Corrosive Toxicity (PDF)

Toxicity of corrosive Presented by ph/Algaly Aktham Torky 1 corrosive ◦ Definition: Substance that damages, destroys and erodes the surface (metals or exposed living tissues as skin, eyes, GIT, respiratory tract) with which it comes in contact. ◦ Types:...

Toxicity of corrosive Presented by ph/Algaly Aktham Torky 1 corrosive ◦ Definition: Substance that damages, destroys and erodes the surface (metals or exposed living tissues as skin, eyes, GIT, respiratory tract) with which it comes in contact. ◦ Types: 1) Acid 2) Alkali 3) Oxidizer(oxidating agent) 2 3 Severity of corrosive: Depends on: conc and volume of ingested corrosives. Duration of time in contact with tissues. % of body surface area exposed to corrosives. corrosive at high conc At low conc cause cause irritation chemical burn 4 Mechanism of toxicity: ◦ The effect of corrosives on living tissues is known as caustic. Amide hydrolysis of Strong acid Protein denaturation Proteins Ester hydrolysis of Saponification Strong alkali Lipids reaction 5 Mechanism of toxicity: Necrosis: cell death Types: Coagulative and Liquefactive necrosis Coagulative necrosis Liquefactive necrosis (acid ) (alkali) formation of gelatinous substance (coagulum) formation of viscous liquid mass in dead tissues in dead tissues architecture of the tissue is maintained architecture of the tissue is not maintained 6 Coagulative and Liquefactive necrosis 7 Mechanism of toxicity: ◦ Acid ingestion: Ingestion of acid hydrolysis of amide bond between amino acids denaturation of protein Coagulative necrosis The stomach is the most affected. Esophagus less affected ???? 1) Most available acids are liquids while Alkalis commonly found as pastes or solids 2) squamous epithelium of Esophagus ( fatty nature) 8 Mechanism of toxicity: Alkali ingestion: ingestion of alkali hydrolysis of ester bond between fatty acids denaturation of fats Liquefactive necrosis hydrolysis of ester bond between fatty acids free fatty acids in blood thrombus formation Alkalis most severely affect the squamous epithelium of Esophagus(fatty nature) 9 Signs & Symptoms of corrosives: ▪ Painful and burning sensation in oral cavity &lips, throat. ▪ Mouth and tongue swelling ▪ Ulceration of oral cavity ▪ Nausea, vomiting with hematemesis ▪ Difficult swallowing (dysphagia), painful swallowing (odynophagia), Drooling (hypersalivation) ▪ chest pain & dyspnea(SOB) ▪ Larynx injury causing laryngospasm ▪ Aspiration of corrosives may cause endotracheal or bronchial necrosis. ▪ Perforation of esophagus (alkali) or stomach (acid) ▪ Stenosis or stricture in esophagus (alkali) , Pyloric stenosis or stricture (acid) ▪ thrombus formation (alkali) 10  No Management of Corrosive toxicity: specific antidote Corrosive acid Corrosive alkali Analgesic Analgesic Diluents &Demulcents Diluents &Demulcents antiemetic drug antiemetic drug TPN TPN Systemic Antibiotic Systemic Antibiotic Corticosteroids Corticosteroids Gastric resection Bouginage using Bougi 11 Management of Corrosive toxicity : TPN is used to provide nutrition as GIT damage hinders the physiological nutrition of the patient. Antibiotics are used to decrease the risk of infection. Corticosteroids are used to decrease inflammation and degree of fibrous tissue formation. Bougienage: A procedure involves the use of a bougie ( a thin cylinder of rubber, plastic, metal, or another material that a physician inserts into or through the esophagus to widen it. 12 Bougienage 13  NOT TO DO: 1. Gastric lavage: more GIT damage 2. Emesis: Emetics are contraindicated as they cause re-exposure to corrosives leading to further injury. 3. Activated charcoal: obscure endoscopic visualization. 4. Neutralization: Neutralization is contraindicated as it releases heat and worsens injury due to thermal injury added to chemical burns. 5. Cathartics: cause damage to the colon, rectum, and anus. 14 15 Case Study A 3-year-old child was presented to the emergency department(ED) after he found two white tablets and ate them before his grandmother could take them away. Grandmother identified the pills as Clinitest® tablets. The ingestion occurred 20 minutes before arrival in the ED. Grandma is a diabetic. The child vomited twice after the ingestion and has been drooling and having difficulty swallowing. The child refused to drink, and when grandma looked in the mouth, she saw red and white spots. The poisonous ingredient in clinitest ® tablets is sodium hydroxide. Physical Examination T: 99.4°F (N= 97°F (36.1°C) to 99°F (37.2°C)) HR: 128 bpm (N= 80 to 120) RR: 31 breaths per minute (N= 25 to 31 ) BP: 100/65 mm Hg (N= 110/55) General: He is pale, agitated, and crying, examination reveals second-degree burns to the oropharynx. Endoscopy revealed ulceration in the end part of the esophagus while the stomach and duodenum were spared. 16 Questions: 1. Should gastric lavage be performed in this patient? Why? 2. Should this child be given steroids? Why? 3. What is the mechanism of toxicity of this corrosive agent? 4. Is there a role for antibiotics in the treatment of corrosive injury to the gastrointestinal tract? 17 18