1. Irritants and Corrosives

2. Irritant Poisons Definition:
Those agents that set up an inflammatory process at the site of application or contact. They do not destroy body tissues
The most common signs and symptoms of irritant and poisons are due to their local action on the mucosa of the GIT, causing inflammatory changes and partial desquamation of the intestinal mucosa
This leads to burning pain, vomiting and diarrhea with bloody stools
After absorption, the main symptoms of toxicity include rapid irregular pulse, fall in blood pressure, convulsions and coma
Examples: mercuric chloride, silver nitrate, iodine, bromine, hydrogen peroxide

3. Poisoning by Mercury
Mercury and its salts are used in the manufacture of thermometers, explosives, lamps and batteries. Organic and inorganic mercurials are used medicinally as antiseptics and diuretics
Acute poisoning due to ingestion of mercuric salts causes metallic taste, severe abdominal pain, vomiting and bloody diarrhea. Death is from uremia
Alkyl mercuric compounds are concentrated in the CNS with ataxia, tremors and convulsions
Chronic poisoning is characterized by loss of appetite, salivation, stomatitis, CNS disturbances, liver damage, nephritis and anuria
Treatment:
Gastric lavage with tap water
Administration of demulcents, e.g., milk and egg white
Give dimercaprol as an antidote

4. Poisoning by Silver
Silver nitrate is used as local styptic (astringent) and antiseptic
Ingestion of a silver salt solution causes burning sensation of GIT, abdominal pain, vomiting with black vomitus, diarrhea, severe shock and convulsions
Repeated use of silver preparations may result in deposition of greyish-blue metallic silver in the pigment layer of the skin
Treatment:
Gastric lavage with NaCl to precipitate silver
Administration of demulcents, e.g., milk and egg white which combines with sliver as proteinate
Administration of cathartics and cleansing enemas

5. Poisoning by Iodine
Iodine is used in medicine as antiseptic and disinfectant
Ingestion of iodine causes gastric pain, vomiting (brown-stained vomitus), diarrhea (bloody stool), collapse and nephritis.
Inhalation of iodine causes inflammation of respiratory tract, cough, and pulmonary edema.
Iodine produces inflammation, desquamation and corrosion of mucous membranes
Treatment:
Gastric lavage with water or 1-1.5% solution of sodium thiosulphate
Administration of starch solution and demulcents, e.g., milk and egg white

6. Poisoning by Bromine
Exposure to bromine vapor causes lacrimation, pharyngitis, salivation, cough, pulmonary edema and ulceration of eyelids and cornea pain, vomiting (brown-stained vomitus), diarrhea (bloody stool)
Inhalation of iodine causes inflammation of respiratory tract, cough, and pulmonary edema.
Bromine produces yellow brown discoloration of the skin, feeling of heat and ulcer
Treatment:
Transferring the patient to fresh air
Administration of oxygen
Treat bronchospasms and pulmonary edema by aminophylline I.V.

7. Poisoning by Hydrogen Peroxide
Hydrogen peroxide is used in medicine as antiseptic and disinfectant
Hydrogen peroxide has two mechanisms of toxicity; local tissue injury and gas formation. The extent of local tissue injury is determined by the strength of the hydrogen peroxide solution:
Dilute hydrogen peroxide (usually 3%) is an irritant
Concentrated hydrogen peroxide (10-30%) is a caustic
Gas formation results when hydrogen peroxide interacts with tissue catalase, liberating molecular oxygen and water.
The main symptoms of toxicity are vomiting, abdominal pain and gastric mucosal erosions
Treatment:
Give water or milk to dilute
Use gastric tube to prevent increased pressure

8. Corrosive Poisons
Corrosives are substances that rapidly destroy tissue at the point of contact.
The most important corrosives are acids and alkalis. Organic acids such as oxalic acid, citric acid and acetic acid are weak corrosives, compared with inorganic ones. Alkalis such as carbonates and bicarbonates have less corrosive effect on mucous membranes than sodium or potassium hydroxides
Corrosive acids destroy tissues by direct chemical action. The tissue protein is converted into acid proteinate which dissolves in the concentrated acid. Hemoglobin is converted into acid hematin and is precipitated.
Intense stimulation by acids causes reflex loss of vascular tone
After ingestion, corrosive penetration of the esophagus and stomach are commonly found
Precipitated blood is frequently found in the stomach
Corrosive alkalis combine with protein to form proteinates and with fats to form soaps, thus producing soft necrotic, deeply penetrating areas upon contact with tissues.
The solubility of these products allow further penetration which may continue for several days.
Pathological findings include:
Gelatinous, necrotic areas at the site of contact
Intense stimulation by alkalis causes reflex loss of vascular tone and cardiac inhibition

9. Poisoning by Sulphuric Acid
Sulphuric acid is used in chemical industries
Local action of sulphuric acid may cause:
First-degree burns, characterized by edema and erythema with hot, painful, red and swollen skin
Second-degree burns, characterized by severe damage and edema as well as the appearance of vesicles and scars
Third-degree burns, characterized by destruction of the skin and deep ulceration
Ingestion of sulphuric acid causes:
severe burning pain in the mouth, pharynx and abdomen, followed by vomiting and bloody diarrhea
The blood pressure falls sharply
Brownish or yellowish stains may be found in the mouth
Asphyxia occurs from the edema of the glottis
Inhalation of sulphuric acid fumes causes:
Cough
Choking
Variable symptoms of headache, dizziness and weakness, followed by pulmonary edema and cyanosis

10. Poisoning by Sulphuric Acid
Treatment:
Skin Contact
Remove acid by flooding with water for at least 15 minutes
Do not use chemical antidotes
Treat damaged areas as for thermal burns
Ingestion
Do not use gastric lavage or emesis because of the danger of perforation
Ingested acid may be diluted by drinking large quantities of water or milk
Treat shock by administration of 5% dextrose in saline
Give morphine sulphate to relieve pain
Treat asphyxia by maintaining an adequate airway
If perforation of the stomach or esophagus is suspected
Inhalation
Give artificial respiration
Treat bacterial pneumonia with organism specific chemotherapy

11. Poisoning by Nitric Acid
Nitric acid produces effects similar to sulphuric acid, but differs in that the skin and GIT becomes yellow
Nitric acid coagulate the tissue proteins and form a yellow xanthoproteic acid
Treatment: Similar to the treatment of sulphuric acid poisoning