TN Toxicology p.1-3 Flashcards
Name 4 principles to consider with all ingestions (4)
- Resuscitation (ABCD3EFG)
- Screening (toxidrome? clinical clues?)
- Decrease absorption of drug
- Increase elimination of drug
Name universal antidotes (4)
DONT
- Dextrose
- Oxygen
- Naloxone
- Thiamine (must give BEFORE dextrose)
Describe use and doses: Dextrose (glucose) (4)
- give to any patient presenting with altered LOC
- measure blood glucose prior to glucose administration if possible
- adults : 0.5-1.0 g/kg (1-2mL/kg) IV of D50W
- children: 0.25 g/kg (2-4mL/kg) IV of D25W
Describe use of oxygen (3)
- do not deprive a hypoxic patient of oxygen no matter what the antecedent medical history (i.e.even COPD with CO2 retention)
- if depression of hypoxic drive, intubate and ventilate
- exception: paraquatordiquat (herbicides) inhalation or ingestion (oxygen radicals increase morbidity)
Describe: Naloxone (4)
- central μ-receptor competitive antagonist
- shorter t1/2 than naltrexone
- antidote for opioids : administration is both diagnostic and therapeutic (1 min onset of action)
- used for the undifferentiated comatose patient
Describe loading dose for adults: Naloxone (2)
- response to naloxone can be drastic, so stepwise delivery of initial 2 mg bolus is recommended
- draw up 2 mg to deliver IV/IM/SL/SC or via ETT (ETT dose = 2-2.5x IV dose)
- 1st dose 0.4 mg (for a chronic opioid user, the initial dose may be much smaller)
- if no response, deliver second dose 0.6 mg
- if still no response, deliver remaining 1 mg
Describe loading dose for child: Naloxone (2)
- 0.01 mg/kg initial bolus IV/IO/ETT (max 2mg per dose)
- children over 20 kg can receive naloxone 2 mg IV
Describe loading maintenance dose: Naloxone (2)
- may be required because half-life of naloxone (30-80 min) is much shorter than many opioids
- hourly infusion rate at 2/3 of initial dose that allowed patient to be roused
Administration of naloxone can cause what in chronic users?
opioid withdrawal
Administration of naloxone can cause opioid withdrawal in chronic users. Name minor withdrawal sx (7)
- lacrimation
- rhinorrhea
- diaphoresis
- yawning
- piloerection
- HTN
- tachycardia
Administration of naloxone can cause opioid withdrawal in chronic users. Name severe withdrawal sx (5)
- hot and cold flashes
- arthralgias
- myalgias
- N/V
- abdominal cramps
Describe thiamine (Vitamine B1) (4)
- 100 mg IV/IM with IV/PO glucose to all patients
- given to prevent/treat Wernicke’s encephalopathy
- a necessary cofactor for glucose metabolism (may worsen Wernicke’s encephalopathy if glucose given before thiamine), but do not delay glucose if thiamine unavailable
- must assume all undifferentiated comatose patients are at risk
Name essential tests for toxicology (9)
- CBC
- electrolytes
- BUN/Cr
- glucose
- INR/PTT
- osmolality
- ABGs
- O2 sat
- ASA, acetaminophen, EtOH levels
Name potentially useful tests for toxicology (10)
- drug levels – this is NOT a serum drug screen
- Ca2+
- Mg2+
- PO43–
- protein
- albumin
- lactate
- ketones
- liver enzymes
- CK
True or false
Negative toxicology screen does not rule out a toxic ingestion
True
signifies only that the specific drugs tested were not detectable in the specimen
Describe use of Urine drug screen in the ED management of the poisoned patient (1)
Urine drug screen is costly and generally not helpful in the ED management of the poisoned patient
Name causes of increased anion gap (8)
“GOLDMARK” (* = toxic)
- Glycols* (ethylene glycol, propylene glycol)
- Oxoproline (metabolite of acetaminophen)*
- L-lactate
- D-lactate (acetaminophen, short bowel syndrome, propylene glycol infusions for lorazepam & phenobarbital)
- Methanol*
- ASA*
- Renal failure
- Ketoacidosis (DKA, EtOH*, starvation)
Name causes of decreased anion gap (4)
- Electrolyte imbalance (increased Na+/K+/Mg2+)
- Hypoalbuminemia (50% fall in albumin ~5.5 mmol/L decrease in the AG)
- Lithium, bromine elevation
- Paraproteins (multiple myeloma)
Name causes of increased osmolar gap (6)
“MAE DIE” (if it ends in “-ol”, it will likely increase the osmolar gap)
- Methanol
- Acetone
- Ethanol
- Diuretics (glycerol, mannitol, sorbitol)
- Isopropanol
- Ethylene glycol
Note: normal osmolar gap does not rule out toxic alcohol; only an elevated gap is helpful
Name causes of Increased O2 saturation gap (3)
- Carboxyhemoglobin
- Methemoglobin
- Sulfmethemoglobin
How to calculate Anion Gap? (1)
= Na+ – CI– – HCO3–
Normal AG ≤12 mM/L
Name causes of normal anion gap in metabolic acidosis (3)
- Renal HCO3- loss:
- renal tubular acidosis
- hyperparathyroidism
- GI HCO3- loss: diarrhea, fistula
- Other:
- NS infusion
- acetazolamide
- hyperkalemia
- hypoaldosteronism
Name Gastrointestinal Decontamination (5)
- single dose activated charcoal
- whole bowel irrigation (very rarely used)
- multidose activated charcoal
- surgical removal in extreme cases
- use of cathartics (i.e.ipecac) and gastric lavage in the ED is not recommended
Describe: Single dose activated charcoal (3)
- use of activated charcoal is a source of much debate amongst toxicologists. Evidence of effectiveness is not strong, and risk of aspiration is high.
- adsorption of drug/toxin to activated charcoal decreases toxin bioavailability
- odourless, tasteless, prepared as slurry with H2O
Name CI of single dose activated charcoal (4)
- unprotected airway
- late presentation after ingestion
- small bowel obstruction
- poor toxin adsorption
Describe dose: single dose activated charcoal (1)
10 g/g drug ingested or 1g/kg body weight (may vary depending on ingestion)
Describe dose of whole bowel irrigation (2)
- 500 mL/h (child) to 2000 mL/h (adult) of polyethylene glycol solution by mouth until clear effluent per rectum
- start slow (500 mL in an adult) and aim to increase rate hourly as tolerated
Name indications: whole bowel irrigation (5)
- awake, alert, can be nursed upright OR intubated and airway protected
- delayed release product
- drug/toxin not bound to charcoal
- drug packages (if any evidence of breakage emergency surgery)
- recent toxin ingestion
Name contra-indications: whole bowel irrigation (3)
- evidence of ileus
- perforation
- obstruction
Multidose activated charcoal may be used for what? (4)
- carbamazepine
- phenobarbital
- quinine
- theophylline for toxins which undergo enterohepatic recirculation
