Toxicology Flashcards
(109 cards)
Which toxins cause hypoglycemia?
ethanol, oral hypoglycemics, Bblockers, salicylates and insulin ingestion
What are the universal antidotes?
DONT= dextrose, oxygen, naloxone, thiamine (consider in adolescent patients who may be thiamine deficient (100 mg IV) ie. eating disorder, alcoholism or chronic disease (IBD))
Dose of naloxone?
Adolescent patient (without habituation): 2 mg bolus q2min up to 8-10 mg, if chronic abuse suspected: 0.2 mg or less warranted
Contraindications to activated charcoal?
unprotected airway or disrupted GI tract (severe caustic ingestion), if charcoal will increase risk/severity of aspiration (e.g. hydrocarbons)
List 4 other ingestions when NOT to use charcoal
Pesticides, petroleum distillates Hydrocarbons, heavy metals Acids/Alkali, alcohol Iron Lithium Solvents
3 indications for WBI
● Sustained release pills ● Ingestions of metals/lithium ● Body packers or body stuffers ● Ingestion of pharmaceutical patches ● Massive overdose ● Bezoar of pills ● Increasing serum level despite gastric decontamination
4 contraindications to WBI?
airway not protected
peritonitis
GI obstruction
hemodynamic instability
Complications: nausea, vomiting, cramping, bloating, aspiration
How to calculate anion gap?
Some causes of high AG?
Calculation: Na- (Cl+HCO3)
normal: 8-12 (depends on lab)
Elevated AG = MUDPILES
(methanol, uremia, DKA, Paraldehyde, INH, lactic acid, ethylene glycol, salicylates)
Differential diagnosis of 1 pill can kill
- Beta blockers (propranolol)
- Clonidine (0.1 mg)
- Calcium channel blockers
- Glyburides (sulfonylurea)
- Theophylline
- TCA
- Methylsalicylate (oil of wintergreen)
General tox management
- ABC
- Disability – drugs (universal antidotes – oxygen, glucose, naloxone + specific antidotes), decontamination (activated charcoal), draw labs
- Exposure/ examine + enhanced elimination
Calculation of osmolar gap (and causes of high OG)
o Osmolar gap = measured osm – calculated osm (2x Na + BUN + glucose)
High osmolar gap suggests ethanol, methanol, ethylene glycol, acetone, sugars (ie. mannitol)
> 10-15 is a high osmolar gap
Which drugs are radio-opaque on xray?
chloral hydrate, heavy metals (iron, lead), iodine, phenothizines, psychotropics, slow-release/ enteric-coated meds
Sympathomimetic toxidrome - drug causes, features, treatment
Cocaine, amphetamines, MDMA
Inc HR, BP, T, Sweaty, Mydriasis, Agitation, psychosis, seizures
Tx- supportive care, benzos, cooling
Features of anticholinergic toxidrome
Inc HR, BP, T Blind – mydriasis Dry Red – flushed skin Mad – delirium Dec bowel sounds
Tx of anticholinergic toxidrome
- NaBicarb if prolonged QRS (TCA)
- Lorazepam for agitation I(avoid Haldol)
- Cooling
- Physostigmine if peripheral and central toxicity (delirium) – NOT in TCA overdose
Features of cholinergic toxidrome
“SLUDGE”: salivation, lacrimation, urination, defecation, gastric cramping, emesis
+ miosis, generally bradycardic, bronchorrhea, bronchospasm (killer B’s)
Tx of cholinergic toxidrome
- Oxygen
- early intubation (avoid succ)
- Remove clothing and vigorously irrigate skin
- Atropine 0.05 mg/kg IV/IM/IO bolus Q5min until secretions and wheezing stops
- Inhaled ipratropium – Pralidoxime (2-PAM)
Toxicologic causes of hyperthermia
Sympathomimetics, anticholinergics, salicylates, Neuroleptics (NMS), SSRI (serotonin syndrome), Succinylcholine (MH)
Tox causes of miosis
Opioids, Organophosphates (cholinergic syndrome), Ethanol, Clonidine, PCP, Barbiturates
When is multi-dose activated charcoal recommended?
- Interrupts enterohepatic recirculation: phenobarbital, phenytoin, carbamazepine, VA, TCA, digoxin, dapsone, quinine, theophylline
- Sustained-release medications
Which toxins are dialysable?
lithium, salicylates, toxic alcohols, phenobarbital, theophylline
Must have low molecular weight, water soluble, low volume of distribution (ie. Not digoxin – large volume), not highly protein-bound
How does naloxone work? What are some side effects?
● Pure opioid receptor antagonist, serum ½ life 1 hr, duration of action 1-4 hr
● Competitively displaces narcotic analgesic at central opioid receptor site
● can cause withdrawal sx ( GI upset, tachycardia, hyperpnea, HTN, sialorrhea, mydriasis, piloerection, yawning, rhinorrhea, hyperalgesia, restlessness, discomfort, diaphoresis, anxiety)
Antidotes for cyanide toxicity
● Sodium thiosulfate
● Hydroxocobalamin - binds cyanide to form vit B12 excreted in the urine
Mechanism of action of NAC
i. Acting as a precursor for glutathione to increase available glutathione (major).*
ii. Increasing non-toxic sulfation metabolism (major).**
iii. Directly reducing NAPQI to APAP (minor).
iv. Directly conjugating NAPQI (minor).
v. Mitigation of adverse intracellular cascades even after NAPQI covalent binding occurs.