Poisoning

Poisoning is the harmful effect that occurs when a toxic substance is swallowed, is inhaled, or comes in contact with the skin, eyes, or mucous membranes, such as those of the mouth or nose.
Poisoning is the most common cause of nonfatal accidents in the home. More than 2 million people suffer some type of poisoning each year.
Drugs-prescription, nonprescription, and illegal-are the most common source of serious poisonings and poisoning-related deaths. Other common poisons include gases, household products, agricultural products, plants, industrial chemicals, vitamins, and foods (particularly certain species of mushrooms and fish). However, almost any substance ingested in sufficiently large quantities can be toxic.
Young children are particularly vulnerable to accidental poisoning in the home, as are older people, often from confusion about their drugs. Also vulnerable to accidental poisoning are hospitalized people (from drug errors) and industrial workers (from exposure to toxic chemicals). Poisoning may also be a deliberate attempt to commit murder or suicide. Most adults attempting suicide by poisoning take more than one drug and also consume alcohol.
The damage caused by poisoning depends on the poison, the amount taken, and the age and underlying health of the person who takes it. Some poisons are not very potent and cause problems only with prolonged exposure or repeated ingestion of large amounts. Other poisons are so potent that just a drop on the skin can cause severe damage.
Some poisons produce symptoms within seconds, whereas others produce symptoms only after hours or even days. Some poisons produce few obvious symptoms until they have damaged vital organs-such as the kidneys or liver-sometimes permanently.

First Aid & Prevention
Anyone exposed to a toxic gas should be removed from the source quickly, preferably out into fresh air. In chemical spills, all contaminated clothing should be removed immediately. The skin should be thoroughly washed with soap and water. If the eyes have been exposed, they should be thoroughly flushed with water. Rescuers must be careful to avoid contaminating themselves.
If the person appears very sick, emergency medical assistance should be called. Bystanders should perform cardiopulmonary resuscitation (CPR) if needed. If the person does not appear very sick, family members or coworkers can contact the nearest poison center for advice. If the caller knows the identity of the poison and the amount ingested, treatment can often be managed at home.
Containers of the poisons or the drugs taken should be saved and given to the family doctor. If the poisoning could be serious, the person must be treated as soon as possible. The poison center may recommend giving activated charcoal at home and, occasionally, may recommend giving syrup of ipecac to induce vomiting, particularly if the person must travel far to reach the hospital. To prevent accidental poisoning, drugs should be kept in their original child-resistant containers. Expired drugs should be flushed down the toilet. In addition, drugs and poisonous substances should be kept out of sight and beyond a child's reach, preferably in a locked cabinet. All labels should be read before taking or giving any drugs.

Diagnosis & Treatment
Identifying the poison is crucial to successful treatment. Labels on bottles and other information from the person, family members, or coworkers best enables the family doctor or the poison center to identify poisons. Urine and blood tests may help in identification as well. Sometimes, blood tests can reveal how serious the poisoning is.
Many people who have been poisoned must be hospitalized. The principles for the treatment of all poisoning are the same: prevent additional absorption; increase elimination of the poison; give specific antidotes (substances that eliminate, inactivate, or counteract the effects of the poison), if available; and prevent reexposure. With prompt medical care, most people recover fully. The usual goal of hospital treatment is to keep the person alive until the poison disappears or is inactivated. Eventually, most poisons are inactivated by the liver or are passed into the urine.
Stomach emptying may be attempted if an unusually dangerous poison is involved or if the person appears very sick. In this procedure, a tube is inserted through the mouth or nose into the stomach. Water is poured into the stomach through the tube and is then drained out (gastric lavage). This procedure is repeated several times.
For many swallowed poisons, hospital emergency departments usually give activated charcoal. Activated charcoal binds to the poison that is still in the digestive tract, preventing its absorption into the blood. Charcoal is usually taken by mouth but may have to be given through a tube that is inserted through the nose into the stomach. Sometimes family doctors give charcoal every several hours to help cleanse the body of the poison.
If a poisoning remains life threatening despite the use of charcoal and antidotes, more complicated treatments may be needed. The most common involve filtering poisons directly from the bloodstream- hemodialysis (which uses an artificial kidney [dialyzer] to filter the poisons) or charcoal hemoperfusion (which uses charcoal to help eliminate the poisons). For either of these methods, small tubes (catheters) are inserted into blood vessels, one to drain blood from an artery and another to return blood to a vein. The blood is passed through special filters that remove the toxic substance before being returned to the body.
Poisoning often requires additional treatment. For example, a person who becomes very drowsy or comatose may need a breathing tube inserted into the windpipe. The tube is then attached to a ventilator, which mechanically supports the person's breathing. The tube prevents vomit from entering the lungs, and the ventilator ensures adequate breathing. Treatment also may be needed to control seizures, abnormal heart rhythms, low blood pressure, high blood pressure, fever, or vomiting.
If the kidneys stop working, hemodialysis is necessary. If liver damage is extensive, treatment for liver failure may be necessary. If the liver or kidneys sustain permanent, severe damage, organ transplantation may be needed.
People who attempt suicide by poisoning need mental health evaluation and appropriate treatment.
[Merck]