Arthritis is a commonly misused term. Pain in a joint is known as arthralgia, whereas swelling of a joint is known as arthritis. Arthritis is a symptom and not a disease. Arthritis can occur in various conditions, just as fever can occur in malaria, flu, typhoid, TB, and urinary infection. There are over 100 causes of arthritis. It is a common clinical problem, and a proper diagnosis of the underlying condition requires a systematic approach.
Some of the patterns of arthritis are mentioned below:
- Arthralgia: Pain in a joint does not necessarily mean swelling. Pain without swelling usually involves many joints at the same time and may not always have an organic cause.
- Periarticular Pain: Pain can also arise from structures around the joints, such as muscles, tendons, ligaments, and bursae. Frozen shoulder, tennis elbow, and housemaid's knees are some examples of such conditions. These are also known as soft-tissue rheumatism and are generally classified under regional pain. Pain occurs during active movement but not if someone else moves the joint (passive movement). Repetitive trauma (occupational or overuse) or acute overexertion usually leads to such problems.
- Swollen Joint: A joint with swelling of synovium can be warm and reddish. It feels boggy or rubbery and is tender to touch. Moreover, the movements are generally restricted, leading to stiffness. Non-inflammatory swelling is firm and may be tender along the joint line. Joints can be deformed and accompanied by wasting of adjoining muscles due to prolonged restriction of movements.
- Inflammatory Pain: It is crucial to identify an inflamed joint at the earliest as inflammation of swollen synovium causes irreversible damage to the cartilage and other structures within the joint. Morning stiffness of more than 30 minutes, relief of pain by movements and exercise, and spontaneous relapses and remissions are some of the essential features of an inflamed joint. Laboratory investigations can also help in identifying inflammation. Inflammatory arthritis occurs in rheumatoid and other autoimmune arthritis, spondarthritis, septic arthritis, and gout.
- Monoarthritis and Polyarthritis: Involvement of a single joint is common in septic arthritis, gout, osteoarthritis, and some other types. Simultaneous or additive involvement of many joints is typical in conditions such as rheumatoid arthritis and Chikungunya arthritis.
- The symmetry of Joint Involvement: Polyarthritis can be symmetric or asymmetric. Symmetric joint involvement is observed in rheumatoid arthritis and other inflammatory autoimmune diseases. It can also occur in metabolic arthropathies, primary generalized osteoarthritis, viral arthritis, and some other conditions. Conversely, asymmetric joint involvement is characteristic of spondarthritides such as ankylosing spondylitis.
- Acute and Chronic Arthritis: Sudden onset of joint pain and swelling is characteristic of conditions such as gout, reactive arthritis, viral arthritis, septic arthritis, sarcoid arthritis, and bleeding disorders. Examination of joint fluid is essential in gout, septic arthritis, and other conditions with swelling of a single joint. Arthritis of more than six weeks duration is called chronic arthritis. Rheumatoid arthritis, osteoarthritis, and spondarthritides are examples of chronic arthritis.
- Association with Systemic Features: Elaborate history and a detailed clinical examination are critical in diagnosing arthritis. Diseases such as systemic lupus erythematosus, vasculitis, scleroderma, Sjögren's syndrome, sarcoidosis, tuberculosis, leprosy, AIDS, and cancer affect different organ systems, including joints. Therefore, these diseases need to be appropriately identified so that proper treatment can be initiated. Fever, hair loss, weight loss, fatigue, loss of appetite, diarrhea, breathlessness, eye pain and redness, dryness of eyes and mouth, liver and spleen enlargement, lymph nodes in the neck, and other areas are some of the features that indicate systemic involvement along with arthritis.
- Childhood Arthritis: Arthritis in children less than 16 years old is a distinct disease with several subtypes. Rheumatic fever, characterized by fever, fleeting joint pains, heart valve defects, and other features, is also seen in children. There are over 100 diseases that can lead to musculoskeletal complaints in children. In addition, sports injuries, infections, inflammatory arthritis, tumors, metabolic syndromes like rickets, congenital diseases, and psychosomatic causes can cause joint pains in children.