Poisoned Patient Lecture and Self Study

Question 1

What is done to stabilize a poisoned patient?

Answer 1

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)

Question 2

What should patients with altered mental status be given?

Answer 2

1. Oxygen
2. Naloxone - in case of OD
3. Thiamine - particularly important for alcoholics who may have WK
4. Glucose

Question 3

Should you try to get a history on a poisoned patient?

Answer 3

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)

Question 4

What are the two most important physical exam assessments?

Answer 4

1. Pulse rate

2. Pupillary size

Question 5

What is the toxidrome for anticholinergic intoxication? Pulse, BP, respirations, Temp, bowel sounds, skin, mental statius, pupils, other?

Answer 5

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)

Question 6

How does the toxidrome for sympathomimetic differ from anticholinergic?

Answer 6

Bowel sounds will be normal, and patient will be very sweaty (no blockade of muscarinic sweat receptors)

Question 7

What is the toxidrome for cholinergic?

Answer 7

SLUDGE

• Salivation
• Lacrimation
• Urination
• Defecation
• Gastric
• Emesis

also decreased pulse, miosis, and fasciulations

Question 8

What is the toxidrome keys for opiates?

Answer 8

Decreased pulse, miosis, and track marks

obvious respiratory depress, sweaty, and depressed mental status

Question 9

What are track marks?

Answer 9

IV spots down the vein of collapse

Question 10

What is the normal anion gap and its calculation?

Answer 10

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)

Question 11

What can increase the anion gap and why?

Answer 11

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

Question 12

How is expected osmolality in the blood calculated?

Answer 12

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

Question 13

What is a typical osmolal gap and how is it calculated?

Answer 13

Measured osmolal - calculated osmolal < 10

Question 14

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?

Answer 14

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

Question 15

What are two agents which require STAT tox-screen analysis and why?

Answer 15

1. Acetaminophen - need to know the level to start N-acetylcysteine treatment
2. Carbon monoxide - need to know when it’s bad enough to give hyperbaric oxygen

Question 16

What syrup is used for emesis and why is this rarely used anymore?

Answer 16

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

Question 17

When is gastric lavage used and when is it contraindicated?

Answer 17

Within 60-90 minutes following a very life-threatening substance.

Contraindication includes corrosive or caustic agents which may cause perforation of bowel or aspiration

Question 18

What is activated charcoal? How does it work?

Answer 18

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

Question 19

What drugs decrease the anion gap?

Answer 19

Lithium and bromide

Question 20

What should be given with charcoal if you need to give multiple doses and why?

Answer 20

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)

Question 21

What agents is charcoal not useful for?

Answer 21

Agents which don’t bind, i.e.:
Metals - iron or lithium
Pesticides, corrosives, and alcohols

Contraindicated in corrosive substances, but generally safe otherwise

Question 22

What is whole bowel irrigation?

Answer 22

Usage of balanced polyethylene glycol solutions to flush the gut, which mechanically cleanse the gut without risk of fluid / electrolyte imbalance

Question 23

When is whole bowel irrigation indicated?

Answer 23

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

Question 24

When is ion trapping use?

Answer 24

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

Question 25

What types of substances are amenable to hemodialysis?

Answer 25

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)

Question 26

Give examples of hemodialysis substance uses:

Answer 26

Salicylates
Methanol
Ethylene glycol
Certain metals
Phenobarbitol

Question 27

What is hemoperfusion and give one example of its usage?

Answer 27

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

Question 28

What types of drugs are likely to cause hyperventilation?

Answer 28

Drugs inducing a metabolic acidosis

i.e. MUDPILES

Question 29

What types of drugs cause tachycardia?

Answer 29

Sympathetic agonists or muscarinic antagonists, or drugs which cause hypoxia (cyanide, salicylates)

Question 30

What types of drugs cause bradycardia?

Answer 30

Muscarinic agonists, sympathetic antagonists, calcium channel blockers, opioids, and sedatives

Question 31

What does ethanol do to temperature, blood pressure, and ventilation?

Answer 31

Decreases all of them

Question 32

What is known to cause hypothermia?

Answer 32

1. Antipsychotics and dopamine-active drugs
2. Ethanol
3. Hypoglyemia

Question 33

What is known to cause hyperthermia?

Answer 33

Anticholinergic agents and sympathomimetics

Question 34

What substances are likely to cause mydriasis?

Answer 34

Anticholinergics, sympathetomimetics, LSD

Question 35

What substances are likely to cause miosis?

Answer 35

Clonidine, cholinergics, narcotics (opioid)

Question 36

What types of drugs cause nystagmus?

Answer 36

CNS-active ones:

Alcohols, sedatives, carbamazepine, PCP (phencyclidine)

Question 37

What should a garlic odor make you think of?

Answer 37

Arsenic poisoning

Question 38

What is the treatment for ethylene glycol poisoning?

Answer 38

Ethanol or 4-methylpyrazole (Antizol)

Question 39

What is the treatment for methemoglobinemia?

Answer 39

Methylene blue

Question 40

What is the treatment for calcium channel blocker overdose?

Answer 40

Calcium