- What are the possible explanations for these findings?
Osteoarthritis: This is the most common form of arthritis, and it becomes more frequent with age. By the age of 65, over 90% of persons have some degree of osteoarthritis, though it is more of a nuisance in most of them than a debilitating condition. The exact etiology is often not known, but "wear and tear" and trauma may play a role. The basic problem: articular hyaline cartilage wears out. Weight bearing joints such as the knee and hip are involved, but small joints such as those of the hands and feet may also be affected. Usually only a few joints are affected, but the condition may be generalized. An underlying condition such as obesity or hemochromatosis may be a factor, leading to a "secondary" osteoarthritis. Obesity impacts weight-bearing joints (hips, knees).
Gout: This is a disorder of purine (adenine, guanine) metabolism with the buildup of sodium urate crystals in joints, particularly the first metatarsophalangeal joint. There can be acute attacks, but over time the urates build up. The urate deposits can produce large chalky deposits that eventually erode the bone and produce pain and deformity. The serum uric acid is often elevated, but it may not be in all cases.
Pseudogout: This condition affects over half of very elderly persons, though in half of cases there are few or no symptoms. This condition results from deposition of calcium pyrophosphate crystals in articular cartilage and in fibrocartilage in menisci and intervertebral disks. The clinical features resemble osteoarthritis.
Lyme disease: Borrelia burgdorferi infection can lead to a chronic arthritis 2 to 3 years following the original deer tick (Ixodes dammini) bite. The disease tends to involve large joints such as the hip. The articular cartilage wears away.
Autoimmune disease: Rheumatoid arthritis produces pain, swelling, and eventual deformity of the small joints of the hands and feet. Larger joints can be involved. The disease affects women more than men. The course is variable, with waxing and waning of the disease. IgM autoantibodies (rheumatoid factor) are often present. Many cases present in middle age, but the presentation can be later, and persons with the disease can live for years.
- What interventions are possible?
Pain medications can be used. If mobility is threatened, one can employ simple assistive implements such as a cane or a walker. Another option is a total knee replacement with a prosthesis.
