Poisoning Lecture Notes PDF - University of Baghdad

University of Baghdad College of Medicine 2022-2023 Title:POISONING Grade:fifth Module: pediatriv Speaker:DR. MUNEERA FADHIL Date:  University of Baghdad/ College of Medicine 2022-2023 objective Definition, c...

University of Baghdad College of Medicine 2022-2023 Title:POISONING Grade:fifth Module: pediatriv Speaker:DR. MUNEERA FADHIL Date:  University of Baghdad/ College of Medicine 2022-2023 objective Definition, circumstances, routes of Poisoning. Important history points in poisoning and specific management. Measures may be taken to prevent or decrease absorption Acetaminophen poisoning , features and management. Hydrocarbons poisoning , features and management. Caustics poisoning , features and management. Organophosphorous poisoning , features and management. Prevention of poisoning Definition of Poisoning: University of Baghdad/ College of Medicine 2022-2023 Exposure to a chemicals or other agents that adversely affects functioning of an organism. Circumstances of Exposure can be: - Intentional, accidental, environmental, medicinal or recreational. Routes of exposure can be:- Ingestion, injection, inhalation or cutaneous exposure. “All substances are poisons...the right dose separates poison from a remedy.” Poisons can include:- University of Baghdad/ College of Medicine 2022-2023 Prescription or over-the-counter medicines taken in doses that are too high. Overdoses of illegal drugs. Carbon monoxide from gas appliances. Household products, such as laundry powder or furniture polish. Pesticides. Indoor or outdoor plants. Metals such as lead and mercury. The effects of poisoning range from short-term illness to brain damage, coma, and death.  Almost all of these exposures in pediatrics age group (pre school) University of Baghdad/ College of Medicine 2022-2023 are unintentional (reflect the propensity for young children to put virtually anything in their mouths). > 90% of toxic exposures in children occur in the home. most involve only a single substance. Ingestion accounts for the vast majority of exposures. ≈ 50% of cases involve non-drug substances (cosmetics, personal care items, cleaning solutions, plants, and foreign bodies). Analgesics, topical preparations, cough and cold products, and vitamins are the most commonly reported Pharmaceutical preparations. University of Baghdad/ College of Medicine 2022-2023 A second peak in pediatric exposures occurs in University of Baghdad/ College of Medicine 2022-2023 adolescence. Exposures in the adolescent age group are primarily intentional. (suicide or abuse or misuse of substances) and thus often result in more severe toxicity.  University of Baghdad/ College of Medicine 2022-2023 APPROACH TO THE POISONED PATIENT The initial approach to the patient with a witnessed or suspected poisoning should be no different than that in any other sick child. Starting with stabilization and rapid assessment of the airway, breathing, circulation, and mental status. In any patient with altered mental status, a serum dextrose concentration should be obtained early and naloxone administration should be considered. A targeted history and physical examination serves as the foundation for a thoughtful differential diagnosis, which can then be further refined through laboratory testing and other diagnostic studies.  University of Baghdad/ College of Medicine 2022-2023 Obtaining an accurate problem-oriented history is of importance. age of the child (toddler or adolescent). acute onset of symptoms without prodrome. sudden alteration of mental status, multiple system organ dysfunction, or high levels of household stress should suggest a possible diagnosis of poisoning. Description of the Exposure.  For household and workplace products, names (brand, University of Baghdad/ College of Medicine 2022-2023 generic, chemical). and specific ingredients, along with their concentrations , can often be obtained from the labels. In the case of an unknown exposure, clarifying where the child was found (e.g., garage, kitchen, laundry room, bathroom, backyard, workplace) can help to generate a list of potential toxins. Next, it is important to clarify the timing of the ingestion and to obtain some estimate of how much of the substance was ingested. It is better to overestimate the amount ingested to prepare for the worst case scenario. Past Medical History University of Baghdad/ College of Medicine 2022-2023 Underlying diseases (can make a child more susceptible to the effects of a toxin). Concurrent drug therapy can also increase susceptibility because certain drugs may interact with the toxin. A history of psychiatric illness can make patients more prone to substance abuse, misuse, intentional ingestions, and polypharmacy complications. Social History University of Baghdad/ College of Medicine 2022-2023 Understanding the child’s social environment helps to identify potential sources of exposures (caregivers, visitors, grandparents, recent parties or social gatherings). environmental stressors (new baby, parent’s illness, financial stress) that might have contributed to the ingestion. Unfortunately, some poisonings occur in the setting of serious neglect or intentional abuse.  University of Baghdad/ College of Medicine 2022-2023 Physical Examination A targeted physical exam is important to identifying the potential toxin and assessing the severity of the exposure. assessing and stabilizing the airway, breathing, circulation, and mental status. Once one has ensured that the airway is secure and the patient is stable from a cardiopulmonary standpoint, a more extensive physical exam can help to identify characteristics of specific toxins or classes of toxins. In the poisoned patient, the key features of the physical exam are University of Baghdad/ College of Medicine 2022-2023 the vital signs, mental status, pupils (size, reactivity) nystagmus, skin, bowel sounds, and odors. These findings might suggest a toxidrome that can guide the differential diagnosis and initial management. N.B. (A toxidrome is a syndrome caused by a dangerous level of toxin in the body. It is often the consequence of a drug overdose, a systemic infection may also lead to a toxidrome). University of Baghdad/ College of Medicine 2022-2023 Laboratory Evaluation University of Baghdad/ College of Medicine 2022-2023 Quantitative blood concentrations for select intoxications (e.g., salicylates, some anticonvulsants, acetaminophen, iron, digoxin, methanol, lithium, ethylene glycol, carbon monoxide, lead). All intoxicant levels must be interpreted in conjunction with the history. Both urine drug-of-abuse screens and the more comprehensive drug screens vary widely in their ability to detect toxins and generally add little information to the clinical assessment, particularly if the agent is known and the patient’s symptoms are consistent with that agent. Serum osmolality is only helpful as a surrogate marker for a toxic alcohol exposure An electrocardiogram (ECG) is a quick and noninvasive bedside test that can yield important clues to diagnosis and prognosis. Abdominal x-ray is most helpful in screening for the presence of lead paint chips or other foreign bodies. Upper endoscopy may be useful for prognosis after significant caustic ingestions. Further diagnostic testing is based on the differential diagnosis and pattern of presentation Decontamination University of Baghdad/ College of Medicine 2022-2023 Regardless of the decontamination method used, the efficacy of the intervention decreases with increasing time since exposure. Decontamination should not be routinely employed for every poisoned patient. Dermal and ocular decontamination begin with removal of any contaminated clothing and particulate matter, followed by flushing of the affected area with tepid water or normal saline. Treating clinicians should wear proper protective gear when performing irrigation. Flushing for a minimum of 10-20 minutes is recommended for most exposures, although some chemicals (e.g., alkaline corrosives) require much longer periods of flushing. Dermal decontamination, especially after exposure to adherent or lipophilic (e.g., organophosphates) agents, should include thorough cleansing with soap and water. Water should not be used for decontamination after exposure to highly reactive agents, such as elemental sodium, phosphorus, calcium oxide, and titanium tetrachloride. inhalational exposure University of Baghdad/ College of Medicine 2022-2023 Decontamination involves moving the patient to fresh air and administering supplemental oxygen if indicated. PREVENTING ABSORPTION Activated Charcoal (single or multiple doses) Cathartics Whole bowel irrigation Enhancing excretion Emesis Gastric Lavage Diuresis Dialysis Hemoperfusion Gastric Lavage University of Baghdad/ College of Medicine 2022-2023 Gastric lavage involves placing a tube into the stomach to aspirate contents, followed by flushing with aliquots of fluid, usually water or normal saline. Although gastric lavage was used routinely for many years, objective data do not document or support clinically relevant efficacy. This is particularly true in children, in whom only small-bore tubes can be used. Lavage is time-consuming and painful, and can induce bradycardia via a vagal response to tube placement. It can delay administration of more definitive treatment (activated charcoal), and under the best circumstances only removes a fraction of gastric contents. Thus, in most clinical scenarios, the use of gastric lavage is no longer recommended. Activated Charcoal : University of Baghdad/ College of Medicine 2022-2023 Decrease or prevent the intestinal absorption of a few drugs and toxins as well as enhance the elimination of drugs already absorbed and present within the systemic circulation. specially prepared to have a very large adsorptive surface area. Many, but not all, toxins are adsorbed onto its surface. Some toxins, including heavy metals, iron, lithium, hydrocarbons, cyanide, and low molecular weight alcohols, are not significantly bound to charcoal. Dose of 10–50 g (≈1 g/kg) for a child is administered. Airway reflexes must be preserved or the airway protected by endotracheal intubation. it should only be considered for phenobarbital, theophylline, phenytoin, carbamazepine, and dapsone poisonings. Cathartics University of Baghdad/ College of Medicine 2022-2023 (sorbitol, magnesium sulfate, magnesium citrate) ❑have been used in conjunction with activated charcoal to prevent constipation and accelerate evacuation of the charcoal–toxin complex. ❑There are no data demonstrating their value and there are numerous reports of adverse effects from cathartics. ❑Cathartics should be used with care in young children and should never be used in multiple doses because of the risk of dehydration and electrolyte imbalance. Whole-Bowel Irrigation University of Baghdad/ College of Medicine 2022-2023 WBI involves instilling large volumes (35 mL/kg/hr in children or 1-2 L/hr in adolescents) of a polyethylene glycol electrolyte solution (e.g., GoLYTELY) to “wash out” the entire GI tract. Careful attention should be paid to assessment of the airway and abdominal exam before initiating WBI, which should never be given to a patient without bowel sounds or with signs of obstruction or ileus, or without a protected airway. Intralipid Emulsion Therapy University of Baghdad/ College of Medicine 2022-2023 for sequestering fat-soluble drugs and decreasing their impact at target organs. University of Baghdad/ College of Medicine 2022-2023 University of Baghdad/ College of Medicine 2022-2023 University of Baghdad/ College of Medicine 2022-2023  University of Baghdad/ College of Medicine 2022-2023 Hydrocarbons Determination of the risk of aspiration pneumonitis :- 1-low viscosity values, such as kerosene, gasoline, lighter fluid, turpentine, mineral seal oil, and mineral spirits, have the highest risk for aspiration. In contrast, more viscous hydrocarbons, such as petroleum, lubricating oil, and paraffin, represent a lower risk. 2-Surface tension. A low surface-tension chemical has the ability to creep or spread along a surface. 3-Volatility, the more volatile the agent, the greater the likelihood for adverse central nervous system effects. University of Baghdad/ College of Medicine 2022-2023  University of Baghdad/ College of Medicine 2022-2023 Pathophysiology These chemicals interfere with surfactant and directly irritate respiratory epithelium. The results are alveolar collapse, bronchospasm, direct damage to the airway epithelium and endothelium, and interstitial pneumonitis resulting in ventilation perfusion mismatch and hypoxemia and hypercapnia. Clinical Presentation :- University of Baghdad/ College of Medicine 2022-2023 Kerosene ingestion: ❖GIT effects Burning sensation, nausea, belching and diarrhea. ❖Respiratory effects Cough, tachypnoea ,tachycardia, cyanosis, pulmonary crepitations, rhonchi, chocking, gagging and grunting. CXR >6 hrs later: Pulmonary infiltrates or peri-hilar densities. Pneumatoceles (2-3 w), pleural effusion or pneumothorax and bacterial super-infection( rare) Resolution 2-7 days. ❖central nervous system effects may occur in at least a quarter of cases; lethargy and much less often semi-coma, coma and convulsions.  University of Baghdad/ College of Medicine 2022-2023 ❖Bone marrow toxicity and haemolysis are not common but the clinician must be aware of the possibility of heart rhythm problems (such as atrial fibrillation and ventricular fibrillation). ❖hepatic and renal failure. ❖skin and mucous membranes Contact with the skin and mucous membranes may cause variable degrees of irritation up to the formation of bullae. Management:- University of Baghdad/ College of Medicine 2022-2023 1- Immediately remove the child from the source of the poisoning and ensure the airway is open (this is always the first priority). 2- Remove contaminated clothing and thoroughly wash the skin with soap and water. If possible perform pulse oximetry and give supplemental oxygen if indicated. 3- Intubation and mechanical ventilation may be needed in a patient with severe hypoxia, respiratory distress or decreased consciousness.  University of Baghdad/ College of Medicine 2022-2023 4- Avoid gastric lavage because of the risk of inhalation and hence pneumonitis. 5- There is No evidence that corticosteroids are helpful. Some texts recommend the routine use of antibiotics but this remains controversial. 6- Admission to an intensive care unit is recommended for patients with early symptoms and signs of lower respiratory involvement because further deterioration of the respiratory function can be rapid. Important points University of Baghdad/ College of Medicine 2022-2023 1- The vomiting should be discouraged ( bec. of risk of inhalation). 2- CXR should not be done before 6 hours. 3- No role of gastric lavage inhalation pneumonitis. 4- No role of steroid but antibiotics are controversial.  University of Baghdad/ College of Medicine 2022-2023 Chronic environmental poisoning Lead is one of the most important chronic environmental toxins. in some low- and middle-income countries contamination of water supplies and the home environment by mining processes and factories remains a significant problem.  University of Baghdad/ College of Medicine 2022-2023 The symptoms of chronic lead exposure are non-specific but include: behavioral changes hyperactivity or decreased activity developmental delay or loss of developmental milestones chronic lead nephropathy.  University of Baghdad/ College of Medicine 2022-2023 More significant exposure may result in: abdominal pain, vomiting, constipation headache and ataxia lethargy, seizures, and coma  University of Baghdad/ College of Medicine 2022-2023 The most important treatment is to prevent further exposure to lead. Chelation therapy can be effective in reversing acute symptoms such as encephalopathy but treatment is complex, particularly as lead is deposited in bone and therefore has a long half-life effect.  University of Baghdad/ College of Medicine 2022-2023 THANK YOU University of Baghdad/ College of Medicine 2022-2023