Toxicology: General measures

  1. The ABC's always come first
  2. Dextrose, Oxygen, Naloxone, Thiamine for AMS ( "the coma cocktail") DONT

Supportive measures alone (Scandinavian method) including mechanical ventilation and circulatory support will permit survival of most patients who are alive upon arrival at the hospital.

History

  • Unreliable, seek multiple sources
  • Pill bottles, drug paraphernalia
  • Establish time and size of ingestion
  • vomiting

Physical Exam

  • Vital signs
  • Mental status, Muscle tone, reflexes
  • Pupils, nystagmus
  • Skin and mucous membranes
  • Respiratory exam
  • Bowel sounds
  • Autonomic nervous system

Laboratory tests

Decontamination/ Elimination

  • Ipecac, Gastric lavage, Activated Charcoal
  • Forced diuresis and urinary pH manipulation
  • Hemodialysis

Antidotes


TOXIDROMES

"A pattern of signs or symptoms that suggests a specific class of poisoning"

Opioids

  • triad of respiratory depression, pinpoint pupils, decreased LOC
  • bradycardia, hypotension, hypothermia
  • needle tracks

Sedative / Hypnotics

benzodiazepines, alcohol, barbituates

  • altered mental status, stupor, coma, slurred speech
  • respiratory depression
  • variable pupil changes
  • hypotension
  • hypothermia
  • barbiturate blisters

Sympathemimetics / Withdrawal

- Cocaine, amphetamines, PCP, pseudoephedrine

  • HTN, tachycardia,
  • Mydriasis
  • Anxiety, delirium
  • Diaphoresis
  • Increased temperature

Anticholinergics

  • TCA, antihistamines, antipsychotics, Gravol
  • Hot as a hare, Red as a beet, Dry as a bone, Blind as a bat, Mad as a hatter
  • Hyperpyrexia, cutaneous vasodilation, decreased saliva, mydriasis, hallucinations
  • tachycardia
  • Urinary retention
  • Decreased bowel sounds
  • Seizures, dysrhythmias

Cholinergics

  • insecticides,carbamate, organophosphates, nerve gas, physostigmine
  • Salivation, Lacrimation, Urination, Defecation, Gastric cramping, Emesis SLUDGE
  • Drowning in secretions, profuse sweating
  • AMS, seizures, coma
  • Muscle fasciculations

Salicylates

  • fever
  • tachypnea
  • tinnitus, lethargy, altered mental status
  • respiratory alkalosis
  • metabolic acidosis, ketosis
  • vomiting

Serotonin

  • fluoxetine, trazadone, meperidine
  • irritability
  • hyperreflexia, tremor, myoclonus, trismus
  • flushing,diaphoresis
  • diarrhea

Extrapyramidal

  • haloperidol, phenothiazines
  • rigidity, tremor
  • opisthotonus, trismus
  • choreoathetosis
  • hyperreflexia

Hallucinogenic

  • amphetamines, cannabinoids, cocaine, LSD, PCP
  • hallucinations, psychosis, panic
  • fever
  • mydriasis

Bradycardia

  • Beta- blockers, calcium-channel blockers, Digoxin
  • Clonidine
  • Phenylpropanolamine
  • Carbamates, organophosphates, physostigmine
  • TCA's
  • Antidysrhythmics ( Types 1A AND 1C)
  • Opioids
  • Hypoxemia, MI, hyperkalemia, hypothermia, hypothyroidism, ICP

Agitation/ Seizures


Temperature alterations


Toxicology laboratory

  1. Arterial Blood Gas with Co-oximetry
  2. CO, MetHgb, CN-
  3. Oxygen saturation gap
  4. Respiratory or metabolic acidosis
  5. Urinalysis
  6. FeCl3
  7. Ketones
  8. Calcium oxalate crystals
  9. Woods lamp
  10. Electrolytes, BUN, Cr
  11. Lactate
  12. Serum ketones
  13. Serum osmolarity

Anion gap metabolic acidosis AG = [Na+] - [Cl-] - [HCO3-]

Methanol

Uremia

Diabetic Ketoacidosiss ( AKA, SKA )

Phenformin, Paraldehyde

Iron, INH

Lactic acidosis

Ethylene Glycol

Salicylates

Osmol Gap

Calculated osmolality = 2[Na+] + [BUN] + [glucose] + [ ethanol]

  • Abdominal X-Ray
  • Choral hydrate, heavy metals, iron, phenothiazines, enteric coated
  • ECG

Toxicology Screening

  • provides direct evidence of ingestion
  • rarely impacts initial management
  • initial supportive measures should never await these results
  • rules in the presence of a drug
  • provides grounds for treatment with a specific antidote
  •  
  • Acetaminophen
  • ASA
  • Digoxin
  • Theophylline
  • Phenobarb
  • Iron
  • Lithium
  • Methanol, Ethylene glycol

Antidotes

  • DON’T
  • Naloxone ( Narcan)
  • Flumazenil
  • Digibind
  • NaHCO3
  • Physostigmine
  • Atropine/ praladoxime
  • NAC
  • Ethanol
  • Glucagon
  • Calcium chloride
  • Amyl nitrite, sodium nitrite, sodium thiosulfate, hydroxycobalamine
  • Methylene blue
  • BAL, EDTA, penicillamine
  • pyridoxine

Gastric emptying

Risk/ Benefit ratio unfavorable for majority of poisonings

Risks

  • Aspiration
  • Upper airway, esophageal, gastric trauma ( perforations)
  • Pneumothorax
  • Dysrhythmias

Benefits

  • 33% ( 13 - 70 %) recovery of ingested toxin
  • ? improved clinical outcomes if performed within 1 hour

Indications (selective use)

  • Toxic substance and toxic amount
  • Less than one hour from presentation and AMS
  • Airway protected

Contraindications

  • Nontoxic substance or amount
  • Vomiting
  • Greater than 1 hour
  • Toxin readily absorbed
  • Caustics, sharps, petroleum
  • Large pills or packets

Evidence

1)Kulig ( 1985) - Gastric emptying + charcoal vs charcoal alone

  • No benefit to Ipecac vs AC alone
  • No benefit to lavage if done > 1 hour after ingestion

2) Albertson ( 1989) - Ipecac + Ac vs AC alone

  • Fewer complications without Ipecac
  • No difference in outcomes

3) Merrigan ( 1990) - Observation vs AC vs Gastric empty+AC

  • No benefit to gastric emptying vs AC alone
  • Gastric emptying increases aspiration pneumonia

4) Pond ( 1995) - 495 Gastric empty + AC vs 417 Ac only

No benefit including < 1 hour and those with severe toxicity

"gastric emptying procedures can be omitted from the treatment regimen for adults after acute overdose, including those that present within one hour of overdose and those that manifest severe toxicity."

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