PAIN is recognised as a complex phenomenon derived from sensory stimuli and modified by individual memory, expectations and emotions. The causes of pain are many and varied – pain can be due to lack of blood supply or ischemia and distension of the particular organ in the body. This is often called a visceral pain. Trauma or burns affecting any part of the human body is another common cause of pain.
Inflammation of the blood vessels or vasculitis and headaches are often classified as a mixed type of pain. Pain can also be caused by involvement of the nerve – neuropathic pain. The commonest is seen in diabetics with diabetic neuropathy or after an attack of herpes zoster – post herpetic neuralgia.
Muscle pain (myalgia) and joint pain due to arthritis are one of the commonest types of pain affecting all of us as we age.
There are many complex neurochemical mediators involved from the brain to the sensory nerve endings which control the intensity and duration of pain suffered by the person depending on the causes.
Over 355 million people worldwide have arthritis. By the year 2025, degenerative bone and joint disorders will be the most important cause of physical disability (up to 25% of all incapacitating conditions). This has led to increasing socioeconomic impact of rheumatic conditions worldwide.
How does the pain and inflammation in arthritis patients affect quality of life? Most of the persons with arthritis have decreased physical functioning and this directly leads to increased psychological distress and decreased social functioning. Patients with pain have more visits to the doctor and are on leave more often, leading to increased work disability.
The prevalence increases sharply with advancing age and by 75 years, 80% of men and women have osteoarthritis (OA). The female to male ratio of knee OA is 1.5 to 1. The risk factors include increased age, obesity, thigh muscle weakness, joint overuse or injury and lastly genetic factors.
The joint with OA has characteristic changes, for example, degeneration of the cartilage, cyst formation and osteophyte formation.
On examination the joints of the person’s hands, especially the terminal interphalangeal joints, are swollen and nodules sometimes form over it. The knee and the hip joints are often other common joints involved in the elderly with OA.
Management of arthritic pain
The doctor managing patients with OA initially will take a detailed history regarding the type of pain – character, duration and location of the pain. The exacerbating and relieving factors of the pain and how it affects the daily activities of the person is important. A full physical examination of the affected joints and the patient as a whole is the next step. A functional and psychological assessment is also necessary in some circumstances.
Current treatment of OA include simple analgesics such as paracetamol, opiod analgesics such as codeine, non-steroidal anti-inflammatory drugs (NSAIDs) and COX-2 selective drugs (eg meloxicam). Glucosamine and intraarticular hyaluronan are other drugs useful in the treatment of OA.
NSAIDs used in the treatment of OA have caused gastric ulcers and erosions in 10-30% of cases and the dangerous complications such as bleeding and perforations have occurred in 2-4%. It is important to note that 42% of the elderly who develop problems with NSAIDs have no symptoms.
NSAIDs should be used in caution in the elderly as there is increased development of gastric complications, worsening of kidney function or development of swelling of legs and cardiac failure .
COX-2 selective drugs such as meloxicam are as effective in reducing the inflammation of patients with OA with less side effects compared to NSAIDs.
Topical NSAIDs, methysalicylate liniment (LMS) or NSAID medicated plasters are useful options in treatment of OA.
Glucosamine sulphate has been shown to be useful in relieving pain and improving function in patients with mild and moderate OA.
In severe knee OA with swelling of the joints, the doctor may decide to aspirate the fluid from inside the swollen joint and inject the joint with a long-acting steroid injection. After resting the joints for about two days, quadriceps strengthening exercises should be started. It is not advisable to repeat the intrarticular injections less than three monthly intervals.
Non-pharmacological management of arthritis include maintaining ideal body weight, regular exercise and improving muscle power.
Appropriate physiotherapy and occupational therapy are most important in reducing the pain and deformity that may follow worsening arthritis. Physiotherapy will concentrate on improving the range of motion, strengthening exercises and providing assistive devices for ambulation. Thermal modalities (hot packs, shortwave diathermy and ultrasound) and TENS or Transcuatneous Electrical Nerve Stimulation has significant benefit in pain relief.
Occupational therapy will provide (for example splints) joint protection and assistive devices for activities of daily living. Aerobic aquatic exercise programmes have also been found to be very useful in reducing the pain associated with osteoarthritis.
Patients who have unbearable pain in spite of all the above treatments and who have progressive limitation in activities of daily living are usually referred to the orthopaedic surgeon for evaluation to consider surgery. Total joint arthoplasty is the best option in the elderly above 60 years with severe OA of the hip or knee – patients have complete pain relief and near normal function after successful surgery.
In summary the management of OA involves a multidisciplinary approach so as to relieve the symptoms and improve joint function. Patients who are educated about the disease and understand the natural history and problems associated with arthritis cope better and report less pain.
Obese patients must lose weight as every 5kg loss of weight can reduce the force on the knee by 15-30kg with each step and hence substantially decrease the pain of knee OA.
Severe pain and disability due to OA is the most feared complication of growing older – recent advances in the management of OA which are safe and easily tolerated improves the quality of life of the elderly with arthritis.
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