Collagen and Joints

Joints are a moving combination of bones. Place where their connection takes place is called placenta. Placenta’s biggest problem is friction; therefore joint surfaces are covered with hyaline cartilage and articular membrane. Their function is to produce so-called synovial fluid, which moistens moving parts of the connecting bones to eliminate possible pain. During illness when deterioration of cartilage occurs or quantity of produced synovial fluid is insufficient, they cease to perform their function in a satisfactory manner. Since bones are not properly shielded, unpleasant pain occurs with every movement. Among other things collagen is responsible for sufficient production of synovial fluid. It also affects the condition of a cartilage by providing it with hardness and elasticity. Additionally, it reduces an activity of enzymes responsible for rheumatic pains and accelerates recovery of the tissues affected.

Collagen and Varicose Veins

Collagen fibers are an important part of the venous endothelium, including the venous valves. Adequate quantity and quality of collagen in the venous walls determine to maintain their normal function and biochemical properties. Veins rich in collagen are resilient and flexible; thereby they better prevent the backflow of blood towards the heart. Studies have shown that proteins such as collagen content are significantly reduced in varicose veins compared to healthy veins.

Collagen and Menopause

Menopause – inevitably occurs in the life of every woman even when she is still young, healthy, and active. The ovaries stop producing sex hormones – estrogen, which have the greatest impact on woman’s skin. During menopause, enzyme that breaks down collagen fibers becomes more active. The researchers report that the density of collagen in the skin drops by an average of 2% per year. During the first 5 years of menopause, the amount of collagen fibers in the skin is reduced by 30-35%.

Collagen and Osteoporosis

Bone collagen metabolism disorders cause decalcification of the skeleton, which contributes to enhanced bone fragility and susceptibility to the fracture. A bone is a porous tissue composed of 90% collagen, where process of linking of collagen with calcium, phosphorus and magnesium takes place. If during youth, not enough collagen was produced to develop collagen-rich bone structure, in old age we are in danger of osteoporosis.

Connective tissue

Structure and Function

Cells, the structural and functional units of life, are organized into tissue, a group of different types of cells and their nonliving intracellular matrix, of glue, that performs a specialized function. The four groups of tissues are epithelial (covering and lining issue; also glands); connective (adipose, blood, bone, cartilage, ligament, and tendon); muscle (skeletal, cardiac, and smooth); and nervous (brain and spinal cord). Connective tissue typically has cells widely scattered throughout a large amount of intracellular matrix (that is a substance in which the cells are embedded), unlike epithelial tissue that typically has cells arranged in an orderly manner and has a limited amount of intracellular matrix.

Connective tissues are categorized as loose (aerolar), dense, and specialized. Some connective tissues are difficult to classify, with the distinction between loose and dense not clearly defined. Also, dense connective tissue may be called fibrous connective tissue because of the large amount of collagen or elastin fibers contained. Because a tissue is defined as a collection of different cells, several types of cells that may be found in various types of connective tissue: fibroblasts, which secrete collagen and other elements of the extracellular matrix, thereby creating and maintaining the matrix; adipocytes, which store excess caloric energy in the form of fat; and mast cells, macrophages, leukocytes, and plasma cells, which have immune functions and, therefore, an active role in inflammation. The components of the matrix are different in the different types of connective tissue and may include fibers, amorphous ground substances (glycoproteins, proteins, and proteoglycans), and tissue fluid. Each type of connective tissue has a characteristic pattern of cells and distinctive amount and type of matrix. For example, bone matrix includes minerals, while blood has plasma for a matrix. Loose connective tissue is the most common type of connective tissue; it holds organs in place and attaches epithelial tissue to underlying tissues. Loose connective tissue can be further categorized based on the type of fibers and how the fibers are arranged: collagenous fibers, which are composed of collagen and are arranged as coils; elastic fibers, which are composed of elastin and are able to stretch; and reticular fibers, which join connective tissue to other tissues. Loose connective tissue has a relatively large amount of cells, matrix, or both, and a relatively small amount of fibers. Loose connective tissue is found in the hypodermis and fascia (the connective tissue that loosely binds structures to one another). Dense connective tissue is identified by the high density of fibers in the tissue and a low density of cells and matrix. The type of fiber that predominates determines the type of dense connective tissue.

Dense collagenous connective tissue for example contains an abundance of collagen fibers and is found in structures where tensile strength is needed, such as the sclera (white) of the eye, tendons, and ligaments. Dense elastic connective tissue contains an abundance of elastin fibers and is found in structures where elasticity is needed (for example, the aorta). Specialized connective tissues include adipose tissue, cartilage, bone, and blood. Adipose tissue is a form of loose connective tissue that stores fat. It is found in he fatty layer around the abdomen, in bone marrow, and around the kidneys. Cartilage is a form of fibrous connective tissue. It is composed of closely packed collagenous fibers embedded in a gelatinous intracellular matrix called chondrin. While the skeleton of human embryos is composed of cartilage, cartilage does not become bone but rather is replaced by bone. The replacement is not universal; cartilage provides flexible support for ears (external pinnae), nose, and trachea.

Blood is a type of specialized connective tissue. Blood may seem to be an unlikely connective tissue, but it fits the definition: different cells widely dispersed in intracellular matrix, working together to perform a specific function. Unlike other connective tissues, blood has no fibers. Blood does have several types of cells: red blood cells or erythrocytes, white blood cells or leukocytes (with subdivisions of monocytes, macrophages, eosinophils, lymphocytes, neutrophils, and basophils), and platelets or thrombocytes. The matrix is liquid and contains enzymes, hormones, proteins, carbohydrates, and fats.

Disorders and Diseases

Connective tissue, like any other tissue, is subject to disorders and diseases. Some disorders are inherited (passed from one generation to the next by means of DNA in chromosomes), while other disorders are related to the environment (such as lack of specific nutrients).

Some inherited connective tissue disorders are Marfan syndrome and osteogenesis imperfecta. In Marfan syndrome, connective tissue grows outside the cell, having deleterious effects on the lungs, heart valves, aorta, eyes, central nervous system, and skeletal system. People with Marfan syndrome are often unusually tall with long, slender arms, legs, and fingers. In osteogenesis imperfecta, or brittle bone disease,the quantity and quality of collagen is insufficient to produce healthy bones. People with this disorder have multiple spontaneous bone breaks. Other connective tissue diseases are environmental, such as scurvy, which is caused by a lack of vitamin C required for the production and maintenance of collagen. Without sufficient vitamin C in the diet, and subsequent lack of collagen, the patient will develop spots on the skin, particularly the legs and thighs; will be tired and depressed; and may lose teeth. Osteoporosis has many factors, but lack of vitamin D and calcium in the diet will lead to a thinning of the bone, subjecting the patient to fractures, primarily of the hip, spine, and wrist. Connective tissue diseases may also be classified as systemic autoimmune disease and may have both genetic and environmental causes. In these situations, the immune system is spontaneously overactivated and extra antibodies are produced. Examples of systemic autoimmune diseases include systemic lupus erythromatosus and rheumatoid arthritis. Systemic lupus erythromatosus can damage the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system. More women than men are diagnosed with lupus, and more black women than other groups. Rheumatoid arthritis is caused when immune cells attack the membrane around joints and destroy the cartilage of the joint; it can also affect the heart and lungs and interfere with vision.

  • M. A. Foote, PH.D.


Structure and Functions Collagen is a complex protein made up of three separate polypeptide chains that form a triple helix. These polypeptides are unusual because every third amino acid is a glycine and because prolines make up an additional 17 percent of the chains. There are at least twenty eight types of collagen made up of forty-three distinct polypeptide chains, each coded for by a different gene. For example, type I collagen, the most common type, has two chains classified as alpha-1 and alpha-2. These peptides are initially produced on the rough endoplasmic reticulum (ER) and then processed in the ER lumen, where sequences at the ends are removed and hydroxyl groups are added to many of the chains, prolines, and lysines. The triple helix then formed is called procollagen. Further processing, including preparation for secretion, takes place in the Golgi bodies. Once secreted, more end sequences are cleaved off to form collagen (also called tropocollagen). In the extracellular region, collagen molecules associate into collagen fibrils and eventually collagen fibers. Collagen is a flexible but not stretchable protein that is an important component of most connective tissues. It is the primary component of tendons and ligaments, giving them the requisite strength to connect muscles to bones and bones to other bones or organs. Cartilage found at joints and in many other structures is mostly collagen. The connective tissues found in the dermal layer of the skin, the capsules surrounding internal organs, and blood vessels are also primarily made of collagen. Bones are initially formed from collagen, which ten serves as matrix for calcium phosphate deposition.

- Richard W. Cheney, Jr., Ph.D.


Causes and Symptoms

Approximately on in six people (more than 15percent) suffers from one of approximately one hundred varieties of arthritis, and 2.6 percent of the population suffers from arthritis that limits their activities. Although many people over seventy-five years of age experience arthritis, the disease can occur in the young as a result of infections, rheumatic conditions, or birth defects. Young and middle-aged adults experience the disease as a result of trauma, infections, and rheumatic or immune reactions. Arthritis may be located in joints, joint capsules, the surrounding muscles, or diffusely throughout the body. Inflammation of the joint lining (synovium) can similarly afflict the linings of other organs: the skin, colon, eyes, heart, and urinary passage. Those suffering from the disease may therefore suffer from psoriasis and rashes, spastic colitis and diarrhea, dryness of the eyes, inflammations of the conjunctive or iris, frequent urination, discharge and burning upon urination, and other symptoms.

The collagen-type arthritic diseases involve the binding materials in the body or connective tissues and may be rheumatologic, generally more diffuse and in the distal joints (as in juvenile rheumatoid arthritis and rheumatic fever), or located in the skin and muscles (dermatomyositis). Psoriatic arthritis causes sever punched-out defects in the joints. Reiter’s and Sjogren’s syndromes involve the eyes and the joints. Genetic conditions, such as Gaucher’s disease, frequently run in families. Metabolic disturbances, such as gout, can leave uric acid deposits in the skin and the joints. Gout sufferers experience very painful, hot, tender, and swollen joints, often in the large toe. Immunologically mediated arthritis may be associated with infections, liver diseases, bowel disturbances, and immune deficiencies. Localized infections may be bacterial, viral, or fungal. Miscellaneous disorders, a basket category, include conditions that do not fit into any of the aforementioned categories: Psychogenic disorders and arthritis associated with cystic disorders are examples. Arthritis may also be associated with tumors that grow from cartilage cells, blood vessels, synovial tissue, and verve tissue. Blood abnormalities may give rise to hemorrhages into joints (a side effect of sickle cell disease and hemophilia) and can be disabling and very painful, sometimes requiring surgery. Traumatic and mechanical derangements, sports and occupational injuries, leg-length disparity, and obesity may elicit acute synovial inflammation with subsequent degenerative arthritis. Finally, wear-and-tear degeneration can occur in joints after year of trauma, repetitive use, and (especially in obese) weight-bearing. The most common arthritic entities are rheumatoid arthritis (also called atrophic or proliferative arthritis), osteoarthritis, hypertrophic arthritis, and degenerative arthritis.

The inflammatory reaction in response to injury or disease consist of fluid changes the dilation of blood vessels accompanied by an increase in the permeability of the blood vessel walls and consequent outflow of fluids and proteins. Injurious substances are immobilized with immune reactions and removed by the cellular responses of phagocytosis and digestion of foreign materials, resulting in the proliferation of fibrous cells to wall off the injurious substances and in turn leading to scar formation and deformities. The chemical reaction to injury commence with a degradation of phospholipids when enzymes are released by injures tissue. Phospholipids, fatty material that is normally present, break down into arachidonic acid, which is further broken down by other enzymes, lipoxygenase and cycloxygenase, resulting in prostaglandins and eicosanoid acids. Most anti-inflammatory medications attempt to interfere with the enzymatic degradation process of phospholipids and could be damaging to the liver and kidneys and to the body’s blood-clotting ability.

Fibrosis is a diffuse muscular pain syndrome with tenderness in the muscles, no muscle spasm, and no limitations in motion; all laboratory tests are within normal limits. It is frequent in postmenopausal women who have a history of migraines, cold extremities, spastic colitis, softening of the bone matrix accompanied by loss of minerals, and irritability. Myofascial trigger points can be found in both men and women, at all ages, with acutely tender nodules or cords felt in muscles. The pain of these trigger points is referred to more distal areas of the muscles that may not be tender to touch.

Joint pathology is generally associated with some limitation in the range of motion. Sensation testing, muscle strength, and reflex changes may also indicate nerve tissue damage. Nerves occasionally pass close to joints and may be pinched when the joint swelling encroaches upon the passage opening. This condition may result in carpal tunnel syndrome, in which the median nerve at the wrist becomes pinched, causing pain, numbness, and weakness in the hand. Pinched nerves may also be associated with tarsal tunnel syndrome, in which the nerve at the inner side of the ankle joint may be compressed and cause similar complaints in the feet. Other nerves may be constricted in exiting from the spine and when passing through muscles in spasm.

Arthritis of the spine leads to progressive loss in motion. The amount lost can be measured by comparing normal motion with the restricted motion of the patient. The neck may be limited in all directions, rotation of the head to the sides can restrict the driving view, and the head may gradually tilt forward. The lower back may also exhibit restriction in all directions; for example, it may be limited in forward bending because of spasms in the muscles in the back. Tilting backward of the trunk may be limited and painful when the vertebral body overgrowth of osteoarthritis or degenerative arthritis restricts the space for the spinal cord. The nerves pinched in their passage from the vertebrae may thus cause radiculitis, irritation of the nerves as they exit from the spine that leads to pain and muscle involvement.

Degenerative and post-traumatic arthritis show joint narrowing, thinning of the cartilage layer, hardening of the underlying bone (called eburnation), and marginal overgrowth of the underlying bone (called osteophytes), resulting in osteoarthritis. The cushions between the vertebrae, called discs, are more than 80 percent water, a figure which diminishes with aging, bringing the joints in the back (the facets) closer together and compressing the facet joints between the vertebrae. Irritation and arthritis of these joints are the result.

- Eugene J. Rogers, M.D. 

- updated by Victoria Price, Ph. D


Structure and Functions

In the musculoskeletal system, the joints are structures that connect individual bones while allowing some type of movement and mechanical support. This skeletal articulation holds together distinct bones with strong but flexible soft tissue that enable movement on components of the skeleton by muscles on opposite sides of the joint that contract or relax. Joints occur between bones and teeth, and between cartilages. Based on their anatomical location, they are grouped between the joints of the trunk and the upper or lower extremity. They can be classified structurally, functionally, or biomechanically.

Structurally, joints may be classified as cartilaginous, fibrous, bony, or synovial, based on the composition of how these bones connect to each other. A cartilaginous joint is connected by hyaline cartilage or fibrocartilage. A fibrous joint is connected by a collagen- and elastin-rich connective tissue. In a bony joint, there is a fusion between bones. Synovial joints are not directly connected but are found within a synovial cavity full of synovial fluid that lubricates and cushions the joint.

Strength and flexibility are important functional features of joints but also contradictory concepts in which greater joint strength translates into less flexibility and otherwise. Functionally, joints are ranked based on the degree of mobility rendered: immobility (synarthrosis), slight mobility (amphiarthrosis), and free mobility (diarthrosis). Synarthroses are immovable joints such as those located between the plates of the skull. Amphiarthroses are joints that allow slight movement such as in the vertebrae. Diarthroses are joints that move freely and are also known as synovial joints. These include the joints in the shoulder, hip, knee, and elbow.

The most common mobile joints present in the body are the hinge joint, pivot joint, ball-and-socket joint, saddle joint, and ellipsoidal joint. Joints allow four types of movement: gliding, angular, circumduction, and rotation. The shape of bones and their articular surfaces, in addition to the ligaments and muscles intersecting the joint, determines the degree of movement permitted at a specific joint.

Biomechanically, joints can be characterized according to number and configuration of articulating elements with regard to the movement that they allow. Therefore, joints are subdivided as simple and compound based upon the number of partaking bones and into combinational and complex joints.

Disorders and Diseases

Problems with joints range from minor injuries (sprains) to serious or chronic joint disease. Age, use, and overuse can diminish joint function or deteriorate this structure further to become diseased. Genetics, direct trauma, misalignment, dislocation, and mechanical loads may also play a role in damaging joints.

Several inflammatory conditions can affect the joints. Synovitis is the inflammation of the lining of the synovial joint, the synovial membrane. The swelling of this membrane causes pain especially when the joint moves. Bursitis (such as tennis elbow) is the inflammation of the bursa that rests between a tendon and skin or between a tendon and bone. The symptoms include joint pain, tenderness, swelling, stiffness, or warmth around the joint.

“Arthritis” is a generic term for a group of chronic medical conditions affecting the joints. The most common one is osteoarthritis (OA), which is characterized by the progressive wearing down of the cartilage in the joints. The symptoms of this degenerative joint disease include swelling, deep aching pain that gets worse after exercise or rainy weather, limited movement, loss of flexibility, stiffness, and grinding of the joint during movement.

Another type of medical condition that afflicts the joints is rheumatoid arthritis (RA), an autoimmune disease. In RA, the body produces an immunocellular reaction that targets the joints and causes inflammation. RA is a chronic autoimmune inflammatory joint disease afflicting the lining of the joints, resulting in painful swelling that will cause bone erosion and joint deformities. Since it is a systemic disease, it may involve other internal organs (lungs, kidneys, heart, or eyes) as well. Some of the associated symptoms are low-grade fever, weight loss, fatigue, morning stiffness, muscle aches, weakness, loss of appetite, skin redness or inflammation, had and foot deformities, and numbness or tingling. Joint loss may appear within the first couple of years after diagnosis. RA frequently involves a lifetime of treatments, medications, exercise, physical therapy, education, and sometimes surgery.

Perspective and Prospects

Joint disorders and diseases were well-known ailments to physicians of ancient Greece and Rome. Evidence of joint problems has been discovered in Egyptian mummies and Roman gladiators. Today, one of every five adults in the United States has some type of joint disease. It is the primary cause of work disability in the United States. Although genetics and traumatic injuries may have a negative impact on joint health, this is a multifactorial disease and, as such, early diagnosis and proper management is essential to improve quality of life. The prevalence of joint disease, however, does not translate into total inevitability. It is possible to conserve joint function and mobility when knowledge, preventive measures, and correct treatments are implemented.

Aging thins the cartilage, which will eventually cause joint pain, stiffness, or disability. Microtraumatic injuries lead to low levels of inflammation, which over time will destroy the protective cartilage at the joints. Excess weight damages the joints in the long run as well, especially the knees, which support body weight. The loss of muscle mass during aging causes the joints to overcompensate by absorbing more of the beating form daily activities and aggravating the affected site.

- Ana Maria Rodriguez-Rojas, M.S.


Structure and Functions

Structurally, ligaments appear to be strap-like bands or round cords. They are strong yet somewhat pliable. In terms of the musculoskeletal system, they serve to stabilize the adjoining bones making up what is referred to as an articulating joint. Ligaments consist of a cellular component called fibroblasts, making up 20 percent of their total tissue volume. The remaining 80 percent of the tissue volume is outside the fibroblast cells and consists of collagen and elastin. The relative proportion of collagen to elastin varies among ligaments. The degree of stabilization also varies and depends on each particular joint, such as shoulder and ankle joint ligaments. This degree of stabilization may be one, which limits the amount of movement or prevents certain movements entirely. Some ligaments surround en entire joint filled with a lubricating fluid called synovium and are termed capsular ligaments. Ligaments located outside this joint capsule are called extracapsular and provide joint stability, while ligaments located inside the capsular ligament are called intracapsular and permit much more movement of the joint.

Other locations outside the musculoskeletal system that consist of ligaments for supporting structures include the broad ligament for the uterus and Fallopian tubes, which attaches these organs to the pelvic wall. Suspensory ligaments are also found in the body supporting a variety of organs, including the eyeball and breasts.

Disorders and Diseases

Ligaments are elastic, and they gradually lengthen under tension. The term sprain describes an injury to a ligament caused by forces that stretch some or all of the ligaments fibers beyond their limit. This type of ligament injury can result in some degree of rupture of some or all of the fibers. In some instances, the ligament injury includes the possibility of pulling attachment from the bones. The classification for grading ligament injuries is based on two factors, the numbers of fibers ruptured and the resulting instability of the joint involved. Ligament injuries are also classified clinically as first-degree (mild), second-degree (moderate), and third degree (severe).

A consequence of a stretched or ruptured ligament can be instability of the joint. Not all injured ligaments require surgery, but if surgery is needed to stabilize the joint, the torn ligament can be repaired. Instability of a joint can, over time, lead to wear to the cartilage and eventually to osteoarthritis. Joint inflammation from trauma or other medical reasons can stiffen the joint ligaments, resulting in restricted motion.

Several immune diseases can affect the ligaments of the body’s joints. Rheumatoid arthritis is a chronic disease that affects the synovial membrane of the joint, which produces the joints lubricant synovium. This fluid becomes thickened and fleshy and erodes the joint structures, including the articular ligaments.

- Jeffrey P. Larson, P.T., A.T.C.


Causes and Symptoms

There are several causes of osteoarthritis (OA), including traumatic injuries, joint overuse, or repetitive movement of a joint, obesity, and genetic or metabolic diseases. The most commonly affected joints are in the hands, hips, knees, and spine. An inherited genetic defect in the production of collagen leads to defective cartilage and to more rapid joint deterioration. OA in the hands or hips may be hereditary. OA in the knees is linked to excess weight. X-rays of more than half the population over sixty-five would show evidence of osteoarthritis in at least one joint.

Cartilage containing synovial fluid and elastic tissue reduces friction as joints move. Osteoarthritis develops when the cartilage wears away and bone rubs against bone. The most prominent symptom of osteoarthritis is joint pain. Other symptoms include morning stiffness or stiffness after long periods of immobility. Early in the disease, individuals may experience joint pain after strenuous exercise. As the disease progresses, joints stiffen and diminished joint mobility is experienced even with slight activity. As joint mobility decreases, the muscles surrounding the joint weaken, thereby increasing the likelihood of further injury to the joint. As the cartilage wears away, crepitus can often be heard as bone moves against bone. The development of Herberden’s nodes on the distal interphalangeal joints and Bouchard’s nodes on the proximal interphalangeal joints of the hands is not uncommon.

- Sharon W. Stark

- updated by Victoria Price, Ph.D.


Causes and Symptoms

Osteogenesis imperfecta, a rare genetic disorder occurring in 1 in 20,000 people, affects the formation of collagen, which in turn alters bone formation, as collagen provides the foundation for mineralization of developing and healing bone. As the name implies, patients with this disorder have imperfect bone formation, resulting in multiple, recurrent fractures. Bones are composed of a complex matrix including strands of cross-linked collagen. Collagen is produced by chondrocytes in newly forming bone. Osteoblasts then add the mineral matrix (calcium salts), which forms a complex with collagen to create bone. Children with osteogenesis imperfecta do not produce collagen molecules that allow for a well-organized, strong, stable structure. Fractures can take place without outside stresses such as those occurring in a fall. Normal muscle contraction can produce enough force in some children to induce a bone break.

The long-term outcome of the disease is variable. Most severely affected infants die from complications of lung disease. Patients with less severe disease usually survive but have fractures of their long bones. Most breaks occur between the ages of two and three and again during puberty, between ten and fifteen. From late adolescence through the adult years, the fracture incidence drops unless the patient becomes pregnant, is nursing, or becomes inactive.

There are two main types of osteogenesis imperfecta. The more severe form, osteogenesis imperfecta congenita, affects bone development during gestation and results in bone fractures before birth. These children continue to have fractures without adequate bone repair. Because of the malformation of bony tissues and frequent fractures, they do not grow normally and have numerous bone deformities.

Other tissues with abundant collagen are also affected in osteogenesis imperfecta congenita. Because these tissues include tendons and ligament, joints become more mobile and less stable. The small bones in the middle ear are similarly affected, resulting in otosclerosis, in which the ossicles stiffen and do not allow the normal transition of sound from the eardrum to the inner ear. Thus, patients have hearing difficulties and subsequent language delays. Because the white parts of the eyes (the sclera) are composed mainly of collagen, these patients tend to have bluish sclera. They also have thinner skin that bleeds easily. Epistaxis (nosebleeding) is likewise common and difficult to control. Patients have deformed teeth, as tooth development is also affected. The second type of osteogenesis imperfecta is known as osteogenesis imperfecta tarda. Patients with this type have a slower onset and milder course of disease. Fractures begin after birth, do not occur as frequently, and tend to heal better, causing less deformity.

  • Matthew Berria, Ph. D.


Causes and Symptoms

Most experts believe that rheumatoid arthritis (RA) occurs as a result of some type of stress on the body that triggers an autoimmune response characterized by chronic inflammation, swelling, and pain in joint spaces as cartilage erodes and bony cysts cause deformities in the joints and joint motion is lost. Certain genes associated with the immune system have been found to increase the possibility of developing RA.

Initially, persons with RA may have general, vague complaints such as fatigue, weakness, weight loss, anorexia, low-grade fever, and tingling in the hands and feet during the weeks or months after some traumatic physical event in their life. Joint stiffness lessens as the day progresses but may recur after inactivity and is worse after strenuous activity. Although all joints may be affected, the proximal interphalangeal or metacarpophalangeal joints and joints of the wrists, knees, ankles, and toes are most often affected. Rheumatoid nodules may be found on the hands and elbows. Sjogren’s syndrome may also be present. There is also potential for renal, cardiovascular, pulmonary, neurological, and ophthalmological involvement. RA is a disease of remissions and exacerbations and therefore should be monitored regularly.

- Sharon W. Stark