Irritants and Corrosives

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

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

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

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

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.

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

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

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

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

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