POISONING 2004 Kent R. Olson, MD, FACEP Medical Director, SF Division California Poison Control System

Case 1: Metabolic Acidosis 20 year old woman found in her parked car, comatose (GCS 8) 3 empty bottles of Tylenol BP 100/50 HR RR 38 Na 150 K 3.5 Cl 124 HCO3 6 pH 6.98 pCO2 12 pO2 198

“MUDPILES” Methanol Uremia DKA Phenformin, Paraldehyde INH Lactate Ethylene glycol, Ethanol Salicylate

Lactic Acidosis Many possible causes: Hypoxia-ischemia Cyanide poisoning Carbon monoxide poisoning Metformin INH... and many others Order a serum lactate level

“SALAD” Gives you a quick “what to order”: Salicylate (order a stat [ASA]) Alcohols (toxic alcohols – order Osm) Lactate (order a state [Lactate]) Anuria (BUN, Cr) DKA (check glucose)

If the [Lactate] = normal Then, you have fewer things to consider, e.g.: Toxic alcohols Methanol = formic acidosis Ethylene glycol = glycolic acidosis Ketoacidosis Mostly beta-hydroxybutyrate

Case, continued... Salicylate negative BUN/Cr = 5/1.1 Glucose 400 mg/dL Lactate 18 mmol/L COHgb not detected Osmolality not sent

“MUDPILES” Methanol Uremia DKA Phenformin, Paraldehyde INH Lactate Ethylene glycol, Ethanol Salicylate

What was it? Serum acetaminophen = 917 mg/L !! She was treated with NAC, IV NaHCO3 (repeat pH 7.29), insulin Next day AST, ALT began to rise Peak measured ALT 5318 Bili to 2.8, INR 3.1

Acetaminophen overdose Acidosis, coma uncommon without fulminant liver failure as prior cause Occasional cases of early coma, severe acidosis with very high drug levels - despite absent liver failure

Mnemonics.. just remember: “Today’s clinical pearl may end up as tomorrow’s fecalith.”...John Wallace, MD c.1979

APAP (mg/L) Possibly Toxic Probably Toxic hrs Serum APAP level Note: co-ingestion of Nyquil plus up to 44 g Tylenol ER Ref: Bizovi K et al: J Toxicol Clin Toxicol 1995; 33:510 Serum acetaminophen (APAP) levels after ingestion of “Tylenol Extended Relief”

New drug: Acetadote™ IV formulation of N-acetylcysteine FDA approved January 2004 Not yet on the market Dose? The UK-European protocol: 150 mg/kg in 200 mL D5W over 15 min + 50 mg/kg in 500 mL D5W over 4 hours mg/kg in 1 L, over 16 hrs

Duration of NAC treatment? Current US oral NAC protocol = 72 hr Acetadote IV = 20 hr Onset of rising AST, ALT ~ hr We recommend Rx (or at least observation) until ~36 hrs after the ingestion to r/o liver damage

Case 2: Little Blue Lady 80 year old woman just returned from transeophageal echocardiogram Perioral cyanosis and blue nail beds Otherwise asymptomatic Pulse oximetry 87% - did not improve with high-flow oxygen

Arterial blood gases: pH = 7.43 pCO2 = 36 pO2 = 266

Methemoglobinemia Fe 2+ in heme is oxidized to Fe 3+ Unable to carry oxygen Many causes: (oxidants) Benzocaine spray (in Hurricaine™) Dapsone Phenazopyridine Nitrites (eg, amyl nitrite)

Another crappy hemoglobin 67 year old man found unresponsive and covered with vomitus Barbeque was heating the trailer COHgb 33% Intubated, hypotensive on Levophed Candidate for HBO?

Carbon monoxide poisoning

CO poisoning, continued... Can cause coma, seizures, death Survivors may have varying degrees of neurological sequelae Persistent coma, vegetative state, etc Subtle mood and memory disorders Incidence up to 30-40%

Controversy over treatment Hyperbaric oxygen (2.5 ATM) versus Normobaric oxygen ?

Literature is inconclusive Most reports are uncontrolled case series Only two RCTs Australian study: no difference Weaver study: small benefit with HBO

Weaver recommends HBO if: COHgb > 25% History of loss of consciousness Metabolic acidosis Age > 50 years Cerebellar findings on neuro exam

Another CO case: 55 year old man found unconscious on his yacht He had gone downstairs 10 min earlier to check on a burning odor Pulled out to fresh air, awake in 10 minutes In ER 2.5 hrs later, COHgb 14.4% alert and normal neuro exam

Child with a Seizure 14 month old boy had a seizure at home. No prior Hx of seizures. Had been playing with Effexor bottle Second seizure on arrival in ER BP 138/87 HR 150 RR 28 T nl Pupils dilated

Common causes of seizures Tricyclic antidepressants Newer antidepressants (SSRIs) especially bupropion (Wellbutrin™) Amphetamines/cocaine INH Diphenhydramine Tramadol (Ultram™)

Toxicology screen showed: Positive for methamphetamine Not tested for venlafaxine (Effexor™) Potential false (+) for amphetamines: Ephedrine, MDMA, pseudoephedrine, etc Bupropion, Labetalol, Ranitidine, Sertraline, Selegiline, Trazodone, others...

Final case: 22 year old man ingested 60 lithium tablets (300 mg) Asymptomatic 1 hour later in ER How to decontaminate the stomach?

Gut decontamination Goal: limit systemic absorption Possible methods: Induced emesis Gastric lavage Activated charcoal Cathartics/whole bowel irrigation

Induced emesis Don’t use: Salt water Finger gag Ipecac? Soapy water?

Ipecac syrup Easy to perform, but NOT very effective Risks: Pulmonary aspiration Wretching, GI injury Delay in administering charcoal Bottom line: OUTDATED

“Pumping the stomach” NOT very effective Risks: Aspiration GI trauma Delay to administering AC Bottom line: RARELY used

Activated charcoal Finely divided powder Huge surface area Drugs and poisons are adsorbed to surface Does NOT bind: Iron Lithium

Activated charcoal... More effective than ipecac, lavage First choice for most drugs & poisons

Whole Bowel Irrigation Mechanical flush GoLytely or COLYTE Balanced salt solution Nonabsorbable PEG No net fluid loss or gain Good for: Lithium, iron, foreign bodies

New national toll-free hotline # Dial from anywhere in the USA Connects to regional poison center 24-hr consultation PharmDs with physician back-up