Toxicology Flashcards

1
Q

What are the main clinical features of large acute lithium OD

A

mainly GI - nausea, vomiting, and pain and diarrhoea
under 25g mild
over 25 mod to severe

neurotox rare

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2
Q

What are the main clinical features of chronic lithium toxicity

A

Neurotoxic:
Grade 1 = tremor, agitation, hyper-reflexia, ataxia
* Grade 2 = stupor, rigidity, hypotension
* Grade 3 = coma, seizures, myoclonus

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3
Q

name three factors that predispose to chronic lithium toxicity

A

impaired kidney function
diabetis insipidus
dehydration
sodium depletion
drug interactions eg NSAIDS

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4
Q

What is the modality for lithium enhanced elimination?
What are the indications?

A

haemodyalsis

Indications;
renal impairement
serum lithium >2.5
established neurotoxicity

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5
Q

What agents may increase chance of heat stroke?

What are the methods for rapidly cooling?

A

MDMA
diuretics
salicylates
anticholinergic agents

Cooling:
Evaporative cooling eg spray and fan
ice packs to groin an axilla
arctic sun

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6
Q

list some conditions and clinical findings linked to alcohol abuse

A
  • Acute alcohol withdrawal – tremor, tachycardia, fever, seizures
  • Wernicke’s encephalopathy – nystagmus, confusion, ataxia
  • Peripheral neuropathy – stocking style sensory loss, loss ankle jerk
  • Cerebellar degeneration – dysdiadochokinesis, nystagmus, ataxia, past pointing etc
  • Several others OK eg alcoholic hepatitis, pancreatitis, gastritis
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7
Q

what is the toxic dose of amitryptiline?

A

over 10mg/kg life threatening

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8
Q

what are the toxic effects of anticholinergics

A
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9
Q

what is the key investigations in TCA overdose

A

**ECG **
to look for QRS widening due to sodium channel blockade
* QRS over 100 seizures
* QRS over 160 VT

Other
paracetamol
VBG
renal function

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10
Q

how do you treat a TCA overdose seizure with end points

A
  • sodium bicarb 8.4% 1-2ml/kg IV, until seizure stops or qrs under 100 then midazolam to terminate seizure
  • Check ECG - if QRS widening for 8.4% sodium bicarb to reduce QRS
  • early intubation to avoid coma due to respiratory acidosis - mention drugs
  • settings - tv 6-8ml/kg, hyperventilate 7.5-7.55, PEEP 5
  • fluids
  • activated charcoal if large ingestion
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11
Q

what is the toxic dose of two main calcium channer blocks

What is the mechanism of toxicity?

A

Verapamil and diltizaem both over 10 tablets. 1 or 2 in children

Mechanism

  • vasodilates and negatively ionotropic and chronotropic by stopping opening of L type calcium channels decreasing cellular contractility
  • Also impairs insulin release
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12
Q

management steps for calcium channel blocker OD causing significant brady cardia

A
  • ABCDE
  • IF fluid boluses
  • 10-20ml boluses of calcium cl
  • adrenaline or noradrenaline
  • high does insulin dextrose - bolus 50ml 50% dextrose plus 0.5-1 unit/kg - then infusion
  • monitor BSL and mg and K
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13
Q

why insulin dextrose in calcium channel blocker OD

A

overcomes metabolic starvation in the heart to increase output

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14
Q

diagnosis and pathophysiology

acute management?

A

Methaemoglobinaemia

fe2 changes to fe3 so haemaglobin becomes methaaemoglobin
reduces oxygen carrying capacity and does not give up what it has

Management
o2 via NRM
remove causatie agent
methyline blue 1mg/kg iver 5 mins with repeated doses if needed

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15
Q

what agents can cause Methaemoglobinaemia

A

prilocaine
dapsone
chlroquine
GTN

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16
Q

what factors can increase chance of toxicity with calcium channel blockers

A

agent - verap and dilt the worst
dose
co-ingestion other cardiac meds
extremes of age
co-morbitidies

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17
Q

features of calcium channel toxicity

A

bradycardia
hypotension
hyperglycaema
pulmonary oedema
lactic acidosis
seizures

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18
Q

what is the lethal dose of digoxin?

A

over 10 mg in adult
4mg in child
Over 10x daily dose

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19
Q

what are the features of acute dig toxicity

A

**GI **- nausea and vomiting
**CNS **- lethargy, confusion, delirium
**CVS **- bradycardia, heart blocks, slow AF, VT, SVT

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20
Q

what are the indications for digibind?
What is the dose

A

Indications
* cardiac arrest
* life threatening arythymia
* lethal dose (over 10mg adult and 4mg child)
* K over 5.5
* dig level over 15

FIVE TEN FIFTEEN

Dose
5 or 10 ampoules

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21
Q

what are the clinical effects of eucalyptus oil ingestion?

A

CNS depression - LOC/seizures
**Respiratory **- aspiration and aspiration pnemonitis, cough, choking
**GI **upset - nausea and vomiting and oral irritation
**CVS **- tachy and hypotension

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22
Q

what is the management of eucalyptus oil ingestion?

A
  • supportive care - intubate and ventilate to protect aiway as needed
  • observe
  • monitor electrolytes and BP
  • consult tox
  • admit
  • no role for antidoes or decontamination
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23
Q

What are the key things in a tox risk assessment

A
  • agent
  • dose
  • co-ingestion
  • time of ingestion
  • co-morbidities
  • clinical features
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24
Q
A

**infections **- meningitis/encephalitis
**toxidrome **- serotonin syndrome, anti cholinergic syndrome, NMS, sympathomimentic toxicity
**endocrine **- thyroid storm
enviromental- heat stroke
delirium tremens
**CNS **- stroke

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25
Q

What is the Hunter Serotonin toxicity Criteria?

A

must have a seritonergic agent in their system plus at least one of the following;

  • spontenous clonus
  • inducible clonus and agitation/diaphoresis
  • ocular clonus and agitation/diaphroresis
  • tremor and hypereflexia
  • tremor and hypertonia
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26
Q

relevant features of history post insulin overdose and how it is relevant to management

A
  1. type of insulin - will affect duration of toxicity and observation
  2. amount - severity of toxicity
  3. multiple sites or one site - one site longer duration of action
  4. diabetic or not - dictates how you ween glucose infusion
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27
Q

for insulin OD what are the treatments

A

IV dextrose infusion aiming BSL over 3.5
IV K aim for normal range

10-50%dextrose

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28
Q
A
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29
Q
A
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30
Q

what are three methods of decontamination used in iron OD and when they would be used

A
  • WBI if over 60mg/kg
  • Gastric lavage via ETT and witing 90 mins ingestion
  • surgical or endoscopic removal over 120mg/kg
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31
Q

what is the drug and dose for iron chellation?

A

Desferrioxamine IV. 15-40 mg/kg/hr

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32
Q
A
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33
Q

iron overdose, List two relevant findings and how it may alter management

A

RUZ consildation with no evidence of iron in GI tract

no need for WBI - may need bronc

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34
Q

what bloods may you order in suspected iron OD

A

serum iron levels 4-6 hours post
VBG for lactate and acid base disturbance
coags - liver involvement
BSL - hypo or hyperglycaemia
U+E - renal involvement
FBC - leucocytosis or thrombocytopenia

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35
Q

Rate
Rhythm
Axis

Main abnormality?
Why does this happen

A

sinus
75
normal

Qt prolongation
K channel blockade

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36
Q

common agents for QT prolongation

A

The anti

Antibiotics - cipro, clarithro
Antidepressants - SSRI, TCA, lithium
antipsychotics - haloperidol, chlorpromazine
antihistamines - loratidine

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37
Q

Examination features of SSRI toxidrome

A
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38
Q

main features

What illicit drugs can cause this?

Treatment?

A

widespread st elevation
narrow complex tachy
depression avr

Drugs
* sympathomimetic eg cocaine, ecstasy
* LSD
* volatile agents

Treatment
IV benzos
calm environment
GTN infusion
?thorombolytics

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39
Q

what underlying condition can predispose you to methaglobulinaemia

40
Q

what is the dose of activated charcoal

A

50g
1g/kg in paeds

41
Q

what are the contraindications for activated charcoal

A

active resus
aspiration risk
charcoal wont bind eg metal
benign agent
sub toxic dose
too long since ingestion

42
Q

what are the features of significant carbamazepine overdose

A

anti cholinergic effects
CNS - LOC, seizure, ataxia, nystagmus
CVS - hypotension, tachy or brady arrthymia, prolonged PR, QRS, QT

43
Q

With any drug related seizure, wht should be ruled out?

A

hypoglycaemia
eclampsia
infection
hyponaetramia
co-ingestion
ICH

44
Q

propanolol
life threatening effects of OD and the management

A
  • Coma - airway protection
  • seizures - benzos
  • brady/hypotension - atropine, adrenaline, noradrenaline
  • sodium channel blockade - bicarb
45
Q

OD low GCS
ECG findings

what drugs tend to do this?

A

broad QRS
RAD
prolonged QT

TCA

46
Q

list the abnormalities and reason why

What is the most likely clinical scenario

A

Severe hyperkalaemia – cellular shift due to metabolic acidosis, renal failure, cell death with rhabdo

High anion gap metabolic acidosis – renal failure, lactic acidosis lost likely

Renal failure – urea/creat less than 100 – suggests intrinsic renal failure – most likely due to rhabdo

scenario - rhabdo from long period on floor post sedation

47
Q

is there a role for decontamination in liquid paracetamol?

what is the threshold for liquid paracetamol and when should you measure level?

A

no - absorption is too quick

200mg/kg of liquid - 2 hours

48
Q

what are the one pill killers for kids?

A

verpamil
diltiazem
sodium channel blocks eg TCA
opiates
gliclazide
theophylline

49
Q

what are the steps when someone gets an anaphylactoid rash with NAC

A

stop
bronchodilator if wheezy
anti histmiane
pred 1mg/kg
start at slower rate

50
Q

what are the indications for activated charcoal in paracetamol OD

A

within 2 hours for immediate release
within 4 hours for sustined release
massive (over 30gm) within 24 hours

51
Q

what is the criteria for cessation of NAC

A

if non toxic - repeat paracetmol below line and falling

if toxic - NAC complete and ALT less than 50 and paracetamol less than 10

52
Q

what are the criteria for transfer to liver unit post paracetamol OD

A

INR > 3.0 at 48 hours or > 4.5 at any time
* oliguria or creatinine > 200 mmol/L
* persistent acidosis (pH < 7.3) or arterial lactate > 3 mmol/L
* systolic hypotension with BP <80 mmHg, despite resuscitation
* hypoglycaemia
* severe thrombocytopenia
* encephalopathy of any degree, or ALOC (GCS < 15) in the absence of sedatives

53
Q

what is a terminal R wave in v3 suggetive of?

A

TCA overdose

54
Q
A
  1. Taken multiple serotonergic medications – risk of serotonin syndrome
  2. Multiple medications that may cause sedation – ALOC/need for airway protection
  3. tCA overdose >30mg/kg – associated with severe toxicity
  4. Paracetamol potential toxic dose ie >10g, or >150mg/kg
55
Q

risk assessment

A

large ingestion of lethal agent
GCS already 14
alreasy showing biochemical signs

56
Q

what are the decontamination methods for K OD

Pro and con for each

A

WBI - good because quikcer then dialysing, hard becuase need intubation and staff to manage this
dialysis - good because definitive but invasise

57
Q

differentials for methaglobulinaemia with prilocane

what is definitive test?

treatment options

A

anaphylaxis
seizure
VT

Test - ABG for saturation gap - pa02 v sats

methyline blue
high flow o2
HBOT
vitamin C
NAC

58
Q
A

HAGMA with respiratory alkalosis

WINTERS = Expected Co2 = 1.5 x HCO3 +7 +/- (accept 3) -

59
Q

what blood gas features are most consistent with toxic alcohol ingestion?

A

high lactate
high osmolar gap
high anion gap

60
Q

what are the important investigations with ?toxic alcohol ingestion and why

61
Q

what are the treatments for toxic alcohol overdose

62
Q

what are the clinical features of salicylate toxicity?

A
  • initial hyperventilation
  • tinnitus
  • nausea
  • vimiting
  • dehydration
  • pyrexia
  • confusion
  • dehydration
63
Q

for salicylate OD

64
Q

what drugs can be used to manage serotonin syndrome

A

benzos

serotonin agonists - olanzapine, chlorpromazine

65
Q

drugs that cause serotonin syndrome

A

Antidepressants:
MAOIs - any
SSRIs - any
SNRIs - any
TCAs - any

Opioids – tramadol, buprenorphine

Anticonvulsants (Valproate, Carbamazepine)

5-HT3 antagonists - ondansetron
Metoclopramide

Lithium

Amphetamines

Antibiotics – ciprofloxacin, erythromycin

66
Q

what conditions need to be met to remove snakebite pressure bandage

A

No clinical signs of envenoming
No lab signs of envenoming
Patient in monitored, witnessed area
Local access to antivenom

67
Q

description

What is it?

What snakes can cause this?

A

ptosis
pupil down and out

third nerve palsy

death adder
tiger
taipan

68
Q

Low GCS
interpret and list tox causes

A

HAGMA

Causes
Cyanide
o Isoniazid, Iron
o Alcohol (ethylene glycol, methanol, propylene glycol)
o Salicylates
o Valproate
o Paraldehyde

69
Q

what are the signs and symptoms of cyanide toxicity

70
Q

treatment for cyanide toxicity

71
Q

what paralytic is unsafe in hyperthermic patient?

72
Q

unresponsive after femoral nerve block with bupivicanine
What do you do?

what are specific antidotes?

A

stop injection
begin CPR as per aLS
support airway and oxygenate

antidotes
intralipid 20% 1-1.5ml/kg every 3 minutes then infusion

73
Q

causes of tachycardia post intubation and historical feature

74
Q

four important complications of GHB overdose

A

coma
agitation
fluctuation consciouness
hypotension
aspiration
secondary injuries

75
Q

what are the indications for intubation with GHB

A
  • cant maintain away
  • hypoventilation
  • extreme agitaiton
  • resp failure
  • aspiraiton
  • concern for head injury
77
Q

why may ETc02 be high after intubating?

A

1) Increased CO2 production – fever, thyrotoxicosis
2) Increased pulmonary perfusion – High CO, hypertension
3) Poor alveolar ventilation – hypoventilation, bronchial intubation
4) Technical mechanical errors – leak or faulty valve

78
Q

key in benztropine OD

A

no sweating

80
Q

features of meth intoxication

A

Agitation/Anxiety/ Hypervigilence
Paranoia/Hallucinations
Psychomotor agitation – restlessness, tremor
Pressured speech
Sweating, flushed skin
Teeth Grinding, Jaw clenching
Mydriasis
Hypertension
Tachycardia

81
Q

what are the indications for haemodialysis in toxic alcohol ingestion

A

large ingestion with osmolar gap over 10
PH less than 7.3
renal failure
clinical deterioration

83
Q

dose dependant clinical features of olanzapine OD

84
Q

Quetiapine:
Lethal dose
Effects
treatment

A
  • over 3 g
  • anticholinergic, plus coma and hypotension
    Histamine receptor blockade
  • benzos for agintation, intubation for coma, fluids and norad (not adrenaline) for hypotension

NO ADREANLINE

85
Q

What are the symptoms of cholinergic syndrome and what causes it?
treatment

A

increased parasympathetic
organophosphates, physostigmine, sarin
benzos for seizures, atropine 0.02mg/kg pr pralidoxime and double dose 3-5 mins

86
Q

Mental status, eyes, lungs, obs, bowel sounds, bladder and neuro for:

Sympathomimetic/gaba withdrawal
Cholinergic
Anticholinergics
Opiod withdrawal
NMS
serotonin syndrome

87
Q

How does fomepizole or alcohol work in methanol poisoning

88
Q

Symptoms toxic alcohol poisoning

89
Q

SS v NMS

90
Q

salicylate dangerous dose

A

over 150 - sx
over 300 severe

91
Q

decontamination of hydrofluric acid

indications endoscopy

A

nothing to eat and drink - remove clothing and flush eyes with saline

endoscopy - abdo pain or GI features eg haematemsis, vomiting

92
Q

nac dose

A

200 mg/kg over 4 hours
100 mg/kg over the next 16 hours

93
Q

100% hydroflouric acid - what level causes systemic

investigations and signs of tox

antidote

A

over 2.5% - hydrogen ions bind to calcium causing cellular damage - seizure possible

Ix
Ca/Mg/K - hypocal/Mg and high K
ECG - prolonged QT interval

**antidote - **
* calcium gluconate IV 10% - 60mmol
* topical calcium gluconate 2.5%
* s/c mix with normal saline
* nebulised for inhalation

94
Q

what electrolye abnormality is mdma linked to and why

A

Na - SIADH/polydipsia

95
Q

toxic dose panadol over 48 hours?

A

anything over normal dose (4g/day)

96
Q

when would you just start NAC

A

over 10g
200mg/kg