Clinical Toxicology Lecture 3 PDF

Al-Mustaqbal University College of Pharmacy 5th stage Clinical Toxicology Lecture: 3 Hydrocarbons & Household Products Toxicity  Hydrocarbons Toxicity The term hydrocarbon refers to the most basic type of organic molecules. As suggested by their name, they are compri...

Al-Mustaqbal University College of Pharmacy 5th stage Clinical Toxicology Lecture: 3 Hydrocarbons & Household Products Toxicity  Hydrocarbons Toxicity The term hydrocarbon refers to the most basic type of organic molecules. As suggested by their name, they are comprised of only 2 elements: hydrogen and carbon. Hydrocarbon molecules have one or more central carbon atoms in a branched or chain-like structure, surrounded by hydrogen atoms. There are four main categories of hydrocarbons: Alkanes, Alkenes, Alkynes, and Aromatic hydrocarbons. Hydrocarbons Toxicity  Hydrocarbons Toxicity The hydrocarbon poisons are mixtures of aliphatic and aromatic hydrocarbons. These compounds vary in their molecular weight, chemical and physical properties. Hydrocarbon products represent a diverse group of substances e,g. gasoline, kerosene, mineral spirits, petroleum naphtha, petroleum ether, mineral seal oil, coal tar, benzene, toluene, xylene, turpentine, … etc  Hydrocarbons Toxicity Ingestion of hydrocarbons result in minimal systemic effects but can cause severe aspiration pneumonitis. For instance petroleum distillates (eg, gasoline, kerosene, mineral oil, lamp oil, paint thinners). Toxic potential mainly depends on viscosity, measured in Saybolt seconds universal (SSU).  Hydrocarbons Toxicity Hydrocarbon liquids with low viscosity (SSU < 60), such as gasoline and mineral oil, can spread rapidly over large surface areas and are more likely to cause aspiration pneumonitis than are hydrocarbons with SSU > 60, such as tar. Note: SSU is the time in seconds required for 60 cc of fluid to flow through a standard orifice.  Hydrocarbons Mechanisms of Toxicity The two most common routes of exposure for hydrocarbons are inhalation and ingestion. Ingestion is the more common route of exposure encountered in acute accidental hydrocarbon poisonings. When ingested, hydrocarbons produce their toxic effects on several organ systems including the lung, CNS, gastrointestinal tract, liver, and heart. Among these, the greatest involvement occurs with the pulmonary system, and aspiration pneumonitis is the greatest cause of morbidity and mortality.  Hydrocarbons Mechanisms of Toxicity CNS involvement following hydrocarbon ingestion is not due to a direct effect on the CNS but occurs secondary to hypoxic cerebral damage resulting from the chemical-induced pneumonitis. Studies have shown that hydrocarbons are absorbed from the GIT in very small quantities and the amount absorbed is not sufficient to be directly responsible for the CNS toxicity.  Hydrocarbons Mechanisms of Toxicity The most serious and potentially lethal complication of hydrocarbon ingestion is the development of a chemical pneumonitis which is related to aspiration of the poison that occurs : 1. Either during ingestion 2. Or vomiting And not by circulating via the blood.  Hydrocarbons Mechanisms of Toxicity The physiochemical properties of hydrocarbons are also important factors for the increased incidence of aspiration.  The risk of aspiration and lung damage is directly proportional to volatility, and indirectly related to viscosity. That is, hydrocarbons that are most likely to be aspirated are highly volatile and have a low viscosity.  Hydrocarbons are also gastric irritants, and spontaneous vomiting sometimes occurs during which there is a greater chance for entry into the trachea.  Hydrocarbons Toxicity Signs & Symptoms After ingestion of even a very small amount of liquid hydrocarbon, patients initially cough, choke, and may vomit. Young children may have cyanosis, hold their breath, and cough persistently. Older children and adults may report burning in the stomach.  Hydrocarbons Toxicity Signs & Symptoms Aspiration pneumonitis causes hypoxia and respiratory distress. Symptoms and signs of pneumonitis may develop a few hours before infiltrates are visible on x-ray. Substantial systemic absorption, particularly of a halogenated hydrocarbon, may cause lethargy, coma, and seizures. Nonfatal pneumonitis usually resolves in about 1 week; mineral or lamp oil ingestion usually resolves in 5 to 6 weeks.  Hydrocarbons Toxicity Signs & Symptoms Arrhythmias usually occur before presentation and are unlikely to recur after presentation unless patients have excessive agitation.  Hydrocarbons Toxicity Diagnosis Chest x-ray and oximetry done about 6 hours after ingestion or sooner if symptoms are severe. If respiratory failure is suspected, arterial blood gases are measured. CNS toxicity is diagnosed by neurologic examination and MRI.  Hydrocarbons Toxicity Diagnosis If patients are too obtunded to provide a history, hydrocarbon exposure may be suspected if their breath or clothing has an odor or if a container is found near them. Paint residue on the hands or around the mouth may suggest recent paint sniffing.  Hydrocarbons Toxicity Treatment Supportive care. Avoidance of gastric emptying which increases risk of aspiration. Any contaminated clothing is removed, and the skin is washed. Charcoal is not recommended.  Hydrocarbons Toxicity Treatment Patients who do not have aspiration pneumonitis or other symptoms after 4 to 6 hours are discharged. Patients who have symptoms are admitted and treated supportively; antibiotics and corticosteroids are not indicated.(no benefit )  Household Products Toxicity HOUSEHOLD PRODUCTS 1. Soaps and 4. Nail polish 2. Bleach 3. Mothball Detergents remover  Soaps & Detergents Toxicity Soap is a salt of a fatty acid that usually results from reacting a natural fat or oil with a strong alkali, such as sodium or potassium hydroxide. Detergent, is technically any cleaning agent, they are usually based on non- soap surfactants.  Soaps & Detergents Toxicity Most soaps are relatively nontoxic and possess an emetic action that is possibly as effective as ipecac syrup. Soap-induced emesis is mediated through a direct effect on the GIT rather than through systemic action. Ingestion of many soap products is not specially dangerous because the product is self- eliminating, and few symptoms, other than gastric upset, will be experienced.  Soaps & Detergents Toxicity Ingestion of a strong detergent product will cause a variety of reactions, this is because detergents contain a wider variety of ingredients than soap products. Most detergents consist of mixtures of inorganic and organic substances, anionic or cationic surfactants, whitening agents, fabric softeners and builders (e.g. carbonate, silicate, sulfate). The major problem from ingestion of detergent products is the builder, because of their high alkalinity, they may induce severe GI damage.  Soaps & Detergents Toxicity Treatment Electrolyte replacement therapy is indicated for severe vomiting or diarrhea. Demulcent (an agent that forms a soothing, protective film when administered onto a mucous membrane surface, for instance: mucilage and oils) is indicated for mild nausea.  Bleach Toxicity Most bleach products are solutions of 3-6% sodium hypochlorite in water. The pH is approximately 11 which makes them highly alkaline. Symptoms of ingestion of bleach include severe irritation and corrosion of mucous membranes with pain and vomiting. There may be a fall in blood pressure with delirium and coma.  Bleach Toxicity Treatment of bleach intoxication includes demulcent therapy. Although the pH of a bleach solution is alkaline, acidic antidotes should not be given. The reason for this is that hypochlorus acid is formed in the stomach when sodium hypochlorite reacts with hydrochloric acid. Hypochlorous acid is not toxic when absorbed in small quantities, since it is buffered by the blood. However, it is extremely irritating to both the mucous membranes of the esophagus and the gastrointestinal tract.  Bleach Toxicity Bleach should never be mixed with strongly acidic or alkaline cleaning agents, because chlorine gas or chloramine gas may be released. Although inhalation of small quantities of either of these gases does not produce severe toxicity, but can cause lacrimation, and irritation of the mucous membranes. In a high concentration, both could cause asphyxiation.  Mothball Toxicity Most products that are used as mothballs contains naphthalene or paradichlorobenzene. Today, naphthalene is used less often than previously because of its great potential for toxicity. it has been replaced with the less toxic substance, Paradichlorobenzene, which if ingested, may induce local irritation of the gastrointestinal tract. However, it requires no antidotal therapy, except for a demulcent, and treatment of nausea and vomiting.  Mothball Toxicity Naphthalene, is a powerful toxic substance that requires immediate medical treatment if ingestion occurs. At special risk are those persons with erythrocytic G6PD. When they ingest naphthalene then erythrocyte membrane will break down which will lead to hemolysis. Treatment is symptomatic and supportive care.  Nail polish remover (acetone) Toxicity Acetone forms the basis for most commercial fingernail polish remover products. Acetone may be readily recognized by its sweet, sharp odor. Intoxication by acetone is a potential health hazard in industry where it is used as a solvent for a variety of lipids. Irritation of the eye, nose, and throat produced at exposures of 500 - 1000 ppm.  Higher concentrations cause CNS depression.  Nail polish remover (acetone) Toxicity In the home, acetone poisoning is less frequent, but it does occur. Acetone is absorbed through the skin, but the quantity that may be absorbed from nail polish removers has no medical problems. Acetone has a drying effect on the skin as it dissolves dermal lipids.  Nail polish remover Toxicity Signs & Symptoms Nausea, vomiting, gastric hemorrhage. CNS sedation, respiratory depression, ataxia, and paresthesia. Ingestion of toxic Coughing, bronchial amounts of acetone irritation. Depression may proceed to induces a variety of coma. signs and symptoms Hyperglycemia and ketonemia. Renal tubular necrosis may occur.  Nail polish remover Toxicity Treatment Symptomatic and supportive care Unless the patient is comatose, activated charcoal and saline catharsis. Diazepam to control seizures. Disinfectants & Antiseptics Toxicity Phenol (Carbolic Acid) Iodine Quaternary Ammonium Compounds (QAC)  Phenol (Carbolic Acid) Toxicity Phenol was one of the oldest disinfectants and deodorizers. Intoxication can occur following absorption of phenolic substances through intact skin, or by ingestion. Topical preparations containing phenol should never contain a concentration greater than 1%.  Phenol (Carbolic Acid) Toxicity Phenol has a strongly characteristic odor and its presence can be readily detected on the breath. Phenol is a protein precipitant which induces strong corrosive actions. It is a cellular depressant and causes a variety of signs and symptoms in respiratory system, GIT, CVS, skin, blood, CNS … etc.  Phenol (Carbolic Acid) Toxicity Death immediately following poisoning usually occurs from respiratory depression. Survival for a day or two after poisoning is often ends with renal damage that eventually leads to death. Long-term complication is esophageal stricture.  Phenol (Carbolic Acid) Toxicity Treatment Immediate lavage of ingested poison is important. Milk, or gelatin solution should be given quickly, these serve as a source of protein for any phenol remaining in the stomach, so it will be precipitated instead of the protein of the stomach lining. Castor oil is frequently recommended as the antidote of choice because phenol has high affinity for it, and because castor oil produces a cathartic action which helps to remove the poison from the GIT quickly.  Iodine Iodine has been used as a topical disinfectant since the early 1800s. It is also used to sterilize contaminated water by placing several drops of a 2% tincture in each liter of water. Iodine is a direct protein precipitant which is corrosive to mucous membranes. In the intestine it is converted to the less toxic iodide, and it also is rapidly deactivated by foodstuff in the gut. Furthermore, it causes a strong vomiting reflex which removes much of the poison, all of these factors help to minimize its toxicity.  Iodine Major symptoms of ingestion are seen on the gastrointestinal tract, with nausea, vomiting, diarrhea, and gastroenteritis. Ingestion can be quickly recognized by the appearance of brown stains in the mouth or on the lips, or of brown-colored vomitus. Death from massive ingestions usually occurs within 48 hours from circulatory collapse due to shock, or from pulmonary edema which is caused by aspirations during emesis.  Iodine poisoning Treatment Gastric lavage with soluble starch should be undertaken to absorb iodine. Then, a 1-5% solution of sodium thiosulfate can be instilled to convert remaining iodine to iodide. Glucocorticosteroids should be administered as quickly as possible to reduce the chance of esophageal fibrosis.  Quaternary Ammonium Compounds (QAC) Quaternary ammonium compounds are cellular cationic surfactants used in a wide variety of products.  QAC such as disinfectants, bactericides, deodorants, and sanitizers. All QACs produce similar symptoms through a similar mechanism.  Quaternary Ammonium Compounds (QAC) Strong aqueous compounds produce superficial necrosis of mucous membranes with which they come into contact. Internally, they cause gastrointestinal tract erosion, ulceration, and hemorrhage throughout the entire intestine. They can also cause damage to the heart, liver, and kidney.  Quaternary Ammonium Compounds (QAC) All QACs cause disinfection only to chemically clean areas. In the presence of any traces of soap, they are inactivated. Thus, soap serves as the best antidote for QAC poisoning. Following skin contamination, the area should be thoroughly cleaned with soap. Following ingestion, a weak soap solution will inactivate any QAC and reduce its toxicity.