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

Negative Inotropic Effects Negative Inotropic Effects Decreased Automaticity & Conduction Decreased Automaticity & Conduction Dilated Vascular Smooth Muscle Dilated Vascular Smooth Muscle SVR SVR COHR AV Block SHOCKSHOCK

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  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”