POISONING

POISONING

Dr.Dhaher JS Al-habbo FRCP London UKAssistant Professor in MedicineDepartment of Medicine College of Medicine

* Paracelsus (1493-1541)‘Grandfather of Toxicology’ “The dose makes the poison” "All things are poison and nothing is without poison, only the dose permits something not to be poisonous."
therapeutic effect
toxic effect
increasing dose

Taking a history in poisoning What toxin(s) have been taken and how much?

Recognition of poisoning Identification of agents involved Assessment of severity Prediction of toxicity

Taking a history in poisoning What toxin(s) have been taken and how much?

What time were they taken and by what route? Has alcohol or any drug of misuse been taken as well? Obtain details of the circumstances of the overdose from family, friends and ambulance personnel Ask the general practitioner for background and details of prescribed medication

Taking a history in poisoning What toxin(s) have been taken and how much?

Assess suicide risk (full psychiatric evaluation when patient has physically recovered) Capacity to make decisions about accepting or refusing treatment? Past medical history, drug history and allergies, social and family history? Record all information carefully

EVALUATION OF THE ENVENOMED PATIENT

Neurotoxic paralysis 'Sleepy' or drooping eyelids Difficulty swallowing, dysarthria and drooling Limb weakness Respiratory distress Excitatory neurotoxicity. Sweating, salivation, piloerection Tingling around mouth, tongue or muscle twitching Dyspnoea (pulmonary oedema)


Assessment of type and extent of envenoming
Coagulopathy. Blood oozing from bite site and/or gums Bruising Melaena, haematemesis Local effects :Pain, sweating, blistering, bruising etc. Myolysis ; Muscle pain or weakness

Important substances involved in poisoning

IN UKAnalgesics, e.g. paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs) Antidepressants, e.g. tricyclic antidepressants (TCAs), selective serotonin re-uptake inhibitors (SSRIs) and lithium Cardiovascular agents, e.g. β-blockers, calcium channel blockers and cardiac glycosides Drugs of misuse, e.g. opiates, benzodiazepines, stimulants (e.g. amphetamines, MDMA, cocaine) Carbon monoxideAlcohol

Important substances involved in poisoning

In South and South-east Asia. Organophosphorus and carbamate insecticides(mostly fatal) Aluminium and zinc phosphide Oleander Snake venoms Antimalarial drugs, e.g. chloroquine Antidiabetic medication

Important substances involved in poisoning

Poisoning in old age Aetiology: commonly results from accidental poisoning (e.g. due to confusion or dementia) or drug toxicity as a consequence of impaired renal or hepatic function or drug interaction. Toxic prescription medicines are more likely to be available. Psychiatric illness: self-harm is less common than in younger adults but more frequently associated with depression and other psychiatric illness, as well as chronic illness and pain. There is a higher risk of subsequent suicide. Severity of poisoning: increased morbidity and mortality result from reduced renal and hepatic function, reduced functional reserve, increased sensitivity to sedative agents and frequent comorbidity.

Epidemiology

More than 2 million toxic exposures reported in 200 Over half were children < 6 years Poisoning third leading cause of death from 1985-1995 Incidence of toxin related deaths increase 300%. All chemicals have potential to be poisons if given a large enough dose Poisoning occurs when exposure to a substance adversely affects function of any organ system

Examination

Physiologic excitation – anticholinergic, sympathomimetic, or central hallucinogenic agents, drug withdrawalPhysiologic depression – cholinergic (parasympathomimetic), sympatholytic, opiate, or sedative-hypnotic agents, or alcohols Mixed state – polydrugs, hypoglycemic agents, tricyclic antidepressants, salicylates, cyanide

Oropharynx for increase salivation or excessive dryness CV: rhythm, rate, regularity Lungs: bronchorrhea or wheezing Abd: bowel sounds, tenderness or rigidity Ext: fasiculations, tremor Neuro: CN, reflexes, muscle tone coordination, cognition, ability to ambulate
Physical Examination

Drug detection

Drug levels

General Management

A (Airway)B (Breathing)C (Circulation)D (Disability- /Glasgow Coma Scale)DEFG ( Don’t ever forget the Glucose)GET A SET OF BASIC OBSERVATIONS

Airway

Airway obstruction can cause death after poisoning Flaccid tongue Aspiration Respiratory arrest Evaluate mental status and gag/cough reflex Airway interventions Sniffing position Jaw thrust Head-down, left-sided position Examine the oropharynx Clear secretions Airway devices: nasal trumpet, oral airway Intubation? Consider naloxone first

Breathing

Determine if respirations are adequate Give supplemental oxygen Assist with bag-valve-mask Check oxygen saturation, ABG Auscultate lung fields Bronchospasm: Albuterol nebulizer Bronchorrhea/rales: Atropine Stridor: Determine need for immediate intubation

Circulation

IV access Obtain blood workMeasure blood pressure, pulseHypotension treatment:Normal saline fluid challenge, 20 mL/kgVasopressors if still hypotensivePRBC’s if bleeding or anemicHypertension treatment:Nitroprusside, beta blocker, or nitroglycerinContinuous ECG monitoringAssess for arrhythmias, treat accordingly

Supportive care

Vital signs, mental status, and pupil size Pulse oximetry, cardiac monitoring, ECG Protect airway Intravenous access cervical immobilization if suspect trauma Rule out hypoglycaemia Naloxone for suspected opiate poisoning

Preventing absorption

Gastric lavage Not in unconscious patient unless intubated (risk aspiration) Flexible tube is inserted through the nose into the stomach Stomach contents are then suctioned via the tube A solution of saline is injected into the tube Recommended for up to 4hrs in Salicylate OD Induced Vomiting Ipecac - Not routinely recommended Risk of aspiration

Preventing absorption

Activated charcoalAdsorbs toxic substances or irritants, thus inhibiting GI absorption Addition of sorbitol →laxative effectOral: 25-100 g as a single dose repetitive doses useful to enhance the elimination of certain drugs (eg, theophylline, phenobarbital, carbamazepine, aspirin, sustained-release products)not effective for cyanide, mineral acids, caustic alkalis, organic solvents, iron, ethanol, methanol poisoning, lithium

Elimination of poisons

Renal elimination Medication to stimulate urination or defecation may be given to try to flush the excess drug out of the body faster. Forced alkaline diuresis Infusion of large amount of NS+NAHCO3 Used to eliminate acidic drug that mainly excreted by the kidney eg salicylates Serious fluid and electrolytes disturbance may occur Need expert monitoring Hemodialysis or haemoperfusion: Reserved for severe poisoning Drug should be dialyzable i.e. protein bound with low volume of distribution may also be used temporarily or as long term if the kidneys are damaged due to the overdose.