Arthritis

Arthritis is a broad medical term used to describe joint disorders. The word comes from "arthr-", meaning joint, and "-itis", meaning inflammation.

In a healthy body, joints are lined with a smooth layer called cartilage. This cartilage prevents bones from rubbing together during movement. Arthritis occurs when this protective layer is lost. This leads to bone grinding on bone. This process causes pain, stiffness, and swelling. It can also cause redness and warmth around the joint. Some types of arthritis even affect organs outside the joints.

One major type is osteoarthritis, which is the most common form. This condition often results from long-term wear-and-tear or prior injury. As cartilage breaks down, the bones begin to erode each other. This often affects weight-bearing joints like the hips, knees, and back. It can also impact the fingers and shoulders.

Osteoarthritis is particularly common in older adults. This may be because aging chondrocytes, or cartilage cells, lose their ability to maintain the tissue. Over 30 percent of women have some degree of osteoarthritis by age 65.

Another significant type is rheumatoid arthritis, which is an autoimmune disorder. In this condition, the immune system mistakenly attacks the body's own tissues. Specifically, it targets the articular cartilage at the ends of the bones. The attack often begins with inflammation of the synovium, the lining of the joint capsule. This inflammation is driven by pro-inflammatory cytokines and a protein called RANKL. This process can lead to severe bone erosion and progressive deformity.

Unlike osteoarthritis, rheumatoid arthritis is often symmetrical, affecting both sides of the body.

Gout is a different type of inflammatory rheumatic disease. It is caused by the excessive production of uric acid in the body. This causes urate crystals to deposit within the joints. These crystals often settle in the extremities, such as the big toe.

During a gout flare, the joint becomes swollen, red, and very warm. The pain from these flares can be significant and debilitating. Other types of arthritis include septic arthritis, lupus, and psoriatic arthritis.

Systemic diseases like lupus can also cause significant joint issues. Lupus is an autoimmune collagen vascular disorder. About 90 percent of patients with lupus experience musculoskeletal involvement.

In these cases, symptoms might mimic rheumatoid arthritis with similar stiffness. However, lupus also causes other issues like extreme photosensitivity, hair loss, and kidney problems. Some people may also develop a characteristic malar, or butterfly, skin rash. This shows how arthritis-like symptoms can be connected to broader systemic health.

Doctors use several methods to diagnose these conditions. They often begin with a clinical physical examination. A professional might evaluate a patient's gait or check the skin for rashes. Imaging is also a vital tool for seeing internal damage. X-rays are commonly used to find joint space narrowing or bone spurs. Other advanced imaging includes CT scans, PET scans, and bone scans. Blood tests can also help identify specific markers of inflammation. For example, doctors look for elevated C-reactive protein (CRP) or rheumatoid factor (RF) levels.

Managing arthritis depends on the specific type and severity. Early treatments often involve resting the joint or using heat and ice. Weight loss and exercise can also reduce the force on weight-bearing joints. Medications like ibuprofen or paracetamol are used to manage symptoms. In very severe cases, a patient might require joint replacement surgery. Arthritis is a major reason people struggle with work or daily activities. It affects more than 20 percent of people in the United States and about 15 percent in Australia.