Other toxidromes Flashcards

1
Q

What are the clinical features of anticholinergic toxidrome?

A

Mad as a hatter = Confused, agitated
Hot as hell = Hyperpyrexia
Blind as a bat = Dilated pupils
Dry as a bone = Dry skin, mouth;retention
Red as a beet = Flushed skin

Or “dry, dilated and delirious”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the obs findings in anticholinergic toxidrome?

A

hypotension
resp depression
tachycardia –> SVT, wide QRS, long QTc, VT
pyrexia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the pathophysiology of anticholinergic overdose?

A

nictonic and muscarinic blockade
tachycardia due to block of vagus nerve
fatal arrhythmias due to anti-adrenergic and sodium channel blocking effects

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give 3 examples of anti-muscarinic agents.

A

TCA
atropine
chlorphenamine
oxybutinin
ipratropium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give 3 examples of anti-nicotinic agents.

A

bupropion
dextromethorphan
depolarising muscle relaxants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the management of anticholinergic toxidrome?

A

**Hypertonic sodium bicarbonate **injection if:
long QRS (>120)
refractory hypotension
cardiac arrest

Aim for arterial pH 7.5 (7.45-7.55)
Give magnesium if prolonged QT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the management of anticholinergic toxidrome?

A

**Hypertonic sodium bicarbonate **injection if:
long QRS (>120)
refractory hypotension
cardiac arrest

Aim for arterial pH 7.5 (7.45-7.55)
Give magnesium if prolonged QT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the clinical features of cholinergic syndrome?

A
  • “Wet and weak”
  • saliva ++
  • urine +
  • resp fluid ++
  • diarrhoea
  • flaccid paralysis
  • resp failure
  • increased sweating
  • HTN
  • bradycardia
  • bronchial secretions
  • seizures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What agents cause cholinergic syndrome?

A
  • sarin
  • organophosphates
  • NOVICHOK
  • excess meds for MG and dementia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the pathophysiology of cholinergic syndrome?

A
  • excess acetylcholine at central and peripheral acetylcholine nerve receptors
  • overstimulation at NMJ
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the management of cholinergic syndrome?

A
  • supportive
  • antimuscarinic e.g. atropine
  • intubation and ventilation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the symptoms of serotonin syndrome?

A
  • agitation/confusion
  • sweating
  • hyperreflexia +/- clonus
  • hyperpyrexia, tachycardia, hypertension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do investigations show in serotonin syndrome?

A
  • low Na
  • high CK
  • DIC
  • metabolic acidosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
A

Log in for toxbase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the causes of serotonin syndrome?

A
  • SSRIs
  • MAOi
  • TCAs
  • Opioids
  • CNS stimulants e.g. MDMA, LSD, cocaine, amphetamines, NPS
  • St John’s wort, nutmeg, cheese, red wine
  • Triptans, ondansetron, linezolid, buspirone, piriton, risperidone, ritonavir
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the management for serotonin syndrome?

A
  • external cooling - wet towels, ice baths etc
  • benzodiazepines for rigidity and agitation
  • intubate, ventilate and paralyse if necessary
  • +/- cyproheptadine (oral) or chlorpromazine (IV)
  • +/- dantrolene/visceral irrigation if still high temp

Avoid IV fluids (or use hypertonic saline instead) - can cause fatal hyponatraemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the clinical features of benzodiazepine toxidrome?

A

CNS depression
* drowsiness
* ataxia
* hypotension
* bradycardia
* hypoventilation with type 2 respiratory failure

18
Q

What is the antidote to benzodiazepine toxicity?

A

Flumazenil - selective GABAA receptor antagonist. It is not necessary to fully reverse the CNS depression as long as they can breathe.

But used if absolutely necessary; only in ventilated intubated patients

Flumazenil has a short half-life

19
Q

What is a serious side effect of giving flumazenil?

A

Seizures - can occur with rapid and complete antagonism of GABAA.

20
Q

What is the flumazenil regimen?

A

500mcg
500mcg
1000mcg

Also ensure adequate fluid resuscitation.

21
Q

What may potentiate the effect of benzodiazepine overdose?

A

Alcohol

22
Q
A
23
Q

Which toxidromes cause pin-point pupils and how do you distinguish between them?

A

Cholinergic - hyperactive bowel sounds
Opioids - hypoactive bowel sounds

24
Q

Which toxidromes cause high temperature and how do you distinguish between them?

A

Sympathomimetic - hyperactive bowel sounds
Anticholinergic - hypoactive bowel sounds

25
Q

What is the antidote to these drugs:
* paracetamol
* Fe
* BZD
* opiates
* beta-blockers

A
  • paracetamol - NAC
  • Fe - desferrioxamine
  • BZD - flumazenil
  • opiates - naloxone
  • beta-blockers - glucagon
26
Q

What is the antidote to these drugs:
* cholinergic excess
* digoxin
* methanol/ethylene glycol
* warfarin

A
  • cholinergic excess - atropine
  • digoxin - digibind
  • methanol/ethylene glycol - fomepizole
  • warfarin - vit K
27
Q

Which of the following toxidromes is incorrect?
* A Opioid – reduced RR, pin point pupils and reduced GCS
* B Cholinergic – bradycardic, pinpoint pupils increased RR
* C Benzodiazepine – Reduced RR, reduced GCS
* D Anticholinergic – bradycardia, hypotension, pyrexia, dilated pupils
* E Serotonin – hypertensive, tachycardic and pyrexial

A

D- anticholinergic cause tachycardia and hypotension (dry, dilated, delirious)

28
Q

Which of the following features would make you prescribe naloxone in opiate OD?
* A GCS 12/15
* B RR 10
* C pCO2 8
* D GCS 10/15
* E BP 100/40

A

C (type 2 resp failure?)

29
Q

What are the key findings in opiate overdose?

A

REDUCED RR, GCS and pinpoint pupils = opiate OD

30
Q

When does opiate toxicity need reversing?

A
  • Fallling GCS
  • Type 2 resp failure
  • abnormal breathing pattern
  • GCS threatening airway patency
31
Q

How does naloxone work?

A

inverse agonist of mu receptors –> withdrawal in long term users of opioids
blocks natural endorphins

SE: seizures

32
Q

What are the normal PR and QRS intervals?

A

PR = 120-200ms or 3-5 small squares
QRS = < 120ms or 2 small squares

33
Q

Patient has taken a large overdose of amitriptylline. You notice that she has a prolonged QTc on her ECG. You repeat the ECG and find the QRS is broadening. What infusion(s) should you write up?
* A Amiodarone
* B Sodium Bicarbonate and Magnesium
* C Magnesium
* D Sodium Bicarbonate
* E Amiodarone and Sodium Bicarbonate

A

B - sodium bicarb and magnesium

Patients with broadening QRS –> give Na bicarb
Patients with long QTc –> give magnesium

NB: drug causing a anticholinergic/serotonin sx as it is a TCA

34
Q

A patient on the ward was prescribed linezolid and tramadol. The nurses call you as she is extremely pyrexial and feeling unwell. She has noted her urine has turned black. What has happened?
* A allergic reaction to linezolid
* B Urosepsis
* C allergic reaction to tramadol
* D rhabdomyolysis secondary to serotonin syndrome
* E rhabdomyolysis secondary to linezolid

A

D - In severe cases of serotonin syndrome you can get convulsions, hyperthermia, rhabdomyolysis, acute kidney injury, coagulopathies and multi-organ failure may develop.

35
Q

A patient has taken a large overdose of diazepam. They are a known alcoholic. GCS is 5, they are hypotensive and have pCO2 8. What should you not do
A test dose flumazenil
B Intubate and ventilate
C intravenous fluids
D give oxygen

A

A - should never use flumazenil as a test.

36
Q

How do you treat bradycardia in beta-blocker overdose?

A

IV glucagon and atropine

37
Q

How do you reverse high INR due to warfarin?

A

Stop warfarin
5mg IV vitamin K AND
Octaplex - prothrombin complex concentrate (short half life)

38
Q

What are the features of ethylene glycol toxicity?

A

Features of toxicity are divided into 3 stages:
Stage 1: symptoms similar to alcohol intoxication: confusion, slurred speech, dizziness
Stage 2: metabolic acidosis with high anion gap and high osmolar gap. Also tachycardia, hypertension
Stage 3: acute kidney injury

39
Q

What is the management of ethylene glycol toxicity?

A
  1. Fomepizole - inhibitor of alcohol dehydrogenase
  2. Haemodialysis for refractory cases

Ethanol used to be used as it works by competing with ethylene glycol for the enzyme alcohol dehydrogenase which limits the formation of toxic metabolites (e.g. glycoaldehyde and glycolic acid) which are responsible for the haemodynamic/metabolic features of poisoning

40
Q

How do you manage methotrexate overdose?

A

IV folinic acid (presents with oral ulceration)