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MANAGEMENT OF ACUTE POISONING Kent R. Olson, MD Medical Director California Poison Control System San Francisco Division Lessons from history A young princess ate part of an apple given to her by a wicked witch She was found comatose and unresponsive, as if in a deep sleep Airway positioning and mouth to mouth ventilation were performed, and she recovered fully Lesson: Best antidote is good supportive care (Love’s first kiss) Case 1: Young woman found unconscious, several empty pill bottles nearby Unresponsive to painful stimuli Shallow breathing Initial management: ABCDs Airway Breathing Circulation Dextrose, drugs, decontamination Airway issues Risks: • Floppy tongue can obstruct airway • Loss of protective reflexes may permit pulmonary aspiration of gastric contents Major cause of morbidity in poisoned patients Assessing the airway “Gag” reflex • Indirect measure • May be misleading • Can stimulate vomiting Alternatives Breathing Assess visually pCO2 reflects ventilation - ABG useful pulse oximetry provides convenient, noninvasive evaluation of O2 saturation Pitfalls pO2 measures dissolved oxygen • can be normal despite abnormal hemoglobin states, eg COHgb, MetHgb Pulse oximetry also fails to detect CO poisoning Interventions Endotracheal intubation • Protects airway • Allows for mechanical ventilation Reverse coma? • Naloxone: note T½ = 60 min • Flumazenil? Don’t forget GLUCOSE “A stroke is never a stroke until it’s had 50 of D50” – Dr. Larry Tierney, 1976 Give Thiamine 100 mg IM or in IV Case, continued… The patient has no gag reflex, and does not resist intubation. She remains unconscious and on a ventilator overnight Awakens and extubated the next day Dx: mixed sedative drug overdose Case 2 47 year old man calls 911, suicidal BP 70/50, HR 50/min Junctional rhythm Hx: uses an antihypertensive Circulation = plumbing Pump working? Enough volume (is it primed)? Adequate resistance (no leaks)? Management of Hypotension Hypovolemia? • IV fluid challenge Pump? • Dopamine Inadequate vascular resistance? • Norepinephrine, phenylephrine Antihypertensives Diuretics Beta blockers Calcium channel blockers ACE Inhibitors Centrally acting agents Vasodilators Calcium channel blockers Bad ODs!! Low Toxic:Therapeutic ratio High mortality Decreased Automaticity & Conduction Negative Inotropic Effects Dilated Vascular Smooth Muscle HR AV Block CO SVR SHOCK Calcium antagonists - treatment Calcium: most effective • High doses may be needed Glucagon – variable results Insulin plus glucose? (experimental) Case 3: An 18 month old takes some of his grandmother’s “sleeping pills” Brought to the ER after a seizure HR 150/min Pupils dilated, skin flushed, mucous membranes dry Common causes of seizures Amphetamines/cocaine Tricyclic and other antidepressants Isoniazid (INH) Diphenhydramine Alcohol withdrawal Many others . . . 30 minutes later, the ECG shows: Tricyclic antidepressants Anticholinergic syndrome Seizures Cardiotoxicity TCA overdose treatment (similar tox possible w/ massive diphenhydramine) Stop the seizures • Benzodiazepines, phenobarbital Treat cardiotoxicity • Sodium bicarbonate 1 mEq/kg IV • IV fluids • Dopamine and/or NE Case 4: now we’re cookin’ 24 year old man with Hx depression Agitated, confused BP 110/70 HR 120 RR 20 T 40.4 C Muscle tone increased, LE clonus Tox screen negative for cocaine, amphetamines Drug-induced Hyperthermia Heat Stroke Malignant Hyperthermia Neuroleptic Malignant Syndrome Serotonin Syndrome Drug-induced “heat stoke” Altered judgment leads to excessive sun/heat exposure Anticholinergic drugs prevent sweating Excessive muscle hyperactivity from seizures, or from extreme agitation Malignant hyperthermia Rare, familial myopathy Triggered by general anesthesia • Succinylcholine • Inhalational agents (eg, Halothane) Muscle rigidity, hypermetabolic state Treatment: dantrolene Neuroleptic Malignant Syndrome Patient on dopamine-blocking drugs • Haloperidol classic cause • Also with newer agents (eg, clozapine) Rigidity (lead-pipe) Autonomic instability Hyperthermia Serotonin Syndrome Current “hot” diagnosis Serotonin-enhancing Rx • SSRIs in OD or multiple combos • MAOI + serotonin-ergic drug Hypertonicity/clonus (esp. lower extr.) Autonomic instability Hyperthermia Hyperthermia treatment Act quickly! • • • • • Remove clothing spray and fan Sedation and anticonvulsants PRN Neuromuscular paralysis if T >40 C Dantrolene if NM paralysis ineffective Consider bromocriptine, cyproheptadine Gut decontamination after OD Goal: reduce systemic absorption • Induce vomiting? • Pump the stomach? • Activated charcoal Ipecac-induced emesis Easy to perform, but not very effective Contraindicated: • Comatose/convulsing • Ingested corrosive or hydrocarbon Bottom line: nobody uses it anymore Pumping the stomach Cooperation not required MD sense of “control” Punitive value? Gastric lavage May stimulate gagging, vomiting Risky if airway reflexes dulled Lack of proven efficacy Bottom line: used only rarely Activated charcoal Finely divided powdered material • Huge surface area Binds most drugs/poisons • Exceptions: • Lithium • Iron Activated charcoal More effective than SI, GL First choice for most ODs Whole bowel irrigation Mechanical flush Balanced salt solution with PEG • No net fluid gain/loss Good for: • Iron • Lithium • Sustained-release pills, foreign bodies Antidotes: The best antidote is supportive care Examples of antidotes: • • • • Digoxin-specific antibodies Atropine & 2-PAM N-acetylcysteine Vitamin B-6 (pyridoxine) Call the Poison Center 1-800-222-1222 - 24 hours Immediate consultation by clinical pharmacists Back-up by MD toxicologists Identify pills, discuss diagnosis & Rx “I don’t think we should go up there, especially without a paddle”
