HUMAN DISEASES (Part 4 of 7)

Other Growth Changes

Some alterations in tissue growth are not cancerous. Atrophy, for example, is a lessening in size. It is the shrinking of cells or tissues for various reasons. Starvation, for instance, causes atrophy of the adipose, or fatty, tissues. Disuse of a body part may also lead to atrophy. When a fractured arm is placed in a cast, the arm's muscles decrease in size from lack of use.

Compensatory hypertrophy, in medicine, condition that results when one of a paired set of organs, such as a kidney or a lung, is removed and the remaining organ increases in size.

Hypertrophy is an increase in size of individual cells or fibres It results in an enlargement of the body part containing these muscles or fibres Hypertrophy of the heart has already been discussed. Compensatory hypertrophy is best seen in paired organs. When a diseased kidney is removed from the body, the remaining kidney grows larger because it now must do the work of two kidneys.

RESPIRATORY SYSTEM DISEASES

The lungs are spongy organs through which vital oxygen enters the body and needless carbon dioxide exits. Oxygen and carbon dioxide are exchanged in and out of capillaries in the many tiny air sac's, or alveoli, in the lungs. Although the breathing passages have defences against invading germs and irritants, the lungs can be stricken by a number of serious diseases.

Chronic bronchitis is a disease that results from infection of the air passages by bacteria or viruses. It is marked by cough and increased production of sputum, an accumulation of saliva, mucus, and pus. Air pollution and cigarette smoking both can aggravate the malady.

Tuberculosis, bacterial disease most frequently affecting lungs; associated with fever and loss of weight; commonly transmitted through the air (droplet infection) but also from drinking unpasteurized milk obtained from infected cows.

Tuberculosis is a complicated disease that most often strikes the lungs. The bacilli that cause it grow from place to place in the lung, leaving cavities in the unoccupied sites.

Symptoms of tuberculosis may include weight loss, fever, chest pain, cough, and sputum. After the active infection is arrested, a period follows when the disease may break out again. Tuberculosis is treated with isoniazid and other drugs.

Pneumonia, or acute infection of the lungs, may occur suddenly in a seemingly healthy person. It is usually marked by fever, cough, and chest pain. Lung X rays show patches of inflammation. Though once quite fatal, the threat of pneumonia has been reduced as a result of antibiotic treatment.

Pleurisy, an inflammation of the pleura; caused by infection, injury, or other chest diseases.

Pleura, the serous membrane that covers the lungs, lines the walls of the thorax, and is reflected upon the diaphragm.

Pleurisy is severe chest pain accompanying each deep breath in a person with an inflamed pleura, the twin membrane around each lung and lining the chest cavity. Pleurisy can attend pneumonia or result from direct infection of the pleura.

Emphysema is a serious lung disease that follows destruction of the elastic and connective tissue fibres supporting the lung. It is linked with advancing age. Certain forms of emphysema are inherited. Heavy cigarette smoking and long exposure to air pollutants seem to encourage the disease. A person with emphysema, lacking sufficient lung elasticity, wheezes and has trouble breathing. Furthermore, air movement in the lungs is reduced and the patient is easily fatigued because he fails to get enough oxygen or get rid of enough carbon dioxide.

Asthma is the wheezing or whistling sound that accompanies each breath when the air passages contain too much mucus. It may follow lung infection or result from an allergic reaction that causes muscle spasms and swelling in the air passages.

Acute pulmonary oedema results when fluid quickly accumulates in the lungs and fills the alveoli. The fluid build-up is caused by heart trouble that, in turn, produces back pressure in the pulmonary veins and the left atrium of the heart to which they carry oxygen-rich blood from the lungs. A person suffering acute pulmonary oedema is suddenly breathless and turns blue because of oxygen-poor blood. The condition is treated with oxygen, digitalis to strengthen heart action, and diuretics to speed fluid removal by the kidneys.

Pneumothorax, presence of air in the usually air-free pleural space between the lungs and chest walls.

Pneumothorax occurs when air gets into the chest between the pleural lining. The lung then collapses. A collapsed lung may occur when the chest is pierced in some way or when an abnormal bleb, or blister, on the lung surface bursts.

Lung abscess is an accumulation of a mass of pus inside the lung. A lung abscess can increase the seriousness of pneumonia and other lung infections, especially in chronically ill persons.

Hyaline membrane disease is a disorder of some prematurely born infants. The alveoli of afflicted babies are lined with a protein material, limiting the amount of oxygen their blood can receive. The disease is often fatal.

Histoplasmosis is a fungus infection of the lungs. Fungi lodge in the lungs and multiply until body defences wall them off. In some areas it was once called "summer flu" because its symptoms resemble those of influenza. Serious cases involve weight loss and a long convalescent period.

Silicosis, disease of the lungs, caused by inhaling tiny sharp particles of stone dust; fibrous tissue forming around particles causes cough, shortness of breath, and weakness.

Pneumoconiosis means "dust disease." It can strike miners and industrial workers who inhale damaging amounts of dust. One of the most serious is silicosis, which results from inhaling quartz dust. Another, anthracosilicosis, arises from inhalation of coal and quartz dust.

SKIN DISEASES

Because of its location the skin is perhaps more susceptible to disease than any other body organ. Even so, it is marvellously designed for its particular jobs of protecting the inner body against harm from the outside surroundings, receiving clues about what is happening externally, and keeping the body cool by means of the evaporation of sweat produced by its sweat glands. The skin is thick, leathery, and tough enough to prevent mechanical injury to the body. It is also covered with a barrier of dead cells that block harmful chemicals from getting into the body.

The skin is richly supplied with nerves that enable the perception of pain, touch, heat, and cold. Blood vessels in the skin can either contract or expand in response to nerve signals.

A person's emotional state can often be observed through changes in skin colour Shame or rage reddens the skin; fear blanches it. The skin may react to disease in a great many ways including formation of blisters, pimples, ulcers, tumours, and by haemorrhage

Blackheads are an accumulation of a horny material in special follicles of the face. The characteristic black dots in blackheads are not dirt but melanin, the pigment responsible for skin colour

Acne is an outcropping of blackheads or pimples on the face of an adolescent. It is brought on by hormonal changes that accompany sexual maturity. It is not caused by food, emotions, or uncleanliness. Antibiotics are available for the treatment of severe acne, but most cases respond well to local application of a peeling agent.

Warts are horny growths caused by virus infection. They are spread from person to person. Although warts cannot be prevented, they can be burned away with an electric needle or a caustic chemical such as nitric acid.

Hives, or urticaria, are itchy, whitish elevations of the skin. They appear and disappear rapidly. Hives are often the result of an allergic reaction to certain foods or medicines.

Persons who suffer severe cases of hives can receive a series of desensitizing shots. Antihistamine drugs sometimes can relieve a bout of hives.

Birthmark, a skin blemish, result of an overgrowth of blood vessels.

Birthmarks are the result of an overgrowth of blood vessels. They usually show up after birth as port-wine-coloured stains or strawberry-coloured marks. The strawberry marks may eventually disappear but at times can be destroyed quickly by the application of extreme cold. Port-wine stains and other long-lasting skin blemishes can be concealed by special cosmetics.

Eczema, or dermatitis, is a superficial inflammation of the skin. It can be an allergic reaction to poison ivy, dyes, or drugs. It can be provoked by such irritants as acids, solvents, or excessive use of soap or detergents. Sunburn can also cause eczema. Some forms of it, such as infantile eczema and seborrhoeic dermatitis, stem from an unknown cause. Nonetheless, nearly all types of eczema can be relieved by the application of corticosteroid creams.

Athlete's foot is a fungus infection of the skin between the toes. The infected area is scaly, moist, and itchy. It usually has a disagreeable smell. Athlete's foot can be relieved when anti fungal drugs are applied to the infected skin each day. Fungus infections that cause a loss of hair or nails must be treated with griseofulvin, an antibiotic.

Bacterial infections such as the psoriasis caused by "staphylococci" germs are rare because of modern standards of hygiene and sanitation. However, the bacterial disease gonorrhoea, which passes between the skin of the sex organs, has risen to epidemic proportions among teenagers in recent years. This and other bacterial infections of the skin are remedied with antibiotics.

NERVOUS SYSTEM DISEASES

The nervous system is the quick communication system of the body. Information from the outside world enters the body through the sense organs and is sent to the spinal cord for instant response or is relayed to the brain for further processing.

Nerves and the membranes that protect portions of the nervous system are susceptible to breakdown or infection. Sometimes, the organisms that cause such diseases as mumps or infectious hepatitis can infect the nervous system, too.

Nervous System Infections

Meningitis is an inflammation of the meninges, or membranes around the brain and spinal cord. It can occur through viruses, bacteria, fungi, or yeasts that get into the nervous system. Meningitis is a serious disease and can be fatal.

Shingles, inflammation of certain nerve tissue caused by virus herpes zoster.

Shingles, or herpes zoster, is a virus-caused inflammation of certain nerve tissue. Painful skin bumps occur over the line of the inflamed nerve or its branches. Shingles and chicken pox are both caused by the same virus.