Copyright © 2007 Dorling Kindersley
Medicine is the practice of dealing with diseases and injuries to the body. One of its most important aspects is PREVENTATIVE MEDICINE, which recommends measures to stop diseases from developing. Two aspects of how doctors deal with existing disease are DIAGNOSIS – working out exactly what is wrong with an ill person – and TREATMENT.
Penicillin is an important antibiotic (natural bacteria-fighting substance). Since the discovery of penicillin in the 1920s, many antibiotics have been developed to target disease-causing bacteria. They have hugely increased life expectancy across the world.
An important aspect of medicine is education about the causes and avoidance of disease. Relevant topics for education vary in different parts of the world. In developed countries, key areas for education include the importance of not smoking, eating a healthy diet, and taking regular exercise.
Many measures can be taken to reduce the risk of illness, from adopting a healthy lifestyle to having the appropriate vaccinations against diseases such as polio, mumps, and measles. Doctors provide advice on medical tests to have at different ages. These may include eye tests, blood pressure checks, and procedures such as mammograms (breast X-rays), which aim to detect disease at an early, treatable stage. People at special risk of a disease (one that runs in the family, for example) may be offered special tests.
Polio is an infectious disease that has been eradicated from many countries through vaccination programmes. Some vaccines are offered routinely in childhood. Others may be advised when travelling to parts of the world where there is a special risk of a disease. Most are given by injection, although one form of polio vaccine is given by drops (onto the tongue), for swallowing.
To make a diagnosis, the doctor first talks to the patient about his or her symptoms and other relevant matters, such as the patient’s family, occupation, and lifestyle. This may be followed by a physical examination. The information gained will guide the doctor on what tests may be needed to confirm the diagnosis. These may include laboratory tests and imaging.
Blood tests are the most common laboratory tests and can provide much information about the functioning of the body. They can be arranged for various reasons, for example, to assess the function of the liver. Urine may also be tested, often to look for infection.
X-rays are the most commonly used imaging method. They can be used to examine bones, often to look for and clarify the extent of a fracture, such as this one of an upper arm bone. They are also often used to examine the chest, in particular, to look for any infection in the lungs and to assess the heart.
Doctors and their colleagues select from a number of different types of treatment when attempting to cure illness. These include drugs, physiotherapy, surgery, and speech therapy. Some therapies are concerned mainly with treating mental rather than physical health. These include counselling, which encourages individuals to talk through their anxieties and concerns.
Modern drug treatment aims to relieve symptoms or to cure or control disease by correcting disturbances in body chemistry. Substances used as drugs range from relatively simple molecules, such as aspirin, to huge, complex protein molecules.
Physiotherapy uses forms of physical energy, such as heat, exercise, electricity, or sound energy, to promote healing or to improve strength and flexibility. Here, ultrasound (high frequency sound waves) is being used to speed up healing after a knee injury. Other types of physiotherapy include massage, hydrotherapy, heat treatment, and various exercise regimens.