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- Accidental poisoning
- Deliberate poisoning
- Symptoms of Poisoning
- First Aid for Poisoning
- Diagnosis of Poisoning
- Prevention of Poisoning
- Treatment of Poisoning
- More Information
- Resources In This Article
Overview of 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.
Possible poisonous substances include prescription and over-the-counter drugs, illicit drugs, gases, chemicals, vitamins, food, mushrooms, plants, and animal venom.
Some poisons cause no damage, whereas others can cause severe damage or death.
The diagnosis is based on symptoms, on information gleaned from the poisoned person and bystanders, and sometimes on blood and urine tests.
Drugs should always be kept in original child-proof containers and kept out of the reach of children.
Treatment consists of supporting the person, preventing additional absorption of the poison, and sometimes increasing elimination of the poison.
More than 2 million people suffer some type of poisoning each year in the United States. Drugs—prescription, over-the-counter, and illicit—are a common source of serious poisonings and poisoning-related deaths (see Acetaminophen Poisoning; see also Aspirin Poisoning). Other common poisons include gases (for example, carbon monoxide), household products (see Caustic Substances Poisoning), agricultural products, plants, heavy metals (for example, iron and lead), vitamins, animal venom, and foods (particularly certain species of mushroom and fish). However, almost any substance ingested in sufficiently large quantities can be toxic.
Poisoning is the most common cause of nonfatal accidents in the home. Young children, because of curiosity and a tendency to explore, are particularly vulnerable to accidental poisoning in the home, as are older people, often due to confusion about their drugs. Also vulnerable to accidental poisoning are hospitalized people (by drug errors) and industrial workers (by exposure to toxic chemicals).
Poisoning may also be a deliberate attempt to commit murder or suicide. Most adults who attempt suicide by poisoning take more than one drug and also consume alcohol. Poisoning may be used to disable a person (for example, to rape or rob them). Rarely, parents with a psychiatric disorder poison their children to cause illness and thus gain medical attention (a disorder called factitious disorder imposed on another).
The symptoms caused by poisoning depend 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 symptoms.
Some poisons cause symptoms within seconds, whereas others cause symptoms only after hours, days, or even years. Some poisons cause few obvious symptoms until they have damaged vital organs—such as the kidneys or liver—sometimes permanently.
Ingested and absorbed toxins generally cause bodywide symptoms, often because they deprive the body's cells of oxygen or activate or block enzymes and receptors. Symptoms may include changes in consciousness, body temperature, heart rate, and breathing and many others, depending on the organs affected.
Caustic or irritating substances injure the mucous membranes of the mouth, throat, gastrointestinal tract, and lungs, causing pain, coughing, vomiting, and shortness of breath.
Skin contact with toxins can cause various symptoms, for example, rashes, pain, and blistering. Prolonged exposures may cause dermatitis.
Eye contact with toxins may injure the eye, causing eye pain, redness, and loss of vision.
The first priority in helping a poisoned person is for bystanders not to become poisoned themselves.
People exposed to a toxic gas should be removed from the source quickly, preferably out into fresh air, but rescue attempts should be done by professionals. Special training and precautions must be considered to avoid being overcome by the toxic gases or chemicals during rescue attempts.
In chemical spills, all contaminated clothing, including socks and shoes, and jewelry 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 or saline. Rescuers must be careful to avoid contaminating themselves.
If the person appears very sick, emergency medical assistance (911 in most areas of the United States) should be called. Bystanders should do cardiopulmonary resuscitation (CPR) if needed. If the person does not appear very sick, bystanders can contact the nearest poison control center for advice. In the United States, the local poison center can be reached at 800-222-1222. More information is available at the American Association of Poison Control Centers web site (www.aapcc.org). If the caller knows or can find out the identity of the poison and the amount ingested, treatment can often be initiated at home if this is recommended by the poison center.
Containers of the poisons and all drugs that might have been taken by the poisoned person (including over-the-counter products) should be saved and given to the doctor or rescue personnel. The poison center may recommend giving the poisoned person activated charcoal (see Prevent absorption of poison) before arrival at a hospital and, rarely, may recommend giving syrup of ipecac to induce vomiting, particularly if the person must travel far to reach the hospital. However, unless specifically instructed to, charcoal and syrup of ipecac should not be given in the home or by first responders (such as ambulance personnel). Syrup of ipecac has unpredictable effects, often causes prolonged vomiting, and may not remove substantial amounts of poison from the stomach.
Identifying the poison is helpful to treatment. Labels on bottles and other information from the person, family members, or coworkers best enable the doctor or the poison center to identify poisons. If labels are not available, drugs can often be identified by the markings and colors on the pill or capsule. Laboratory testing is much less likely to identify the poison, and many drugs and poisons cannot be readily identified or measured by the hospital. Sometimes, urine and blood tests may help in identification as well. Blood tests can sometimes reveal the severity of poisoning, but only with a very small number of poisons.
Doctors examine people to look for signs that suggest a certain type of substance. For example, doctors look for needle marks or track marks suggesting people have injected drugs. Doctors also examine people for symptoms characteristic of certain kinds of poisoning. Doctors look to see whether people have traces of a drug or substance on their skin or whether drug patches for drugs absorbed through the skin may be hidden in skin folds, on the roof of the mouth, or under the tongue.
For certain poisonings, abdominal x-rays may show the presence and location of the ingested substances. Poisons that may be visible on x-rays include iron, lead, arsenic, other metals, and large packets of cocaine or other illicit drugs swallowed by so-called body packers or drug mules. Batteries and magnets are also visible on x-rays, as are fangs, teeth, cartilaginous spines and other animal parts that may break off and remain embedded in the body after an animal attack or envenomation.
Kits can now be bought over the counter that are meant to identify drugs in the urine. The accuracy of these kits can vary significantly. Thus, results should not be regarded as proof that a certain drug has or has not been taken. Testing is best done in consultation with a professional. If done without a professional, results should be discussed with a professional who has experience with drug testing. The professional can help people interpret test results and draw the appropriate conclusions.
In the United States, widespread use of child-resistant containers with safety caps has greatly reduced the number of poisoning deaths in children younger than age 5. To prevent accidental poisoning, drugs and other potentially dangerous substances should be kept in their original containers. Toxic substances, such as insecticides and cleaning agents, should not be put in drink bottles or cups, even briefly. Other preventive measures include
Expired drugs should be disposed of by mixing them with cat litter or some other substance that is not tempting and putting them in a trash container that is inaccessible to children. People can also call a local pharmacy for advice on how to properly dispose of drugs. All labels should be read before taking or giving any drugs or using household products.
Limiting the amount of over-the-counter pain reliever in a single container reduces the severity of poisonings, particularly with acetaminophen, aspirin, or ibuprofen. The identifying marks printed on pills and capsules by the drug manufacturer can help prevent confusion and errors by people, pharmacists, and health care practitioners.
Some people who have been poisoned must be hospitalized. With prompt medical care, most recover fully.
The principles for the treatment of all poisoning are the same:
The usual goal of hospital treatment is to keep people alive until the poison disappears or is inactivated by the body. Eventually, most poisons are inactivated by the liver or are passed into the urine.
Poisoning often requires treatment, termed supportive care, to stabilize the heart, blood pressure, and breathing until the poison disappears or is inactivated. 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 mechanical ventilator, which 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, fever, or vomiting. If a poison causes a high fever, the person may need to be cooled, for example, with a cooling blanket, or sometimes by applying cool water or ice to the skin.
Stomach emptying (inducing vomiting or stomach pumping), once commonly done, is now usually avoided because it removes only a small amount of the poison and can cause serious complications. Stomach emptying rarely improves a person's outcome. However, stomach pumping may be done very rarely 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. If people are drowsy because of the poison, doctors usually first put a plastic breathing tube through the mouth into the windpipe (endotracheal intubation). Endotracheal intubation helps keep the gastric lavage liquid from entering the lungs. In the hospital, doctors do not give syrup of ipecac to empty the stomach because its effects are inconsistent.
Activated charcoal is sometimes given in hospital emergency departments to people who have swallowed poisons. 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 by a cooperative patient. Insertion of a tube through the nose or mouth for the purpose of providing activated charcoal in an uncooperative or obtunded patient is not recommended. Sometimes doctors give charcoal every 4 to 6 hours to help cleanse the body of the poison. Not all poisons are inactivated by charcoal. For example, charcoal does not bind alcohol, iron, or many household chemicals.
If a poison remains life threatening despite the use of charcoal and antidotes, more complicated treatments that remove the poison may be needed. The most common treatments are hemodialysis and charcoal hemoperfusion.
In hemodialysis, an artificial kidney (dialyzer) is used to filter the poisons directly from the bloodstream.
In charcoal hemoperfusion, charcoal is used to help eliminate the poisons (see Table: Hemofiltration and Hemoperfusion: Other Ways of Filtering the Blood).
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.
Whole-bowel irrigation is a treatment method designed to flush a poison from the gastrointestinal tract. It is used only occasionally, for example, for serious poisoning caused by poisons that get stuck in the intestinal tract or need to be moved physically (such as packets of hidden, smuggled drugs) or poisons that are absorbed slowly (such as some sustained-release drugs) or not absorbed by activated charcoal (such as iron and lead).
Alkaline diuresis is sometimes used. With this procedure, a solution containing sodium bicarbonate (the chemical in baking soda) is given by vein to make the urine more alkaline or basic (as opposed to acidic). This can increase the amount of certain drugs (such as aspirin and barbiturates) excreted in the urine.
Although most poisons and drugs do not have specific antidotes (unlike the popular perception from TV and movies), some do. Some common drugs that might require specific antidotes include acetaminophen (antidote is N-acetylcysteine), aspirin (antidote is sodium bicarbonate), and heroin (antidote is naloxone). Some poisonous bites and stings also have antidotes (see Snakebites). Not everyone who has been exposed to a poison requires its antidote. Many people recover on their own. But with severe poisoning, antidotes can be lifesaving.
Common Specific Antidotes
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