Other toxidromes Flashcards by Zuzanna Łoboda

What are the clinical features of anticholinergic toxidrome?

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”

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What are the obs findings in anticholinergic toxidrome?

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

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What is the pathophysiology of anticholinergic overdose?

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

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Give 3 examples of anti-muscarinic agents.

TCA
atropine
chlorphenamine
oxybutinin
ipratropium

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Give 3 examples of anti-nicotinic agents.

bupropion
dextromethorphan
depolarising muscle relaxants

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What is the management of anticholinergic toxidrome?

**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

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What is the management of anticholinergic toxidrome?

**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

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What are the clinical features of cholinergic syndrome?

“Wet and weak”
saliva ++
urine +
resp fluid ++
diarrhoea
flaccid paralysis
resp failure
increased sweating
HTN
bradycardia
bronchial secretions
seizures

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What agents cause cholinergic syndrome?

sarin
organophosphates
NOVICHOK
excess meds for MG and dementia

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What is the pathophysiology of cholinergic syndrome?

excess acetylcholine at central and peripheral acetylcholine nerve receptors
overstimulation at NMJ

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What is the management of cholinergic syndrome?

supportive
antimuscarinic e.g. atropine
intubation and ventilation

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What are the symptoms of serotonin syndrome?

agitation/confusion
sweating
hyperreflexia +/- clonus
hyperpyrexia, tachycardia, hypertension

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What do investigations show in serotonin syndrome?

low Na
high CK
DIC
metabolic acidosis

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What are the causes of serotonin syndrome?

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

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What is the management for serotonin syndrome?

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

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What are the clinical features of benzodiazepine toxidrome?

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

What is the antidote to benzodiazepine toxicity?

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

What is a serious side effect of giving flumazenil?

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

What is the flumazenil regimen?

500mcg
500mcg
1000mcg

Also ensure adequate fluid resuscitation.

What may potentiate the effect of benzodiazepine overdose?

Alcohol

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

Cholinergic - hyperactive bowel sounds
Opioids - hypoactive bowel sounds

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

Sympathomimetic - hyperactive bowel sounds
Anticholinergic - hypoactive bowel sounds

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

* paracetamol - NAC * Fe - desferrioxamine * BZD - flumazenil * opiates - naloxone * beta-blockers - glucagon

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

* cholinergic excess - atropine * digoxin - digibind * methanol/ethylene glycol - fomepizole * warfarin - vit K

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

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

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

C (type 2 resp failure?)

What are the key findings in opiate overdose?

REDUCED RR, GCS and pinpoint pupils = opiate OD

When does opiate toxicity need reversing?

* Fallling GCS * Type 2 resp failure * abnormal breathing pattern * GCS threatening airway patency

How does naloxone work?

inverse agonist of mu receptors --> withdrawal in long term users of opioids blocks natural endorphins SE: seizures

What are the normal PR and QRS intervals?

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

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

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

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

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

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 - should never use flumazenil as a test.

How do you treat bradycardia in beta-blocker overdose?

IV glucagon and atropine

How do you reverse high INR due to warfarin?

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

What are the features of ethylene glycol toxicity?

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

What is the management of ethylene glycol toxicity?

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

How do you manage methotrexate overdose?

IV folinic acid (presents with oral ulceration)