Arthritis

What is it?

Arthritis is a term used to describe more than 100 diseases that are characterized by damage to one or more joints. This may be due to the body’s response to an injury (such as a fracture) or an infection (viral, bacterial, or fungal). It may be due to gradual wear and tear on the joints or or due to an autoimmune disorder. A patient may have more than one type of arthritis. Symptoms include joint pain, swelling, stiffness, and redness that last more than two weeks.

Arthritis affects both sexes and all ethnicities. Most types are more common in adults, but arthritis can occur at any age. Common types of arthritis include:

Osteoarthritis – associated with the aging process, joint damage, and joint deterioration; it is the most common form of arthritis, affecting about 20 million people in the United States.

Rheumatoid arthritis – an autoimmune disorder that affects about 2 million people in the U.S.

Juvenile rheumatoid arthritis – found in about 50,000 children under the age of 16 in the U.S. It may affect one or more joints, organs and can cause eye inflammation.

Gout – causes about 5% of all cases of arthritis. It is a disorder associated with excess uric acid that deposits needle-like crystals into affected joints, especially the patient’s big toe.

Septic arthritis – a less common type of arthritis that is caused by an infection in a joint. It can cause serious joint damage in a short period of time.

Osteoarthritis

What is it?

Osteoarthritis (OA) is the most common form of arthritis, affecting about 20 million people in the United States. Also called degenerative joint disease (DJD), OA is associated with joint injury and with the aging process. It is a chronic disease that causes deterioration of the joint cartilage and the formation of new bone (bone spurs) at the edges of the joints. Cartilage and synovial fluid are meant to provide a smooth, low friction transition between the ends of bones. When cartilage loses its elasticity and wears down, joint movement becomes less smooth. Eventually cartilage can completely erode and the opposing bone ends can rub together. This leads to pain that may be intermittent or chronic, to stiffness in the morning and after rest, to small pieces of bone and fragments of cartilage in the remaining synovial fluid, and to a loss of mobility.

OA occurs equally in men and women before age 55 but more often in women after that age. It is also common in athletes who sustain multiple joint injuries over time. The primary cause is mechanical (for example, joint damage caused by running or excess weight-bearing) but, more rarely, it may be metabolic, genetic, or chemical in nature. Obesity, muscle weakness, and other diseases such as rheumatoid arthritis and hemochromatosis can increase the risk of developing OA and can exacerbate the symptoms associated with it. The joints most commonly affected by OA are those of the hips, knees, hands and fingers, big toe, neck, and lower back.

Tests

The goal of testing is to diagnose OA, to distinguish it from other forms of arthritis and causes of joint pain and stiffness, and to monitor the side effects of various treatments.

Laboratory Tests

There is no specific laboratory test to diagnose OA. It is diagnosed by a doctor using a patient’s medical history, a physical exam, X-rays, and in some cases with an examination of synovial fluid from an affected joint. Tests that may be ordered to rule out other conditions and to evaluate the patient’s health include:

Rheumatoid factor (RF) and Cyclic Citrullinated Peptide Antibody (CCP) – used to help diagnose rheumatoid arthritis and differentiate it from osteoarthritis.

Synovial fluid analysis – to detect crystals that may be present in the joint and to look for signs of joint infection.

Erythrocyte sedimentation rate (sed rate or ESR) – this test shows the presence of inflammation in the body. ESR will be increased in RA but not in osteoarthritis.

C-reactive protein test (CRP) —this test also indicates inflammation and tests for the activity of the disease. It may be used to help differentiate osteoarthritis and RA. An increased level of CRP occurs in RA but not in osteoarthritis.

Complete Blood Count (CBC) – this is a group of tests that are used to help evaluate the patient’s red and white blood cells and hemoglobin. It may be ordered to monitor the side effects of some OA treatments.

Comprehensive Metabolic Panel (CMP) – this is a group of tests that may be used to help evaluate and monitor the patient’s kidney and liver function.

Non-Laboratory Tests

X-rays of the affected joints may show loss of cartilage and narrowing of the joint space but will frequently not show significant changes early in the disease.

MRI (magnetic resonance imaging) – may also be used to examine affected joints.

Osteoporosis

Bone is a living tissue that is constantly being broken down and rebuilt. When the balance between breakdown and rebuilding is disturbed – for example, by hormonal changes or dietary changes – the bone may lose some of the minerals that contribute to its density and strength. A condition of diminished bone density is called osteopenia. When a significant loss in bone density occurs, such that the bone is markedly weakened and susceptible to fracture, the condition is termed osteoporosis.

Osteoporosis increases the risk of bone fractures, especially in the hips, spine, and wrists. Although it can affect anyone, the risk of developing osteoporosis increases with age, affects women significantly more often than men, and is most prevalent in Caucasian and Asian women. According to the National Osteoporosis Foundation (NOF), 10 million people in the United States have osteoporosis and another 34 million have low bone mass and are at risk of developing the disease. Of those who have osteoporosis, 80% are women.

Most of the people at risk for osteoporosis are not aware of it. It is called a “silent disease” because there are usually no symptoms until a person has a bone fracture. This breakage, frequently in the hip, the vertebrae of the spine, or in the wrist, can occur with very little pressure and can cause the person significant pain and protracted or permanent disability. If the fracture causes severe debility where the patient’s general health is affected, it may be a contributing factor in the death of the patient.

Bones are primarily a combination of type-I collagen protein and calcium phosphate. The protein forms a spongy network that is “mineralized” by the addition of the calcium compound to make the bones both strong and flexible. Bone is living tissue that is slowly but continuously replaced. During a process called bone resporption, cells called osteoclasts dissolve bone on a microscopic scale and enzymes break down the collagen network. This is followed by the formation of new bone by cells called osteoblasts, which secrete osteocalcin and precursors to collagen and create a new protein framework. The framework is then mineralized to create new bone. This on-going process is called bone turnover or bone remodeling and it takes place throughout the body, normally replacing about 8-10% of the body’s bone each year.

During childhood, bone formation proceeds at a faster rate than bone resorption, and bone mass increases to peak at about 30 years of age. After this peak, bone formation slows and resorption begins to outpace it, resulting in a decline in bone mass with age. An inadequate intake of calcium and vitamin D during childhood, the use of medications that contain steroids (such as asthma medications), anorexia, inactivity, smoking, and excess alcohol consumption can all increase the risk of a person developing osteoporosis later in life. Some diseases, such as thyroid disease, Cushing’s disease, rheumatoid arthritis, kidney disease, hyperparathyroidism, and vitamin D deficiency can also have an effect on bone health. Those with a strong family history of osteoporosis may also be at an increased risk of developing it themselves.

Women who go through menopause may experience an increased rate of bone mass loss with a decrease in estrogen. Going through menopause early can exacerbate the loss. According to the NOF, some women can lose up to 20% of their bone mass in the first 5 to 8 years following menopause. Men with decreased testosterone levels are also at risk for increased bone loss.

There are two types of osteoporosis:

Primary- or high turnover or age-related osteoporosis. Occurs in some women aged 50-75 due to the sudden decrease in estrogen as a result of menopause. This causes rapid calcium loss from the bones, making the women susceptible to hip, wrist, forearm, and spinal compression fractures. Age-related osteoporosis occurs in men and women older than 75 years of age and may be due to a decrease in calcium absorption or vitamin D deficiency. Changes in lifestyle, calcium or vitamin D supplements, or other medications decreasing bone loss may slow the progression of this type of osteoporosis.

Secondary– or low turnover osteoporosis. Occurs when bone loss and formation are not equal and more bone is broken down than replaced. It affects both men and women and may be due to several different disorders including rheumatoid arthritis, hyperparathyroidism, Cushing’s disease, chronic kidney disease, multiple myeloma, or drugs such as anti-epileptics, glucocorticoids or lithium. Treatment of the underlying disease or cause may slow the loss of bone density in secondary osteoporosis.