Toxicology Flashcards
(21 cards)
Venomous snakes in Viperidae family
Crotalinae (pit vipers): rattlers, cottonmouths, copperheads & western diamondbacks
Crotalinae characteristics (5)
- Heat-sensing nostril pit
- Triangular-shaped head
- Elliptical pupils
- Green tail tip
- Long, folding fangs
Venomous Elapidae snakes
Coral snakes
Elapidae characteristics (2)
- Red stripes adjacent to yellow
2. Short, fixed fangs
Viperidae bite clinical presentation
- Local reaction (pain, edema, erythema, bullae) —> systemic toxicity (metallic taste, rhabdo, compartment syndrome, coagulopathy)
Elapidae bite clinical presentation
- Minimal local reaction —> marked systemic neurotoxicity (ptosis, vertigo, paresthesias, slurred speech, drowsiness, dysphagia, restlessness, increased salivation & proximal muscle weakness)
- May lead to respiratory paralysis
- Envenomation always warrants admission
Types of snake antivenin
- Polyvalent immune Fab (CroFab): sheep product; minimal allergic reactions
- Antivenin polyvalent (Crotalidae): horse serum; only for moderate/severe envenomations
Antivenin for Elapidae scarce; only give if symptomatic
Indications for HD in lithium toxicity
- Lithium >4.0 + impaired kidney function
- Lithium >5.0
- Seizure, dangerous dysrhythmia or AMS
- Symptomatic + contraindication for aggressive fluid repletion
Amiodarone adverse effects
Thyroid disease, pulmonary fibrosis & hepatotoxicity
Carbon monoxide hyperbaric indications
- CO level >25% (15% if pregnant)
- Loss of consciousness
- Severe metabolic acidosis (pH <7.1)
- Concern for end-organ ischemia
Arsine gas poisoning presentation & management
Presentation: Abdominal pain, hematuria & jaundice (massive RBC hemolysis)
Treatment: IVF’s, urine alkalinization, plasma/RBC exchange transfusions
Explain the toxicokinetics of acetaminophen
Normally metabolized through sulfation and glucuronide conjugation; in setting of overdose, process overwhelmed and APAP shunted to CYP450 (2E1) pathway, generating toxic metabolite NAPQI. Glutathione binds and detoxifies NAPQI, but hepatotoxicity occurs once glutathione stores are depleted by 70%.
Malignant hyperthermia pathophysiology
Mutation in RYR1 gene —> unregulated accumulation of calcium from sarcoplasmic reticulum to intracellular space —> sustained muscle contraction, hyperthermia, rhabdomyolysis, hyperkalemia & cardiac dysrhythmia
Plants containing anticholinergic alkaloids
- Belladonna
- Nightshade
- Jimson weed
Plants containing cardiac glycosides
(can cause digoxin toxicity)
- Foxglove
- Oleander
- Lilly of the Valley
- Squill
- Ouabain
- Dogbane
- Wallflower
(also cane toad venom)
Half-life of carboxyhemoglobin on AA vs 100% NRB
AA: 3 hours
100% NRB: 75 minutes
Beta-blocker toxicity management
- calcium: promotes intracellular calcium flux –> improved myocardial contraction
- glucagon: bypasses beta-receptors and activates adenyl cyclase –> improved myocardial contraction
- high-dose insulin (1 u/kg bolus then 1-10 u/kg/hr drip): powerful inotrope
- lipid emulsion therapy?
How to distinguish BB from CCB toxicity
Patients with CCB have relatively preserved neurological function and moderate hyperglycemia
Scorpion envenomation
- usually 2/2 Centruroides species
- neurotoxin leads to local cholinergic & adrenergic manifestations (systemic rare)
- opsoclonus (rotary nystagmus)
- can treat with atropine & antivenom
Silo Filler’s disease pathophysiology, presentation & management
- path: inhalation of nitrogen oxides produced from plant material
- pres: farmer enters silo within 1-2 days of it being filled; cough, chest tightness, vascular collapse, shock, ARDS
- mgmt: supportive; ?high-dose corticosteroids
Ethylene glycol toxicity
- Antifreeze
- Flank pain, hematuria & oliguria
- Labs with AGMA, increased osmol gap, low Ca, AKI, UA w/ Maltese crosses & fluorescent urine
- Toxic metabolite is oxalic acid
- Treat with fomepizole
