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POISONING 2004

This medical overview delves into the management of a 20-year-old woman's acute poisoning, presenting with metabolic acidosis related to acetaminophen overdose. Initial symptoms highlighted include coma and vital sign instability, necessitating urgent intervention and serum level monitoring. The case illustrates the utility of the mnemonic "MUDPILES" for differential diagnosis in metabolic acidosis and emphasizes the importance of prompt therapeutic action. Other reported cases extend to carbon monoxide poisoning and methemoglobinemia, showcasing varied presentations of poisoning and their implications for treatment.

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POISONING 2004

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

  2. 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 140-160 RR 38 • Na 150 K 3.5 Cl 124 HCO3 6 • pH 6.98 pCO2 12 pO2 198

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

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

  5. “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)

  6. 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

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

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

  9. 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

  10. 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

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

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

  13. 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 + • 100 mg/kg in 1 L, over 16 hrs

  14. Duration of NAC treatment? • Current US oral NAC protocol = 72 hr • Acetadote IV = 20 hr • Onset of rising AST, ALT ~ 24-30 hr • We recommend Rx (or at least observation) until ~36 hrs after the ingestion to r/o liver damage

  15. 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

  16. Arterial blood gases: • pH = 7.43 • pCO2 = 36 • pO2 = 266

  17. Methemoglobinemia • Fe2+ in heme is oxidized to Fe3+ • Unable to carry oxygen • Many causes: (oxidants) • Benzocaine spray (in Hurricaine™) • Dapsone • Phenazopyridine • Nitrites (eg, amyl nitrite)

  18. 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?

  19. Carbon monoxide poisoning

  20. 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%

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

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

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

  24. 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

  25. 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

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

  27. 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 . . .

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

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

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

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

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

  33. Activated charcoal • Finely divided powder • Huge surface area • Drugs and poisons areadsorbed to surface • Does NOT bind: • Iron • Lithium

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

  35. 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

  36. 1-800-222-1222 • New national toll-free hotline # • Dial from anywhere in the USA • Connects to regional poison center • 24-hr consultation • PharmDs with physician back-up

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