The natural environment can be hazardous, and, with increased travel and leisure, people today are more likely than ever to be exposed to potentially life-threatening conditions. Although the human body can adjust to some extent, it cannot cope with poisons or prolonged exposure to extremes of environment.
The first article in this section covers deliberate or accidental drug overdose and poisoning. In adults, many drug overdoses are intentional, whereas in children poisoning usually occurs as a result of the accidental ingestion of common household substances.
Disorders caused by extremes of temperature are described next. Heat exhaustion and heatstroke are almost inevitable consequences of spending too long in very high temperatures. In hypothermia, the body’s temperature falls to life-threatening levels as a result of excessive cold. If the body tissues are cold enough, they may freeze. This condition is known as frostbite and is particularly likely to affect extremities that are inadequately protected.
Illness can also result from exposure to extremes of elevation, and this is described next. Altitude sickness not only affects mountaineers but may also occur in people travelling to cities at high altitudes. Decompression sickness, more commonly known as “the bends”, usually results from a rapid decrease in pressure when a person surfaces too rapidly after a deep dive underwater.
The next articles in this section deal with environmental injuries that affect oxygen supply to the brain. Drowning and near-drowning are both caused by water preventing normal breathing. The more general term of asphyxiation is used to describe oxygen deprivation that results from a wider variety of causes, such as an object in the throat or carbon monoxide poisoning.
The final articles covered here deal with poisoning from snake and spider bites and scorpion stings. Such injuries are painful but rarely serious. Most of these environmental disorders can be easily prevented by simple measures.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.