Decontamination Health Dictionary

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Decontamination: From 1 Different Sources

n. 1. a combination of processes used to remove adherent proteins, microorganisms, and infectious agents or other contaminants from surgical instruments and the environment so there is no risk or spread of infection or disease. Instruments are sterilized in an autoclave to finish the decontamination process. 2. the reduction or removal of chemical agents from a site following a terrorist attack or industrial accident; this includes decontaminating people who have come into contact with such agents.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Anthrax

A serious disease occurring in sheep and cattle, and in those who tend them or handle the bones, skins and ?eeces – even long after removal of the latter from the animals. It is sometimes referred to as malignant pustule, wool-sorters’ disease, splenic fever of animals, or murrain. It is now a rare condition in the United Kingdom. The cause is a bacillus (B. anthracis) which grows in long chains and produces spores of great vitality. These spores retain their life for years, in dried skins and ?eeces; they are not destroyed by boiling, freezing, 5 per cent carbolic lotion, or, like many bacilli, by the gastric juice. The disease is communicated from a diseased animal to a crack in the skin (e.g. of a farmer or butcher), or from contact with contaminated skins or ?eeces. Nowadays skins are handled wet, but if they are allowed to dry so that dust laden with spores is inhaled by the workers, serious pneumonia may result. Instances have occurred of the disease being conveyed on shaving brushes made from bristles of diseased animals. A few countries are believed to have developed anthrax as a weapon of war to be delivered by shells or rockets, despite international agreements to ban such weapons.

In the wake of the devastating terrorist attacks on buildings in New York and Washington on 11 September 2001, modi?ed anthrax spores were sent by mail from an unidenti?ed source to some prominent Americans. Several people were infected and a few died. This was the ?rst known use of anthrax as a terror weapon.

Prevention is most important by disinfecting all hides, wool and hair coming from areas of the world. An e?cient vaccine is now available. Treatment consists of the administration of large doses of the broad-spectrum antibiotic, CIPROFLOXACIN. If bioterrorism is thought to be the likely source of anthrax infection, appropriate decontamination procedures must be organised promptly.

Symptoms

EXTERNAL FORM This is the ‘malignant pustule’. After inoculation of some small wound, a few hours or days elapse, and then a red, in?amed swelling appears, which grows larger till it covers half the face or the breadth of the arm, as the case may be. Upon its summit appears a bleb of pus, which bursts and leaves a black scab, perhaps 12 mm (half an inch) wide. The patient is feverish and seriously ill. The in?ammation may last ten days or so, when it slowly subsides and the patient recovers, if surviving the fever and prostration.

INTERNAL FORM This takes the form of pneumonia with haemorrhages, when the spores have been drawn into the lungs, or of ulcers of the stomach and intestines, with gangrene of the SPLEEN, when they have been swallowed.

It is usually fatal in two or three days. Victims may also develop GASTROENTERITIS or MENINGITIS.... anthrax

Charcoal

Activated charcoal is a ?nely powdered material with a huge surface area (1,000 m2/g) prepared from vegetable matter by carbonisation. It is capable of binding a variety of drugs and chemicals and is used in the treatment of poisoning as a method of gastric decontamination. It is not systemically absorbed. It is also used occasionally for ?atulence and as a deodorant for skin ulcers.... charcoal

Ecstasy

Ecstasy refers to a morbid mental condition, associated with an extreme sense of wellbeing, with a feeling of rapture, and temporary loss of self-control. It often presents as a form of religious obsession, with a feeling of direct communication with God, saintly voices and images being perceived. In milder cases the patient may preach as though with a divine mission to help others. Ecstasy may occur in happiness PSYCHOSIS, SCHIZOPHRENIA, certain forms of EPILEPSY, and abnormal personalities.

The term is also a street drug name for an amphetamine derivative, 3, 4-methylenedioxymethamphetamine or MDMA, increasingly used as a ‘recreational’ drug. It is classi?ed as a class A drug under the Misuse of Drugs Act 1971. MDMA is structurally similar to endogenous CATECHOLAMINES and produces central and peripheral sympathetic stimulation of alpha and beta ADRENERGIC RECEPTORS. It is taken into nerve terminals by the serotonin transporter and causes release of the NEUROTRANSMITTER substances serotonin and dopamine. Following this, SEROTONIN depletion is prolonged. As serotonin plays a major part in mood control, this leads to the characteristic ‘midweek depression’ experienced by MDMA users.

Several fatalities in young people have been attributed to adverse reactions resulting from MDMA use/abuse and possibly accompanying alcohol consumption. The principal effects are increase in pulse, blood pressure, temperature and respiratory rate. Additional complications such as cardiac ARRHYTHMIA, heatstroke-type syndrome, HYPONATRAEMIA and brain haemorrhage may occur. There is also concern over possible effects on the mental concentration and memory of those using ecstasy.

Management of patients who get to hospital is largely symptomatic and supportive but may include gastric decontamination, and use of DIAZEPAM as the ?rst line of treatment as it reduces central stimulation which may also reduce TACHYCARDIA, HYPERTENSION and PYREXIA.... ecstasy

Gastric Lavage

A method of gastric decontamination used in the treatment of poisoning. It is not used routinely. Lavage involves the passage of a lubricated tube via the mouth and OESOPHAGUS into the stomach. Patients are positioned on their side with the head lower than the feet. A small quantity of ?uid (300 ml) is passed into the stomach and the contents then drained out (by gravity) by lowering the end of the tube. This is repeated until the solution is clear of particulate matter. The procedure should be done only by an experienced health professional.... gastric lavage

Emetics

An emetic is a substance which induces VOMITING (emesis). Emetics were previously used for gut decontamination in the treatment of poisoning but are now considered obsolete. This is because the e?cacy of emesis as a means of gut decontamination is unproved; there is a delay between administration and actual emesis, during which time continued absorption of the poison may occur; and some emetics have effects other than vomiting which may mask the clinical features of the ingested poison. The most commonly used emetic was syrup of ipecacuanha (ipecac). Salt (sodium chloride) water emetics were also used but there are many cases of fatal HYPERNATRAEMIA resulting from such use and salt water emetics should never be given. The most common method of gut decontamination currently used is the administration of activated CHARCOAL.... emetics

Lead Poisoning

Lead and lead compounds are used in a variety of products including petrol additives (in the UK, lead-free petrol is now mandatory), piping (lead water pipes were once a common source of poisoning), weights, professional paints, dyes, ceramics, ammunition, homeopathic remedies, and ethnic cosmetic preparations. Lead compounds are toxic by ingestion, by inhalation and, rarely, by skin exposures. Metallic lead, if ingested, is absorbed if it remains in the gut. The absorption is greater in children, who may ingest lead from the paint on old cots

– although lead-containing paints are no longer used for items that children may be in contact with.

Acute poisonings are rare. Clinical features include metallic taste, abdominal pain, vomiting, diarrhoea, ANOREXIA, fatigue, muscle weakness and SHOCK. Neurological effects may include headache, drowsiness, CONVULSIONS and COMA. Inhalation results in severe respiratory-tract irritation and systemic symptoms as above.

Chronic poisonings cause gastrointestinal disturbances and constipation. Other effects are ANAEMIA, weakness, pallor, anorexia, insomnia, renal HYPERTENSION and mental fatigue. There may be a bluish ‘lead line’ on the gums, although this is rarely seen. Neuromuscular dysfunction may result in motor weakness and paralysis of the extensor muscles of the wrist and ankles. ENCEPHALOPATHY and nephropathy are severe effects. Chronic low-level exposures in children are linked with reduced intelligence and behavioural and learning disorders.

Treatment Management of patients who have been poisoned is supportive, with removal from source, gastric decontamination if required, and X-RAYS to monitor the passage of metallic lead through the gut if ingested. It is essential to ensure adequate hydration and renal function. Concentrations of lead in the blood should be monitored; where these are found to be toxic, chelation therapy should be started. Several CHELATING AGENTS are now available, such as DMSA (Meso-2,3dimercaptosuccinic acid), sodium calcium edetate (see EDTA) and PENICILLAMINE. (See also POISONS.)... lead poisoning

Prion

n. an abnormal form of a constituent protein (PrP) of brain cells. The abnormal proteins are very stable: they are not removed by the normal cellular processes of degradation and are resistant to radiation and sterilization (therefore surgical instruments need first to undergo *decontamination). They are believed to interact with normal PrP in such a way as to convert it to the abnormal form, which accumulates in the brain. Prions are now widely accepted as being the causal agents of a range of serious diseases including *Creutzfeldt–Jakob disease, *Gerstmann–Straussler–Scheinker syndrome, and *kuru, all of which are *spongiform encephalopathies. Different mutations in the PrP gene are believed to be responsible for the different forms of these so-called prion disorders.... prion

Poisons

A poison is any substance which, if absorbed by, introduced into or applied to a living organism, may cause illness or death. The term ‘toxin’ is often used to refer to a poison of biological origin. Toxins are therefore a subgroup of poisons, but often little distinction is made between the terms. The study of the effects of poisons is toxicology and the effects of toxins, toxinology.

The concept of the dose-response is important for understanding the risk of exposure to a particular substance. This is embodied in a statement by Paracelsus (c.1493–1541): ‘All substances are poisons; there is none which is not a poison. The right dose di?erentiates a poison and a remedy.’

Poisoning may occur in a variety of ways: deliberate – SUICIDE, substance abuse or murder; accidental – including accidental overdose of medicines; occupational; and environmental

– including exposure during ?re.

Ingestion is the most common route of exposure, but poisoning may also occur through inhalation, absorption through the skin, by injection and through bites and stings of venomous animals. Poisoning may be described as acute, where a single exposure produces clinical effects with a relatively rapid onset; or chronic, where prolonged or repeated exposures may produce clinical effects which may be insidious in onset, cumulative and in some cases permanent.

Diagnosis of poisoning is usually by circumstantial evidence or elimination of other causes of the clinical condition of the patient. Some substances (e.g. opioids) produce a characteristic clinical picture in overdose that can help with diagnosis. In some patients laboratory analysis of body ?uids or the substance taken may be useful to determine or con?rm the o?ending agent. Routine assays are not necessary. For a very small number of poisons, such as paracetamol, aspirin, iron and lead, the management of the patient may depend on measuring the amount of poison in the bloodstream.

Accurate statistics on the incidence of poisoning in the UK are lacking. Mortality ?gures are more reliable than morbidity statistics; annually, well over 100,000 cases of poisoning are admitted to hospital. The annual number of deaths from poisoning is relatively small – about 300 – and in most cases patients die before reaching hospital. Currently, CARBON MONOXIDE (CO) is by far the most common cause of death due to poisoning. The most common agents involved in intentional or accidental poisoning are drugs, particularly ANALGESICS, ANTIDEPRESSANT DRUGS and SEDATIVES. Alcohol is also commonly taken by adults, usually in combination with drugs. Children frequently swallow household cleaners, white spirit, plant material – such as belladonna (deadly nightshade) and certain mushrooms; for example, death cap and ?y agaric – aftershave and perfume as well as drugs. If possible, the suspect container, drug or plant should be taken with the victim to the hospital or doctor. The use of child-resistant containers has reduced the number of admissions of children to hospital for treatment. Bixtrex® is an intensely bitter-tasting agent which is often added to products to discourage ingestion; however, not everybody is able to taste it, nor has any bene?cial e?ect been proven.

Treatment of poisoning usually begins with decontamination procedures. For ingested substances this may involve making the patient sick or washing the stomach out (GASTRIC LAVAGE): this is usually only worthwhile if performed soon after ingestion. It should be emphasised that salt (sodium chloride) water must never be given to induce vomiting, since this procedure is dangerous and has caused death. For substances spilt on the skin, the affected area should immediately be thoroughly washed and all contaminated clothing removed. Following eye exposure, the affected eye/s should be thoroughly irrigated with saline or water.

Treatment thereafter is generally symptomatic and supportive, with maintenance of the victim’s respiratory, neurological and cardiovascular systems and, where appropriate, monitoring of their ?uid and electrolyte balance and hepatic and renal function. There are speci?c antidotes for a few substances: the most important of these are PARACETAMOL, iron, cyanide (see CYANIDE POISONING), opioids (see OPIOID), DIGOXIN, insecticides and some heavy metals. Heavy-metal poisoning is treated with CHELATING AGENTS – chemical compounds that form complexes by binding metal ions: desferrioxamine and pencillinamine are two such agents. The number of people presenting with paracetamol overdose – a common drug used for attempted suicide – has fallen sharply since restrictions were placed on its over-thecounter sales.

When a patient presents with an illness thought to be caused by exposure to substances at work, further exposure should be limited or prevented and investigations undertaken to determine the source and extent of the problem. Acutely poisoned workers will usually go to hospital, but those suffering from chronic exposure may attend their GP with non-speci?c symptoms (see OCCUPATIONAL HEALTH, MEDICINE AND DISEASES).

In recent years, legislation has been enacted in the UK to improve safety in the workplace and to ensure that data on the hazardous constituents and effects of chemicals are more readily available. These o?cial controls include the Control of Substances Hazardous to Health (COSHH) and the Chemicals (Hazard Information and Packaging) Regulations (CHIP) and are UK legislation in response to European Union directives.

The National Poisons Information Service is a 24-hour emergency telephone service available to the medical profession and provides information on the likely effects of numerous agents and advice on the management of the poisoned patient. The telephone numbers are available in the medical literature. In the UK this is not a public-access service. People who believe they, or their relatives, have been poisoned should seek medical advice from their GPs or attend their local hospital.

Toxbase The National Poisons Information Service provides a primary clinical toxicology database on the Internet: www.spib.axl.co.uk. This website provides information about routine diagnosis, treatment and management of people exposed to drugs, household products and industrial and agricultural products.

(See also APPENDIX 1: BASIC FIRST AID.)... poisons


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