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Toxicology Flashcards

1
Q

Tylenol

A

Metabolized into NAPQI by glucuronidation via glutathione stores (less in chronic ETOH)

**Think of 140!

140mg/kg is toxic dose
140 level at 4h = BAD
140mg/kg = loading dose of NAC

Antidote: N acetyl cysteine (watch for anaphylactoid rxn IV, give over 1h)
Restores glutathione which metabolizes toxic byproduct NAPQI

Rumack-Matthew Nomogram

4 phases of poisoning:

  1. 1st 24h = N/V, fatigue, sweating, abd pain (AST/ALT elevation after 18h)
  2. 24-72h = RUQ pain, dark urine, jaundice
  3. 72-96h = hematuria, fever, tachypnea, blurred vision, lethargy, confusion, coma
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2
Q

Anticholinergics

A

Drug = Atropine, Scopolamine (can mimic antipsychotics, antihistamines, TCA’s)

Antidote: Physostigmine (reversible acetylcholinesterase inhibitor)
Manage seizures with benzo’s

Indications for physostigmine: (don’t give on exam without talking to poison control, or at all)
Hemodynamic compromise, psychosis or severe agitation.
**Can cause bradycardia, do not use if prolonged PR or QRS on initial EKG.
**Do not use if seizing, known TCA ingestion, QRS widening, reactive airway disease

Blind as a bat (mydriasis)
Mad as a hatter (AMS)
Red as a beet (hot, dry)
Hot as a hare (febrile)
Tachycardic
Loss of bowel/bladder tone (retention)

Deadly Nightshade, Belladonna, Jimson Weed

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3
Q

Cholinergics

A

AChE inhibitors, ACH builds up…
Drug: Organophosphates, Some mushrooms, insectisides

Antidote: Atropine, 2-PAM
Atropine is muscarinic antagonist, blocks ACH peripherally. 1-2 mg IV bolus q3-5 minutes until secretions dry.
2-PAM reverses nicotinic sx - reactivates AChE by binding to OP particle instead, must be used within 48h of onset.

SLUDGE: (muscarinic)
Salivation
Lacrimation
Urination
Diarrhea
GI
Emesis
(also Bradycardia, Bronchorrhea, Bronchospasm)

Fasciculations, weakness and paralysis (nicotinic)

**If intubating, avoid Succ as it is degraded by AChE and may cause prolonged paralysis!

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4
Q

Sympathomimetics

A

Looks just like anticholinergic but SWEATY

Cocaine, Epinephrine, Meth

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5
Q

Opiates

A

Coma, Pinpoint Pupils, Respiratory Depression

Demerol has dilated pupils

Antidote: Narcan

Opioids are synthetic derivatives of opiates

Synthetics not on tox screens: Fentanyl, methadone, demerol… do not cross react with naturals such as codeine and morphine

Withdrawal not life threatening except in neonates, can seize. Tx neonates with clonidine patches.

Tramadol can cause seizures, risk of serotonin syndrome. Narrow therapeutic index. Basically PO demerol.

Methadone can lead to Torsades

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6
Q

Iron

A

> 40-60 mg/kg potentially fatal (20% elemental iron sulfate)

325mg x20% x pills ingested

Stage 1: Abd pain, vomiting (hours)
Stage 2: Quiescent
Stage 3: (12-48h) Shock and metabolic acidosis
Stage 4: Liver failure and possible death
Stage 5: GI scarring

Antidote: Deferoxamine (not orally) -
Chelates the iron
WBI (charcoal ineffective)

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7
Q

Isopropyl

A

Antidote: Fomepizole, ETOH

Possible some pneumonitis
Toxic metabolite of acetone

**Does not cause an acidosis

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8
Q

Osmolar Gap

A

Calculated = 2NA + BUN/2.8 + Glu/18 + ETOH/4.6

Calculated minus Measured (normal = -14 to +14)

Ethylene Glycol, Methanol, ETOH, Isopropyl

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9
Q

Methanol

A

Wood EtOH, Moonshine

Snow blindness, produces formic acid/formaldehyde

Antidote = Fomepizole, ETOH
Needs dialysis if late, already has metabolites

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10
Q

Ethylene Glycol

A

Antifreeze

Produces glycol acid and oxalic acid
**Crystals in urine - calcium oxalate -> ATN and hypocalcemia

Hepatic and renal failure

Antidote = Fomepizole, ETOH
Needs dialysis if late, already has metabolites

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11
Q

Dialysis Indications

A 
Works for:
Ethanol (if very high)
Methanol
Aspirin
Lithium
Barbiturates
Gentamycin
Cephalosporins
Paraquat
Ethylene Glycol
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12
Q

Aspirin

A 
Acute:
>150mg/kg
Low Mortality
Tinnitus, Dizziness
Resp Alkalosis, Metabolic Acidosis

Non-cardiogenic pulmonary edema, cerebral edema

Chronic:
High mortality, old
Pseudo Sepsis

Antidote:  Bicarb
Alkalinize to pH of 7.5
Charcoal
Replace K and Mg
**Dialysis if seizures, coma, pulmonary edema, renal failure
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13
Q

TCA’s

A

Anticholinergic-like symptoms, signs of seizures, arrythmias, apnea

EKG findings: (Na blockade)
QRS widening
R axis deviation
Terminal R wave > 3mm in aVR

Antidote = Bicarb in high doses

Na-K pump poisoning

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14
Q

Methemoglobinemia

A

Oxidizes Fe2+ to Fe3+

Small kids, G6PD high risk
Sats at 85% despite O2, need co-ox
“Chocolate” blood

Antidote: Methylene blue, O2
Methylene blue accelerates reduction by NADH/NADPH
**Avoid in G6PD, may need exchange transfusion

Drugs = pyridium, benzocaine, Dapsone

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15
Q

Carbon Monoxide

A

Headache, whole family is sick, dog sick

HbCO binds more than HbO2

Cherry colored skin/lips

Half life CO:
4-6 hours RA
1 hours NRB
20-30 min HBO

Needs Co-ox
PaO2/ABG not accurate
Hyperbarics if pregnant, persistent deficits, syncope, dying, or >25%
O2 by NRB

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16
Q

Cyanide

A

Global cell hypoxia, inhibition of oxidative phosphorylation

Headache, vertigo, confusion, syncope, coma, death
Severe lactic acidosis
VBG appears arterial

**Fires with plastic burning
Bitter almond smell

Antidote = **Cyanokit which is Hydroxycobalamin (binds CN)

Or, old way (can kill if it’s CO) =
Nitrates (controlled MetHB that bones CN) then Thiosulfate

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17
Q

Digoxin

A 
Yellow halo vision
Bradycardia
PVC's
PAT with a block
Junctional rhythm with bidirectional ventricular tachycardia

EKG shows Salvador Dali mustache
Plants = Foxglove, Oleander, Lilly of Valley

Antidote = DigiFAB
Activated charcoal
Atropine may work
**Avoid TV pacing - irritable myocardium
**Avoid calcium despite hyperkalemia - will cause stone heart

**Hyperkalemia is a bad sign! (>5) in acute toxicity
Chronically low K/Mag makes more susceptible
Poisoning Na-K pump

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18
Q

CCB/B-blocker

A

Bradycardia, hypotension, shock
**Hypoglycemia with kids

Rx = aggressive GI decontamination (charcoal if early, WBI)
Glucagon
Epinephrine, Atropine
Calcium
Hyperinsulinemia - euglycemic therapy (bypasses cAMP)
Intralipid

Beta blocker will be much more hypoglycemic, glucagon works for B-blockers
CCB is hyperglycemia

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19
Q

INH

A

Seizing refractory to benzo’s

Antidote = B6 (pyridoxine)
1g for each gram INH

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20
Q

Dialysis Contraindications

A 
Doesn't work for:
Digoxin
TCA's
B-Blockers
Benzodiazapines
Sulphonylureas
Phenytoin
21
Q

Charcoal Contraindications

A 
Obtunded
Toxin with risk of seizures
Ileus
Hydrocarbons
Caustic Ingestions
Alcohols
Metals
22
Q

Whole Bowel Irrigation indications

A 
Iron
Lithium
Sustained release agents
Enteric coated agents
Body packers (not stuffers)

1-2L/h (adults) and 500ml/h (kids)
Consider NGT and pump
Continue until clear

23
Q

NSAIDs

A

COX inhibitor, decreases prostaglandin production

Well tolerated acutely, acute UGI bleed uncommon.
Large ingestions: sleepy, mild ataxia or disorientations
Massive ingestions: Seizures, coma, acidosis

Chronic: PUD, analgesic nephropathy, agranulocytosis with some

Tx = Supportive

24
Q

Anesthetics

A

Seizures (rare recurrence due to fast metabolism)
VT/VF - Bicarb IV push
Lipid emulsion rescue IVP followed by infusion

25
Q

Coumadin

A

Inhibit 2, 7, 9, 10 vit K dependent factors

Hypercoaguable in first 2-7 days if underlying Protein C issue, so follow INR
**don’t give vit K if early

Only treat if bleeding, otherwise just hold warfarin

Actively bleeding = FFP
Vit K for largely elevated INR

26
Q

Heparin/LMWH

A

Inactivates thrombin and activate factor 10a
LMWH targets anti-factor 10a

Antidote = protamine
1mg per 100 units heparin

HIT - antibodies that activate platelets, thrombosis

27
Q

Plavix

A

Antiplatelet agent
Can get neutropenia, hemorrhage, and TTP
Tx = administer platelets

28
Q

Cocaine

A

Inhibits re-uptake of catecholamines, also Na channel blockade

HTN, hyperthermia, Rhabdo, MI, seizures, VT

Tx = Benzo’s, cooling, nitrates, CCB

**No Beta Blockers!

29
Q

Amphetamines

A

Causes catecholamine release

HTN, Tachycardia, hyperthermia, ICH, rhabdo

Tx = Benzo’s, cooling, nitrates, CCB

**No Beta Blockers!

30
Q

GHB

A

Fast onset, minutes
2-6 hour duration
Euphoria and prosexual properties

Bradycardia, Bradypnea, Coma with rapid awakening

Withdraw just like DT’s
Tx supportive

31
Q

Crotalid features

A 
Diamond head
Elliptical pupil
Single row of scales behind anal plate
Facial pits
\+/- rattles

Indications for antivenom:
Progressive swelling
Thrombocytopenia

32
Q

Black Widow

A

Found in woodpile or hidden space, not aggressive

Central bite with bullseye lesion

Rare “acute abdomen” with negative CT
No reported deaths

Tx = pain control, benzo’s, possibly anti-venom but worse than actual bite

Can discharge if pain controlled, ons for 6h if anti-venom given

33
Q

Brown Recluse

A

Small, violin shape on head

Southeast and Midwest only

Necrotic Arachnidism
Central ulcer after eschar
RARE: Hemolysis, DIC, shock

Supportive tx, abx if secondary infection, tetanus

34
Q

Scorpion

A

Bark Scorpion, Arizona

Small, light to dark brown, lobster claws

Nocturnal

Neurotoxic venom
Immediate pain/paresthesia at site
Autonomic effects (HTN, tachycardia, diaphoresis, N/V) can progress to paralysis

Antivenom if needed, otherwise supportive care

35
Q

Ciguatera

A

Sodium channels and cholinergic receptors

Onset in 6h, N/V/D
Hot cold reversal
Feeling of loose teeth
Bradycardia
Respiratory Arrest

Tx = Mannitol

36
Q

Scombroid

A

Poor refrigeration of fish

Histadine breaks down to histamine-like compounds

Peppery taste

Rapid onset, flushing, HA, N/V/D less common

**if only 1 person has it, possible allergic rxn

Tx = supportive

37
Q

Jellyfish

A

Nematocysts

Burning pain, pruritus, arrythmias

Antidote for Box Jellies

Vinegar for 30 min

38
Q

Stonefish/Stingray

A

Dorsal spine

Heat labile toxin = hot water

If barb retained, explore wound well
Cover for vibrio

39
Q

Button Batteries

A

Alkali’s, metals

Endoscopic retrieval if larger (>penny)
Past pylorus, usually watch

40
Q

Clonidine

A

Opioid mimic
Bradycardia/Hypotension

Alpha agonist

Supportive care
Atropine for bradycardia
Narcan?

41
Q

Hydrofluoric Acid

A

Rust remover
Glass etching

Pain out of proportion
Delayed onset
Dysrhythmias

Hypocalcemia, Hyperkalemia, Hypomagnesemia

QTc prolongation and VT

Topical and SQ injection of calcium gluconate for small BSA
IV calcium for large BSA or ingestion

42
Q

Lead

A

Acute: Abd pain, hemolysis, encephalopathy, seizures, death
Chronic: Malaise, weight loss, arthralgias, anemia, **basophilic stippling of RBC’s

TX = supportive
Chelators: BAL, ETDA, DMSA

43
Q

Lithium

A

Tox usually from drug-drug
NSAIDs, ACEi’s, Diuretics

N/V/D, tremors, cardiac
Cardiac usually not clinically significant

Charcoal doesn’t work (metals)
WBI
Renal elimination only (HD)
IVF

44
Q

Dilantin

A

Gingival hyperplasia

Oral toxicity = CNS depressant, cerebellar dysfunction, seizures uncommon, NO CARDIAC

IV toxicity = Hypotension (not seen with phosphenytoin)

45
Q

Carbamazepine

A

Sodium channel blockade and QRS widening
Treat with bicarb

Seizures at high doses
SIADH and hyponatremia at high doses

46
Q

Serotonin Syndrome

A 
AMS
Febrile
Mydriasis
Agitation
Rigidity/Tremor LE>UE
**Clonus

Must have exposure to serotonin

MAOI
Lithium
SSRI
DXM
TCA's
Demerol
Ecstasy
47
Q

Hypoglycemic agents

A 
Ethanol (peds)
Insulin
B-blockers (peds)
Salicylates
Quinine

Not metformin (lactic acidosis)

48
Q

Anion Gap Metabolic Acidosis

A 
Methanol
Uremia
DKA
Paraldehyde
INH/Iron
Lactic Acidosis
Ethylene Glycol
Salicylates

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