2. Published BMJ 2003;326:466 ( 1 March )
doi:10.1136/bmj.c199. www.patient.co.uk
Last Updated: 21 Jan 200903/28/162
Arsenic
Poisoning
3. Arsenic Poisoning
03/28/163
Arsenic is a heavy metal that exists in 3 metallic forms:
beta or black
alpha or yellow
gamma or grey
It also exists in compounds:
organic (arsines)
inorganic
Inorganic compounds are more toxic than organic compounds.
Elemental arsenic is least toxic..
4. 03/28/164
Poisoning can occur by
ingestion
inhalation
dermal absorption.
Toxicity is due to arsenic's effect on many cell enzymes, which affect
metabolism and DNA repair.
Arsenic is excreted in urine, but can also accumulate in many body
tissues.
5. 03/28/165
Arsenic has been used in medicines, as a pigment, a
pesticide, and as a weapon of murder.
It shares many toxic features with the other heavy
metals like mercury and lead.
It is used in the production of glass and
semiconductors.
It is found in some water supplies and seafood, and
is used in various industries.
6. Epidemiology
03/28/166
In Victorian times arsenic was commonly used for
murder but nowadays it is used much less as it is more
difficult to acquire.
Contamination of water supplies has occurred in parts
of.
Bangladesh and West Bengal, affecting millions of people.
Chile, Argentina, Mexico and the USA.
China, Taiwan, Thailand.
8. Etiology (cont.)
03/28/168
» Ceramic enamels
» Paints
» Tobacco (6 mcg per pack)
» Burning of fossil fuels as arsenic is a contaminant.
» From the diet, as organic arsenic from fish and sea food.
9. Etiology (cont.)
03/28/169
Occupational exposure can occur in:
The smelting industry (arsenic is a by-product of
ores containing lead, gold, zinc, cobalt and nickel).
The microelectronics industry (as gallium arsenide).
Coal power plants.
Manufacture of glass and fireworks
Use of pesticides.
Contact with wood treated with arsenic as a
preservative.
10. Presentation
03/28/1610
A. History
Arsenic exposure is usually occupational or
environmental, but can result from deliberate
poisoning.
Exposure to arsine gas is usually the result of an
industrial accident.
Take a work and travel history when a patient
presents with painful peripheral neuropathy.
11. 03/28/1611
A. History (cont.)
Other history:
hobbies.
unusual forms of alcohol or diet
supplements.
herbal medicines.
Many organ systems are involved.
12. Overview of acute poisoning
features
03/28/1612
Symptoms usually start within
30 minutes - 2 hours.
Acute arsenic ingestion is typically follows :
severe gastroenteritis,
garlic Hypersalivation.
odour
13. 03/28/1613
Characteristic sequence of multi-organ
failure, with: neurological symptoms
(within hours) and cardiac features,
succeeded by adult respiratory distress
syndrome and renal/liver dysfunction.
15. Details of acute poisoning
features
03/28/1615
Gastrointestinal:
Hypersalivation.
abdominal pain.
vomiting, diarrhoea leading to hypovolaemic shock.
Trivalent arsenic is corrosive - may cause oral
burns, dysphagia and G-I bleeding.
16. 03/28/1616
Cardiovascular:
Myocardial depression
Dehydration, hypovolaemia or shock
ECG changes including ST segment changes,
prolong QT interval, ventricular tachycardia, torsa
de pointes, & ventricular fibrillation .
Gangrene of extremities
22. Features of chronic arsenic
poisoning
Skin lesions:
Typically start about 10
years after first exposure
Hyper pigmentation
(especially arms and upper
chest) - diffuse dark areas
or‘raindrop’ pigmentation
03/28/16 22
23. Also exfoliative dermatitis,
alopecia, conjunctivitis,
corneal ulceration.
Keratoses occurs on palms
and soles
03/28/16 23
29. Differential diagnosis
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Other forms of poisoning e.g.
Lead
Mercury
Botulism
Gastroenteritis
Haemolytic uraemic syndrome
The skin lesions look like other forms of dermatitis
30. Investigations
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A. Acute poisoning
Monitoring – for at least 4 hours after suspected ingestion:
pulse, blood pressure, respiratory rate, oxygen saturation and
ECG, urine output.
Haematology, biochemistry and arterial blood gases – as for
any acutely ill patient.
Urinalysis.
ECG.
Arsenic levels in blood and urine (Chest X-ray and plain x-ray
abdomen (inorganic arsenic compounds are radio-opaque).
31. Arsenic levels
Normal values
mcg/L
Note
whole blood
concentration
< 50 blood levels are of limited use, as the
half-life of inorganic arsenic in the blood
is short (approx 2 hours
24 hour urinary
excretion
<50
mcg/day
organic arsenical compounds found in the
urine are usually from food sources such as
shellfish, rather than arsenic toxicity. Ask if
shellfish have been eaten in the last few days,
and check whether the laboratory
differentiates organic from inorganic arsenic
compounds.
spot urinary arsenic
concentration
<30
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32. Arsenic levels (cont.)
03/28/1632
Hair samples become positive 30 hours after
exposure but may give falsely high results. They do
not differentiate between ingestion and external
exposure.
33. 03/28/1633
B. Chronic arsenic poisoning
Urinary concentrations are useful in chronic exposure.
Hair samples (as above).
Arsenic levels in drinking water (high drinking water levels in
conjunction with relevant clinical features are useful for diagnosis
in some settings).
Investigation and screening for complications may be appropriate
(e.g. look for diabetes, hypertension).
34. Management
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A. Management of acute arsenic
poisoning:
Remove patient from source of arsenic; if
skin contamination wash with copious
water; seal contaminated clothing.
Resuscitate (ABC principles).
35. 03/28/1635
Management of acute arsenic poisoning (cont):
Gastric lavage – consider if a significant amount ingested < 1
hour ago and patient has not vomited, or if plain x-ray indicates
arsenic present in the stomach. (Activated charcoal is unlikely to
be of benefit - it does not absorb arsenic.)
Whole bowel irrigation with polyethylene glycol may be used, to
prevent arsenic absorption.
36. 03/28/1636
Management of acute arsenic poisoning (cont):
Supportive treatment:
Oxygen (humidified for inhaled arsenic); bronchodilators if
bronchospasm; PEEP (positive end-expiratory pressure) for pulmonary oedema.
Intravenous fluids for hypovolaemia; blood transfusion for GI
haemorrhage.
Inotropes for myocardial depression.
Torsa de pointes may be treated with magnesium sulphate, pacing or
isoprenaline.
Treat seizures (diazepam, lorazepam +/- phenytoin).
Analgesia.
37. 03/28/1637
Management of acute arsenic poisoning (cont):
Renal impairment:
Maintain an alkaline urine using sodium bicarbonate over 2 hours and repeat as
necessary.
Haemodialysis does not reduce arsenic concentrations but may be needed for
renal failure.
Bone marrow suppression: red cell and/or platelet transfusions.
Burns (from skin contamination) are treated conventionally.
Eye contact: treat as for a chemical eye burn
38. 03/28/1638
Management of acute arsenic poisoning
(cont):
Chelation:
Consider chelation therapy in patients who are symptomatic and/or
have urine concentration > 200 mcg/L.
DMPS is the chelation agent of choice. DMSA is an alternative (oral
preparation only, so unsuitable if patient is vomiting).
Dimercaprol (BAL) or penicillamine have also been used, but are
superseded by DMPS and DMSA.
39. Management of chronic arsenic
poisoning
03/28/1639
Provide arsenic-free drinking water, to reduce the risk of
further disease developing.
Chelation therapy may have a role, but its effectiveness is
uncertain. Also, it is of no use if exposure to arsenic
continues.
40. Management of chronic arsenic
poisoning (cont.)
03/28/1640
Micronutrients and antioxidants may be beneficial,
especially in undernourished populations. It is
recommended that all patients with skin lesions be given
multivitamins.
Certain plant compounds may help to remove arsenic
from tissues.
Skin care for keratoses and any associated bacterial or
fungal infections.
41. Management of chronic arsenic
poisoning (cont.)
03/28/1641
Screen and treat for complications, e.g. diabetes,
hypertension.
Other household members:
Check other members of the family as they may also
have been exposed.
Pregnancy and breastfeeding: arsenic is probably
transferred to the baby via the placenta and breast
milk
42. Prognosis
03/28/1642
The prognosis varies with the amount and rate of arsenic
ingestion.
Effects and complications can occur at different times after
exposure - from days to years later.
44. Prevention
03/28/1644
Test all groundwater sources of drinking water for arsenic.
Provision of uncontaminated water for all is essential, but
not yet achieved. Some plants have the ability to remove
arsenic from the environment.