Transport of drugs to the tissues

Drugs are transported to the tissues, via the circulation, partly in solution and partly attached, or bound, to plasma proteins, particularly albumin. Only the unbound part of the drug is small enough to get out of v the circulation and into the tissues through the capillary walls and thus exert an effect. The binding value … Read more

Metabolism, activity and excretion

When a drug enters the bloodstream there is always a portion that is carried through the liver, which is the principal site of drug metabolism. Some drugs are pharmacologically active to start with, and are metabolized in the liver to form inactive substances before they are eliminated from the body (synthetic reactions). Some antibacterial drugs … Read more

How do drugs act?

We know how drugs pass into and out of the body, but the mode of action of many of them is still unclear. It seems that some drugs interact with special cell or tissue elements to produce their characteristic pharmacological effects. The receptors involved appear to be proteins, enzymes, lipoproteins and nucleic acids. The complex … Read more

Dosage and side-effects

The dose of a drug is tailored to the amount that will elicit a desired response and is tolerated without excessive side-effects. This dose varies from person to person and may depend on the weight and sex of the patient. Kidney and liver damage may delay excretion, and a reduction in dose may be needed … Read more

Main groups of drugs

For those people who do need drugs, however, there is a vast array to choose from. One group already mentioned is the chemotherapeutic agents that are used to treat bacterial or related infections without being unduly toxic to the patient. These include sulphonamides, which are useful in treating urinary tract infections, and antibiotics, which are … Read more

Vaccination

We can raise our immunity against some infectious diseases by introducing into our bodies controlled doses of the organisms or their products that cause disease. These doses, known as vaccines, are most often introduced into the body by inoculation. After this, you are said to have been immunized or vaccinated, depending on the type of … Read more

Blood transfusion

Blood transfusion is the process of passing blood from a donor into the circulatory system of the recipient. The reason for the procedure may be severe anaemia or the loss of a great amount of blood through injury. Blood is usually taken from an arm vein of a healthy donor by inserting a needle into … Read more

Operations

Surgery can be broadly classified into three groups according to the time scale involved. First, there is the routine operation, for which there is no desperate urgency, for example a hernia repair; second is the urgent operation, such as a cancer operation, involving a condition which needs to be dealt with quickly; third is the … Read more

Some common operations

There are literally hundreds of operations that can be performed on each part of the body, and new operations are constantly being devised. Even so, often the most frequently performed are some of the most traditional with a long history of proven success. Appendicectomy A significant number of people in the Western world develop appendicitis … Read more

Breathing difficulties

Respiration is one of the most important vital functions for human beings. During respiration, oxygen combines with the circulation to provide all the tissues in the body with the fuel necessary to produce energy. Breathing is so vital that someone who has stopped breathing needs first aid fast. Unless oxygenated blood reaches the brain within … Read more

Post-operative care

After surgery people usually wake up in some discomfort and often with tubes coming from seemingly everywhere. What are these tubes, and what do they do? One of the commonest is the ‘drip’ tube, carrying an intravenous infusion which may be a clear fluid containing sugar and body salts, or blood, and quite often drugs. … Read more

Bruising

A severe knock or heavy fall may cause bruising without a fracture. The bruise is a result of blood leaking from damaged blood vessels within soft tissue, underneath the skin. The eventual green and yellow discoloration that results is caused by the red haemoglobin pigment in the blood being broken down into its constituent pigments. … Read more

Cartilage injury of the knee

This is one of the commonest sporting injuries, often caused by someone attempting to kick a ball and kicking the ground instead. It may also occur in accidents in which the knee is twisted sideways while slightly flexed. The result is that one of the two ‘floating’ cartilages in the knee joint tear, usually at … Read more

Poisoning

A poison is any chemical substance that can cause death or injury if taken in large enough quantities. Every common drug or medicine, safe in the recommended dosage, is in essence a poison; so too are apparently innocuous household substances such as salt and even water (both are fatal in excess). Most poisoning incidents needing … Read more

Painkillers and prescribed drugs

An aspirin overdose may lead to stomach pain, vomiting, sweating and a raised temperature, perhaps with deafness and ringing in the ears. Delirium and hallucinations may also develop. Aspirin poisoning may be fatal: prompt medical attention is essential. Paracetamol in excess can be fatal because of its effects on the liver. The symptoms of nausea … Read more

Bleeding

A tourniquet should be applied to a wound only by trained medical personnel, because if applied too long this may cut off all the blood supply to the area and lead to gangrene. Also, do not give the casualty food or drink, which might delay surgery. Advise the casualty to keep still, because this encourages … Read more

Shock

Clinical shock should not be confused with a shock meaning someone’s emotional reaction to bad news or sudden excitement. Clinical shock is the body’s reaction to a significant loss in overall blood volume or the diversion of the blood supply away from the major organs, for example in the event of major burns, extreme bleeding … Read more

Unconsciousness

Unconsciousness may develop for a number of reasons, not all of which will be obvious to someone who has just arrived on the scene of an accident. Depending on the cause and the extent of the injury or illness, the level of unconsciousness may also vary – from slight loss of consciousness, as in a … Read more

Head injuries

When a knock to the head does not fracture the skull but nevertheless causes temporary brain damage as a result of the way the brain has been shaken about, this is called concussion. Bleeding into the space occupied by the brain, from a knock to the head, or a skull fracture or penetrating injury, is … Read more

Epilepsy

Epilepsy is a disorder characterized by changes in the electrical activity of the brain that cause a fit (seizure). The symptoms of an epileptic attack depend on the location, spread and intensity of these electric changes. A major (grand mal) epileptic fit usually starts with the sufferer losing consciousness and becoming completely rigid, which causes … Read more

Diabetic coma

Most diabetics take insulin and carefully time and measure their meals or snacks to control their blood sugar. A coma may result from either too much or too little sugar in the bloodstream. A coma resulting from too much sugar comes on gradually, and the diabetic can usually correct the problem or seek medical A … Read more

Hypothermia

Normal body temperature is about 37°C. If someone is exposed to very cold weather without adequate clothing, or is immersed in cold water for a period of time, the core body temperature may drop enough for hypothermia to develop (usually if the body temperature drops below about 35°C). One particular group in society is especially … Read more

Bites

Because of the prevalence of rabies in most parts of the world – the exceptions are the United Kingdom, New Zealand, Australia, Japan, Norway, Finland and Sweden – a skin-penetrating bite or scratch from a dog, cat or any domestic or wild animal is a serious matter warranting medical attention as soon as possible. First … Read more

Drowning

Someone who has been rescued from drowning needs to get rid of as much water as possible out of his or her lungs and needs artificial respiration to get air in. This should be started quickly. Complete recovery is possible, particularly if the accident occurred in seaw-ater, if first aid is given within five minutes. … Read more

Burns and blisters

Only small burns involving the superficial skin layer should be treated at home. First aid in every case of burns involves cooling the burn by holding the affected part under cold running water for at least ten minutes. This should be done as quickly as possible, because it helps to reduce further tissue damage. Whenever … Read more

Fainting

Fainting is temporary loss of consciousness, lasting from a few seconds to a minute or two. It is, in effect, the body’s mechanism for restoring a failing circulation (especially to the brain) by adopting a horizontal position. Causes include standing in the same position for too long, being in a hot stuffy room or missing … Read more

Heat exhaustion and hypothermia

Heat exhaustion is usually caused by losing too much water and salt from the body in hot weather, especially when the person affected has been taking part in vigorous physical activity. It may develop into heat- stroke if the person becomes so dehydrated that he or she stops sweating, with the result that body temperature … Read more

Coma

At the extreme end of the spectrum of unconsciousness, is coma. Whatever the cause, whether head injury, a stroke, a tumour or a drug overdose, the condition is characterized by the unresponsiveness of the patient to any of the usual methods employed to stimulate consciousness, while, at the same time, vital organs can be kept … Read more

Injuries to bones and joints

The bones and joints of the skeleton, and the muscles that move them, are more than strong enough to carry out the movements, and withstand the forces, we subject them to in normal daily life. Sprains, dislocations and fractures may result, however, if the bones and joints come into contact with excessive force, as can … Read more

Surgical examination

The diagnosis of certain illnesses frequently requires special (microscopic) examination of samples of the organ or tissue involved. These examinations are carried out in the laboratory by a pathologist, who has specialized in the study of disease processes. Two sub-specialists within pathology are involved: the cytologist , who concentrates on small numbers of individual cells … Read more

Endoscopy

When the problem area lies within a body cavity, special techniques may be needed for inspection and biopsy. Techniques for looking inside the digestive and respiratory passages are called endoscopy. In contrast with the first endoscopes, which were rigid metal tubes (still in use for special cases), recent v developments in fibre-optic cables have allowed … Read more

First aid

Accidents always happen, whether one has taken preventive measures or not. If an accident is serious it is obvious that the help of someone who has undergone a first aid course is of value. Such a person literally can save lives. When accidents are only minor, a knowledge of the principles of first aid is … Read more

Whether – and how – to move a casualty

If you are the only one at the scene of an accident, and there are many casualties, it may be that the most you can do is to check that everyone’s airway is clear and put those who are unconscious into the recovery position. First aid should be given at the site of an accident: … Read more

Accidents and their prevention

Many people die and are injured every year because of accidents that could have been prevented. Statistics in Western countries show that approximately an equal amount of people die in road accidents as in accidents at home; and out of all those who seek hospital treatment for injuries resulting from home accidents, half are children. … Read more

Emergency childbirth

Birth may be imminent if a woman starts having contractions at intervals of less than two minutes. The mother should be assisted to a bed protected by plastic or newspapers and covered with clean towels. Everything should be scrupulously clean (including your hands) and you should have to hand: blankets or towels, swabs or towels, … Read more

Radiological examination

Until the end of the last century doctors had no means of seeing beneath the surface of their patients’ bodies, other than by opening them up in an exploratory surgical operation. Diagnosis of internal disorders proceeded by inference from the patient’s history and the doctor’s method of external examination. A medical revolution began on 11 … Read more

Minor accidents

However careful you are, you may not always be able to prevent minor accidents such as splinters, blisters and insect bites from happening, especially in the case of young children. It is useful to know when and how to treat these yourself and when to seek medical advice. First aid kit A well-equipped first aid … Read more

X-rays

X-rays, like light rays, are a form of electromagnetic radiation. They are produced in a special vacuum tube after accelerated electrons (which are negatively-charged particles) have hit a tungsten target. Like light rays, X-rays are absorbed more by some substances than by others. Air and gases absorb least X-rays, whereas materials of a high density, … Read more

Foreign bodies in the eye

The smallest particle of dust or grit in the eye may cause great discomfort and pain; but often the natural watering of the eye that results is enough to wash the foreign body out, a process that can be encouraged by blinking several times. The eye should not be rubbed as this may cause the … Read more

CT scanning

The development of computerized tomography (CT scanning) constituted a dramatic advance in radiological techniques, especially in respect of producing an image of the brain. Although conventional X-rays are used, detection of any abnormality is by a crystal or gas system of far greater sensitivity; thus lower-power X-rays can be used, with an increase in safety. … Read more

Foreign bodies in the ear or nose

Children, in particular, seem to have a special talent for putting beads, peanuts, or whatever will fit, up their nose or their ears. In the case of a foreign body in the nose, breathing through the nose may be obstructed, and you should tell the child to breathe through the mouth. Do not try to … Read more

Radionuclide scanning

Slightly different from X-ray imaging is radionuclide scanning, which uses radioactive isotopes. These are unstable substances that emit gamma rays as they decay or change into a more stable state. The radioisotopes used in medicine decay quickly and give off only weak amounts of radiation, so that the risk of radiation is low. The isotope … Read more

Swallowed foreign bodies

If swallowed, sharp, jagged or pointed items have different physical effects to smooth, rounded ones. Sharp objects tend to get stuck somewhere in the throat, thus increasing the risk of perforation, bleed- ing and inflammation of the upper part of the gastrointestinal tract. The casualty usually feels a sudden stinging pain. Giving the casualty something … Read more

Hazards of X-rays

The pioneers of X-ray imaging soon realized that X-rays could damage the body. Indeed, high-power X-rays precisely focused are used to destroy malignant tissue. Because of the dangers of radioactivity of all kinds, strict safety precautions are observed by those working with irradiating equipment. The staff wear protective aprons and headgear, or retire behind a … Read more

Ultrasound

Ultrasound imaging uses no radiation and is believed to be free from risks. Very high-frequency sound waves, inaudible to the human ear, are transmitted into the body by a probe in contact with the skin. Echoes are reflected back to a receiver in the probe from the junctions between tissues of different types. For instance, … Read more

Nuclear scanning (NMR)

This recently-developed technique involves placing the person in a strong magnetic field that aligns or ‘polarizes’, the protons (positively-charged atomic particles) in his or her tissues. When the magnetic field is switched off the protons return to their normal positions; as they do so they emit tiny pulses of electromagnetic energy that can be detected … Read more

ECG and EEG

Like many sophisticated machines, the human body uses electricity to send messages from one part of the body to another in order to control and co-ordinate its many activities. The ‘wires’ along which these messages are passed are the nerve cells and their long connecting axones. The voltage of these stimuli is minute – as … Read more