Blood-poisoning Health Dictionary

Blood pressure is that pressure which must be applied to an artery in order to stop the pulse beyond the point of pressure. It may be roughly estimated by feeling the pulse at the wrist, or accurately measured using a SPHYGMOMANOMETER. It is dependent on the pumping force of the heart, together with the volume of blood, and on the elasticity of the blood vessels.

The blood pressure is biphasic, being greatest (systolic pressure) at each heartbeat and falling (diastolic pressure) between beats. The average systolic pressure is around 100 mm Hg in children and 120 mm Hg in young adults, generally rising with age as the arteries get thicker and harder. Diastolic pressure in a healthy young adult is about 80 mm Hg, and a rise in diastolic pressure is often a surer indicator of HYPERTENSION than is a rise in systolic pressure; the latter is more sensitive to changes of body position and emotional mood. Hypertension has various causes, the most important of which are kidney disease (see KIDNEYS, DISEASES OF), genetic predisposition and, to some extent, mental stress. Systolic pressure may well be over 200 mm Hg. Abnormal hypertension is often accompanied by arterial disease (see ARTERIES, DISEASES OF) with an increased risk of STROKE, heart attack and heart failure (see HEART, DISEASES OF). Various ANTIHYPERTENSIVE DRUGS are available; these should be carefully evaluated, considering the patient’s full clinical history, before use.

HYPOTENSION may result from super?cial vasodilation (for example, after a bath, in fevers or as a side-e?ect of medication, particularly that prescribed for high blood pressure) and occur in weakening diseases or heart failure. The blood pressure generally falls on standing, leading to temporary postural hypotension – a particular danger in elderly people.... blood pressure

This illness is characterised by vomiting, diarrhoea and abdominal pain, and results from eating food contaminated with metallic or chemical poisons, certain micro-organisms or microbial products. Alternatively, the foods – such as undercooked red kidney beans or ?sh of the scombroid family (mackerel and tuna) – may contain natural posions. Food poisoning caused by chemical or metallic substances usually occurs rapidly, within minutes or a few hours of eating. Among micro-organisms, bacteria are the leading cause of food poisoning, particularly Staphylococcus aureus, Clostridium perfringens (formerly Cl. welchii), Salmonella spp., Campylobacter jejuni, and Escherichia coli O157.

Staphylococcal food poisoning occurs after food such as meat products, cold meats, milk, custard and egg products becomes contaminated before or after cooking, usually through incorrect handling by humans who carry S. aureus. The bacteria produce an ENTEROTOXIN which causes the symptoms of food poisoning 1–8 hours after ingestion. The toxin can withstand heat; thus, subsequent cooking of contaminated food will not prevent illness.

Heat-resistant strains of Cl. perfringens cause food poisoning associated with meat dishes, soups or gravy when dishes cooked in bulk are left unrefrigerated for long periods before consumption. The bacteria are anaerobes (see ANAEROBE) and form spores; the anaerobic conditions in these cooked foods allow the germinated spores to multiply rapidly during cooling, resulting in heavy contamination. Once ingested the bacteria produce enterotoxin in the intestine, causing symptoms within 8–24 hours.

Many di?erent types of Salmonella (about 2,000) cause food poisoning or ENTERITIS, from eight hours to three days after ingestion of food in which they have multiplied. S. brendeny, S. enteritidis, S. heidelberg, S. newport and S. thompson are among those commonly causing enteritis. Salmonella infections are common in domesticated animals such as cows, pigs and poultry whose meat and milk may be infected, although the animals may show no symptoms. Duck eggs may harbour Salmonella (usually S. typhimurium), arising from surface contamination with the bird’s faeces, and foods containing uncooked or lightly cooked hen’s eggs, such as mayonnaise, have been associated with enteritis. The incidence of human S. enteritidis infection has been increasing, by more than 15-fold in England and Wales annually, from around 1,100 a year in the early 1980s to more than 32,000 at the end of the 1990s, but has since fallen to about 10,000. A serious source of infection seems to be poultry meat and hen’s eggs.

Although Salmonella are mostly killed by heating at 60 °C for 15 minutes, contaminated food requires considerably longer cooking and, if frozen, must be completely thawed beforehand, to allow even cooking at a su?cient temperature.

Enteritis caused by Campylobacter jejuni is usually self-limiting, lasting 1–3 days. Since reporting of the disease began in 1977, in England and Wales its incidence has increased from around 1,400 cases initially to nearly 13,000 in 1982 and to over 42,000 in 2004. Outbreaks have been associated with unpasteurised milk: the main source seems to be infected poultry.

ESCHERICHIA COLI O157 was ?rst identi?ed as a cause of food poisoning in the early 1980s, but its incidence has increased sharply since, with more than 1,000 cases annually in the United Kingdom in the late 1990s. The illness can be severe, with bloody diarrhoea and life-threatening renal complications. The reservoir for this pathogen is thought to be cattle, and transmission results from consumption of raw or undercooked meat products and raw dairy products. Cross-infection of cooked meat by raw meat is a common cause of outbreaks of Escherichia coli O157 food poisoning. Water and other foods can be contaminated by manure from cattle, and person-to-person spread can occur, especially in children.

Food poisoning associated with fried or boiled rice is caused by Bacillus cereus, whose heat-resistant spores survive cooking. An enterotoxin is responsible for the symptoms, which occur 2–8 hours after ingestion and resolve after 8–24 hours.

Viruses are emerging as an increasing cause of some outbreaks of food poisoning from shell?sh (cockles, mussels and oysters).

The incidence of food poisoning in the UK rose from under 60,000 cases in 1991 to nearly 79,000 in 2004. Public health measures to control this rise include agricultural aspects of food production, implementing standards of hygiene in abattoirs, and regulating the environment and process of industrial food production, handling, transportation and storage.... food poisoning

Blood consists of cellular components suspended in plasma. It circulates through the blood vessels, carrying oxygen and nutrients to the organs and removing carbon dioxide and other waste products for excretion. In addition, it is the vehicle by which hormones and other humoral transmitters reach their sites of action.

Composition The cellular components are red cells or corpuscles (ERYTHROCYTES), white cells (LEUCOCYTES and lymphocytes – see LYMPHOCYTE), and platelets.

The red cells are biconcave discs with a diameter of 7.5µm. They contain haemoglobin

– an iron-containing porphyrin compound, which takes up oxygen in the lungs and releases it to the tissue.

The white cells are of various types, named according to their appearance. They can leave the circulation to wander through the tissues. They are involved in combating infection, wound healing, and rejection of foreign bodies. Pus consists of the bodies of dead white cells.

Platelets are the smallest cellular components and play an important role in blood clotting (see COAGULATION).

Erythrocytes are produced by the bone marrow in adults and have a life span of about 120 days. White cells are produced by the bone

marrow and lymphoid tissue. Plasma consists of water, ELECTROLYTES and plasma proteins; it comprises 48–58 per cent of blood volume. Plasma proteins are produced mainly by the liver and by certain types of white cells. Blood volume and electrolyte composition are closely regulated by complex mechanisms involving the KIDNEYS, ADRENAL GLANDS and HYPOTHALAMUS.... blood

A blood clot arises when blood comes into contact with a foreign surface – for example, damaged blood vessels – or when tissue factors are released from damaged tissue. An initial plug of PLATELETS is converted to a de?nitive clot by the deposition of FIBRIN, which is formed by the clotting cascade and erythrocytes. (See COAGULATION.)... blood clot

The number of each of the cellular components per litre of blood. It may be calculated using a microscope or by an automated process.... blood count

See TRANSFUSION – Transfusion of blood.... blood transfusion

See FUNGUS POISONING.... mushroom 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

See BLOOD GROUPS.... abo blood groups

A department in which blood products are prepared, stored, and tested prior to transfusion into patients.... blood bank

A functional, semi-permeable membrane separating the brain and cerebrospinal ?uid from the blood. It allows small and lipid-soluble molecules to pass freely but is impermeable to large or ionised molecules and cells.... blood brain barrier

See ERYTHROCYTES and LEUCOCYTES.... blood corpuscle

An individual who donates his or her own blood for use in patients of compatible blood group who require transfusion.... blood donor

Removal of venous, capillary or arterial blood for haematological, microbiological or biochemical laboratory investigations.... blood test

Tube through which blood is conducted from or to the heart. Blood from the heart is conducted via arteries and arterioles through capillaries and back to the heart via venules and then veins. (See ARTERIES and VEINS.)... blood vessel

Speci?cally, this describes the measurement of the tensions of oxygen and carbon dioxide in blood. However, it is commonly used to describe the analysis of a sample of heparinised arterial blood for measurement of oxygen, carbon dioxide, oxygen saturation, pH, bicarbonate, and base excess (the amount of acid required to return a unit volume of the blood to normal pH). These values are vital in monitoring the severity of illness in patients receiving intensive care or who have severe respiratory illness, as they provide a guide to the e?ectiveness of oxygen transport between the outside air and the body tissues. Thus they are both a guide to whether the patient is being optimally ventilated, and also a general guide to the severity of their illness.... blood gases

People are divided into four main groups in respect of a certain reaction of the blood. This depends upon the capacity of the serum of one person’s blood to cause the red cells of another’s to stick together (agglutinate). The reaction depends on antigens (see ANTIGEN), known as agglutinogens, in the erythrocytes and on ANTIBODIES, known as agglutinins, in the serum. There are two of each, the agglutinogens being known as A and B. A person’s erythrocytes may have (1) no agglutinogens, (2) agglutinogen A, (3) agglutinogen B, (4) agglutinogens A and B: these are the four groups. Since the identi?cation of the ABO and Rhesus factors (see below), around 400 other antigens have been discovered, but they cause few problems over transfusions.

In blood transfusion, the person giving and the person receiving the blood must belong to the same blood group, or a dangerous reaction will take place from the agglutination that occurs when blood of a di?erent group is present. One exception is that group O Rhesus-negative blood can be used in an emergency for anybody.

	Agglutinogens	Agglutinins	Frequency
	in the	in the	in Great
Group	erythrocytes	plasma	Britain
AB	A and B	None	2 per cent
A	A	Anti-B	46 per cent
B	B	Anti-A	8 per cent
O	Neither	Anti-A and	44 per cent
	A nor B	Anti-B

Rhesus factor In addition to the A and B agglutinogens (or antigens), there is another one known as the Rhesus (or Rh) factor – so named because there is a similar antigen in the red blood corpuscles of the Rhesus monkey. About 84 per cent of the population have this Rh factor in their blood and are therefore known as ‘Rh-positive’. The remaining 16 per cent who do not possess the factor are known as ‘Rh-negative’.

The practical importance of the Rh factor is that, unlike the A and B agglutinogens, there are no naturally occurring Rh antibodies. However, such antibodies may develop in a Rh-negative person if the Rh antigen is introduced into his or her circulation. This can occur (a) if a Rh-negative person is given a transfusion of Rh-positive blood, and (b) if a Rh-negative mother married to a Rh-positive husband becomes pregnant and the fetus is Rh-positive. If the latter happens, the mother develops Rh antibodies which can pass into the fetal circulation, where they react with the baby’s Rh antigen and cause HAEMOLYTIC DISEASE of the fetus and newborn. This means that, untreated, the child may be stillborn or become jaundiced shortly after birth.

As about one in six expectant mothers is Rh-negative, a blood-group examination is now considered an essential part of the antenatal examination of a pregnant woman. All such Rh-negative expectant mothers are now given a ‘Rhesus card’ showing that they belong to the rhesus-negative blood group. This card should always be carried with them. Rh-positive blood should never be transfused to a Rh-negative girl or woman.... blood groups

A procedure performed during a mother’s labour in which a blood sample is taken from a vein in the scalp of the FETUS. This enables tests to be performed that indicate whether the fetus is, for example, suffering from a shortage of oxygen (HYPOXIA). If so, the obstetrician will usually accelerate the baby’s birth.... fetal blood sampling

Sanguinaria canadensis. N.O. Papaveraceae.

Habitat: Widely distributed throughout North America.

Features ? Root reddish-brown, wrinkled lengthwise, about half-inch thick. Fracture short. Section whitish, with many small, red resin cells which sometimes suffuse the whole. Heavy odour, bitter and harsh to the taste.

Part used ? Root.

Action: Stimulant, tonic, expectorant.

Pulmonary complaints and bronchitis. Should be administered in whooping-cough and croup until emesis occurs. The powdered root is used as a snuff in nasal catarrh, and externally in ringworm and other skin eruptions. The American Thomsonians use it in the treatment of adenoids. Dose, 10 to 20 grains of the powdered root.... blood root

Cadmium poisoning is a recognised hazard in certain industrial processes, such as the manufacture of alloys, cadmium plating and glass blowing. Sewage sludge, which is used as fertiliser, may be contaminated by cadmium from industrial sources; such cadmium could be taken up into vegetable crops and cadmium levels in sewage are carefully monitored.

A tin-like metal, cadmium accumulates in the body. Long-term exposure can lead to EMPHYSEMA, renal failure (see KIDNEYS, DISEASES OF) and urinary-tract CALCULI. Acute exposure causes GASTROENTERITIS and PNEUMONITIS. Cadmium contamination of food is the most likely source of poisoning. The EU Directive on the Quality of Water for Human Consumption lays down 5 milligrams per litre as the upper safe level.... cadmium poisoning

See ERYTHROCYTES; BLOOD.... red blood cell

Around 2,000 mushrooms (toadstools) grow in England, of which 200 are edible and a dozen are classi?ed as poisonous. Not all the poisonous ones are dangerous. It is obviously better to prevent mushroom poisoning by ensuring correct identi?cation of those that are edible; books and charts are available. If in doubt, do not eat a fungus.

Severe poisoning from ingestion of fungi is very rare, since relatively few species are highly toxic and most species do not contain toxic compounds. The most toxic species are those containing amatoxins such as death cap (Amanita phalloides); this species alone is responsible for about 90 per cent of all mushroom-related deaths. There is a latent period of six hours or more between ingestion and the onset of clinical effects with these more toxic species. The small intestine, LIVER and KIDNEYS may be damaged – therefore, any patient with gastrointestinal effects thought to be due to ingestion of a mushroom should be referred immediately to hospital where GASTRIC LAVAGE and treatment with activated charcoal can be carried out, along with parenteral ?uids and haemodialysis if the victim is severely ill. In most cases where effects occur, these are early-onset gastrointestinal effects due to ingestion of mushrooms containing gastrointestinal irritants.

Muscarine is the poisonous constituent of some species. Within two hours of ingestion, the victim starts salivating and sweating, has visual disturbances, vomiting, stomach cramps, diarrhoea, vertigo, confusion, hallucinations and coma, the severity of symptoms depending on the amount eaten and type of mushroom. Most people recover in 24 hours, with treatment.

‘Magic’ mushrooms are a variety that contains psilocybin, a hallucinogenic substance. Children who take such mushrooms may develop a high fever and need medical care. In adults the symptoms usually disappear within six hours.

Treatment If possible, early gastric lavage should be carried out in all cases of suspected poisoning. Identi?cation of the mushroom species is a valuable guide to treatment. For muscarine poisoning, ATROPINE is a speci?c antidote. As stated above, hospital referral is advisable for people who have ingested poisonous fungi.... fungus poisoning

See LEUCOCYTES.... white blood cell

The toxic effect of mercury has been known since days of the medieval alchemists. Charles II presented all the symptoms we now recognise as mercurial poisoning, presumably the result of medication received over many years. Its symptoms simulate multiple sclerosis, when chronic. They are: constant fatigue, pins and needles in the limbs, resting tremor, nausea, dizziness, ataxia, pains in the bones and joints, drooling (excessive salivation), blue line along the gums. In children they may include all kinds of vague aches and pains, chorea, hyperthyroidism and facial neuralgia. Weakness, walking difficulties, metallic taste in the mouth, thirst, mental deterioration. It is now known to cause a number of serious nerve dystrophies.

Mercury has an affinity for the central nervous system. Soon it concentrates in the kidney causing tubular damage. A common cause is the mercurial content (50 per cent) in the amalgam fillings in teeth which, under certain conditions, release a vapour. Fortunately, its use in dentistry is being superceded by an alternative composite filling.

A common cause of poisoning was demonstrated in 1972 when 6,000 people became seriously ill (600 died) from eating bread made from grain treated with a fungicide containing methylmercury. For every fungus in grain there is a mercuric compound to destroy it. The seed of all cereal grain is thus treated to protect its power of germination.

Those who are hypersensitive to the metal should as far as possible avoid button cells used in tape recorders, cassette players, watch and camera mechanisms. As the mercury cells corrode, the metal enters the environment and an unknown fraction is converted by micro organisms to alkylmercury compounds which seep into ground waters and eventually are borne to the sea. When cells are incinerated, the mercury volatilises and enters the atmosphere. (Pharmaceutical Journal, July 28/1984)

Mercury poisoning from inhalation of mercury fumes goes directly to the brain and pituitary gland. Autopsies carried out on dentists reveal high concentrations of mercury in the pituitary gland. (The Lancet, 5-27-89,1207 (letter))

Treatment. For years the common antidote was sulphur, and maybe not without reason. When brought into contact sulphur and mercury form an insoluble compound enabling the mercury to be more easily eliminated from the body. Sulphur can be provided by eggs or Garlic.

Old-time backwoods physicians of the North American Medical School used Asafoetida, Guaiacum and Echinacea. German pharmacists once used Bugleweed and Yellow Dock. Dr J. Clarke, USA physician recommends Sarsaparilla to facilitate breakdown and expulsion from the body.

Reconstructed formula. Echinacea 2; Sarsaparilla 1; Guaiacum quarter; Asafoetida quarter; Liquorice quarter. Dose: Liquid Extracts: 1 teaspoon. Tinctures: 2 teaspoons. Powders: 500mg (two 00 capsules or one-third teaspoon). Thrice daily.

Chelation therapy.

Formula. Tinctures. Skullcap 2-15 drops; Pleurisy root 20-45 drops; Horehound 5-40 drops. Mercurial salivation. Thrice daily. (Indian Herbology of North America, by Alma Hutchens) Dental fillings: replace amalgam with safe alternative – ceramic, etc. Evidence of a link between tooth fillings containing mercury and ME has caused the use of dental amalgam to be banned in Sweden. ... mercury poisoning

See blood glucose.... blood sugar

The process of blood solidification. Clotting is important in stemming bleeding from damaged blood vessels. However, unwanted blood clotting can occur inside major blood vessels and cause a myocardial infarction (heart attack) or stroke (see thrombosis).

When a blood vessel is damaged, it constricts immediately to reduce blood flow to the area. The damage sets off a series of chemical reactions that lead to the formation of a clot to seal the injury. First, platelets around the injury site are activated, becoming sticky and adhering to the blood-vessel wall. Then, the activated platelets release chemicals, which, in turn, activate blood clotting factors. These factors, together with vitamin K, act on fibrinogen and convert it to fibrin. Strands of fibrin form a meshwork, which traps red blood cells to form a clot.

There are several anticlotting mechanisms to prevent the formation of unwanted clots. These include prostacyclin (a prostaglandin), which prevents platelet aggregation, and plasmin, which breaks down fibrin (see fibrinolysis). Blood flow washes away active coagulation factors; and the liver deactivates excess coagulation factors.

Defects in blood clotting may result in bleeding disorders.

Excessive clotting (thrombosis) may be due to an inherited increase or defect in a coagulation factor (see factor V), the use of oral contraceptives, a decrease in the level of enzymes that inhibit coagulation, or sluggish blood flow through a particular area.

Treatment is usually with anticoagulant drugs such as heparin or warfarin.... blood clotting

ASPIRIN is a commonly available analgesic (see ANALGESICS) which is frequently taken in overdose. Clinical features of poisoning include nausea, vomiting, TINNITUS, ?ushing, sweating, HYPERVENTILATION, DEHYDRATION, deafness and acid-base and electrolyte disturbances (see ELECTROLYTES). In more severe cases individuals may be confused, drowsy and comatose. Rarely, renal failure (see KIDNEYS, DISEASES OF), PULMONARY OEDEMA or cardiovascular collapse occur. Severe toxicity may be delayed, as absorption of the drug may be prolonged due to the formation of drug concretions in the stomach. Treatment involves the repeated administration of activated CHARCOAL, monitoring of concentration of aspirin in the blood, and correction of acid-base and electrolyte imbalances. In more severely poisoned patients, enhanced excretion of the drug may be necessary by alkalinising the urine (by intravenous administration of sodium bicarbonate – see under SODIUM) or HAEMODIALYSIS.... aspirin poisoning

See ATROPINE; BELLADONNA POISONING.... atropine poisoning

See TRANSFUSION – Transfusion of blood.... autologous blood transfusion

Atropa belladonna (deadly nightshade) is a relatively rare plant and severe poisoning is not common. The berries, which are black, ripen from August to October and are the most commonly ingested part of the plant. However, all parts of the plant are toxic. The berries contain ATROPINE and other unidenti?ed ALKALOIDS, the leaves HYOSCINE and atropine, and the roots hyoscine. All these alkaloids have an ANTICHOLINERGIC e?ect which may cause a dry mouth, dilated pupils with blurred vision, TACHYCARDIA, HALLUCINATIONS and PYREXIA. There may also be ATAXIA, agitation, disorientation and confusion. In severe cases there may be CONVULSIONS, COMA, respiratory depression and ARRHYTHMIA. Clinical effects may be delayed in onset for up to 12 hours, and prolonged for several days. Treatment is supportive.... belladonna poisoning

See VENESECTION.... blood-letting

See ANAEMIA; LEUKAEMIA; LYMPHOMA; MYELOMATOSIS; THROMBOSIS.... blood, diseases of

This is the main cause of anaemia in infections. The micro-organism responsible for the infection has a deleterious e?ect upon the blood-forming organs, just as it does upon other parts of the body.

Toxins. In conditions such as chronic glomerulonephritis (see KIDNEYS, DISEASES OF) and URAEMIA there is a severe anaemia due to the e?ect of the disease upon blood formation.

Drugs. Certain drugs, such as aspirin and the non-steroidal anti-in?ammatory drugs, may cause occult gastrointestinal bleeding.... defective blood formation

Love, Protection, Exorcism, Potency... dragons blood

Ergot poisoning, or ergotism, occasionally results from eating bread made from rye infected with the fungus, Claviceps purpurea. Several terrible epidemics (St Anthony’s Fire), characterised by intense pain and hallucinations, occurred in France and Germany during the Middle Ages (see ERYSIPELAS). Its symptoms are the occurrence of spasmodic muscular contractions, and the gradual production of gangrene in parts like the ?ngers, toes and tips of the ears because of constriction of blood vessels and therefore the blood supply.... ergot poisoning

When LYSOL is swallowed it burns the mouth and throat. Brown discoloration of the affected tissues, accompanied by the characteristic smell of lysol on the breath, is typical.

Treatment This is urgent. If the skin has been contaminated with the lysol, it must be washed with water, and any lysol-contaminated clothing must be taken o?. Do not make the victim vomit if he or she has swallowed a corrosive substance such as lysol or phenol. Call an ambulance and say what the victim has taken. See APPENDIX 1: BASIC FIRST AID.... lysol poisoning

The course of the circulation is as follows: the veins pour their blood, coming from the head, trunk, limbs and abdominal organs, into the right atrium of the HEART. This contracts and drives the blood into the right ventricle, which then forces the blood into the LUNGS by way of the pulmonary artery. Here it is contained in thin-walled capillaries, over which the air plays freely, and through which gases pass readily out and in. The blood gives o? carbon dioxide (CO2) and takes up oxygen (see RESPIRATION), and passes on by the pulmonary veins to the left atrium of the heart. The left atrium expels it into the left ventricle, which forces it on into the aorta, by which it is distributed all over the body. Passing through capillaries in the various tissues, it enters venules, then veins, which ultimately unite into two great veins, the superior and the inferior vena cava, these emptying into the right atrium. This complete circle is accomplished by any particular drop of blood in about half a minute.

In one part of the body there is a further complication. The veins coming from the bowels, charged with food material and other products, split up, and their blood undergoes a second capillary circulation through the liver. Here it is relieved of some food material and puri?ed, and then passes into the inferior vena cava, and so to the right atrium. This is known as the portal circulation.

The circle is maintained always in one direction by four valves, situated one at the outlet from each cavity of the heart.

The blood in the arteries going to the body generally is bright red, that in the veins dull red in colour, owing to the former being charged with oxygen and the latter with carbon dioxide (see RESPIRATION). For the same reason the blood in the pulmonary artery is dark, that in the pulmonary veins is bright. There is no direct communication between the right and left sides of the heart, the blood passing from the right ventricle to the left atrium through the lungs.

In the embryo, before birth, the course of circulation is somewhat di?erent, owing to the fact that no nourishment comes from the bowels nor air into the lungs. Accordingly, two large arteries pass out of the navel, and convey blood to be changed by contact with maternal blood (see PLACENTA), while a large vein brings this blood back again. There are also communications between the right and left atria, and between pulmonary artery and aorta. The latter is known as the ductus arteriosus. At birth all these extra vessels and connections close and rapidly shrivel up.... circulatory system of the blood

This body manages regional TRANSFUSION centres. Among its aims are the maintenance and promotion of blood and blood products based on a system of voluntary donors; implementing a cost-e?ective national strategy for ensuring adequate supplies of blood and its products to meet national needs; and ensuring high standards of safety and quality.... national blood authority

Poisoning by saxitoxin, a toxin present in some shellfish, usually in tropical or subtropical seas. Symptoms of respiratory arrest, or brain involvement occur in some 8% of cases, resulting in death. Saxitoxin is related to tetrodotoxin.... paralytic shellfish poisoning

Cyanide inhibits cellular RESPIRATION by binding rapidly and reversibly with the ENZYME, cytochrome oxidase. E?ects of poisoning are due to tissue HYPOXIA. Cyanide is toxic by inhalation, ingestion and prolonged skin contact, and acts extremely quickly once absorbed. Following inhalation of hydrogen cyanide gas, death can occur within minutes. Ingestion of inorganic cyanide salts may produce symptoms within 10 minutes, again proceeding rapidly to death. On a full stomach, effects may be delayed for an hour or more. Signs of cyanide poisoning are headache, dizziness, vomiting, weakness, ATAXIA, HYPERVENTILATION, DYSPNOEA, HYPOTENSION and collapse. Loss of vision and hearing may occur, then COMA and CONVULSIONS. Other features include cardiac ARRHYTHMIA and PULMONARY OEDEMA. Patients may have a lactic ACIDOSIS. Their arterial oxygen tension is likely to be normal, but their venous oxygen tension high and similar to that of arterial blood.

Treatment Administration of oxygen when available is the most important ?rst-aid management. Rescuers should be trained, must not put themselves at risk, and should use protective clothing and breathing apparatus. In unconscious victims, establish a clear airway and give 100 per cent oxygen. If breathing stops and oxygen is unavailable, initiate expired-air resuscitation. If cyanide salts were ingested, mouth-to-mouth contact must be avoided and a mask with a one-way valve employed instead. Some commercially available ?rst-aid kits contain AMYL NITRATE as an antidote which may be employed if oxygen is unavailable.

Once in hospital, or if a trained physician is on the scene, then antidotes may be administered. There are several di?erent intravenous antidotes that may be used either alone or in combination. In mild to moderate cases, sodium thiosulphate is usually given. In more severe cases either dicobalt edetate or sodium nitrite may be used, followed by sodium thio-sulphate. Some of these (e.g. dicobalt edetate) should be given only where diagnosis is certain, otherwise serious adverse reations or toxicity due to the antidotes may occur.... cyanide poisoning

See CYANIDE POISONING.... prussic acid poisoning

As a result of trauma. This is perhaps the simplest example of all, when, as a result of an accident involving a large artery, there is severe haemorrhage.

Menstruation. The regular monthly loss of blood which women sustain as a result of menstruation always puts a strain on the blood-forming organs. If this loss is excessive, then over a period of time it may lead to quite severe anaemia.

Childbirth. A considerable amount of blood is always lost at childbirth; if this is severe, or if the woman was anaemic during pregnancy, a severe degree of anaemia may develop.

Bleeding from the gastrointestinal tract. The best example here is anaemia due to ‘bleeding piles’ (see HAEMORRHOIDS). Such bleeding, even though slight, is a common cause of anaemia in both men and women if maintained over a long period of time. The haemorrhage may be more acute and occur from a DUODENAL ULCER or gastric ulcer (see STOMACH, DISEASES OF), when it is known as haematemesis.

Certain blood diseases, such as PURPURA and HAEMOPHILIA, which are characterised by bleeding.... loss of blood

This occurs from eating poorly preserved scromboid ?sh such as tuna, mackerel and other members of the mackerel family. In such ?sh, a toxic histamine-like substance is produced by the action of bacteria or histidine, a normal component of ?sh ?esh. This toxin produces nausea, vomiting, headache, upper abdominal pain, di?culty in swallowing, thirst, itching and sometimes URTICARIA. The condition settles as a rule in 12 hours. ANTIHISTAMINE DRUGS sometimes ameliorate the condition.... scrombotoxin poisoning

See POISONS.... self-poisoning

See: BLEEDING (haemoptysis). ... coughing of blood

Popular blood tonic of the 1930s, 1940s and 1950s. Ingredients: Liquid Extract Liquorice 5 per cent, Infusion Gentian Co Conc 10 per cent, Infusion Senna Conc 5 per cent. And 25 per cent alcoholic extractive from Burdock 5 per cent, Red Clover 5 per cent, Queen’s root 2.5 per cent, Yellow Dock root 1.25 per cent, Poke root 2.5 per cent, Sarsaparilla 2.5 per cent. (Carter Bros) ... glentona herbal blood purifier

MORPHINE and CODEINE are natural opium ALKALOIDS found in the opium poppy (Papaver somniferum). The other opioids are either synthetic or semi-synthetic analogues of these. Their main use is in the treatment of moderate to severe PAIN, but they are also used as antidiarrhoeal and antitussive agents. As a result of induced tolerance (see DEPENDENCE) and great individual variability, the amount of opioid substances required to cause serious consequences varies enormously.

The most common effects of opioid overdose are vomiting, drowsiness, pinpoint pupils, BRADYCARDIA, CONVULSIONS and COMA. Respiratory depression is common and may lead to CYANOSIS and respiratory arrest. HYPOTENSION occurs occasionally and in severe cases non-cardiogenic pulmonary oedema and cardiovascular collapse may occur. Cardiac ARRHYTHMIA may occur with some opioids. Some opioids have a HISTAMINE-releasing e?ect which may result in an urticarial rash (see URTICARIA), PRURITUS, ?ushing and hypotension. Activated CHARCOAL should be given following overdose and NALOXONE administered to reverse respiratory depression and deep coma.... opioid poisoning

Paracetamol is one of the safest drugs when taken in the correct dosage, but overdose may occur inadvertently or deliberately. Initially there may be no symptoms or there may be nausea, vomiting, abdominal pain and pallor. Then, 16–24 hours after ingestion, liver damage becomes evident and by 72–120 hours the patient may have JAUNDICE, COAGULATION abnormalities, hepatic failure (see LIVER, DISEASES OF), renal failure (see KIDNEYS, DISEASES OF), ENCEPHALOPATHY and COMA. Treatment involves the administration of antidotes such as METHIONINE (within 8 hours) orally or intravenous ACETYLCYSTEINE.

An overdose of paracetamol is a common choice of those attempting to commit suicide. Since the government restricted the number of paracetamol tablets an individual may purchase over the counter, the incidence of people taking the drug in overdose with the intention of taking their lives has fallen sharply.... paracetamol poisoning

These have almost completely replaced BONE MARROW TRANSPLANT, used to treat malignancies such as LEUKAEMIA and LYMPHOMA for the past 20 years. The high doses of CHEMOTHERAPY or RADIOTHERAPY used to treat these diseases destroy the bone marrow which contains stem cells from which all the blood cells derive. In 1989 stem cells were found in the blood during recovery from chemotherapy. By giving growth factors (cytokines), the number of stem cells in the blood increased for about three to four days. In a peripheral-blood stem-cell transplant, these cells can be separated from the peripheral blood, without a general anaesthetic. The cells taken by either method are then frozen and returned intravenously after the chemotherapy or radiotherapy is completed. Once transplanted, the stem cells usually take less than three weeks to repopulate the blood, compared to a month or more for a bone marrow transplant. This means that there is less risk of infection or bleeding during the recovery from the transplant. The whole procedure has a mortality risk of less than 5 per cent – half the risk of a bone marrow transplant.... peripheral-blood stem-cell transplants

In the United Kingdom this occurs in two main forms. Shell?sh may be the cause of typhoid fever (see ENTERIC FEVER) as a result of their contamination by sewage containing the causative organism. They may also be responsible for what is known as paralytic shell?sh poisoning. This is caused by a toxin, or poison, known as saxotoxin, which is present in certain planktons which, under unusual conditions, multiply rapidly, giving rise to what are known as ‘red tides’. In these circumstances the toxin accumulates in mussels, cockles and scallops which feed by ?ltering plankton. The manifestations of such poisoning are loss of feeling in the hands, tingling of the tongue, weakness of the arms and legs, and di?culty in breathing. There is also growing evidence that some shell?sh poisoning may be due to a virus infection. (See also FOOD POISONING.)... shellfish poisoning

As a natural beverage, a cup of tea brings you many health benefits. One of them is related to blood pressure. Based on the type of tea you drink, it can help lower your blood pressure. Find out more about teas for blood pressure! Problems with blood pressure Blood pressure represents the pressure made by the circulating blood on the walls of the blood vessels. However, problems appear in the case of hypertension and hypotension. Hypertension is a medical condition caused by a high blood pressure, while hypotension is caused by a low blood pressure. Both can be treated with one of the various types of tea for blood pressure. Tea for high blood pressure If you’ve got problems with hypertension (high blood pressure), hibiscus tea can help, as it is known to lower blood pressure. You can also pick one of these herbal teas: chrysanthemum tea, flax tea, periwinkle tea, red root tea, self-heal tea, white peony root tea, valerian tea, or wild cherry bark tea. You can also drink hyssop tea, barberry tea, and rosemary tea, regardless of the blood pressure problem. These three teas will help regulate your blood pressure and reduce the risk of getting either high or low blood pressure problems. Tea for low blood pressure In the case of hypotension (low blood pressure), some of the teas you can try include lovage tea, ephedra tea, wu yi tea, cat’s claw tea, vervain tea, or wheatgrass tea. Black tea can help too, though you have to be careful with it as it has a high content of caffeine. Forbidden teas for blood pressure problems There are several teas which you should avoid drinking, no matter if you’ve got problems with high blood pressure or low blood pressure. The list of teas you shouldn’t drink includes arnica tea, black cohosh tea, gentian tea, juniper tea, lobelia tea, red ginseng tea, sage tea, stone root tea, and yohimbe tea. Also, generally it isn’t recommended to drink tea that lowers blood pressure if you’ve got hypotension, or tea that leads to high blood pressure if you’ve got hypertension. Whether you’ve got problems with high blood pressure or low blood pressure, try a more natural treatment: choose one of the many teas for blood pressure!... tea for blood pressure

Alteratives. The blood is a fluid from which every variety of cell and tissue derives its special form of food for the repair of constant wastage resulting from functions they perform. When the blood becomes vitiated from lack of exercise, too little oxygen, debilitating personal habits and sophisticated foodstuffs the whole body suffers. The vital fluid then needs to be cleansed of its impurities. Nature’s blood purifiers are unique in the world of medicine, restoring biochemical balance and promoting healthy elimination.

Blood tonic. Decoction, tablets, tinctures or fluid extracts:– Echinacea 3; Burdock 2; Goldenseal 1. See also: ALTERATIVES. ... blood purifiers

A Harvard study links coffee consumption with cancer of the pancreas. No association has been found between tea-drinkers and cancer. Some authorities claim coffee is not carcinogenic until roasted.

While an internal mechanism slows down the body, caffeine in tea, cola and coffee restores alertness. Caffeine acts by blocking the action of the compound, adenosine – one of the building blocks of DNA which promotes cell energy. Caffeine interferes with natural metabolic processes. In the aged, coffee increases production of uric acid, causing irritation of the kidneys, joint and muscle pains. vCaffeinism is responsible for a wide range of disorders. Increases the heart beat, promotes excessive stomach acid and increases flow of urine. It may give rise to birth defects and should be taken with caution in pregnancy.

Symptoms. Restlessness, nervous agitation, extreme sensitiveness. Intolerance of pain, nervous palpitation, all senses acute.

To antidote. Chamomile tea.

Practitioner. Tincture Nux vom BP: 10 drops to 100ml water. Dose: 1 teaspoon thrice daily. Inhalation: Strong spirits of Camphor.

Diet. Plenty asparagus. ... caffeine poisoning

Most antifreeze in the contains ethylene glycol, which is poisonous.

Drinking antifreeze initially produces effects similar to alcohol intoxication, but vomiting, stupor, seizures, and coma may follow; acute kidney failure may occur within 24–36 hours.

Antifreeze poisoning requires immediate medical attention.... antifreeze poisoning

Tests to screen for and diagnose bleeding disorders, usually resulting from deficiencies or abnormalities of blood coagulation factors or of platelets (see blood clotting). Tests are also used to monitor treatment with anticoagulant drugs.... blood-clotting tests

See culture.... blood culture

The level of glucose in the blood. Abnormally high blood glucose (sometimes called sugar) levels are an indication of diabetes mellitus. (See also hyperglycaemia; hypoglycaemia.)... blood glucose

See blood film.... blood smear

Cells, also called blood corpuscles, present in blood for most or part of their lifespan. They include red blood cells, which make up about 45 per cent by volume of normal blood, white blood cells, and platelets. Blood cells are made in the bone marrow by a series of divisions from stem cells.

Red blood cells (also known as RBCs, red blood corpuscles, or erythrocytes) transport oxygen from the lungs to the tissues (see respiration). Each is packed with haemoglobin, enzymes, minerals, and sugars. Abnormalities can occur in the rate at which RBCs are either produced or destroyed, in their numbers, and in their shape, size, and haemoglobin content, causing forms of

anaemia and polycythaemia (see blood, disorders of).

White blood cells (also called WBCs, white blood corpuscles, or leukocytes) protect the body against infection and fight infection when it occurs. The 3 main types of are granulocytes (also called polymorphonuclear leukocytes), monocytes, and lymphocytes. Granulocytes are further classified as neutrophils, eosinophils, or basophils, and each type of granulocyte has a role in either fighting infection or in inflammatory or allergic reactions. Monocytes and lymphocytes also play an important part in the immune system. Lymphocytes are usually formed in the lymph nodes. One type, a T-lymphocyte, is responsible for the delayed hypersensitivity reactions

White (see allergy) and Red blood blood cell is also involved in cell (neutrophil) protection against cancer. T-lymphocytes manufacture chemicals, known as lymphokines, which affect the function of other cells. In addition, the T-cells moderate the activity of B-lymphocytes, which form the antibodies that can prevent a second attack of certain infectious diseases. Platelets (also known as thrombocytes), are the smallest blood cells and are important in blood clotting.

The numbers, shapes, and appearance of the various types of blood cell are of great value in the diagnosis of disease (see blood count; blood film).... blood cells

Disorders resulting from abnormalities in any of the components of blood or from infection. Disorders include types of anaemia, polycythaemia, bleeding disorders, and unwanted clot formation (thrombosis), hypoalbuminaemia (albumin deficiency) and agammaglobulinaemia (deficiency of gamma-globulin). Blood disorders such as sickle cell anaemia, thalassaemia, and haemophilia are inherited. Bone marrow cancers that affect production of blood components include leukaemia, polycythaemia vera, and multiple myeloma. Blood poisoning is usually due to septicaemia or a toxin such as carbon monoxide. Some drugs can cause blood abnormalities as a side effect. (See also anaemia, haemolytic; anaemia, iron-deficiency; anaemia, megaloblastic; malaria; hyperbilirubinaemia.)... blood, disorders of

The process of giving blood for use in blood transfusion.

Donated blood is tested for a range of infectious agents such as hepatitis B and hepatitis C and antibodies to HIV. After being classified into blood groups, the blood is stored in a blood bank, either whole or separated into its different components (see blood products). Apheresis is a type of blood donation in which only a specific blood component, such as plasma, platelets, or white cells, is withdrawn from the donor. blood film A test that involves smearing a drop of blood on to a glass slide for examination under a microscope. The blood film is stained with dyes to make the blood cells show up clearly.

The test allows the shape and appearance of blood cells to be checked for any abnormality, such as the sickleshaped red blood cells characteristic of sickle cell anaemia.

The relative proportions of the different types of white blood cells can also be counted.

This examination, called a differential white cell count, may be helpful in diagnosing infection or leukaemia.

Blood films are also used in diagnosing infections, such as malaria, in which the parasites can be seen inside the red blood cells.

Blood films are usually carried out together with a full blood count.... blood donation

The use of a person’s own blood, donated earlier, for blood transfusion. Autologous transfusion eliminates the slight but serious risk of contracting a serious infectious illness from contaminated blood. There is no risk of a transfusion reaction occurring as a result of incompatibility between donor and recipient blood. Up to 3.5 litres of blood can be removed and stored in several sessions at least 4 days apart and up to 3 days before planned surgery. Blood may be salvaged during surgery, filtered and returned to the circulation, reducing the need for transfusion of donated blood.... blood transfusion, autologous

A general term given to arteries, veins, and capillaries (see circulatory system).... blood vessels

The toxic effects of chemicals present in some defoliant weedkillers. Ingesting chlorates can cause kidney and liver damage, corrosion of the intestine, and methaemoglobinaemia (a chemical change in haemoglobin in the blood). Small doses of chlorates can prove fatal. Symptoms of poisoning include ulceration in the mouth, abdominal pain, and diarrhoea.... chlorate poisoning

Donated blood that is separated into its various components: red cells, white cells, platelets, and plasma (see blood donation). Each blood product has a specific lifespan and use in blood transfusion. Packed red cells (blood with most of the plasma removed) are used to treat patients with some forms of chronic anaemia and babies with haemolytic disease of the newborn. Washed red cells (with white blood cells and/or plasma proteins removed) are used when a person needs repeated transfusions because there is less risk of an allergy to any of the blood components developing.

Platelets may be given in transfusions for people with blood-clotting disorders. Patients who have life-threatening infections may be treated with granulocytes, a type of white blood cell. Fresh frozen plasma is used to correct many types of bleeding disorder because it contains all the clotting factors. Albumin, prepared from the plasma of whole blood, is used mainly to treat shock resulting from severe blood loss until compatible whole blood becomes available. Purified albumin preparations are used to treat nephrotic syndrome and chronic liver disease.

Concentrates of blood clotting factors and are used in the treatment of haemophilia and Christmas disease.

Immunoglobulins (also called antibodies), which are extracted from blood plasma, can be given by injection (see immunoglobulin injection) to protect people who are unable to produce their own antibodies or have already been exposed to an infectious agent, or to provide short-term protection against hepatitis A.

Immunoglobulins are given in large doses to treat certain autoimmune disorders.... blood products

Analysis of a sample of blood to give information on its cells and proteins and any of the chemicals, antigens, antibodies, and gases that it carries. Such tests can be used to check on the health of major organs, as well as on respiratory function, hormonal balance, the immune system, and metabolism. Blood tests may look at numbers, shape, size, and appearance of blood cells and assess the function of clotting factors. The most important tests are blood count and blood group tests if transfusion is needed. Biochemical tests measure chemicals in the blood (see acid–base balance; kidney function tests; liver function tests). Microbiological tests (see immunoassay) look for microorganisms that are in the blood, as

in septicaemia. Microbiology also looks for antibodies in the blood, which may confirm immunity to an infection. blood transfusion The infusion of large volumes of blood or blood products directly into the bloodstream to remedy severe blood loss or to correct chronic anaemia. In an exchange transfusion, nearly all of the recipient’s blood is replaced by donor blood. Before a transfusion, a sample of the recipient’s blood is taken to identify the blood groups, and it is matched with suitable donor blood. The donor blood is transfused into an arm vein through a plastic cannula. Usually, each unit (about 500 ml) of blood is given over 1–4 hours; in an emergency, 500 ml may be given in a couple of minutes. The blood pressure, temperature, and pulse are monitored during the procedure.

If mismatched blood is accidentally introduced into the circulation, antibodies in the recipient’s blood may cause donor cells to burst, leading to shock or kidney failure. Less severe reactions can produce fever, chills, or a rash. Reactions can also occur as a result of an allergy to transfused blood components. All

blood used for transfusion is carefully screened for a number of infectious agents, including HIV (the AIDS virus) and hepatitis B and hepatitis C.

In elderly or severely anaemic patients, transfusion can overload the circulation, leading to heart failure.

In patients with chronic anaemia who need regular transfusion over many years, excess iron may accumulate (haemosiderosis) and damage organs such as the heart, liver, and pancreas.

Treatment with desferrioxamine to remove excess iron may be needed.... blood tests

The main mechanism by which blood clots are formed, involving a complex series of reactions in the blood plasma (see blood clotting).... coagulation, blood

A symptom, medically known as haemoptysis, that is caused by rupture of a blood vessel in the air-ways, lungs, nose, or throat. The coughed-up blood may appear as brightred or rusty-brown streaks, clots in the sputum, a pinkish froth, or, more rarely, blood alone. In all cases, medical assessment is needed. Many disorders can cause haemoptysis. The most common are infections, such as pneumonia or bronchitis; and congestion in and rupture of blood vessels in the lungs due to heart failure, mitral stenosis, or pulmonary embolism. A cancerous tumour can also produce haemoptysis by eroding the wall of a blood vessel.

Investigations into coughing up blood include chest X-ray, and, in some cases, bronchoscopy. In about a 3rd of cases, no underlying cause is found. Treatment depends on the cause.... coughing up blood

The toxic effects of plant poisons that cause leaves to drop off.

Defoliants are poisonous if swallowed.

Widely used defoliants include sodium chlorate, potassium chlorate, phenoxy herbicides, and paraquat.... defoliant poisoning

The toxic effects that occur as a result of swallowing the cleaning agents in shampoos, laundry powders, and cleaning liquids.... detergent poisoning

See faeces, abnormal; rectal bleeding.... faeces, blood in the

The presence in the faeces of blood that cannot be seen by the naked eye, but can be detected by chemical tests. Such tests are widely used in screening for cancer of the colon (see colon, cancer of). Faecal occult blood may also be a sign of a gastrointestinal disorder such as oesophagitis, gastritis, or stomach cancer; cancer of the intestine (see intestine, cancer of); rectal cancer (see rectum, cancer of); diverticular disease; polyps in the colon; ulcerative colitis; or irritation of the stomach or intestine by drugs such as aspirin. (See also rectal bleeding.)... occult blood, faecal

A usually harmless condition in which a small amount of blood is present in the semen.

Occasionally, there is an underlying cause (such as an infection or, very rarely, cancer) that requires treatment.

Blood in the semen may also occur after a prostate biopsy.... semen, blood in the

The harmful effects on the body as a result of an excessive dose of a drug. Accidental poisoning is most common in young children. In adults, it usually occurs in elderly or confused people who are unsure about their treatment and dosage requirements. Accidental poisoning may also occur during drug abuse. Deliberate self-poisoning is usually a cry for help (see suicide; suicide, attempted). The drugs that are most commonly taken in overdose include benzodiazepine drugs and antidepressant drugs. Anyone who has taken a drug overdose and any child who has swallowed tablets that belong to someone else should seek immediate medical advice. It is important to identify the drugs that have been taken. Treatment in hospital may involve washing out the stomach (see lavage, gastric). Charcoal may be given by mouth to reduce the absorption of the drug from the intestine into the bloodstream. To eliminate the drug, urine production may be increased by an intravenous infusion. Antidotes are available only for specific drugs. Such antidotes include naloxone (for morphine) and methionine (for paracetamol).

Drug poisoning may cause drowsiness and breathing difficulty, irregular heartbeat, and, rarely, cardiac arrest, fits, and kidney and liver damage.

Antiarrhythmic drugs are given to treat heartbeat irregularity.

Fits are treated with anticonvulsants.

Blood tests to monitor liver function and careful monitoring of urine output are carried out if the drug is known to damage the liver or kidneys.... drug poisoning

Poisons may be swallowed, inhaled, absorbed through skin, or injected under the skin (as with an insect sting).

Poisons may also originate in the body, as when bacteria produce endotoxins, or when metabolic disorders produce poisonous substances or allow them to build up.

Poisoning may be acute (a large amount of poison over a short time) or chronic (gradual accumulation of poison that is not eliminated quickly).

Unintentional poisoning occurs mainly in young children.

Adults may be poisoned by mistaking the dosage of a prescribed drug (see drug poisoning), by taking very high doses of vitamin or mineral supplements, by exposure to poisonous substances in industry, or by drug abuse.

Poisoning may also be a deliberate attempt to commit suicide.... poisoning

See food poisoning.... shellfish poisoning

Strychnine is a poisonous chemical found in the seeds of Strychnos species (tropical trees and shrubs). Its main use is as an ingredient in some rodent poisons; most cases of strychnine poisoning occur in children who accidentally eat such poisons.

Symptoms begin soon after ingestion and include restlessness, stiffness of the face and neck, increased sensitivity of hearing, taste, and smell, and photosensitivity, followed by alternating episodes of seizures and floppiness. Death may occur from respiratory arrest.

The victim is given intravenous injections of a tranquillizer or a barbiturate, with a muscle-relaxant drug if needed.

Breathing may be maintained by a ventilator.

With prompt treatment, recovery usually occurs in about 24 hours.... strychnine poisoning

See mushroom poisoning.... toadstool poisoning

A symptom of bleeding from within the digestive tract. Vomiting blood may be caused by a tear in the lower oesophagus (see Mallory–Weiss syndrome), bleeding from oesophageal varices, erosive gastritis, peptic ulcer, or, rarely, stomach cancer. Blood can also be vomited if it is swallowed during a nosebleed. Vomited blood may be dark red, brown, black, or may resemble coffee grounds. Vomiting of blood is often accompanied by the passing of black, tarry faeces.

The cause of vomiting blood is investigated by endoscopy of the oesophagus and stomach, or by barium X-ray examinations. If blood loss is severe, blood transfusion, and possibly surgery to stop the bleeding, may be required.... vomiting blood

(blood corpuscle) any of the cells that are present in the blood in health or disease. The cells may be subclassified into three major categories, namely red cells (*erythrocytes); white cells (*leucocytes), which include granulocytes, lymphocytes, and monocytes; and *platelets (see illustration). The blood cells account for approximately 40% of the total volume of the blood in health; red cells comprise the vast majority.... blood cell

Blood group of people donor can receive blood from... donor’s blood group

... blood plasma see plasma.

see serum.... blood serum

(FOBT) a noninvasive test used to identify microscopic blood (see occult) in faeces. It is widely used as a screening test for colorectal cancer.... faecal occult blood test

see Guthrie test.... heel-prick blood test

(NHSBT) a *special health authority established in 2005 to provide a safe and reliable supply of blood, organs, stem cell services, and diagnostics to hospitals. NHSBT also provides specialist therapeutic apheresis services, which remove or replace a single component of blood (e.g. malignant white cells or low-density lipoprotein), at six sites in England.

NHS Blood and Transplant website... nhs blood and transplant

haemopoietic *stem cells collected from umbilical cord blood donated at birth, which can be stored indefinitely and used if a sibling or any other blood-compatible baby develops an illness (such as leukaemia) that could only be treated by cord-blood stem-cell transplantation. This facility is now available in the UK and the USA.... umbilical cord blood banked stem cells

(blood clotting) the process whereby blood is converted from a liquid to a solid state. The process may be initiated by contact of blood with a foreign surface (intrinsic system) or with damaged tissue (extrinsic system). These systems involve the interaction of a variety of substances (*coagulation factors) and lead to the production of the enzyme thrombin, which converts the soluble blood protein *fibrinogen to the insoluble protein *fibrin, forming the blood clot. Finally, fibrin is broken down by the action of *plasmin. Anticoagulants and tissue plasminogen activators act by inhibiting or activating various pathways in this cascade (see illustration). Blood coagulation is an essential mechanism for the arrest of bleeding (*haemostasis). See also platelet activation.... blood coagulation

any one of the many types into which a person’s blood may be classified, based on the presence or absence of certain inherited antigens on the surface of the red blood cells. Blood of one group contains antibodies in the serum that react against the cells of other groups.

There are more than 30 blood group systems, one of the most important of which is the ABO system. This system is based on the presence or absence of antigens A and B: blood of groups A and B contains antigens A and B, respectively; group AB contains both antigens and group O neither. Blood of group A contains antibodies to antigen B; group B blood contains anti-A antibodies or *isoagglutinins; group AB has neither antibody and group O has both. A person whose blood contains either (or both) of these antibodies cannot receive a transfusion of blood containing the corresponding antigens. The table illustrates which blood groups can be used in transfusion for each of the four groups.

Blood group... blood group