Category: Toxicology

Salicylate Overdose

Salicylate toxicity is the great toxicologic mimicker!!!

Step 1: When to Suspect Salicylate Overdose

  • Signs of CNS stimulation
    • Tachypnea
    • Hyperthermia
    • Altered mental status
  • Signs of GI irritation
    • Nausea/Vomiting
    • Abdominal pain
  • Common “mimicker”
    • Sepsis
    • Acute abdomen

Step 2: Testing Plan

  • Electrolyte panel
    • Anion gap metabolic acidosis
      • Sodium – Chloride – Bicarb
        • Normal anion gap (AG) is <10
        • Caused by salicylic acid and lactic acid
  • Blood gas
    • Mixed respiratory ALKALOSIS and metabolic ACIDOSIS

Step 3: Obtain Serum Salicylate Level

Step 4: Treatment Plan

  • Mild salicylate toxicity
    • Alkalinize urine with sodium bicarbonate (NaHCO3) drip
  • Severe salicylate toxicity
    • Dialysis

Additional Reading

Acetaminophen Overdose

Acetaminophen is the most important overdose in toxicology

Step 1: Check a Serum Acetaminophen Level

  • Common situations where testing is ordered
    • Suicidal ideation
    • Severe depression
    • Overdose

Step 2: Consult the Rumack-Matthew nomogram

  • Only works for acute/single ingestions of acetaminophen
  • Loses reliability if patient is on drugs that affect bowel motility
  • If the time of ingestion is KNOWN
    • Measure acetaminophen level 4 hours post-ingestion
    • Plot on nomogram and treat if above line
  • If time of ingestion is UNKNOWN
    • Determine earliest possible time of ingestion
    • Plot on nomogram and treat if above line

Step 3: Order hepatic labs (LFTs)

  • AST
  • ALT
  • Alk Phos
  • PTT/PT/INR

Step 4: Identify Phase of Toxicity

  • Phase 1/Day 1
    • High acetaminophen levels
    • Normal LFTs
    • Minimal symptoms
  • Phase 2/Day 2
    • Acetaminophen level starts decreasing
    • LFTs level starts increasing
    • Mild GI symptoms develop
      • Abdominal pain
      • Nausea/vomiting
  • Phase 3/Day 3
    • Acetaminophen levels are normalized
    • LFTs are peaking
  • Phase 4
    • Recovery

Step 5: Give N-Acetylcysteine (NAC)

  • If patient meets criteria on Rumack-Matthew nomogram
  • If patient is in phase 1, 2, or 3

Additional Reading

  • Acetaminophen Overdose and NAC Dosing (MDCalc)

The “Big 5” Toxidromes

Poison Control Hotline: 1-800-222-1222

Step 1: Evaluate the Airway

  • General principles
    • “If they can’t speak, they can’t control their airway”
    • “If GCS is <8, intubate”
  • In the real world, it’s a clinical judgement call

Step 2: Toxicology History

  • What did they take?
  • How much did they take?
  • Why did they take it?
  • When did they take it?

Step 3: Toxicology Exam

  • Vital signs
  • Pupils
  • Skin

Step 4: Medication List

  • Make note of all bottles with patient
  • Make EXTRA note if any pills seem to be missing
  • Bonus points if you bring your attending a med list

Step 5: Common Toxicology Tests

  • Assessing for damage
    • Electrolytes
    • Liver function test
    • EKG
    • Pregnancy
  • Assessing for co-ingestion
    • Serum acetaminophen
    • Serum salicylate
    • Serum alcohol
    • Urine drug screen

The “Big 5” Toxidromes

  • Anticholinergic
    • Increased vitals
    • Big pupils
    • Dry skin
    • Treatment – Physostigmine (rarely given)
  • Cholinergic
    • Decreased vitals
    • Small pupils
    • Moist skin
    • Treatment – Atropine
  • Opioid
    • Decreased vitals
    • Small pupils
    • Dry skin
    • Treatment – Naloxone
  • Sedative/Hypnotic
    • Decreased vitals
    • Normal pupils
    • Dry skin
    • Treatment – Flumazenil (rarely given)
  • Sympathomimetics
    • Increased vitals
    • Big pupils
    • Moist skin
    • Treatment – Benzodiazepines

Additional Reading

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