Poisoning (University of Alkafeel) PDF

‫‪POISONING‬‬ ‫‪cont.‬‬ ‫أ‪.‬د‪.‬فالح عبد الحسن دلي‬ Objectives 1-Knowing the most common and Important poisonings 2-Understanding the Different maneuvers and antidotes for treatment of poisoning Email :[email protected] Website :http://Alkafeel.edu.iq *Paracetamol (Acetaminophen) The...

‫‪POISONING‬‬ ‫‪cont.‬‬ ‫أ‪.‬د‪.‬فالح عبد الحسن دلي‬ Objectives 1-Knowing the most common and Important poisonings 2-Understanding the Different maneuvers and antidotes for treatment of poisoning Email :[email protected] Website :http://Alkafeel.edu.iq *Paracetamol (Acetaminophen) The most commonly used in overdose in the UK. Toxicity is caused by an intermediate reactive metabolite that binds covalently to cellular proteins, causing cell death. This results in hepatic and occasionally renal failure. In therapeutic doses, the toxic metabolite is detoxified in reactions requiring glutathione But in overdose, glutathione reserves become exhausted. Email :[email protected] Website :http://Alkafeel.edu.iq  Management Activated charcoal may be used in patients presenting within 1 hour. Acetylcysteine given intravenously or oraly is highly efficacious if administered within 8 hours of the overdose act by replenishing hepatic glutathione Should be administered to all patients with acute poisoning Must be started as early as possible Follow up Liver and renal function, PT and (INR) This drug is save, occasionally it may lead to allergy and anaophylaxis An alternative antidote is Methionine 2.5 g orally (adult dose) every 4 hours to a total of four doses, but this may be less effective, especially after delayed presentation Liver transplantation should be considered for paracetamol poisoning with life-threatening liver failure Email :[email protected] Website :http://Alkafeel.edu.iq Salicylates (aspirin) Clinical features Nausea, vomiting, tinnitus and deafness. Direct stimulation of the respiratory center >>>>> hyperventilation and respiratory alkalosis. Later Severe Poisoning >>>> Metabolic Acidosis Different Organs and Systems Impairement will occur (RENAL, CARDIAC , CNS, PULMAONARY0 Disturbed consciousness and fits may occur, especially in children. Toxicity is enhanced by acidosis, which increases salicylate transfer across the blood–brain barrier. Email :[email protected] Website :http://Alkafeel.edu.iq Management Activated charcoal should be administered if the patient presents within 1 hour. Measure plasma salicylate concentration 2-4 hourly Correction of dehydration Metabolic acidosis >>>> Intravenous Sodium Bicarbonate (8.4%) Urinary alkalinisation Haemodialysis is very effective in severe cases A-Removing salicylate B-Correcting associated acid–base and fluid balance abnormalities. Management of complications: pulmonary oedema, coma, convulsions or refractory acidosis. Email :[email protected] Website :http://Alkafeel.edu.iq AntidepressantsTricyclic antidepressants Charecterized by Sodium Channel-blocking Anticholinergic α-adrenoceptor-blocking >>> Hemodynamic consequences and significant morbidity and mortality. Anticholinergic effects ????? Severe Convulsions, coma and arrhythmias (ventricular tachycardia, ventricular fibrillation and, less commonly, heart block). Hypotension: Inappropriate Vasodilatation or Impaired Myocardial contractility. Email :[email protected] Website :http://Alkafeel.edu.iq  Activated charcoal within 1 hour. cardiac monitoring and 12-lead ECG followup Prolongation of the QRS interval and QT interval prolongation have a high risk of arrhythmia Arterial blood gases should be measured in suspected severe poisoning. In serious cases repeated doses of intravenous sodium bicarbonate (50 mL of 8.4%solution) A- Correct pH B- Reduce risk of arrhythmias. Hypoxia and electrolyte abnormalities should also be corrected. Anti-arrhythmic Prolonged seizures should be treated initially with intravenous Benzodiazepines Email :[email protected] Website :http://Alkafeel.edu.iq Beta-blockers Bradycardia and Hypotension In severe cases Heart block Pulmonary oedema Cardiogenic shock Email :[email protected] Website :http://Alkafeel.edu.iq Management Careful Intravenous fluids >>>>> Hypotension with care of fluid overload Bradycardia and Hypotension: high doses of Atropine (up to 3 mg in an adult) Or an infusion of Isoproterenol Glucagon (5–10 mg over 10 mins, then 1–5 mg/hr by infusion) counteracts β- blockade Hyperinsulinaemia Euglycaemic Therapy: Intravenous insulin with Hypertoni glucose (10–20%) in unresponsive patients to other strategies. High doses of insulin inhibit lipolysis and increase glucose uptake and the efficiency of glucose utilization. Lipid emulsion therapy in severe poisoning ????? Email :[email protected] Website :http://Alkafeel.edu.iq Calcium channel blockers Dihydropyridines (e.g. nifedipine, amlodipine) >>>>>> Vasodilatation Non dihyropyridine (diltiazem and verapamil)>>>>> Bradycardia and Reduced myocardial contractility. Clinical features Hypotension due to vasodilatation or myocardial depression is common Bradycardias and heart block may occur, especially with verapamil and diltiazem. Systemic effect with GIT Upset , Disturbed alertnmess, metabolic acidosis, hyperglycaemia and hyperkalaemia may occur. Email :[email protected] Website :http://Alkafeel.edu.iq Management Hypotension careful IV fluid Persistent hypotension IV Calcium Gluconate (10 mg IV over 5 mins, repeated as required). Isoproterenol and glucagon may also be useful. hyperinsulinaemia euglycaemic therapy Cardiac pacing : severe unresponsive bradycardias or heart block. Email :[email protected] Website :http://Alkafeel.edu.iq Iron Clinical features Serious drug in overdoses Early Gastrointestinal disturbance with the passage of grey or 2 black stool >>>hyperglycaemia, leucocytosis, haematemesis, rectal bleeding, 1 >>>>Drowsiness, convulsions, coma, metabolic acidosis and cardiovascular collapse in severe cases. 3 Early symptoms may improve or resolve within 6–12 hours Hepatocellular necrosis can develop 12–24 hours after 4 overdose and may lead to hepatic failure. Gastrointestinal strictures are late complications Email :[email protected] Website :http://Alkafeel.edu.iq Management Activated charcoal X Gastric lavage may be considered Measure serum levels Desferrioxamine shouldn’t be delayed 1- Severe features don’t wait for serum level 2- High serum iron concentrations (e.g. > 5 mg/L). Desferrioxamine may cause hypotension, allergic reactions and occasionally pulmonary oedema. Email :[email protected] Website :http://Alkafeel.edu.iq  Opioids Misuse of illicit drugs such as heroin or from suicidal or accidental overdose opiates as Addiction Medicinal They present with disturbed alertness or consciousness and Nausea and vomiting Physical SIGNS: Respiratory depression Pinpoint pupils Disturbed consciousness from Drowsiness or sleepiness to Coma Coldness and Cyanosis Features of opioid poisoning can be prolonged for up to 48 hours after use of long-acting agents such as methadone or oxycodone Email :[email protected] Website :http://Alkafeel.edu.iq Management of Opioid poisoning Naloxone (0.4–2 mg IV in an adult, repeated if necessary) What are the Excessive doses may precipitate acute withdrawal in chronic opiate users withdrawal symptoms? or pain in those receiving opioids for pain management. Repeated doses or an infusion are needed specially for long acting opioids Patients should be monitored for at least 6 hours after the last naloxone dose at RCU Email :[email protected] Website :http://Alkafeel.edu.iq Carbon Monoxide Colourless, Odourless gas produced by Incomplete combustion It binds with haemoglobin with 250 affinity more than O2 >>> hypoxia and unite to cytochrome oxidase inhibiting cellular respiration >>>>> Muscles Weakness That’s why most patients die before reaching hospital. Email :[email protected] Website :http://Alkafeel.edu.iq  Clinical Features Early features include headache, nausea, irritability, weakness and tachypnoea. If not picked up early then Cardiorespiratory Collapse and Death Survived may have Cerebral oedema and rhabdomyolysis Long term complications in survivors includes many Neuropsychiatric and Extrapyramidal manifestations as personality change, memory loss and concentration impairment, urinary or faecal incontinence and Gait disturbance Poisoning during Pregnancy may cause fetal hypoxia and intrauterine death. Email :[email protected] Website :http://Alkafeel.edu.iq Management Removal from exposure immediately A high flow oxygen should be administered via a tightly fitting facemask An ECG and ECG monitor should be performed in all patients with acute CO poisoning, especially those with pre-existing heart disease. Arterial blood gas analysis Pulse oximetry may provide misleading oxygen saturations because carboxyhaemoglobin and oxyhaemoglobin are both measured. Convulsions should be controlled with Diazepam. Email :[email protected] Website :http://Alkafeel.edu.iq Organophosphorus insecticides and nerve agents Widely used as Pesticides, especially in developing countries. Mortality is high (5–20%). Nerve agents, chemical warfare, are derived from OP insecticides and are much more toxic. G (originally synthesized in Germany) such as tabun, sarin and soman, are volatile, absorbed by inhalation or via the skin, and dissipate rapidly after use. ‘V’ (‘venomous’) agents, such as VX, are contact poisons unless aerosolised, and contaminate ground for weeks or months. Email :[email protected] Website :http://Alkafeel.edu.iq Mechanism of toxicity Inactivate acetylcholinesterase (AChE), resulting in the accumulation of acetylcholine (ACh) in cholinergic synapses in nervous system The effect will appear after 3-24 hours according to the agent used But more rapid with Sarin gas (Minutes ) The difference of timing is due to effect of ageing What is AGEING? Email :[email protected] Website :http://Alkafeel.edu.iq  Clinical Features Vomiting Profuse diarrhoea, Bronchospasm , Bronchorrhoea and Salivation may cause severe respiratory compromise. Excess sweating and miosis Muscles fasciculations generalised flaccid paralysis may develop resulting in respiratory failure. What is Ataxia, coma, convulsions, and arrythmias may develop torsades de pointes ? Email :[email protected] Website :http://Alkafeel.edu.iq Management Suction to remove excessive secretions High-flow oxygen External decontamination Gastric lavage or activated charcoal may be considered if the patient presents sufficiently early. Treatment of Fits Monitor ECG, oxygen saturation, blood gases, temperature, urea and electrolytes and glucose. Early administration of Atropine is potentially life-saving (2 mg IV) doubled every 5–10 minutes until clinical improvement occurs. Further bolus doses given until , the skin is dry, blood pressure is adequate and heart rate is > 80 bpm. Look for anticholinergic features ????? Oxime such as Pralidoxime chloride can be added Email :[email protected] Website :http://Alkafeel.edu.iq  References 1-Davidsons Principles and Practice of Medicine 24th edition 2-The Johns Hopkins Internal Medicine Board Review-2016 5th edition 3-Organophosphate Toxicity - Medscape Reference Email :[email protected] Website :http://Alkafeel.edu.iq