OSTEOARTHRITIS (OA)

Osteoarthritis is the most common form of arthritis, affecting around 5-10% of the total population, particularly women. It develops when articular cartilage (the smooth covering over bones in the joints) starts to break down, usually as a result of trauma, ageing or failure of joint repair and maintenance mechanisms. Degradation of the cartilage can be associated with underlying bone damage, thickening and bone-on-bone friction.

Symptoms include stiffness, pain and tenderness in the joints and surrounding muscles and ligaments, possibly with fatigue, reduction in motor skills, and deformities. The most common pattern of joint involvement in OA involves the major weight-bearing joints such as the hips, knees or lower spine, with neck and hands also being frequently affected sites.

There is no single cause for OA, with identified risk factors including:

	Being overweight
	Advancing age
	Low socio-economic status
	Hereditary factors
	Chronic stress across joints or joint trauma (such as in sports injuries)
	Other metabolic or inflammatory disorders

Because of the gender differences in incidence, hormones (especially oestrogen) are suspected to have a relationship to OA, but there is conflicting evidence.

Osteoporosis-not arthritis
Osteoporosis is a non-arthritic disorder, not to be confused with OA. It is a condition in which the bones lose calcium, become fragile and tend to break more easily, and usually affects people over 40, mostly women as hormonal changes accompanying menopause accelerate the loss of calcium.

RHEUMATOID ARTHRITIS (RA)

Rheumatoid arthritis affects around 2-3% of the population, again with greater incidence in women. It is a progressive disease, with onset most likely between 25-50 at a time when people are active in the workplace or family care roles. RA is characterised by inflammation within joints that serves no evidently useful purpose and which damages joint structures. The synovial membrane that lines joints is thickened and an over-production of synovial (joint) fluid occurs.

SYMPTOMS: The joints become painful, swollen, stiff and, as the process continues, deformed from damage to the cartilage and other soft tissue. Other symptoms include:

	Fatigue
	Interrupted sleep
	Weight loss
	Anaemia
	Nodules (in 30% of people)
	Ulcers
	Atrophic skin
	Muscle weakness
	Impaired joint function
	Inflammation of the heart, lungs, eyes, nerves, blood vessels and lymph glands

There is significant morbidity and mortality (over half of patients will have to reduce significantly or stop work after ten years of the disease). Like OA, RA is multifactorial in origin (genetic, hormonal, environmental and other factors). Family history is a key risk factor. Hormonal influences are evident with pregnancy associated remissions, a lifelong protective effect of pregnancy, and never having children conferring risk. Other possible contributing factors include race, diet, trauma, and 'triggering agents' (most likely bacteria or virus). Climatic conditions can exacerbate discomfort.

FIBROMYALGIA

Fibromyalgia (previously known as fibrositis) is a condition in which discomfort is widespread and felt within the muscles and ligaments, which may be tender. Damage to joints or other tissues is not a feature. A common association with sleep dysfunction and irritable bowel symptoms suggests an underlying neural irritability. Fatigue, feelings of demoralisation and seemingly insoluble life stresses may be part of the picture.

Fibromyalgia is to be distinguished from 'soft tissue rheumatism' which refers to irritation or inflammation of structures such as ligaments and the synovial sacs (bursae) that lubricate tendon movement.

SYSTEMIC LUPUS ERYTHEMATOSUS: Systemic Lupus Erythematosus (usually abbreviated to lupus or SLE) is a chronic inflammatory autoimmune disease of the connective tissues. It affects the skin, especially in sun exposed areas such as the cheeks, which become red and scaly and various internal organs (kidneys, heart, lungs and brain can all be affected by inflammation and subsequent scar tissue). Lupus often causes:

	General fatigue
	Tiredness
	Loss of concentration and memory

Internal organ involvement can lead to organ failure and death.

GOUT

Gout is caused by the reaction of defence cells in joints to the presence of uric acid crystals. Uric acid (a.k.a. urate) is a by-product of the breakdown of the purines in the body. (Purines are components of the genetic template (DNA) and of certain messenger substances within cells.) Gout is characterised by severe acute attacks of joint pain and swelling, which typically affect joints such as the big toe, the ankle, knee and elbow. An excess of urates can also cause kidney damage, including the formation of stones.

ROSS RIVER VIRUS

The mosquito-transmitted Ross River virus and the similar Barmah Forest virus cause epidemic polyarthritis-acute arthritis in many joints causing severe aches and pain. Viral arthritis does not usually damage the joints like RA, but the arthritis and fatigue can sometimes last for years before the joint returns to normal. Symptoms include chronic fatigue, rashes, severe headaches, impaired concentration and memory as well as depression. There is no specific treatment or vaccination, although scientists are working to develop a vaccine.

JUVENILLE ARTHRITIS (JA)

Juvenile Arthritis can resemble adult RA but other distinctive patterns also occur. With one in 1,000 Australian children having Juvenile Arthritis it is one of the most prevalent and chronic illnesses among children. It has a higher prevalence than juvenile diabetes or cerebral palsy but often, because the symptoms are dismissed as "growing pains", Juvenile Arthritis goes untreated during the early stages of the disease. While some patients go into remission, others battle the symptoms lifelong.