. The space between the two bones - the joint space, is filled with a fluid known as synovial fluid. The synovial fluid is secreted by a membrane present in the joint known as 'synovium' and the function of the synovial fluid is to lubricate the joint and ensure smooth movements. Inflammation or long term damage to any of these structures is likely to result in arthritis.

The first symptom of arthritis would naturally be painful joints. The site of the pain is according to the joint affected and more advanced the disease worse will be the pain. In some cases, particularly in arthritis of the joints of spine, nerves may become compressed between the affected joints leading to pain which will be radiating away from the joints into the area of supply of those nerves.

Arthritis is divided into two main sub types depending on the underlying disease process. First is inflammatory arthritis; most of the causes of arthritis like rheumatoid arthritis, ankylosing spondylitis, infective arthritis are of inflammatory origin. In this type of arthritis the person's own infection fighting cells come and attack the joints. The second is degenerative arthritis which results from the wear and tear of the joints over a prolonged period of time, the most common example of this type of arthritis is osteoarthritis.

The different types of arthritis have their own specific symptoms and signs.

Here are some of the medical terms that are used.

• Monoarticular: arthritis affecting only one joint
• Polyarticular: arthritis affecting more than one joint.
• Migratory: arthritis moving from joint to joint.
• Small joints; joints of the hand and feet
• Large joints: any other joints besides hands and feet.
• Contractures: abnormal and permanent contraction of the muscle surrounding the affected joints, resulting in severe limitation of movements.

INVESTIGATIONS

The diagnosis of arthritis is based mainly upon the history and examination. However in most cases certain tests are done.

• Tests for rheumatoid factor (RF): the major value of RF is to confirm the diagnosis of rheumatoid arthritis.
• ESR and C reactive protein: provide a guide to the activity of inflammation. These are blood tests with little diagnostic value but are very useful to monitor the response of treatment.
• Blood uric acid level: good confirmatory test for gout.
• Synovial fluid exam: synovial fluid is drawn from the joint with a long needle and examined. This test is of particular importance if infective arthritis is suspected.
• Antinuclear antibodies (ANA): these are a variety of antibodies including (ANCA), anticardiolipin antibodies, antibodies against double stranded DNA. The level of each of these antibodies rises in specific types of arthritis.