Addiction

Addiction, physiological or psychological dependence on a substance, such as alcohol or heroin, and tendency to require increasing amounts of the substance. Another evidence of addiction is the occurrence of physical or psychological withdrawal symptoms if the substance is suddenly taken away. These symptoms may include severe pain, nausea, cramps, hallucinations and violent headaches. They also may be milder, such as irritability, insomnia, restlessness during the work day, and a desire for the substance so strong that the victim carries out his normal activities with great difficulty.

A person can become addicted to legally prescribed medication as well as to such illegal drugs as heroin or cocaine. Doctors limut the number of times prescriptions for certain medications can be refilled to protect their patients from addiction. However, tranquilizers, sedatives, and barbiturates are used illicitly by many people who may become dependent on them without realizing what is happening. Users of sleeping pills know that over a long time, they require higher closes to achieve sleep.

Adaption

Adaption, the adjustment of an organism, whether a plant, animal or man, to its environment. Adaption also refers to the ability of a part of the body to adjust. For example, the pupil of the eye automatically adapts itself to the amount of light striking it. It does this quickly, so that within a few second, a person going from a brightly lit area to semi-darkness can see satisfactorily. Humans adapt well, so that they can survive in cold or hot climates, in rainy or dry seasons, and under either sparsely populated or crowded conditions. They can also adapt to stress. The human organs and glandular system enable people to live and work under different circumstances and to relax when the stress conditions are removed. An entire species, human or animal, also may adapt slowly to radically changed circumstances through the process of evolution.

ADAM’S APPLE

Adam’s apple, a projection of the thyroid cartilage at the front of the throat, enclosing and protecting the two vocal cords. The adam’s apple actually consists of the left and right thrroid cartilages, meeting at a right angle and making the easily noticed projection that sometimes appears to ride up and down at the knot of a man’s necktie. It is more prominent in men than in women, because the angle in a man’s Adam’s apple is sharper and there is usually less fat in the neck. The picturesque name derives from the biblical firt man and the forbidden fruit he ate.

ACUTE

Acute, a medical term signifying the abrupt onset of an ailment. The opposite term is chronic, signifying the prolonged duration of a disorder, usually at a less intense level. The acute phase of any disease, though brief, may be severe, requiring immediate and possibly emergency attention and treatment.

Actinomycosis

Actinomycosis, a fungus infevtion involving the deep tissues of the skin and mucous membranes, usually of the face, neck, chest and abdomen. It usually affects cattle and hogs but may be transmitted to humans. People working on farms acquire the disease by handling or chewing straw used by infected cattle or by inhaling dust where infected animals are kept. The fungus inhabits the mucous membranes of the mouth, the areas around decayed teeth, and diseased tonsils. The disease begins as a swelling of the jaw, which characteristically has a lumpy feeling. Actinomycosis is sometimes called lumpy jaw. The skin turns dark red and abscesses develop. In humans, about half the cases of actinomycosis affect only the face and neck areas. Sometimes, it travels to the chest region and involves the lungs and air passages. It may also afflect the abdomen, causing a large internal abscess or one that drains pus outside the body. The most unusual forms of the disease affect the brain, heart valves, or the anus. Cattle and hogs infected with this disease must be destroyed.

In humans, actinomycosis was once almost alyaws fatal, but now can be treated successfully with penicillin or other antibiotics. Treatment also includes x-ray therapy and draining of the abscesses.

Actinomycin

Actinomycin, an antibiotic used to treat actinomycosis and other bacterial and fungal infections. One form of actinomycin is used in the management of certain types of cancer.

Actinomyces

Actinomyces, a fungus responsible for causing actinomycosis, a serious disease of pigs and cattle. A related organism causes this disease in humans but it is rare.

ACTH

Acth, the abbreviation for adrenocorticotropic hormone. Acth is produced by the anterior lobe of the pituitary gland. The bloodstream carries the hormone to the adrenal glands, situated just above the kidneys. There, acth stimulates the cortex (outer layer) of the adrenals to produce corticosterone and other hormones. If the pituitary does not produce sufficient acht, the adrenal core will become smaller and its output of hormones will decline.

Unlike some other hormones, acth has not yet been synthesized in the laboratory. It is isolated from the pituitary glands of cattle and pigs. Injected into humans. Acth is used to treat many diseases, including certain allergies and asthma. It has an anti-inflammation action which make it useful in the treatment of rheumatoid arthritis and rheumatic fever. Acth is being used experimentally in other illnesses.

Acrosclerosis

Acrosclerosis, a chronic progressive disease involving the hardening of the skin and blood vessels of the hands and sometimes of the ankles, the skin becomes waxy, smooth, leathery, and tight. The face loses its expression, becoming masklike. The individual becomes weak and loses weight. The blood supply to the fingers, toes, ears, and nose is diminished, especially during cold weather. Acrosclerosis is one of the collagen diseases, ailments of the connective tissues of the body. The cause is unknown and treatment is rarely satisfactory.

Acrodynia

Acrodynia, a disease of infants and young children, up to about three years of age. Its characteristics are swollen, bluishred hands and feet, muscular pains, and disordered digestion. A child suffering with acrodynia becomes generally sluggish, physically and mentally. Contact with mercury can cause acrodynia. Mercury and its compounds are found in some paints and in certain ointments. Children eating paint chips may suffer this form of mercury poisoning. As well as the better-know lead poisoning, acrodynia is not contagious but it may last for months. It can be treated sucecessfully. However, if treatment is delayed, permanent brain damage may occur. Generalized arthritis is also a possible complication. This ailment is also called pink disease because o of its characteristic red skin rash.

Acromegaly and giantism

Acromegaly and giantism are disturbances of the growth process affecting bone and muscle development to the point where an adult victim can attain a height of eight to nine feet and a weight of 500 pounds.

Causes
The two conditions are the result of over secretion of the growth-stimulating hormone somatotrophin by the anterior lobe of the pituitary gland. When the glandular disorder occurs in adulthood, it is often caused by a slowly developing tumor in the area.

Symptoms
When the pituitary oversecretion begins in childhood, the resulting condition is called giantism or gigantism. It is characterized by overgrowth of the long bones of the skeleton, and overdevelopment of the musculature and internal organs. Abnormal height and grotesquely large hands and feet are manifest before adulthood.
The onset of acromegaly occurs gradually after normal maturation of the body has taken place. The bones of the hands, feet and face becomes abnormally enlarged, and the soft tissues of the nose, ears and cheeks thicken.

Complications
In neither condition is basic intelligence affected. Giantism may be accomplished by other metabolic disturbances, and the sexual drive may either be lost entirely or abnormally intensified. Acromegaly may be complicated by disturbances in vision, by muscle pains, fatique, and weakness of sexual impulses. A significant number of adult victims develop diabetic symptoms and heart disorders.

Treatment
Hyperactivity of the pituitary gland in childhood may respond to certain types of hormone treatment. Since the onset of the condition in adulthood is usually triggered by the development of a tumor, treatment consists of radiation therapy or surgical removal, or a combination of both.

Acrocyanosis

Acrocyanosis, a disorder of the hand and, less commonly , the feet characterized by a luish discoloration (cyanosis), profuse sweating, and occasionally swelling. The condition is often associated with emotional stress and asthenic personality. Sometimes, disorders the endocrine glands may be involved.

protection from cold is usually sufficient treatment (unless there are under lying indocrine abnormalities, in which case they must be specifically treated). Occasaionally, tolazoline or nocotinyl alcohol may be given orally to dilate the blood vessels.

Acriflavine

Acriflavine, once used as an antiseptic and in the treatment of gonorrhea. It has been superseded by a broad range of antibiotics. Acriflavine is an orange yellowish crystalline substance, derived from coal tar.

Acquired Hemolytic anemia

When there is increased destruction of the red blood cells, it is called hemolytic anemia. When this condition is not inherited, but is caused by some other factor, it is called acquired hemolytic anemia. The causes include poisons, hypersensitivity to certain drugs, and other diseases.

ACOUSTIC NERVE

Acoustic nerve, the eighth cranial nerve, related to hearing and to the sense of balances. Symptoms of some heurological ailments are associated with this nerve, among them loss of hearing, ringing in the ears, dizziness, and disequilibrium.

ACONITE

Aconite, a brownish-orange drug derived from the root of monkshood, once used medically to slow the heart action, reduce temperature, and ameliorate pain. If taken inadvertently, it acts as a poison, causing a tingling sensation in the mouth, a burning pain in the stomach, weakened pulse, slower breathing rate, and a cold wet skin. First-aid treatment for aconite poisoning is to make the person vomit by giving him a tablespoon of mustard in a glass, of water. He should be put in bed, kept warm, and massaged. He should be encouraged to drink plenty of hot coffee. A doctor should be called immediately.

ACNE

Acne is a condition in which inflammation and infection of the sebaceous (oil) glands and ducts results in pimples, pustules and cysts on the skin surface.

Causes
The underlying cause of acne, which ot one degree or another affects approximately 80 percent of all teenagers, is the glandular revolution that takes place with the onset of puberty. At this time, the pituitary governor of glandular activity alters the proportion of the male sex hormone androgen and the female sex hormone estrogen so that sexual maturation can be accomplished. Between puberty and maturity, both boys and girls have consistently high level of androgen. This temporary increase in the androgen level stimulates the production of the sebaceous glands which ordinarily discharge the fluid secretion sebum through the pores for lubricating the skin. Over production of sebum causes it to turn into a paste which backs up and plugs up the ducts extending from the glands in the underlying derma through the layers of the epidermis.

Symptoms
Since the skin pores are tiny and often clogged by dirt or cosmetics, the fatty sebum accumulates under the skin and forms a pimple, a whitehead or a black head. These manifestations of acne are most likely to appear on the parts of the body where the glands are most numerous, particularly around the nose, the cheeks and the shoulders. The dark color of the characteristic blackheads is not the result of dirt, but of the discoloring effect of air on the fatty substance in the clogged pore. Bacteria on the skin surface may eat their way through the pasty accumulation into the ducts and the derma itself causing not only pimples in which pus gathers but, in severe cases, cysts that damage underlying tissue.

Treatment
In a majority of cases, acne is a transitory condition that gradually diminishes with the stabilization of hormones in adulthood. In its mild form, it can usually be controlled by a rigorous routine of cleanliness and the avoidance of rich desserts, fried foods and cola beverages. Creams and cosmetics that further clog the pores should be eliminated in favor of medicated chop and hot water. Sun lamp treatment and medications containing vitamin A may be used under a doctor’s supervision. Pimples should not be “squeezed” since this method of eliminating pus can lead to more serious infection.

Severe cases of acne that leave the skin pitted and scarred require professional attention. The technique of dermabrasion, in which high-speed rotary wire brushes remove the outer layer of damaged skin, produces satisfactory result in many instances. It should not be undertaken unless a qualified dermatological specialist has been consulted.

Adolescents are especially sensitive about their pimples. A youngster whose emotional well-being is seriously threatened by skin problems may require a few senssions with a sympathetic psychotherapist for the necessary reassurance that acne in most cases is only a temporary condition.

ACIDOSIS

Acidosis, the tendency toward overacidity that characterizes certain diseases. The blood is normally slightly alkaline, and is so maintained by blood chemicals and by the action of the lungs and kidneys in removing waste products. Uncorrected acidosis causes disorientation, come, and death.

When extensice loss of fluid results from vomiting or diarrhea, so much alkaline substance may be lost that acidoses develops. The most readily recognized symptoms of acidosis are headache, weakness, rapid breathing, and a fruity odor on the breath. Laboratory tests enable a doctor to make a precise diagnosis of the acid-alkaline balance. The treatment for acidosis consists of replacing the lost fluid, by mouth if possible and by injection into the tissues or veins if necessary, and then determining the basic cause of the condition and implementing appropriate remedial measures.

ACID

Acid, a large and diverse group of chemicals, both organic and inorganic, having the common properties of a sour taste, solubility in water, and the release of hydrogen ions in solution. Mineral, or inorganic acids, include hydrochloric, nitric, and sulfuric. The organic group includes citric, lactic, and uric acids. A simple test for an acid is to put a small quantity on litmus paper, which acid turns from blue to red.

Many acids play important roles in the chemical processes that are a normal and vital part of the functions of body cells and tissues. Amino acids are the fundamental units of proteins. Ascorbic acid (vitamin C), found in citrus fruits, tomatoes, and many vegetables, is an essential part of a balanced diet. A disturbance of the acid content of the body can lead to serious disease. For example, a high level of uric acid produce gout.

Some inorganic acids corrode human tissues. Taken internally, they seriously damage the mouth, throat, esophagus, and stomach. If they enter the larynx, they will interfere with breathing. Antidotes for acid poisoning include large doses of milk of magnesia, milk, soapy water, or egg whites. Hot-water sponges and moist compresses applied to the throat will aid breathing and hot moist applications on the abdominal area can relieve stomach pains. If the skin is burned by sulfuric or nitric acid, theburned area should be washed immediately with diluted banking soda solution (4 tablespoons of baking soda in a quart of water), then bathed continuously with the soda solution. Basically, first-aid treatment for acid burns involves the neutralization of the affected area by an alkali, the chemical reverse of an acid. If an acid is swallowed, vomiting should not be induced, since this will burn the esophangus and throat a second time.

Achondrioplasia

Achondroplasia, a disturbance of the growth process that produces a type of dwarfism. The condition is congenital, beginning with the growth of the embryo. The torso is usually normal, but the head is disproportionately large and the arms and legs are smaller than normal and curved. Most infants with this ailment are stillborn. In those who survive, mental and sexual development and life expectancy are not affected. Their muscles generally are stronger than those of normal individuals. A dwarf is different from a midget, whose body proportions are normal although the entire body is unusually small. Achondroplasia is an abnormal development of the embryo that affects the growth of the bones. Other growth disturbances are caused by nutritional or hormonal deficiencies.

Achlorhydria

Achlorhydria, the absence of hydrochloric acid in the gastrointestinal juices. Hydrochloric acid aids digestion by activating the enzyme pepsin in the stomach, and by breaking down foods into components that can be absorbed by the blood. Complete achlorhydria is rare, occurring only in about ten percent of patients with stomach disorders. Persons with a less than normal secretion of hydrochloric acid may have few digestive symptoms, or none at all. However, achlorhydria is sometimes a symptom of serious disease, such as cancer or destruction of the stomach lining by inflammation. Pernicious anemia is associated with achlorhydria.

Achilles tendon

Achilles tendon, the strong prompinent tendon at the back of the heel, connecting the calf muscles to the heel bone. Tapping the Achilles tendon normally produces an ankle jerk, or reflex. If this reflex is missing or if it is exaggerated, disease or injury of the nerves of the leg muscles or the spinal cord may exist. The name derives from homer’s Iliad, in which Achilles was vulnerable only in his heel, the one part of his body which remained dry when his mother dipped him in the River Sytx in the belief that this would render him impervious to injury.

ACHE

Ache, a dull, constant, sometimes throbbing pain. A backache often is described as a dull pain, and a toothache or headache as a throbbing pain. A dull aching pain of the bones occurs in influenza, and muscular rheumatism involves aching of the muscles.

An ache, like all other types of pain, is useful and even life-saving. It is a warning signal, indicating that something is wrong. Without the ache of a strained back, a decayed tooth, a bruised muscle, or an inflamed joint, a person would not know that something was wrong until much more damage had been done.

How quickly a person feels pain and how much he or she can tolerate is both physiological and psychological. The pain threshold is a measure of the stimulus needed in order to register pain. The ability to sustain pain without complaining, crying, or inability to work varies greatly from person to person. An inpends on many factors, including his previous experience with aches, his childhood training with regard to appropriate responses to aches, his general state of health, and the presence or absence of fatique. If someone is busy with work or play, an ache may hardly be noticed.

Aching, possibly caused by the buildup of toxic substances, often follows strenuous exercise. The achiness gradually disappears with rest. The same aching feeling accompanies many illnesses, including a severe cold and malfunctioning kidneys. In such illnesses, the accumulation of wastes in the system produce the symptom of generalized aching until the illness disappears or is successfully treated.

Accident-Prone

Accident-Prone, Term used to describe people who have many more accidents than is average for people of comparable age and occupation. Often, their accidents recur at the same time of the month, week, or even hour. The accidents are more frequent in summer than at other times of the year and are often associated with emotional stress. Frequently, people who seem to be accident-prone have fewer accidents after attaining maturity; but some appear to remain accident-prone throughout life.

Absorption

Absorption, the taking in of fluids or other substances by the skin, mucous membranes, or organs of the body. The absorbed material may be gaseous or fluid. Thus, the skin and mucous membrances, such as those lining the mouth and nose, absorb drugs applied on their surfaces. The digestibe system absorbs solid and liquid foods. The large intestine absorbs fluid and the small intestine takes in carbohydrates, tats, and proteins for further absorption by the blodd and distribution throughout the body.

Abscess

Abscess, a localized pocket of pus in a cavity formed by tissues that have broken doen as the result fo infection or injury. The inflamed area forming the cavity is ed, painful, and swolleh, an abscess is caused when bacteria enter a samlll wound, such as that caused by spolinter. White blodd cells collect at the infected area to seal off the infection, to absorb the bacteria, and to liquwfy then. The formation of thick yellowish pus results from thes sctivity. The accumulating pus and the swelling of the inflamed tissues press against the nerves, creating paoin,. The redness is caused by a concentration of blodd in the area. An abscess “comes to a head” as the wall of surrounding tissure becomes thin. When the abscess ruptures and the pus escapes, the pain and swelling subside.

A large, extremely painfull abscess, such as a boil, should be prefessianally treated. A physician will open the abscess ffely wit a sterilezed instrument and remove the pus with9out unnecessarily irritiating the tissue. Wven a sall skin absecess should not be squeexed, sicne this is likely to spread the infection.

An abscess may form within the body as wll as on the skin surface. They can occur, for example, in the chest, abdominal cavity, joints, glands or at the rott of a tooth. Sometimes , a doctor may have to cut into and drain an abscess to prevent its sac of infection from spreading into surrounding tissues or escaping into the loddstream. If an abdominal absess rupturesk, the resulting general infection (called peritonitis) requires immediate emergency care. Awieespred bdy infection. Ro sepsis, results from the emptying of an abscess into the bloodstream.

Abrasion

Abrasion, a superficial injury to the skin or mucous membranes. A skinned knee or elbow are examples. Most abrasions come under the category of minor injuries, occurring in commonplace everyday situations. Nevertheless, abrasions should not be taken lightly, as they are higly susceptible to infection. Cleansing with soap and water is usually sufficient protection. If much bleeding or oozing of fluid takes place, the abraded area should be covered with sterile gauze after it is cleaned. In dentistry, abrasion refers to the wearing away of tooth surface caused by chewing.

Achard-Thiers Syndrome

Achard-Thiers Syndrome, a disorder in diabetic women characterized by development of excessive hair on the face and chin. The condition is also called virilism. Women with this syndrome often have changes of the voice and menstrual difficulties. Their breasts get smaller, they gain weigh, and the clitoris enlarges.

Achard-Thiers syndrome may be associated with enlargement of the adrenal glands and with excess androgenic (male) hormones in the bloodstream. In drastic cases, surgical removal of the adrenal glands may be required; the woman must then, however, take for life the hormones normally manufactured by the adrenal cortex, as these are essential to life.

Acetylsalicylic acid

Acetylsalicylic acid, the scientific term for aspirin. Aspirin has been used since 1893 to relieve pain and reduce fever. Aspirin does not cure anya illness, but it may prevent the serious brain damage that an exceptionally high fever can cause. Aspirin does not interfere with the body’s ability to fight a disease. Large amounts of aspirin are fatal to infants, and adult doses can induce intestinal bleeding in children. Exactly how aspirin works in the body still unknown. For persons who suffer digestive symptoms when taking aspirin, equally effective substitutes are available.

Accommodation

Accommodation, the ability of the lens of the eye to adjust itself for viewing near or distant objects. For distance vision, the pupils of the eye bicome large, the lens flattens, and they direct away from each other. The prcess is reversed for close vision. After obout the age of 40, the lenses begin to harden and the ability of the eye to accommodate diminished. Special glasses may be required for close vision. Glasses may be fitted with bifocals (two lenses in one) or trifocals (three lenses in one) to help a middle-aged or older person accommodate his vision.