Medical emergencies

Question 1

what is the meaning of summation anaphylaxis?

Answer 1

this describes the idea that anaphylaxis is not an “all or nothing” reaction. In fact, it is a spectrum, and sometimes additional factors are needed to cause significant disease

this might include:

1. beta blockade
2. intercurrent illness
3. exercise!
4. ACEi/ARB
5. alcohol
6. “stress”

Question 2

what is the most common cause of induction anaphylaxis?

Answer 2

suxamethonium is the most common of the induction agents

Question 3

what are the two most common types of non-IgE mediated anaphylaxis?

what is the old term for this?

what type of reaction is it? (using the class I-IV classification)

Answer 3

1. radiocontrast media is the one examiners love
   - high rates in patients with asthma, atopy and betablockers
   - no role for pre-treatment
   - less with low-osmol/nonionic
2. aspirin/NSAIDs/COX2 inhibitors

this used to be called, “anaphylactoid”

it is a type ?? reaction

Question 4

how does glucagon work in the setting of anaphylaxis with beta blockade?

Answer 4

glucagon stimulates cyclic AMP.

a spike in cyclic AMP is a mechanism to stop mast cell degranulation (the process of binding the intracellular vesicles from releasing their contents)

Not really sure why this works. The overall process is to overcome the adrenergic blockade

(might have to rewrite this slide sometime!)

Question 5

by what mechanism does ACEi cause angioedema?

Answer 5

ACEi blocks the peripheral bradykinin kinase as well as ACE

it is most common in the first few months, but can happen years after starting.

Question 6

what is the dose for adrenaline?

is there anything you would adjust the dose for? Any comorbidities?

where do you inject?

Answer 6

IM (DO NOT GIVE SUBCUT INTO DELTOID)
using the 1:1000 prep

give 0.3 - 0.5mL

Adjust the dose for age/body mass/known or suspect IHD

inject to the upper, outer thigh

may need repeating every 5 - 10 minutes

IV treatment should only be given by those who are experienced in this

Question 7

what percentage of patients have a biphasic reaction?

Answer 7

now thought to be much lower than previous estimates.

probably around 1 - 5%!

Question 8

in what situations do we use gastric lavage?

what is the alternative that we use now?

Answer 8

really only if potentially life threatening ingestion within one hour of taking

HOWEVER, it is high risk because we can not protect airway easily (unless tubed)

activated charcoal is the preferred agent in ED now

Question 9

what is the role of activated charcoal and how does it work?

Answer 9

this is the preferred method of reducing absorption of agent

it “adsorbs” chemicals.

It does not work in:

• iron
• lithium
• alcohols
• acids
• alkalis
• petrol
• pesticides

Question 10

what are the requirements for haemodialysis relating to poisons?

Answer 10

the drug needs to have a small volume of distribution. Otherwise, it would require seriously long term dialysis and would take ages to clear

(this is my interpretation)

• it seems that it is most effective for smaller molecules and those that are hydrophilic
• – things like lithium, methanol, ethylene glycol and salicylate poisoning.

Question 11

Which of the following most increases the risk of hepatotoxicity of paracetamol when taken in overdose?

A. Cigarette smoking.
B. Old age.
C. Chronic Alcohol ingestion.
D. Acute Alcohol ingestion.
E. Hepatitis B Virus (HBV) infection.

Answer 11

chronic alcohol ingestion is the one that changes the metabolism pathways

the rest shouldn’t have any specific effect

Question 12

what does it mean when we say anti-cholinergic effects?

Answer 12

• Blind as a bat (dilated pupils)
• Red as a beet (vasodilation)
• Hot as a hare (hyperthermia)
• Dry as a bone (dry skin)
• Mad as a hatter (hallucinations/agitation)
• Bloated as a Toad (ileus, urinary retention)
• And the heart runs alone (tachycardia)

Ataxia;
Decreased mucus production in the nose and throat; consequent dry, sore throat
Xerostomia or dry-mouth with possible acceleration of dental caries
Cessation of perspiration; consequent decreased epidermal thermal dissipation leading to warm, blotchy, or red skin

Increased body temperature
Pupil dilation (mydriasis); consequent sensitivity to bright light (photophobia)

Loss of accommodation (loss of focusing ability, blurred vision – cycloplegia)

Double-vision (diplopia)

Increased heart rate (tachycardia)

Urinary retention
Diminished bowel movement, sometimes ileus (decreases motility via the vagus nerve)

Increased intraocular pressure; dangerous for people with narrow-angle glaucoma.