poisoning 2004

POISONING 2004

Kent R. Olson, MD, FACEPMedical 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 140-160 RR 38Na 150 K 3.5 Cl 124 HCO3 6pH 6.98 pCO2 12 pO2 198

“MUDPILES”

MethanolUremiaDKAPhenformin, ParaldehydeINHLactateEthylene glycol, EthanolSalicylate

Lactic Acidosis

Many possible causes:Hypoxia-ischemiaCyanide poisoningCarbon monoxide poisoningMetforminINH . . . 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 alcoholsMethanol = formic acidosisEthylene glycol = glycolic acidosis

KetoacidosisMostly beta-hydroxybutyrate

Case, continued . . .

Salicylate negativeBUN/Cr = 5/1.1Glucose 400 mg/dLLactate 18 mmol/LCOHgb not detectedOsmolality not sent

“MUDPILES”

MethanolUremiaDKAPhenformin, ParaldehydeINHLactateEthylene glycol, EthanolSalicylate

What was it?

Serum acetaminophen = 917 mg/L !!

She was treated with NAC, IV NaHCO3 (repeat pH 7.29), insulinNext day AST, ALT began to rise

Peak measured ALT 5318Bili to 2.8, INR 3.1

Acetaminophen overdose

Acidosis, coma uncommon without fulminant liver failure as prior causeOccasional 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

1

10

100

1000

0 5 10 15 20 25

APAP(mg/L)

Possibly Toxic

Probably Toxic

hrs

Serum APAP level

Note: co-ingestion of Nyquil plus up to 44 g Tylenol ERRef: Bizovi K et al: J Toxicol Clin Toxicol 1995; 33:510

Serum acetaminophen (APAP) levels afteringestion of “Tylenol Extended Relief”

New drug: Acetadote™

IV formulation of N-acetylcysteineFDA approved January 2004Not yet on the marketDose? 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

Duration of NAC treatment?

Current US oral NAC protocol = 72 hrAcetadote IV = 20 hrOnset 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

Case 2: Little Blue Lady

80 year old woman just returned from transeophageal echocardiogramPerioral cyanosis and blue nail bedsOtherwise asymptomaticPulse oximetry 87% - did not improve with high-flow oxygen

Arterial blood gases:

pH = 7.43 pCO2 = 36 pO2 = 266

Methemoglobinemia

Fe2+ in heme is oxidized to Fe3+

Unable to carry oxygen Many causes: (oxidants)

Benzocaine spray (in Hurricaine™)DapsonePhenazopyridineNitrites (eg, amyl nitrite)

Another crappy hemoglobin

67 year old man found unresponsive and covered with vomitusBarbeque was heating the trailerCOHgb 33%Intubated, hypotensive on LevophedCandidate for HBO?

Carbon monoxide poisoning

CO poisoning, continued . . .

Can cause coma, seizures, deathSurvivors may have varying degrees of neurological sequelae

Persistent coma, vegetative state, etcSubtle 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 seriesOnly two RCTs

Australian study: no differenceWeaver study: small benefit with HBO

Weaver recommends HBO if:

COHgb > 25%History of loss of consciousnessMetabolic acidosisAge > 50 yearsCerebellar findings on neuro exam

Another CO case:

55 year old man found unconscious on his yachtHe had gone downstairs 10 min earlier to check on a burning odorPulled out to fresh air, awake in 10 minutesIn 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 bottleSecond seizure on arrival in ERBP 138/87 HR 150 RR 28 T nlPupils dilated

Common causes of seizures

Tricyclic antidepressantsNewer antidepressants (SSRIs)

especially bupropion (Wellbutrin™)Amphetamines/cocaineINHDiphenhydramineTramadol (Ultram™)

Toxicology screen showed:

Positive for methamphetamineNot tested for venlafaxine (Effexor™)

Potential false (+) for amphetamines:Ephedrine, MDMA, pseudoephedrine, etcBupropion, 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 absorptionPossible methods:

Induced emesisGastric lavageActivated charcoalCathartics/whole bowel irrigation

Induced emesis

Don’t use:Salt waterFinger gag

Ipecac?Soapy water?

Ipecac syrup

Easy to perform, butNOT very effectiveRisks:

Pulmonary aspirationWretching, GI injuryDelay in administering charcoal

Bottom line: OUTDATED

“Pumping the stomach”

NOT very effectiveRisks:

AspirationGI traumaDelay to administering AC

Bottom line: RARELY used

Activated charcoal

Finely divided powderHuge surface areaDrugs and poisons areadsorbed to surfaceDoes NOT bind:

IronLithium

Activated charcoal . . .

More effective than ipecac, lavageFirst choice for most drugs & poisons

Whole Bowel Irrigation

Mechanical flushGoLytely or COLYTE

Balanced salt solutionNonabsorbable PEGNo net fluid loss or gain

Good for:Lithium, iron, foreign bodies

1-800-222-1222

New national toll-free hotline #Dial from anywhere in the USAConnects to regional poison center

24-hr consultationPharmDs with physician back-up