Реферат: Bone Diseases Essay Research Paper Bone diseases

Bone Diseases Essay, Research Paper

Bone diseases most directly

influence the ability to walk or to move any part of

the body–hands, limbs, neck, and spine. They are

related to joint disorders–ARTHRITIS,

COLLAGEN DISEASE, DISLOCATION of

joints, and RHEUMATISM. The medical

specialty pertaining to bone disorders is

ORTHOPEDICS. Fractures are the most

common bone disorders. They can occur as the

result of an accident or be secondary to metabolic

diseases. Fractures are life-threatening to aged

people having the metabolic bone disease

OSTEOPOROSIS, in which bones become

porous and brittle. A person, mostly women,

having osteoporosis may break a hip during a fall

and possibly die from complications. Birth Defects

Congenital bone diseases constitute a wide

spectrum, ranging from the unimportant–for

instance, mild bow legs–to severe lesions, such as

spina bifida, in which the lower end of the spine

fails to develop properly and the baby is born with

paralysis and misshapen vertebrae. Congenital

diseases may have hormonal bases: for example,

fibrous DYSPLASIA, in which fibrous tissue

replaces that of some bones, often results in bone

deformity; in addition, some girls with this disease

physically mature so early that they are capable of

pregnancy and childbirth at the age of seven.

Congenital defects also may have genetic bases,

as in families who have extra fingers or toes or in

the disease osteogenesis imperfecta, in which

children have such brittle bones that many are

fractured. Disorders of growth and development

include several kinds of dwarfism and gigantism.

Bones or limbs may develop deformity as the

result of known causes, such as the infection

poliomyelitis, or unknown or variable causes, such

as curvature of the spine (SCOLIOSIS) or

CLUBFOOT. Infections Infections of bone, called

osteomyelitis, are usually caused by pus-producing

bacteria, especially Staphylococcus and

Streptococcus. Before the development of

antibiotics, children frequently contracted this

disease. Today bone infections are introduced

primarily through fractures and during surgical

operations. People infected with syphilis,

tuberculosis, leprosy, or yaws are susceptible to

bone damage. Metabolic Disorders Metabolic

abnormalities often involve defects in the storage

of minerals, particularly calcium and phosphate

ions, in the skeleton. Diseases of the kidney can

cause a metabolic imbalance of phosphate and

calcium so that weakening of the bone occurs.

Other metabolic bone diseases are osteoporosis,

gout, OSTEOARTHRITIS, and PAGET’S

DISEASE. Nutritional Disorders Nutritional

deficiencies that result in bone damage include

RICKETS in children and osteomalacia in adults,

caused by a lack of vitamin D. In children, calcium

and phosphate are poorly distributed on bones

during development, resulting especially in

deformity of the legs and arms. In adults, bones of

the spine, pelvis, and legs become demineralized

and the bones weaken. SCURVY–caused by a

lack of vitamin C–also affects bone tissues. A

study in the late 1980s indicated that the mineral

boron is nutritionally important, as well.

Apparently, it reduces loss of the bone minerals

calcium, phosphate, and magnesium and helps to

maintain adequate blood levels of estrogen and

testosterone, which play a role in bone health.

Toxic Diseases The importance of toxic conditions

of bones to public health became evident because

of such tragedies as thalidomide-induced birth

defects and radium poisoning. The drug

THALIDOMIDE was given to pregnant women in

England and Germany for use as a sleeping pill

and to treat nausea. It caused an epidemic in

which thousands of babies were born with

deformed or missing limbs. Women employed

during the 1920s as painters of luminescent clock

dials were unwittingly exposed to radium from the

paint as they licked their brushes. Many died,

either from anemia or from bone cancer, alerting

doctors to the dangers of radioactivity and

subsequent radiation injury. Other types of toxic

bone disease include fluoride and lead poisoning

and overexposure to X rays. Tumors Bone

tumors, although not common, are not rare; benign

tumors are more common than malignant ones

(sarcomas). Metastatic tumors–those which arise

primarily in another tissue and spread by the blood

to the skeleton, where they usually grow in many

places at once–are very common in bones,

although tumors originating in bones are not. The

skeleton is second only to the lung as a site for

metastases of CANCER. More fatalities and

greater pain are associated with metastases of

bone than with any other type of cancer.

Treatments Treatments for bone diseases vary as

widely as the causes. Physical disorders often

require mechanical therapy–for instance, plaster

casts for fractures and braces and splints for

support. Drugs are used for metabolic problems,

and antibiotics for infections. Corrective surgery

benefits many people having such diseases as

scoliosis. Therapy can involve

REHABILITATION MEDICINE, by which

victims of injury, deformity, and amputation can

learn how to function as normally as possible.

Jonathan Cohen, M.D. Bibliography: Avoli, L. V.,

and Krane, S. M., eds., Metabolic Bone Disease,

2d ed. (1987); Berry, C. L., ed., Bone and Joint

Disease (1982); Greenfield, G. B., Radiology of

Bone Diseases, 4th ed. (1986); Maroteaux,

Pierre, Bone Diseases of Children, trans. by H.

Kaufmann (1979); Uhthoff, H. K., ed., Current

Concepts of Bone Fragility (1986).