HEALTH - Why cough medicine is a waste of money... and so are whitening toothpastes and those costly antibacterial wipes

Why cough medicine is a waste of money... and so are whitening toothpastes and those costly antibacterial wipes 

• £2.5 billion is spent on over-the-counter medicines including cough medicines, whitening toothpastes, insect bite relief and insomnia remedies 
• But emerging evidence suggests a vast number of these pills and potions are useless - with some actually making our health worse 
• Expert at Birmingham University claims High Street chemists are 'endorsing quackery' in the pursuit of profits  
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By JOHN NAISH FOR THE DAILY MAIL

PUBLISHED: 00:34 GMT, 11 November 2014 | UPDATED: 13:32 GMT, 11 November 2014

Each year we spend £2.5 billion on over-the-counter medicines from chemists, corner shops and supermarkets, a figure that has been growing by nearly 10 per cent annually. 

Yet emerging evidence suggests many of these pills and lotions are utterly useless — and some can actually make our health worse.

Anthony Cox, a clinical pharmacy lecturer at Birmingham University, claims that by selling such products, High Street chemists are ‘endorsing quackery’ in the pursuit of profits.

‘Community pharmacists should stop selling over-the-counter medicines that have little evidence of efficacy,’ he wrote in The Pharmaceutical Journal in August. 

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Emerging evidence suggests many over-the-counter medicines from chemists, corner shops and supermarkets are utterly useless — and some can actually make our health worse

Even some of the biggest-selling products have no scientific basis to prove they work. Here, we identify several of the items you don’t need in your bathroom cabinet.

COUGH MEDICINE 

What we spend a year: £96 million

What does everyone do when they get a cough? 

They go out and buy some cough medicine, of course. Yet there is little, if any proof, that it will help you recover.

Dr Tim Ballard, vice-chairman of the Royal College Of General Practitioners, says: ‘The medical evidence behind cough medicines is weak, and there’s no evidence they’ll reduce the duration of illnesses.’

If your cough is caused by a viral infection, as coughs most commonly are, there is no quick way of getting rid of it — you simply have to wait for the immune system to clear the virus. 

Cough medicines won’t speed up this process, no matter what ‘wonder’ ingredients are proclaimed on the package.

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The NHS Choices website suggests cough sufferers make their own remedy of honey and lemon

A review of 17 studies involving 2,876 adults and eight studies involving 616 children by the influential Cochrane Collaboration in 2008 found no robust evidence that dextromethorphan or diphenhydramine — two common ingredients in over-the-counter cough medicines — helped. Anthony Cox warns some costly cough medicines may even be harmful. 

‘The drug combinations they contain can be illogical — such as an expectorant, which produces mucus, with a cough suppressant, which quashes the urge to eject mucus,’ he says. 

‘These are often more likely to bring about an adverse effect, such as drowsiness and nausea, or no effect.’

A spokesman for the Proprietary Association of Great Britain, which represents makers of over-the-counter drugs, says: ‘Cough medicines will not “cure” a cough, but they can help relieve the symptoms.’

The NHS Choices website suggests cough sufferers make their own remedy of honey and lemon. 

‘The honey is a demulcent, which means it coats the throat and relieves the irritation that causes coughing,’ it says. 

The lemon is there only to add sharpness to the flavour.

EAR-WAX REMOVER

What we spend a year: £7.8 million

A bottle of eardrops from the chemist may contain impressive-sounding ingredients such as glycerol and urea hydrogen peroxide to help loosen or dissolve wax.

There is, however, no good clinical evidence to show these work any better than simply putting water in your ear to soften wax, according to a study by the Cochrane Ear, Nose And Throat Disorders Group.

Its study in 2009, led by Martin Burton, an otolaryngologist (ear, nose and throat specialist) at the Oxford Radcliffe Hospitals NHS Trust, concluded: ‘Saline or water seems to be as effective as any over-the-counter agent. And both have the virtue of being cheap and readily available.’

ANTIHISTAMINES FOR INSOMNIA

What we spend a year: £42.5 million

Many over-the-counter sleep-aid pills contain the antihistamine diphenhydramine.

This is commonly used to quell allergic reactions and has the side-effect of drowsiness. 

However, there is no scientific evidence to support its usefulness for treating insomnia.

Indeed, the NHS Choices website warns: ‘Good evidence of diphenhydramine’s efficacy is lacking.’

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Many over-the-counter sleep-aid pills contain the antihistamine diphenhydramine. This is commonly used to quell allergic reactions 

and has the side-effect of drowsiness

There are only two robust clinical studies that have tested its effectiveness in treating insomnia.

The first, published in the journal Sleep in 2005, compared a sleep-aid dose of diphenhydramine with a placebo pill in 20 elderly insomniacs. 

The participants reported no difference in how long they took to drop off to sleep, how well they slept or for how long.

The second study, in the same journal report, examined 184 adults with mild insomnia. 

Automated readings of their brain, eye and muscle activity found that taking diphenhydramine had no more effect than placebo pills.

Diphenhydramine’s other side-effects can include dry mouth, dizziness, headaches, constipation and urinary retention.

PAIN-RELIEF RUBS WITH ASPIRIN

What we spend a year: £20 million

The active ingredient in aspirin, salicylate, is proven to reduce pain and inflammation when swallowed. But that does not mean it is effective in a skin rub for muscle aches. 

The idea is that by putting the painkiller next to the strained muscle, it soothes the area faster and more effectively.

However, a comprehensive review of research by the Cochrane Database of Systematic Reviews in 2009 found little evidence that over-the-counter pain-relieving creams containing salicylate have any effect on muscle aches and pains when compared with a sham placebo cream.

Dr Andrew Moore, an Oxford University biochemist who led the review, concluded that such creams are a waste of money.

Those containing non-steroidal anti-inflammatory painkiller gels, such as ibuprofen or diclofenac, work considerably better, he said.

INSECT-BITE CREAMS 

What we spend a year: £14 million

There are dozens of over-the-counter creams and pills to relieve itching and swelling caused by insect bites — but there is little evidence they do much to help. 

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There is no solid evidence the £14 million we spend each year on insect bite creams and pills to relieve itching and swelling. do much 

to help

Creams that contain painkillers or anaesthetics, or those with antihistamines and antiseptics, are only ‘marginally effective’, according to a review by the Drug And Therapeutics Bulletin in 2012.

It warned that these chemical-laden creams can make skin even more sensitive.

Other options include steroid tablets and ointments, such as hydrocortisone. 

But once again there is no solid evidence to suggest they work, unless the people using them suffer from reactive skin conditions such as eczema, the journal reported.

A simple antiseptic cream can have a soothing ‘kiss-it-better’ effect for a child with an insect bite, as well as being an infection-fighting precaution.

ANTIBACTERIAL SOAPS AND WIPES 

What we spend a year: £239 million

Although it seems common sense that antibacterial soap can protect ourselves and our families from illness caused by bacteria, this is not what the evidence shows.

More than four decades of research by the U.S. government’s Food And Drug Administration, along with numerous independent studies, have produced no evidence that triclosan, the active ingredient in many antibacterial soaps, hand gels and wipes, has any health benefits over old-fashioned soap and water.

One basic problem is that antibacterial soaps specifically target bacteria rather than viruses. But it is viruses that cause the majority of illnesses, such as colds and flu.

The most effective scientifically proven way to keep bacteria at bay is regular hand-washing with ordinary soap, along with good food hygiene in the kitchen.

Antibacterial soaps may actually cause health problems, too. 

Evidence shows children with prolonged exposure to triclosan over months or years have a greater chance of developing allergies, including peanut allergies and hay fever, according to studies in the Journal of Allergy And Clinical Immunology in 2012, and in Environmental Health Perspectives in 2011.

This may be due to the fact that youngsters who use antibacterial soaps and cleansers reduce their exposure to bacteria. 

But the bugs may be essential for training their developing immune systems to respond appropriately to potential infections and allergens.

WHITENING TOOTHPASTES 

What we spend a year: £60 million

More than 40 per cent of us use whitening toothpastes — even though they often cost three times more than standard toothpaste.

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More than 40 per cent of us use whitening toothpastes, at a cost of £60 million a year, but investigators at the Cochrane Oral Health 

Group said there is a complete lack of clinical studies to back up makers' claims

The pastes purport to work by bleaching or being abrasive. However, investigators at the Cochrane Oral Health Group complained last February there is a complete lack of clinical studies to back up makers’ claims.

Some of these products proclaim that they use hydrogen peroxide as a bleaching agent to whiten out stains.

But Dr Nigel Carter, chief executive of the British Dental Health Foundation, says: ‘Toothpastes sold in the EU can legally contain only 0.1 per cent hydrogen peroxide, in order to be safe.

‘The chance of that amount having an effect on teeth is virtually non-existent. You need at least 30 times that to achieve anything.’

Dr.E busts some of the myths and tricks of modern toothpastes

Source: http://www.dailymail.co.uk

CHEMICAL HAZARD - Children more susceptible to environmental carcinogens

Children are more vulnerable to carcinogens than are adults. Children have many more years of life ahead of them after a toxic exposure in which to develop a tumour.

Malignant transformation is a slow process. Children's ability to detoxify environmental chemicals is not fully developed. They lack certain mechanisms possessed by adults that enhance the removal of toxic chemicals from the body.

Thus children's exposures to environmental carcinogens must be minimised.

There are many reasons why toxic chemicals are greater threats to children than to adults.

-- Pound for pound, children breathe more air, drink more water and consume more food than adults. This higher rate of intake means that children will receive higher doses of whatever contaminants are present in the air, water or food.

(In the US, it has been estimated that children aged 1-5 eat 3-4 times more per unit of body weight than the average adult. Infants and children drink more than 2 1/2 times as much water daily as adults do as a percentage of body weight. And the air intake of a resting infant is twice that of an adult under the same conditions.)

-- Children are also more susceptible to chemicals because of their smaller size. For example, a typical newborn weighs 1/20 of the weight of an adult male, but the infant's surface area is 1/8 as great. Therefore, the total area of skin that could be exposed to a chemical (by bathing in polluted water or rolling in dirt for instance) is 2 1/2 times as great per unit of body weight in the infant as in the adult.

-- Children absorb a greater proportion of many substances from the intestinal tract or lung. For example, children take up approximately half of the lead that they swallow while adults absorb only about one-tenth.

-- Children indulge in more hand-to-mouth activity than adults and transfer more foreign substances into their bodies through this route. Since children often play in the dirt, they are also closer to the source of many pollutants.

-- Children's biology is different. Their immune system is less developed, and may be less protective. For some toxicants, the body has developed biochemical detoxifying mechanisms; in some instances, these are less developed in children.

-- Cells that are developing (in children) are generally more vulnerable than cells that have completed development (in adults). This is particularly true for the central nervous system.

Source: http://consumer.org.my/

HEALTH HAZARD - Metal toxicity

From Wikipedia, the free encyclopedia

Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous soluble compounds. Certain metals have no biological role, i.e. are not essential minerals, or are toxic when in a certain form.^[1] In the case of lead, any measurable amount may have negative health effects.^[2] Often heavy metals are thought as synonymous, but lighter metals may also be toxic in certain circumstances, such as beryllium and lithium. Not all heavy metals are particularly toxic, and some are essential, such as iron. The definition may also include trace elements when considered in abnormally high, toxic doses. An option for treatment of metal poisoning may be chelation therapy, which is a technique which involves the administration of chelation agents to remove metals from the body.

Toxic metals sometimes imitate the action of an essential element in the body, interfering with the metabolic process to cause illness. Many metals, particularly heavy metals are toxic, but some heavy metals are essential, and some, such as bismuth, have a low toxicity. Most often the definition of toxic metals includes at least cadmium, lead, mercury and the radioactive metals.^{[citation needed]} Metalloids (arsenic, polonium) may be included in the definition. Radioactive metals have both radiological toxicity and chemical toxicity. Metals in an oxidation state abnormal to the body may also become toxic: chromium(III) is an essential trace element, but chromium(VI) is a carcinogen.

Toxicity is a function of solubility. Insoluble compounds as well as the metallic forms often exhibit negligible toxicity. The toxicity of any metal depends on its ligands. In some cases, organometallic forms, such as methylmercury and tetraethyl lead, can be extremely toxic. In other cases, organometallic derivatives are less toxic such as the cobaltocenium cation.

Decontamination for toxic metals is different from organic toxins: because toxic metals are elements, they cannot be destroyed. Toxic metals may be made insoluble or collected, possibly by the aid of chelating agents. Alternatively, they can be diluted into a sufficiently large reservoir, such as the sea, because immediate toxicity is a function of concentration rather than amount. However, bioaccumulation has the potential to reverse this.

Toxic metals can bioaccumulate in the body and in the food chain.^{[citation needed]} Therefore, a common characteristic of toxic metals is the chronic nature of their toxicity. This is particularly notable with radioactive heavy metals such as radium, which imitates calcium to the point of being incorporated into human bone, although similar health implications are found in lead or mercury poisoning. The exceptions to this are barium and aluminium, which can be removed efficiently by the kidneys.

Testing for poisoning

People are continually exposed to metals in the environment.^[3] Medical tests can detect metals often, but this is to be expected and alone is not evidence that a person is poisoned.^[3] Metal screening tests should not be used unless there is reason to believe that a person has had excessive exposure to metals.^[3] People should seek medical testing for poisoning only if they are concerned for a particular reason, and physicians should consider a patient's history and physical examination before conducting tests to detect metals.^[3]

People who have metal tests when such testing is not indicated often have results higher than the typical range, even when they are not experiencing metal toxicity.^[3]People who get such results may be overly concerned, then seek further unnecessary health care.^[3]

Treatment for poisoning

Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. It should only be used in people who have a diagnosis of metal intoxication.^[4] That diagnosis should be validated with tests done in appropriate biological samples.^[4]

Chelation therapy is administered under very careful medical supervision due to various inherent risks.^[5] When the therapy is administered properly, the chelation drugs have significant side effects.^[4] Chelation administered inappropriately can cause neurodevelopmental toxicity, increase risk of developing cancer, and cause death.^[4]

Specific types of poisoning

Aluminium phosphide poisoning

Main article: Aluminium phosphide poisoning

Aluminium has no known biological role and its classification into toxic metals is controversial. Significant toxic effects and accumulation to tissues have been observed in renally impaired patients.^[6]

Acute aluminium phosphide poisoning (AAlPP) is a large, though under-reported, problem in the Indian subcontinent. Aluminium phosphide (AlP), which is readily available as a fumigant for stored cereal grains, sold under various brand names such as QuickPhos and Celphos, is highly toxic, especially when consumed from a freshly opened container.^[7][8] Death results from profound shock, myocarditis and multi-organ failure.^[9] Aluminium phosphide has a fatal dose of between 0.15 and 0.5 grams (0.0053 and 0.0176 oz).^[10] It has been reported to be the most common cause of suicidal death in North India.^[11]

Arsenic poisoning

Main article: arsenic poisoning

Arsenic poisoning is a medical condition caused by elevated levels of arsenic in the body. The dominant basis of arsenic poisoning is from ground water that naturally contains high concentrations of arsenic. A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning from drinking water.^[12]

Beryllium poisoning

Main article: Beryllium poisoning

Beryllium poisoning is illness resulting from the toxic effect of beryllium in its elemental form or in various chemical compounds. The toxicity of beryllium depends upon the duration, intensity and frequency of exposure (features of dose), as well as the form of beryllium and the route of exposure (i.e. inhalation, dermal, ingestion). According to the International Agency for Research on Cancer (IARC), beryllium and beryllium compounds are Category 1 carcinogens; they are carcinogenic to both animals and humans.^[13]

Cadmium poisoning

Main article: Cadmium poisoning

Cadmium is an extremely toxic metal commonly found in industrial workplaces. Due to its low permissible exposure limit, overexposures may occur even in situations where trace quantities of cadmium are found. Cadmium is used extensively in electroplating, although the nature of the operation does not generally lead to overexposures. Cadmium is also found in some industrial paints and may represent a hazard when sprayed. Operations involving removal of cadmium paints by scraping or blasting may pose a significant hazard. Cadmium is also present in the manufacturing of some types of batteries. Exposures to cadmium are addressed in specific standards for the general industry, shipyard employment, construction industry, and the agricultural industry.^[14]

Copper toxicity

Main article: Copper toxicity

Copper toxicity, also called copperiedus, refers to the consequences of an excess of copper in the body. Copperiedus can occur from eating acid foods cooked in uncoated copper cookware, or from exposure to excess copper in drinking water or other environmental sources.

Iron poisoning

Main article: Iron poisoning

Iron poisoning is an iron overload caused by a large excess of iron intake and usually refers to an acute overload rather than a gradual one. The term has been primarily associated with young children^[15] who consumed large quantities of iron supplement pills, which resemble sweets and are widely used, including by pregnant women—see overnutrition (approximately 3 grams is lethal for a 2 year old).^[16] Targeted packaging restrictions in the US for supplement containers with over 250 mg elemental iron have existed since 1978, and recommendations for unit packaging have reduced the several iron poisoning fatalities per year to almost nil since 1998.^[17][18] No known cases of iron poisoning have been identified that are associated with iron mining.

Lead poisoning

Main article: Lead poisoning

Lead poisoning is a medical condition in humans and other vertebrates caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It interferes with the development of the nervous system and is therefore particularly toxic to children, causing potentially permanent learning and behavior disorders. Symptoms include abdominal pain, confusion, headache, anemia, irritability, and in severe cases seizures, coma, and death.

Lithium poisoning

Lithium is used in some medications, specifically to treat bi-polar disorder. The level of "sufficient" medication is thought by many physicians to be close to toxic tolerance for kidney function. Therefore the patient is often monitored for this purpose.^[19][20]

Manganese poisoning, or manganism

Main article: Manganism

Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese and first identified in 1837 by James Couper.^[21]

Mercury poisoning

Main article: Mercury poisoning

Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury (chemical symbol Hg) is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses. Its zero oxidation state Hg⁰ exists as vapor or as liquid metal, its mercurous state Hg₂²⁺ exists as inorganic salts, and its mercuric state Hg²⁺ may form either inorganic salts or organomercury compounds; the three groups vary in effects. Toxic effects include damage to the brain, kidney, and lungs. Mercury poisoning can result in several diseases, including acrodynia (pink disease), Hunter-Russell syndrome, and Minamata disease.

Symptoms typically include sensory impairment (vision, hearing, speech), disturbed sensation and a lack of coordination. The type and degree of symptoms exhibited depend upon the individual toxin, the dose, and the method and duration of exposure.

Silver poisoning, or Argyria

Main article: Argyria

Argyria or argyrosis is a condition caused by inappropriate exposure to chemical compounds of the element silver, or to silver dust.^[22] The most dramatic symptom of argyria is that the skin turns blue or bluish-grey. It may take the form of generalized argyria or local argyria. Generalized argyria affects large areas over much of the visible surface of the body. Local argyria shows in limited regions of the body, such as patches of skin, parts of the mucous membrane or the conjunctiva.

Thallium poisoning

Main article: Thallium poisoning

Thallium and its compounds are often highly toxic.^[23] Contact with skin is dangerous, and adequate ventilation should be provided when melting this metal.^[24] Many thallium(I) compounds are highly soluble in water and are readily absorbed through the skin.^{[citation needed]} Exposure to them should not exceed 0.1 mg per m² of skin in an 8-hour time-weighted average (40-hour work week). Thallium is a suspected human carcinogen.^[24]

Tin poisoning

Main article: Tin poisoning

Tin poisoning refers to the toxic effects of tin and its compounds. Cases of poisoning from tin metal, its oxides, and its salts are "almost unknown"; on the other hand certain organotin compounds are almost as toxic as cyanide.^[25]

Zinc toxicity

Main article: Zinc toxicity

Even though zinc is an essential requirement for a healthy body, excess zinc can be harmful, and cause zinc toxicity. Such toxicity levels have been seen to occur at ingestion of greater than 225 mg of Zinc.^[26] Excessive absorption of zinc can suppress copper and iron absorption. The free zinc ion in solution is highly toxic to bacteria, plants, invertebrates, and even vertebrate fish.^[27][28][29]

Society and culture

It is difficult to differentiate the effects of low level metal poisoning from the environment with other kinds of environmental harms, including nonmetal pollution.^[30]Generally, increased exposure to heavy metal in the environment increases risk of developing cancer.^[31]

Without a diagnosis of metal toxity and outside of evidence-based medicine, but perhaps because of worry about metal toxicity, some people seek chelation therapy to treat autism, cardiovascular disease, Alzheimer's disease, or any sort of neurodegeneration.^[4] Chelation therapy does not improve outcomes for those diseases.^[4]

Source: http://en.wikipedia.org/

HEALTH HAZARD - Heavy Metal Poisoning

PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

Heavy metals are commonly defined as those elements with a high (>5.0) relative density. There is, however, an ongoing debate regarding the exact definition and, in terms of health, it is better to think of these as metals or semi-metal compounds which have the potential to cause environmental or human toxicity. Heavy metal poisoning can be acute or chronic and may be caused by the following:

• Lead.
• Mercury.
• Iron.
• Cadmium.
• Thallium.
• Bismuth.
• Arsenic (technically not a true metal but a semi-metal - ie non-metal with some metallic properties).

The metals may enter the body by:

• Ingestion.
• Inhalation.
• Absorption through the skin or mucous membranes.

They are then stored in the soft tissues of the body. The heavy metals once absorbed, compete with other ions and bind to proteins, leading to impaired enzymatic activity resulting in damage to many organs throughout the body.

Epidemiology

Heavy metal poisoning is rare in the UK, even in industries where there is an increased risk.^[1]

• The most common cause of heavy metal poisoning is lead. The incidence of lead poisoning has been falling steadily in affluent countries, due to removal of lead from paint, petrol and food cans.^[2]
• Lead poisoning remains a problem, however, in older housing where lead water pipes and lead paint may still be present. In housing such as this, there is a particular risk to children and the American Centre for Disease Control and Prevention recognised this and recommended screening of children in areas considered to pose a threat from this hazard, in order to prevent the children from developing neurological damage.^[3]
• Other sources of lead poisoning are occupations (eg, smelting, battery manufacture), traditional remedies, or occasionally foreign bodies (lead weights).
• Mercury can be found in the elemental state (dental amalgam, thermometers), inorganic (industrial processes) and organic compounds (pesticides, wood preservatives, some medicines, and contaminated fish).
• Ingestion of disc batteries by children can also lead to heavy metal poisoning amongst other problems. These batteries can contain varying amounts of metals including mercury, manganese and cadmium.
• Poisoning from other heavy metals most often occurs in individuals regularly exposed to the metals in their work environment.
• Criminal poisoning with lead has been reported.

Presentation

The presentation will depend on the age of the individual, the metal absorbed, and whether this was the result of acute exposure - eg, vapour inhalation, or exposure over a more prolonged period of time.

Differential diagnosis

The differential diagnosis will depend on the symptoms and signs displayed, but may include causes of encephalopathy, dementia, substance abuse and causes of vomiting and diarrhoea.

Investigations

Investigation of any person in whom a diagnosis of heavy metal poisoning is a possibility may include:

• Full history - including occupational history, age of house and water supply if known.
• Examination.
• FBC and film - basophilic stippling with lead and arsenic poisoning, normochromic or microcytic anaemia with lead toxicity.
• Blood levels for lead and mercury.
• 24-hour urine collection - mercury and arsenic levels.
• Long bone X-ray in children - horizontal metaphyseal lines ('lead bands' caused by failure of the bones to remodel, not seen in adults).
• CXR - may show radiodense pulmonary emboli following injection of mercury.

Management

Also, see separate article Acute Poisoning - General Measures.

Current advice on the management of any form of heavy metal poisoning may be obtained from the UK National Poisons Information Service or TOXBASE.

Specific metals

See separate articles Arsenic Poisoning, Lead Poisoning, Tungsten Poisoning and Thallium Poisoning. 

Mercury poisoning

The toxic dose for mercury compounds is about 10-50 mg/kg. Mercury is poorly absorbed from the gut and ingestion is usually harmless (unless aspiration occurs). A single dose (eg, a broken thermometer) usually causes no problems. It is only slowly absorbed through the skin but can cause contact dermatitis.

In the mid-1950s to 1968 the people of Minamata, Japan suffered chronic mercury poisoning from pollution from a local factory (Minamata disease). 'Mad as a hatter' is derived from poisoning among hatmakers who used mercuric nitrate to soften the hair of animal hides.

Acute poisoning:

• An acute pneumonitis (± adult respiratory distress syndrome (ARDS)).
• Flu-like symptoms.
• Irritability.
• Myalgia.
• Gastrointestinal upset.
• Subsequent peripheral neuropathy, hepatic dysfunction or renal failure may develop.

Chronic poisoning:

• Irritability.
• Personality changes.
• Headache.
• Peripheral neuropathy.
• Memory problems.
• Ataxia.
• Coma.
• Respiratory problems (pneumonitis and ARDS).
• Gastrointestinal upset (abdominal pain, gingivitis and stomatitis, nausea, vomiting).
• Renal problems include acute renal failure, nephrotic syndrome and acute tubular necrosis.

Management of inhalation of mercury should be treated with intravenous (IV) hydrocortisone to minimise pulmonary complications. Acute intakes of inorganic mercury should be treated with chelating agents such as d-penicillamine.

Iron poisoning

Iron overdose can present with:

• Nausea ± vomiting.
• Abdominal pain and diarrhoea.
• Possible gastrointestinal bleeds.
• Serious overdose, which causes hepatocellular necrosis (jaundice, hepatic failure).
• Gastric outflow obstruction, which may be a late complication.

Iron poisoning needs urgent treatment with emergency admission and desferrioxamine (IV) as an antidote. Chronic iron excess is dealt with in the separate article Iron Overload.

Cadmium poisoning

Toxic by inhalation and ingestion and also, although occurring rarely, absorption through the skin. Symptoms develop 12-36 hours after inhalation (cadmium fume fever is an occupational illness due to exposure to fumes during welding).

Presents with:

• Metallic taste and increased salivation.
• Nausea, vomiting and diarrhoea.
• Impaired sensation.
• Difficulty breathing, cough, chest pain.

Complications include pneumonitis and pulmonary oedema.

Chronic exposure may cause anaemia, emphysema or renal failure, and cadmium may be a risk factor in the development of prostate or lung cancer.

At present there is no effective therapy for cadmium poisoning, and treatment is supportive and symptomatic. It is hoped that some of the newer chelating agents may help in reducing cadmium levels in the body.

Bismuth poisoning

Has a few industrial uses in pigments, ceramics and low-melting alloys.
Can cause:

• Kidney damage and the development of a nephrotic syndrome.
• May also cause the development of a reversible encephalopathy.

 A chelating agent can be used in the management, but treatment is not always necessary.

Source: http://www.patient.co.uk/