Poisoned Patient Lecture and Self Study Flashcards
What is done to stabilize a poisoned patient?
ABC’s - Airway Breathing, Circulation
- > Intubate early
- > Treat shock and increase blood pressure via a specific vasopressor (i.e. dopamine / epinephrine when you need to constrict the arteries for a calcium channel blocker overdose)
What should patients with altered mental status be given?
- Oxygen
- Naloxone - in case of OD
- Thiamine - particularly important for alcoholics who may have WK
- Glucose
Should you try to get a history on a poisoned patient?
Yes, although it might not be accurate. May give clues as to exposure, timing, dose, and the time-scale of the exposure (acute vs chronic)
What are the two most important physical exam assessments?
- Pulse rate
2. Pupillary size
What is the toxidrome for anticholinergic intoxication? Pulse, BP, respirations, Temp, bowel sounds, skin, mental statius, pupils, other?
Increased pulse, blood pressure, temperature
Variable respirations
Bowel sounds will be absent with urinary retention
Skin will be dry / hot (dry as a bone, red as a beet)
Patient will be agitated / delirium / seizures (mad as a hatter)
Patient will have mydriasis (blind as a bat)
How does the toxidrome for sympathomimetic differ from anticholinergic?
Bowel sounds will be normal, and patient will be very sweaty (no blockade of muscarinic sweat receptors)
What is the toxidrome for cholinergic?
SLUDGE
- Salivation
- Lacrimation
- Urination
- Defecation
- Gastric
- Emesis
also decreased pulse, miosis, and fasciulations
What is the toxidrome keys for opiates?
Decreased pulse, miosis, and track marks
obvious respiratory depress, sweaty, and depressed mental status
What are track marks?
IV spots down the vein of collapse
What is the normal anion gap and its calculation?
Normal is 12 +/- 4 mEq / L
AG = Na - (HCO3 + Cl)
Can choose to include K+ in cations if you want, but generally you have more cations because there are negative ions not accounted for (organic acids, proteins which are negatively charged like albumin)
What can increase the anion gap and why?
Introduction of organic acid metabolites like lactate, ketones, formic acid, and oxalic acid, making bicarbonate and chloride account for less of the anions in the blood, also consuming biocarbonate to neutralize the acid:
MUDPILES: Methanol Uremia Diabetes Paraldehyde / phenoformin Iron / isoniazid Lactate Ethylene glycol Salicylates
How is expected osmolality in the blood calculated?
mOsm = 2 (Na) + glucose / 18 + BUN / 2.8
Since sodium is the only cation of significance in plasma, multiplying by two should give the rough sum of cationic and anionic osmolytes
What is a typical osmolal gap and how is it calculated?
Measured osmolal - calculated osmolal < 10
What are some important toxins which can increase the osmolal gap, and if they aren’t present does this mean they are not a concern?
Methanol. ethanol, ethylene glycol, acetone, osmotic diuretics
Increase the gap by increasing the measured plasma osmolality without increasing the calculated osmolality
-> can still be a concern even if not measured
What are two agents which require STAT tox-screen analysis and why?
- Acetaminophen - need to know the level to start N-acetylcysteine treatment
- Carbon monoxide - need to know when it’s bad enough to give hyperbaric oxygen
What syrup is used for emesis and why is this rarely used anymore?
Ipecac
-> rarely used because there’s only a short window where it’s effective, it can be dangerous, and delays the time to charcoal administration
When is gastric lavage used and when is it contraindicated?
Within 60-90 minutes following a very life-threatening substance.
Contraindication includes corrosive or caustic agents which may cause perforation of bowel or aspiration
What is activated charcoal? How does it work?
Heated and steam/acid-treated wood pulp which has a massive surface area for adsorption
Works by preventing the enterohepatic circulation of some drugs as well
What drugs decrease the anion gap?
Lithium and bromide
What should be given with charcoal if you need to give multiple doses and why?
Cathartics like saline or sorbitol, which increase the osmotic load and help flush out the gut so it doesn’t get stuck. This decreases the incidence of GI destruction (give with first charcoal use of the day)
What agents is charcoal not useful for?
Agents which don’t bind, i.e.:
Metals - iron or lithium
Pesticides, corrosives, and alcohols
Contraindicated in corrosive substances, but generally safe otherwise
What is whole bowel irrigation?
Usage of balanced polyethylene glycol solutions to flush the gut, which mechanically cleanse the gut without risk of fluid / electrolyte imbalance
When is whole bowel irrigation indicated?
Ingestion of massive amounts of toxic substance, substances which are not absorbed by charcoal, sustained release substances, and wrapped packages of substances
-> golf balls of stuff in the bowel which slowly release more drug
When is ion trapping use?
Alteration of pH (generally for organic acids only), increase pH of urine to decrease the protonation and enhance elimination by kidney
If you try to drop pH to increase the excretion of bases, you often cause rhabdomyolysis / renal failure
What types of substances are amenable to hemodialysis?
Substances which are present only in plasma (low Vd), have high water solubility, molecular weight is low, and low protein binding (will be able to be accessed through membrane)
Give examples of hemodialysis substance uses:
Salicylates Methanol Ethylene glycol Certain metals Phenobarbitol
What is hemoperfusion and give one example of its usage?
Pumping blood through a cartridge filled with charcoal or resin beads, removing polar and nonpolar metabolites which may even be bound to protein
-> useful in theophylline poisoning
What types of drugs are likely to cause hyperventilation?
Drugs inducing a metabolic acidosis
i.e. MUDPILES
What types of drugs cause tachycardia?
Sympathetic agonists or muscarinic antagonists, or drugs which cause hypoxia (cyanide, salicylates)
What types of drugs cause bradycardia?
Muscarinic agonists, sympathetic antagonists, calcium channel blockers, opioids, and sedatives
What does ethanol do to temperature, blood pressure, and ventilation?
Decreases all of them
What is known to cause hypothermia?
- Antipsychotics and dopamine-active drugs
- Ethanol
- Hypoglyemia
What is known to cause hyperthermia?
Anticholinergic agents and sympathomimetics
What substances are likely to cause mydriasis?
Anticholinergics, sympathetomimetics, LSD
What substances are likely to cause miosis?
Clonidine, cholinergics, narcotics (opioid)
What types of drugs cause nystagmus?
CNS-active ones:
Alcohols, sedatives, carbamazepine, PCP (phencyclidine)
What should a garlic odor make you think of?
Arsenic poisoning
What is the treatment for ethylene glycol poisoning?
Ethanol or 4-methylpyrazole (Antizol)
What is the treatment for methemoglobinemia?
Methylene blue
What is the treatment for calcium channel blocker overdose?
Calcium
