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 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

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-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

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

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

Fe2+ in heme is oxidized to Fe3+

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 areadsorbed 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

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