Overdose Flashcards
Anticholinesterase toxicity (e.g. organophosphate)
Bradycardia, miosis, salivation
Manage with:
Atropine
Pralidoxime
TCA overdose effects, management
- Anticholinergic
- CNS (e.g. seizures)
- Cardio (e.g. prolonged QRS, hypotension) - blocks fast sodium channels and decreases myocardial conduction velocity (like class IA quinidine); QRS >100 ms associated with increased risk for ventricular arrhythmia
Therefore, ABC supportive care and cardiac monitoring
1. Hypotension - treat with isotonic saline boluses, then vasopressors if necessary
2. QRS/arrhythmia - treat with sodium bicarbonate if QRS >100 ms (also improved hypotension) - sodium overcomes blockade while alkalinization makes TCA less active
Conjunctival injection
Marijuana
Psychomotor impairment can last up to a day, beyond period of euphoria
Yawning
Opioid withdrawal
Nystagmus, ataxia
Phencyclidine intoxication
Usually also violent behavior, agitation, didssociation
Alcohol + cocaine coingestion
Creates metabolite cocaethylene - prolongs and enhances cocaine sympathomimetic effects
PCP intoxication - pathophysiology, treatment
- NMDA agonist (excitatory, psychotic)
- Dopamine, NE, serotonin receptors
- Sigma receptor complex (psychotic, anticholinergic)
Treat with benzos
Benzo overdose treatment
Flumazenil - competitive antagonist
Hydroxocobalamin
Cyanide poisoning - would expect lactate >10
Fomepizole
Ethylene glycol or methanol poisoning - inhibits ADHase
Ethylene glycol or methanol poisoning - treatment
- Fomepizole
- NaCO3
- Hemodialysis
Illicit drugs associated with hypertension
Cocaine and other stimulants (MDMA/Ecstasy), PCP, marijuana
MDMA leads to what two toxicity profiles?
Sympathomimetic toxicity
Serotonin syndrome - includes drug-induced SIADH
Acute iron poisoning - signs
Iron directly injures GI mucosa by free radical production and lipid peroxidation, causing:
Abdominal pain, hematemesis, melena, diarrhea, green/black stool from tablets
Shock (multiple causes)
Anion gap metabolic acidosis
Liver necrosis (1-2 days later)
Hydroflouric acid burns - concerns and treatment
Hypomagnesemia/hypocalcemia (binding); resulting K release from cells into blood
Cardiac arrhythmia
Direct cardiotoxic effect
Treat with irrigation and calcium gluconate gel/intradermal injection or iv for cardiac arrhythmia
What must be accounted for in methadone overdose?
Long half-life - need to admit to hospital for prolonged observation in case naloxone redosing is needed
What should be done for alkaline cleaner ingestion in kid?
Take off clothes, endoscopy within 24 hr later (but not immediately since injuries may not be immediately present) +/- nasogastric tube (do not place blindly), barium swallow 2-3 weeks later
PCP vs meth
PCP has nystagmus, lower duration than meth
Both have psychomotor agitation, hallucinations, tachycardia, hypertension
Anticholinergic plants
- Mushrooms
- Jimsonweed
- Nightshade
Explain the biphasic response to nicotine poisoning
Early/stimulatory phase (<1 hr) - nicotinic agonism - agitation, nausea/vomiting, HTN, tachycardia, myoclonus, seizures
Late/inhibitory phase (1-4 hr) - overwhelmed nicotinic receptors, functional inhibition - delayed parasympathetic effects, neuromuscular blockade
Variable muscarinic effects (e.g. drooling, wheezing, diarrhea)
Salicylate treatment
- IV sodium bicarbonate - alkalinizes serum and urine to aid in its (anion) excretion)
- Hemodialysis - indicated if unable to tolerate large volume of sodium bicarbonate required
When is hemodialysis preferred over IV sodium bicarbonate for salicylate treatment?
When cannot tolerate large volumes:
ESRD, renal failure
Salicylate-induced pulmonary edema
Also severe ingestions resulting in shock or seizure, refractory acidosis, or clinical worsening despite bicarb
Is iron poisoning anion gap metabolic acidosis?
Yes - from iron absorption and lactic acid production
Acidic vs alkaline ingestion necrosis
Acidic - coagulation necrosis - protein denaturation results in eschar, preventing further injury
Alkaline - liquefactive necrosis - cell membrane dissolution allows deeper penetration of tissues and more severe injury
