Toxicology Flashcards
1
Q
Approach to toxicology mnemonic
A
R - RSI - DEAD
Risk assessment
Resus
Supportive
Investigations
Decontamination
Enhanced elimination
Antidotes
Disposition
2
Q
Activated charcoal dose and time indications
A
1g/kg, max 50g
2hrs post-IR; 4hr post-MR
3
Q
Multi-dose Activated Charcoal (MDAC) dose, regime and drugs
A
50g q4hrly (paeds 0.5g/kg)
Prevents Drugs Crossing Too Quickly
Phenobarbitone, phenytoin
Dapsone
Carbamazepine (commonest), colchicine, CCB
Theophylline
Quinine
+Warfarin
4
Q
Whole bowel irrigation dose, regime and indication
A
Macrogol 3350 (Movicol) 1L stat then 1L/hr (30mL/kg/hr, paeds)
Commence within 4 hours of ingestion and continue until diarrhoea runs clear
Metals - Iron, lithium, potassium
Modified-release preparations - verapamil, diltiazem, metformin, theophilline
Colchicine
Body packer
Contraindicated if signs of bowel obstruction of haemorrhage
5
Q
Dialysis for toxins, examples mnemonic
A
BLAST ME
Barbiturates
Lithium
Alcohols (methanol, ethylene glycol)
Salicylates
Theophylline
Metformin
Epileptics (carbemazepine, sodium valproate - not phenytoin)
+Potassium , paraquat
Small molecule
Small Vd
Low protein binding
Rapid redistribution from tissues
Slow endogenous elimination
6
Q
Toxins causing HAGMA
A
Lactic acid:
- Metformin
- Cyanide
- Iron
Other:
- Salicylates
- Paracetamol
- Toxic alcohols
- CO
OR
A SULK CoP IT
Alcohols
Salicylates
Urea
Lactate
Ketones
CO,CN
Paracetamol
Iron, isoniazid
Toluene
7
Q
One Pill Can Kill list (+mnemonic)
A
BAT COST
Bblockers - propranolol
Amphetamines - ecstasy
Theophylline
CCB - verapamil, diltiazem
Chloroquine
Opioids
Sulphonylureas
TCAs
8
Q
Toxin-mediated myocardial ischaemia
A
CO
Cyanide
MetHb
Cocaine
9
Q
Drugs causing QRS prolongation
A
Mainly through Na-channel blockade
Antidepressants
- TCAs; amitriptyline
- Venlafaxine (SNRI)
Antiepileptics
- Carbamazepine
- Lamotrigine
Antihistamines
- Diphenhydramine
Antiarrhythmics
- Flecainide
- Propranolol
Local anaesthetics
- Bupivacaine, ropivocaine, lignocaine
Antimalarials
- Chloroquine, hydroxychloroquine, quinie
Cocaine
10
Q
Drugs causing long QT
A
Antiarrythmics
- Amiodarone
- Sotalol
Antidepressants
- Citalopram, escitalopram
Antihistamines
- Diphenhydramine
Antimicrobials
- Erythromycin, clarithromycin
- Fluconazole
Antipsychotics
- Haloperidol, droperidol
Antiamalrials
- Chloroquine, hydroxychloroquine, quinine
Other
- Cocaine
- Methadone, oxycodone
- Organophosphate and carbamate pesticides
11
Q
Serotonin syndrome features and management
A
CNS: agitation, sedation, seizures
Autonomic: fever, sweating, flushing, mydriasis, tachycardia
Muscular: hyperreflexia, clonus, tremor, hypertonia, rigidity
Supportive care
Sedation - benzos
Cooling - Passive vs intubation + paralysis
Antidotes (mild-mod)
- Cyproheptadine: 12mg PO/NG + 8mg TDS
- Olanzapine - 5-10mg
- Chlorpromazine 25mg in 1L NS0.9% over 30-60 mins
12
Q
Hunter criteria for serotonin syndrome
A
Serotonergic agent + one of:
- Spontaneous clonus
- Tremor + hyper-reflexia
- Inducible clonus/occular clonus + A/D/FT
- Agitation
OR
- Diaphoresis
OR
- Fever + Tone increased
13
Q
MDMA toxicity features
A
Combined sympathomimetic + serotonin syndrome incl.:
Sudden onset
Bruxism (teeth grinding)
Severe hyponatraemia - water intoxication + heat + SIADH
Hepatotoxicity
14
Q
Neuroleptic malignant syndrome
A
Tetrad:
- Altered mental status
- Muscle rigidity
- Fever
- Autonomic dysfunction incl. hypertension/unstable BP, tachycardia
DSM V criteria:
Major (must have all three)
- Exposure to dopamine antagonist drug)
- Severe muscle rigidity
- Hyperthermia
Minor (at least two of)
- Tachycardia, hypertension, labile BP, sweating
- Raised CK + leukocystosis
- Dysphagia, tremor
- Altered conscious state, mutism, incontinence
Antidote:
Bromocriptine 2.5mg q8hrly -> titrate to max 5mg q4hrly
Poor evidence
15
Q
Anticholinergic toxidrome
A
Hot as a desert
- Hyperthermia
Red as a beet
- Flushing
Blind as a bat
- Mydriasis, decreased VA, photophobia
Mad as a hatter
- Altered mental status, incoherent speech, agitation, delirium, carphologia (picking), hallucinations
Dry as a bone
- Dry skin and mucous membranes, urinary retention
+ Seizures, coma, tachycardia, absent bowel sounds
16
Q
Anticholinergic toxidrome treatment
A
Physostigmine - 0.5mg IV (20mcg/kg paeds)
Sedation - benzos or droperidol
IDC for urinary retention
17
Q
Common anticholingeric agents
A
Antihistamines (sedating) - diphenhydramine
Antidepressants - TCAs (amitriptyline)
Antipsychotics -olanz, quetiapine
Urinary drugs - oxybutinin, solifenacin
Antiemetics - prometazine, prochlorperazine
Anti-movement disorder - benztropine
18
Q
Sympathomimetic toxidrome signs and symptoms
A
Cardiovascular
- Tachyarrhythmias
- Hypertension
- ACS, MI
- Hypotension (if severe), myocardial depression, pulmonary oedema
CNS
- Excitation: anxiety, euphoria, agitation, tachyponea, delirium, seizures
- Acute behavioural disturbance
- Thrombotic or haemorrhagic strokes, ICH
Neuromusclar
- Hyperreflexia
- Tremor
Autonomic
- Hyperthermia (usually >39degC)
- Sweating, flushing, pallor, mydriasis
Metabolic
- Hypokalaemia, hyperglycaemia, lactic acidosis
GI
- Nausea, vomiting, diarrhoea
Other
- Rhabdo -> renal failure
- Respiratory barotrauma (PTx) due to valsalva during smoking
19
Q
Sympathomimetic agents
A
Medications
- Beta-adrenergic receptor antagonists; salbutamol
- Catecholamines; adrenaline, norad, dopamine, isoprenaline
- Indirect sympathomimetics; dexamphetamine, methylphenidate
- MAO-I; phenelzine
- SNRI; duloxetine, venlafaxine
- Xanthines; theophylline, caffeine
Recreational drugs
- Amphetamines; meth, MDMA
- Cocaine
20
Q
Sympathomimetic toxidrome treatment
A
Sedation - IV benzos +/- droperidol
Cooling - IV fluids, active cooling (incl. intubation, paralysis)
Control hypertension - often benzos adequate
If hypotensive (severe) - trial A/NA, may use HIET
Seek and treat complications - ACS, ICH, rhabdo, dissection
21
Q
Cholinergic toxidrome
A
Brady/tachy + wet, weak, wheeze and wild
CNS
- Agitation, delirium, coma, seizures
Neuromuscular
- Fasciculations, weakness, paralysis
Autonomic
- Salivation, lacrimation, sweating, flushing, miosis
Respiratory
- Pulmonary secretions, bronchoconstriction
Cardiovascular
- Brady or tachycardia, arrhythmias
- Hypertension, or hypotension (if severe)
Metabolic
- Hypokalaemia, hyperglycaemia, metabolic acidosis
GI
- Abdo pain, vomiting, diarrhoea
22
Q
Cholinergic toxidrome treatment
A
Supportive:
A - intubation if excess secretions (ATROPINE prior)
B - IPPV if resp muscle weakness/resp failure
C - IVF, pressors, inotropes
ICU admit
Specific:
Atropine
- Bolus:1.2mg IV double every 5 mins, titrate aiming:
- Drying of chest secretions
- Chest clear without wheeze
- HR >80
- SBP >80 mmHg
- Doesn’t work on nicotinic receptors, no muscle weakness improvement
- Infusion: 10% total loading dose/hr
Benzodiazepines - for agitation, seizures
Pralidoxime - controversion, not for routine use
23
Q
HIET dosing
A
Slow injection
- 1U/kg actrapid
- 250mL 10% dextrose
THEN infusion
- 1U/kg/hr actrapid
- 100mL/hr Dextrose 10%
- Titrate to BSL 4-8
Monitor BSL q30min; K 2 hourly
24
Q
Treatment of QRS widening secondary to drug toxicity
A
Serum alkalinisation
- Sodium bicarb 8.4% 1-2mL/kg up to 100mL (1-2mmol/kg up to 100mmol) every 3-5 mins max 6mmol/kg
- Titrated to narrowing of QRS complex
- Aim pG 7.45-7.55
AND
Hyperventillation
- Intubation and mechanical ventilation
- Aim pH 7.45-7.55, paCO2 30-35
Inidcations:
- QRS >120ms
- Hypotension
- Cardiac arrest
- Seizures not responding to benzos
Other options:
- Hypertonic saline
- Lidocaine 1mg/kg (competitive agonist at Na channels)
25
Management of QT prolongation (not yet TdP)
Electrolyte optimisation
- Mg >1.0
- K+ >5.0
- Ca >2.0
26
Management of TdP
Move to resus area
Pads on
Magnesium
- MgSO4 50%, 4mL (8mmol) IV over 10 mins (paeds 0.1mL/kg up to 4mL, 0.2mmol/kg up to 8mmol)
Isoprenaline
- 20mcg IV q2mins boluses
- Infusion 2-10mcg/min
- Aim HR >90
If arrest/pulseless:
- ALS *avoiding amiodarone*
i.e. CRP, defib, 2g Mg bolus (8mmol)
If recurrent TdP
- Mg 2g (8mmol) stat, aim Mg >1.5
- Isoprenaline 20mcg IV q2min -> 10mcg/min, aim HR >90
OR
- TC/TV overdrive pacing
Endpoints
- No further episodes of TdP
- Normal QT
- K>5.0, Mg>1.5
- Cease LQT drugs + negative inotropes
- Optimise renal function
27
Hyperthermia toxidrome differential
1. Sympathomimetic
2. Serotonergic
3. NMS
4. Anticholinergic
5. Salicylates (uncoupling of oxidate phosphorylation)
6. Malignant hyperthermia
28
Treatment of hypoglycaemia in tox patients
Adult:
- 50mL 50% dextrose
- 250mL 10% dextrose
Child:
- 2mL/kg 10% dextrose
29
Peads sedation doses
Midazolam 0.3mg/kg PO
Midazolam 0.1mg/kg IV/IM
Droperidol 0.1mg/kg IM
Ketamine 4mg/kg IM
Ketamine 0.5-1mg/kg IV
30
Antidepressant toxicity: mirtazapine
Relatively safe: mild CNS depression only
No serotonin syndrome
Rx: supportive care
31
Antidepressant toxicity: MAO-I
Dangerous++, usually delayed and gradual toxidrome
Serotonergic + sympathomimetic
e.g. phenylzine, selegiline
Rx:
Activated charcoal if able
Supportive care:
- HTN; benzos, then GTN infusion
- Hypotension - IVF boluses, inotropes
- Arrhythmias - AVOID BBlockers (unopposed alpha)
- Hyperthermia - cool IVF, external methods, etc.
- Serotonergic - Consider cyproheptadine if severe
- Seizures - benzos
32
Antidepressant toxicity: SSRIs
Mild toxicity
Serotonergic toxidrome rare unless massive OD or MAO-I co-ingestion
Citalopram/escitalopram - dose-dependent LQT
33
Antidepressant toxicity: SNRIs
Mild toxicity
Noradrenergic symptoms--> sympathomimetic toxidrome
Serotonergic toxidrome rare
Venlafaxine highest risk toxicity
Dose-dependent:
- Seizures (can be delayed)
* Risk >2g; 50% if >5g
- Cardiac
* Highest risk >8g
* Tachyarrhythmias
* Takotsubo
* Severe hypotension
34
Antidepressant toxicity: TCA effects
CNS + ECG changes/CVS + anticholinergic
1. CNS - coma, seizures
2. Respiratory - resp depression
3. CVS - Tachycardia, arrhythmia, hypotension
4. ECG - Tachy, wide QRS/arrhythmia, terminal R wave in aVR*, LQT (no risk TDP)
5. Anticholinergic toxidrome
35
Antidepressant toxicity: TCA treatment
GI decontamination (activated charcoal)
Supportive care
Inotropes + pressors
Serum alkalinsation (pH 7.45-7.55)
Rx arrhythmias w/ bicarb 1mmol/kg max 100mmol up to 600mmol
Rx seizures w/ benzos (then bicarb)
36
Paracetamol toxicity: IR single dose ingestion
Tox dose: >200mg/kg OR 10g
Massive OD >50g (or >1g/kg if <50kg)
Activated charcoal if <2hr or <4hr if big OD or MR
NAC required within 8hrs
- High dose if 2x nomogram (or MR >30g)
If 4-8hrs:
- Wait for level at 4hrs, Rx as per nomogram
If >8hrs, start NAC and stop if:
- Paracetamol level 24hrs, start NAC and stop if:
- Paracetamol level <10mg/L AND
- ALT <50
Rpt bloods 2hrs before end of second bag
Extend NAC if: panadol level >10 OR ALT >50
Can cease extended NAC only when:
- Clinically well
- ALT or AST peak and fall
- INR <2.0
37
Paracetamol toxicity: Staggered IR
Measure >4hrs after FIRST ingestion
If above nomogram: treat as per single ingestion
If below:
- No Rx if no panadol within 2hrs
- Otherwise, repeat bloods 2hrs later
38
Paracetamol toxicity: Staggered/supratherapeutic IR use
>= 10g (200mg/kg) in 24 hours
>= 12g (300mg/kg) in 48 hours
No role for AC
Bloods ON ARRIVAL
Start NAC if:
- Paracetamol level >=20 mg/L
- OR ALT >=50
- OR Symptomatic and won't get bloods back within 2hrs
Repeat bloods 8hrs after initial and stop if:
- Paracetamol level <10 mg/L
- ALT <50
39
Paracetamol toxicity: Modified release overdose
AC if <4hrs
<10g - bloods at >4hrs + 4hrs later; treat as per nomogram
>=10g (or 200mg/kg) - Start NAC and complete full 2 bag regimen
>30h - start NAC at high dose regimen
May need to extend NAC if paracetamol level 10 two hours before completion of 2nd bag
If mixture of MR + IR, treat as per MR
40
Paracetamol toxicity: <6yo, liquid paracetamol
No role for AC
Bloods at 2hrs - No NAC if
41
NAC dosing regimes
Standard dose
- 200mg/kg (up to 22g) in 500mL NaCl over 4 hours
- 100mg/kg (up to 11g) in 1000mL NaCl over 16 hours
High dose
- Double second bag i.e. 200mg/kg x2
- Same volumes i.e. 500mL -> 1000mL
Extended NAC
- As above then repeat second standard bag
- 100mg/kg (up to 11g) in 1000mL over 16 hours
Can be NS or 5% dextrose
Paeds dosing same NAC but different fluid volume:
- 1st bag 7mL/kg NS
- 2nd bag 14mL/kg NS
42
NAC hypersensitivity symptoms and treatment
Rash, urticaria, flushing
Angioedema
Bronchospasm
N+V
Hypotension
Treatment:
- Stop infusion
- Antihistamines (e.g. cetirizine 10mg)
- Bronchodilators
- IVF
- Adrenaline, if severe
Can restart infusion when reaction subsides at HALF RATE
Not an allergy, does not contraindicate further treatment with NAC
43
Liver transplant criteria; for transfer if:
1. Renal: oliguria or Cr >200microg/L
2. INR >3.0 at 48hrs OR >4.5 at any time
3. pH <7.3 after resuscitation
4. Encephalopathy or any degree
5. Shock (SBP <80mmHg)
6. Hypoglycaemia
7. Thrombocytopaenia (severe)
44
Paracetamol liver failure criteria
King's College Criteria
RIPE
- Renal failure, Cr >300
- INR >6.5
- pH <7.30 (ABG)
- Encephalopathy, grade 3/4
pH alone
OR all three others
45
Local anaesthetic toxicity: features
1. CNS
- Tinnitus, dizziness, perioral paraesthesia, tremor, confusion, coma, seizures
2. CVS
- Early: tachy, HTN
- Severe: brady, hypoTN, arrest
- ECG: conduction blocks, wide QRS, VF/VT
3. Respiratory
- Resp depression, apnoea
4. MetHb
- Maily prilocaine/benzocaine
- Kids more at risk
46
Local anaesthetic toxicity: treatment
CVS:
- Inotropes + pressors
- Serum alkalinisation - for wide QRS
* Bicarb
* Intubate and hyperventillate
* K+ replacement for above
CNS:
- Benzos for seizures alongside bicarb
Intralipid (if above not sufficient)
- 1.5mL/kg of 20% lipid emulsion (~100mL 20% for standard adult)
- q5min, max 8 doses (12mL/kg)
- Can start infusion, 0.25mL/kg/min
MetHb
- Methylene blue 1.5mg/kg
47
Calcium channel blocker toxicity: Non-DHP (Verapamil/diltiazem)
CVS:
- Sinus brady
- Conduction blocks
- Hypotension
- Myocardial depression and vasoplegia
- Cardiogenic shock
- Pulmonary oedema
CNS:
- Due to shock
- Confusion, agitation, seizures (rarely)
Metabolic:
- Hyperglycaemia
- Lactic acidosis
Treatment
GI decontamination
- AC +/- MDAC/WBI (if MR)
Treat hypotension
- IVF resus
- CaCl - 20mL 10% CaCl + infusion (0.2mL/kg)
* Aim iCa 1.5-2.0 mmol/L
- Adrenaline 0.1mcg/kg IV bolus then infusion
- HIET (1U/kg actrapid + 50mL 50% glucose, then 1U/kg/hr + 10-50% glucose, aim BSL 4-8)
ECMO in arrest
Monitor and treat hyperglycaemia and lactic acidosis
- IVF, Ca, adrenaline, HIET, ECMO
6hr discharge rule for IR
48
Calcium channel blocker toxicity: DHP
CVS: vasoplegia
Hyperglycaemia
GI decontamination with AC
IVF
Vasopressors - norad, vasopressin
CaCl, aiming iCa 1.5-2.0
6hr discharge rule for IR
49
Beta blocker toxicity
CNS: coma, seizures
CVS: myocardial depression, bradycardia, wide QRS, LQT
Resp: bronchospasm
Metabolic: hypoglycaemia
Decontamination w/ AC
Bedside echo to assess ventricular function
Intubate if required - pre-med w/ atropine 600mcg
BP support
- IVF
- Atropine 600mcg/isoprenaline 20mcg q20min for bradycardia
- Adrenaline, HIET
Seizures
- Treat with GLUCOSE - 50mL 50%
Prolonged CPR, ECMO, bicarb
50
Beta blocker toxicity - propranolol + sotalol
PS I killed you
- Propranolol + sotalol deadly
Propranolol
- Na channel blockade -> QRS widening; may require serum alkalinisation w/ bicarb
- Coma
- Seizures
Sotalol
- LQT -> TdP (Mg, K, Ca, isoprenaline etc.)
51
Antipsychotic toxicity: signs and symptoms
Block:
1. Dopamine - acute dystonias
2. Serotonin
3. Histamine - reduced GCS
4. Muscarinic - anticholinergic Sx
5. Adrenergic - hypotension, CVS collapse
Note: anti-alpha adrenergic effects (esp. quetiapine) means use of adrenaline can result in unopposed B agonism and worsen hypoTN. Use metaraminol or norad
52
Antipsychotic toxicity: special considerations (A-COQ)
A-COQ - All reduce GCS
Amisulpride
- Reduced GCS
- LQT + TdP
- Prolonged ECG monitoring (16hrs)
Clozapine
- Reduced GCS
Olanzapine
- Reduced GCS
- High risk anticholinergic delirium
Quetiapine
- Beware MR formulation
- Reduced GCS, coma, seizures
- High risk anticholinergic delirium
- Avoid adrenaline (unopposed beta agonism), use metaraminol or norad
53
Lithium toxicity: chronic, signs and symptoms (+ grades)
1. CNS
- Tremor, ataxia
- Hypertonia, hyperreflexia
- Sedation, coma, seizures
2. GI
- N+V, diarrhoea
3. CVS
- Hypotension, bradycardia
- LQT, arrhythmias rare
4. Renal
- Li-assoc. nephrogenic DI
-> Dehydration + hyper Na
5. Endocrine
- Thyroid dysfunction
6. Metabolic
- LOW anion gap metabolic acidosis (LAGMA)
Grades:
Mild - tremor, ataxia, N+V
Mod - stupor + rigidity
Severe - coma + seizures
Toxic level >1.0
54
Lithium toxicity: RFs for chronic tox + investigations when suspected
>50yo
Dehydration
Development of DI
Renal impairment
Assoc. nephrotoxins (NSAIDs, diuretics, ACE-I)
HypoNa (promoted renal retention of Li)
Hypothyroid
Intercurrent illness
Ix:
Serum Li q6hrly
EUC incl. Na
ECG for LQT
TFTs
55
Lithium toxicity: management of chronic toxicity
All about improving renal clearance
No role for AC
Cease Li
Cease nephrotoxins (NSAIDs, diuretics, ACE-Is)
IVF rehydration - Dehydration + DI
Benzos - for seizures
Haemodialysis (rarely required), use in:
- CNS tox (coma, seizure)
- Serum Li >4.0 + renal impairment
- Serum Li >5.0
- Continue until serum Li <1.0
56
Lithium toxicity: acute
Rarely toxic - renally excreted before significant neurotox
Measure serum Li q6hrly to establish peak and monitor elimination
Consider WBI if >50g
Treat as per chronic
No role for AC (doesn't bind)
57
Digoxin toxicity: acute, signs and symptoms
Dose >6mg (0.3mg/kg paeds)
1. CVS
- Early ECG changes: STD 'reverse tick'; ectopics, 1st deg HB
- Bradyarrhythmias - esp. slow AF
- Tachyarrhythmias - junctional and atrial tachycardia
- BIDIRECTIONAL VT 'pathognomonic' of dig tox
- Higher degree HBs
- CVS collapse: hypotension, syncope, arrest
2. GI
- N+V, abdo pain, diarrhoea
3. Metabolic
- HyperK
- Note: HypoK and hypoMg can worsen dig tox
4. CNS
- Lethargy, confusion, delirium
- Visual changes: yellowing of vision
Specifics:
1. Reverse tick STD
2. Slow AF and junctional tachys
3. Bidirectional VT
4. Yellowing of vision
5. HypoK/Mg makes it worse
58
Digoxin toxicity: acute, managment
Decontamination
Stop exacerbators (CCB/BB/nephrotoxins)
Support CVS
Give digiFab
Treat hyperK - avoid Ca
Give Mg
Digoxin immune Fab (DigiFab):
Not arrest: x2 vials (2x40mg) over 30mins
Use if:
- Ventricular arrhythmias
- Brady + shock
- Severe hyperK (>6mmol/L)
- Can give second dose 30 mins later if partial response
Arrest: x5 vials (5x40mg) as bolus
SEs: HypoK, CCF
59
Digoxin toxicity: chronic, RFs
RFs
- Advanced age
- Renal and liver disease
- Drugs: BBs, CCBs, NSAIDs, K+-sparing diuretics
- P-glycoprotein interaction
- Hypo/hyperthyroid
- HYPO K, Mg
- HYPER Ca
- MI
- Hypoxia
- Acid-base disturbance
60
Digoxin toxicity: chronic, treatment
Stop digoxin
Stop contributory drugs:
- Negative chronotropes - BBs, CCBs
- K-sparing diuretics
- Nephrotoxics - NSAIDs, macrolines, ACE-Is
Correct dehydration
Correct electrolytes (hypoK+Mg)
Cardiac monitoring
Support CVS
Digibind
- Not arrest: 1x40mg vial
- Arrest: 2x40mg vials
61
Aspirin toxicity: Signs and symptoms, expected dose ranges
1. CNS
- Fever
- Confusion, coma, seizures
2. Ears
- Hearing impairment, tinnitus
- Dizziness
3. GIT
- N+V, epigastric pain
4. Metabolic
- 1) Primary resp alkalosis (first)
- 2) Metabolic acidosis (second)
- Hypoglycaemia (or hyper)
- HypoK
5. Haem
- Anti-platelet effect, bruising
6. Renal
- AKI
7. Respiratory
- Non-cardiogenic pulm oedema (in severe OD)
Mild <150mg/kg
Mild-mod <300mg/kg
Severe <500mg/kg
Potentially fatal >500mg/kg
62
Aspirin toxicity: Management
Decontamination
- Prolonged time, AC up to 6 hours + second dose serum level if continues to rise
IVF + treat hypoK
- HypoK impedes renal excretion of aspirin
Urinary alkalinisation
- Correct K+ first
- Sodium bicarb 1mmol/kg (max 100mmol) bolus
- Sodium bicarb 25mmol/hr infusion in 5% dextrose
- Titrate to UO 1-2mL/kg/hr + urinary pH 7.5-8.0
- Continue 6+ hours, until:
* serum salicylate level in therapeutic range and falling
* acid-base disturbance resolved
* patient asymptomatic
Hypoglycaemia - seek and treat
- Use glucose for seizures, if present
Dialysis, rarely required unless fluids + alkalinisation failing, used for:
- Deterioration with worsening acidosis despite maximal supportive care
- Anuric or oliguric AKI
- Acute pulmonary oedema
- Salicylate level >1000 ("high") and not responding to urinary alkalinisation
Avoid intubation if possible
- If required, pretreat with IV bicarb and hyperventilate pre- and post-intubation
63
Clonidine toxicity
Centrally-acting alpha-2 agonist
Toxic dose: >10mcg/kg
Can look like opioid overdose:
- Sedation, miosis, seizures
- Resp depression
- Bradycardia (can persist >48hrs)
Tx:
CVS support
- Atropine for symptomatic bradycardia
- IVF
64
Stimulant toxicity: signs and symptoms
Methamphetamine (ice): sympathomimetic
MDMA: serotonergic
1. CNS
- Excitation
- Acute behavioural disturbance
- Seizures
- Intracranial events, CVA, ICH
2. CVS
- Tachy, arrhythmias
- Hypertension
- ACS
3. Neuromuscular
- Hyperreflexia, tremor
- Rhabdo
4. Autonomic (sympathetic)
- Hyperthermia (>39 degC)
- Sweating, flushing, pallor, mydriasis
5. Electrolytes
- HypoNa (SIADH, H20 intox)
- HypoK, hyperglycaemia, lactic acidosis
6. GI
- N+V, diarrhoea
7. Respiratory
- PTx, pneumomediastinum
8. Complications of HTN
- Dissection, mesenteric ischaemia, ICH
65
Stimulant toxicity: management
No role for decontamination
- Except WBI for body packers
1. Sedation - benzos
2. Hyperthermia - cold IVF, external
3. HTN/tachy - benzos, GTN if refractory
4. Seizures - IV benzos (may need large doses)
5. HypoNa - Fluid restrict
- Acute seizure or AMS - NaCl 3% 100mL over 10 mins (up to 300mL)
6. Seek and treat complications
- ACS, dissection, arrhythmia
- ICH
- Rhabdo
66
Cocaine toxicity
>1g can be lethal
Na channel blocker -> wide QRS
Sympathomimetic + serotonergic
Vascular - thrombosis, vasospasm, accelerated atherosclerosis
Seizures
Mx:
Sedation - Benzos/drop
Cooling - Cool IVF, active cooling
HTN - IV benzos +/- GTN infusion
CVS collapse - Inotropes
Seizures - IV benzos (may need high doses)
Seek and treat complications
- ACS, dissection
- Thrombotic/haemorrhagic stroke
- PTx, pneumomediastinum
- Rhabdo
Cocaine-induced ACS/chest pain
- Benzos, 5mg IV midaz
- Nitrates, GTN +/- infusion
- Aspirin 300mg
- Alpha blockers (phentolamine)
- AVOID BBlockers
- PCI rather than thrombolysis
VF: Lignocaine 1mg/kg, may be more effective than amiodarone
67
GHB toxicity
Rapid onset <1hr
Short duration 2-4 hrs
CNS: Agitation -> sedation -> coma
Myoclonic jerks (nil treatment required)
Airway - loss of reflexes
Breathing - resp depression/loss of drive
Circulation - rare bradycardia + hypotension
Intubate if:
- Airway compromise
- Vomiting
- Hypoventilation/apnoea
- Coma >1hr
68
Toxic alcohols: parent alcohol, toxic metabolite and expected effect
Methanol -> formic acid -> visual loss
Ethylene glycol -> glycolic acid + oxalic acid -> AKI
69
Toxic alcohol: dose, signs and symptoms
Serum methanol or ethylene glycol >50mg/dL
OR
Ingestion >1mg/kg
1. CNS
- Sedation, coma, seizures
- Retinal toxicity (methanol)
2. Metabolic
- HAGMA
- High osmolar gap
- High lactate gap (ethylene glycol)
- HyperK, hypoCa, low BSL
3. GI
- N+V, abdo pain
4. CVS
- Hypotension (due to HAGMA)
5. Renal
- AKI
- Ca oxalate crystals in urine (ethylene glycol)
If very high lactate on gas: ethylene glycol
70
Toxic alcohol: management
Ethanol or fomepizole
Metabolite co-factors
HD if severe
Ethanol
- 0.6g/kg PO/NG stat
- 5-10g/hr (paeds 0.1-0.2g/kg/hr)
- Aim serum ethanol 0.1-0.2 g/dL (22-44mmol/L)
OR IV
- 6mL/kg 10% ethanol IV
- 50-100mL/hr (paeds 1-2mL/kg/hr) ethanol 10%
DOUBLE RATE IF ON HD
Continue until serum methanol or ethylene glycol <20mg/dL + normalisation of acid-base disturbance + osmolar gap
Fomepizole
- 15mg/kg IV loading
- 10mg/kg q12hrly (q4hrly if on HD)
- Continue as per EtOH
Haemodialysis if:
- Severe metabolic acidosis
- AKI
- Serum methanol or ethylene glycol conc >50mg/dL
- Endpoint: normalisation of acidosis + osmolar gap
Co-factors for metabolism of toxic metabolites
Methanol - IV folate 50mg QID (*folate sounds like formic acid)
Ethylene glycol - IV pyridoxine 50mg QID + IV thiamine 100mg QID
71
Isopropyl alcohol toxicity
Intoxication clinically same as ethanol
No acidosis
High osmolar gap
Ketosis (acetone)
Mx is supportive
72
Toxins with high osmolar gap
Ethanol
Toxic alcohols: methanol, ethylene glycol, isopropyl alcohol
Mannitol
Glyerol
Aspirin
73
Benzodiazepine toxicity
Alprazolam (Xanax) most dangerous - significant reduced GCS, may need tubing
GI decontamination not for benzos
Close observation of GCS
Supportive care
Flumazenil usually NOT recommended
- Can precipitate seizures, esp. if benzo-dependent
Flumazenil 200mcg IV if:
- Not benzo dependent
- To avoid intubation, particularly in children, elderly, resp disease
- Iatrogenic overdose
74
Opioid toxicity: treatment
Support airway and breathing (BVM)
Naloxone if hypoventilation
Adult: IV 100mcg q2min, max 10mg OR IM 1mg
Paeds: 10mcg/kg q2min
Titrated to RR >8
Infusion: 2/3rd the effective bolus dose/hr
Seek advice for patients:
- Not responsive to naloxine
- Co-ingestions
- Prolonged naloxone infusion required
Disposition
Admit if: repeat naloxone or infusion
Monitor:
- IR - 12hr
- MR - 24 hr
- Tramadol - 16hr (delayed seizures
75
Opioid toxicity: special consideration symptoms
Serotonergic toxidrome - tramadol, tapentadol, methadone
Delayed-onset seizures - tramadol
LQT/TdP - methadone, oxycodone
76
Buprenorphine toxicity
Partial agonist with long half-life, high first pass metabolism
- Extended monitoring
- Higher doses of naloxone required
Significant respiratory depression (out of proportion to sedation)
77
Insulin overdose: symptoms, treatment and disposition
1. CNS
- Dizziness, confusion, headache
- Drowsiness, seizures, coma
2. Autonomic
- Tremor, tachycardia, sweating, nausea
3. Metabolic
- Hypoglycaemia (lol)
Glucose:
- 50mL 50% OR 250mL 10% glucose
- Infusion, titrated to BSL 4-8
- Eat complex carbs, as able
- Monitor and replace K+
Monitoring:
Short acting - 8hrs
Long-acting - 16hrs
78
Sulfonylurea overdose
Delayed hypoglycaemia
GI decontamination
Glucose replacement - Aim BSL 4-8
Octreotide
- 50mcg subcut (2mcg/kg) TDS for 24hrs
- OR 50mcg IV bolus then 25mcg/hr infusion
Monitor K
Monitor BSLs for 12 hours post-octreotide cessation
79
Metformin overdose
1. Metabolic
- HAGMA, lactic acidosis, hyperK
2. GI
- N+V, abdo pain
3. CVS
- Cardiogenic shock (acidosis)
4. CNS
- Sedation, coma, seizures (acidosis)
5. Renal failure
6. Liver failure
Mx - correct lactic acidosis
- GI decontamination
- ABC - CVS support
- Sodium bicarbonate
- Haemodialysis
Haemodialysis if:
- Severe acidosis, pH <7.0
- Severe lactataemia, lac >20
- Shock
- AKI
Sodium bicarb
- Bridging to HD
- 1-2mmol/kg (1-2mL 8.4%) IV every 3-5 mins, max 6mmol/kg
- Aim pH >7.3
80
Carbon monoxide poisoning: toxic levels and symptoms
Non-smoker <3%
Smoker <10-15%
Levels correlate poorly with toxicity
SO2 and PO2 often misleadingly normal
Can use co-oximetry to differentiate
- Will be abnormal in CO poisoning
1. CNS
- Sedation, coma, seizure
- Cognitive, cerebellar signs, Parkinsonian features
2. CVS
- AMI, hypotension
3. Metabolic
- Lactataemia, hyperglycaemia
4. Eyes
- Retinal changes incl. haemorrhages
5. Skin
- Cherry red, haemorrhages
6. Heam
- DIC
7. MSK
- Rhabdo
81
Carbon monoxide poisoning: treatment
High-flow oxygen
- Aids in dissociation of CO from Hb
- Commenced ASAP for 6+ hours
- CO elimination half-life
* 320 mins on RA
* 70 mins on 100% FiO2
* <30 mins on hyperbaric O2 (theoretical)
Hyperbaric O2
- Poor evidence for outcomed
- Consider if:
* COHb >20%
* <6 hours since poisoning
* Pregnant (improved foetal oxygenation)
* Myocardial ischaemia
Seek and treat hypotension
Seek and treat MI
- Serial ECGs and trops
82
Cyanide poisoning: investigations and management
Blood gas
- Lactate >10 = severe
- Signs of impaired O2 extraction from blood i.e. high venous PO2 with reduced difference in PvO2 vs PaO2
AC <2hrs (if ingested)
CVS support
Antidotes:
- Hydroxocobalamin - 5g (paeds 70mg/kg) in 200mL NaCL 0.9% IV - repeat, if needed
If severe, add:
- Sodium thiosulfate 25% 50mL IV (GI SEs)
- Sodium nitrITE (in conjunction with sodium thiosulfate, temporising measure, toxic (intentional metHb))
- Dicobalt edetate (sure... Only if hydroxocobalamin not available. Toxic)
82
Cyanide poisoning: sources and symptoms
Lethal dose >1-1.5mg/kg (free ions more toxic than compounds)
Usually inhalational due to fires
Also: cyanide salts, stone fruit kernals, SNP infusion (iatrogenic)
Binds cytochrome oxidase and inhibits oxidative metabolism
Rapidly fatal
If survive long enough to be seen in hospital, usually only mild-mod toxicity
1. CNS
- Mild: headache, weakness, dizziness
- Severe: agitation, confusion, coma, tetany, seizures
2. CVS
- Tachy/brady, arrhythmias hypotension
- MI, cardiac arrest
3. Respiratory
- Cyanosis, resp distress -> depression
4. Metabolic
- HAGMA, lactic acidosis
5. GI
- N+V
83
Methaemaglobinaemia: sources
1. Nitrates/nitrites: SNP, GTN, amyl nitrate (poppers)
2. Local anaesthetic: esp, prilocaine
3. Antibiotics: sulfonamides, dapsone
4. Antimalarials: chloroquine
High risk in G6PD
Causes oxidation: Fe2+ (ferrous) -> Fe3+ (ferric) iron
84
Methaemoglobinaemia: blood fraction and clinical effects
1. Cyanosis
2. Headache, agitation -> reduced GCS
3. Severe CNS: coma, seizures
4. Metabolic acidosis
5. Delayed haemolytic anaemia
<10% none
10-20% cyanosis/grey
20-30% mild CNS
30-50% mod CNS
50-70% severe CNS + arrhythmias + acidosis
>70% lethal
Note on cyanosis:
SO2 plateaus as low as 85%, even when PaO2 lower (cyanosis out of keeping with sats)
PaO2 (ABG) - saturation gap (ABG PaO2 doesn't match sats probe SO2)
85
Methaemoglobinaemia: management
Stop causative agent
Methylene blue
- 1-2mg/kg IV, over 5 mins (1% solution)
- Give if >20% + symptoms or >25% + no symptoms
- Can repeat 1mg/kg after 30 mins if remains >25% or hypoxic
- CI: G6PD (haemolysis), SSRI (serotonin syndrome)
Other:
- Hyperbaric O2
- Exchange transfusion
- NAC
86
Colchicine overdose: toxic dose and features
Toxic: >500mcg/kg (1 tab/kg)
Highly cytotoxic - inhibits mitosis of dividing cells
-> Multi-organ failure
<12 hrs
- Vomiting + profuser diarrhoea
---> dehydration, hypovolaemia, AKI
1-7 days
Multiorgan failure:
- Heart: myocardial depression, arrhythmias, CVS collapse
- AKI, rhabdo
- Liver failure
- Metabolic acidosis
- Consumptive coagulopathy
- Bone marrow failure + cytopaenias
Death
>10 datys
- Recovery + alopecia
87
Colchicine overdose: treatment
Supportive + urgent toxicology input
Decontamination
- OFFER if: >6mg or >0.1mg/kg
- GIVE if: >20mg or >0.3mg/kg
- AC ASAP *lifesaving*
- MDAC if >0.5mg/kg
- May require sedation + intubation for same
A+B - not a problem til MOF
C - Severe dehydration due to diarrhoea
IVF
Pressors + inotropes
VA ECMO
Neutropaenias - GCSF (granulocyte-colony stimulating factor) + DW haem
Note:
Decontamination dose cut-offs lower if higher risk toxicity incl.
- Drugs that interact w/ colchicine
- CKD
- Liver impairment
Offer if >0.05mg/kg + give (+MDAC) if >0.1mg/kg
88
Iron overdose: signs and symptoms by dose and time
PC: Haemorrhagic gastroenteritis + MOF
GI + shock + HAGMA --> improvement --> MOF --> GI scarring + obstructions
<20mg/kg - asymptomatic
<60mg/kg - GI symptoms
60-120mg/kg - Systemic tox incl. MOF
>120mg/kg - lethal
<6 hours
- Haemorrhagic gastroenteritis: N+V, haematemesis, bloody diarrhoea
- Dehydration --> hypotension
- Metabolic acidosis
6-24 hours
- GI effects may resolve
1-2 days
MOF:
- Haemorrhagic gastroenteritis
- Metabolic acidosis
- CVS collapse
- Renal failure
- CVS: coma, seizures
- Pulmonary oedema
- Hepatotoxicity
- Coagulopathy
Months
- GI scarring, obstruction
89
Iron toxicity: investigations and management
Peak serum iron conc.
- 6hrs post-ingestion
- Peak serum iron >90umol/L severe
VBG
- HAGMA (lactic acidosis)
- AXR: radio-opaque tablets (->WBI)
Secure airway if decreased GCS
CVS support if collapse
Bowel clearance:
WBI if:
- >60mg/kg ingestion
- <4hrs
- Radio-opaque tablets on AXR
Endoscopy if:
- Tablets visible in stomach on AXR
Desferrioxamine chelation
- 15mg/kg/hr, max 80mg/kg/24hr
- If severe systemic toxicity (GI bleed, coma, shock, metabolic acidosis)
- Peak serum iron >90umol/L (5mg/L)
- Can cause hypersensitivity reactions: flushing, hypotension, ARDS
- Can turn urine orange-red
90
Iron toxicity: 15-30-60-90-120
15 - desferrioxamine 15mg/kg/hr
30 - Peak iron normal range 10-30umol/L (likely asymptomatic)
60 - >60mg/kg for WBI + expect symptoms
90 - Peak serum iron >90umol/L (=bad) for chelation therapy, expect systemic tox
120 - ingestion >120mg/kg lethal
91
Flurosis/hydrofluric acid toxicity: determinants and features of toxicity
Determinants:
- Route of exposure - ingestion, dermal, inhalation, ocular
- Duration of exposure
- Body surface area exposed
- Concentration of HF acid solution
Cutaneous:
- Features can be delayed
- Severe pain, out of proportion to clinical findings
- Erythema, oedema, blistering
- *Liquefactive necrosis*
Electrolyte disturbances
- Low Ca
- Low Mg
- High K
Metabolic acidosis
CVS:
- LQT
- VT/VF
- Arrest
CNS:
- CNS depression
- Tetany
- Seizures
92
Flurosis/hydrofluric acid toxicity: treatment
Calcium gluconate, calcium gluconate, calcium gluconate
Treat systemic hypocalcaemia
- Calcium gluconate 10% 30mL (6.6mmol) IV, over 2-3 mins
- Can repeat after 10 mins if required
Dermal:
- Topical
*CaGlu 2.5% gel applied liberally
- Regional IV infusion
* 10mL 10% CaGlu in 40mL NS a la Bier's block
- Intra-arterial
* 10mL 10% CaGLu in 50mL NS over 4 HOURS
Inhalational:
- Nebulised 2.5% CaGlu
If LQT:
- 10-20mmol Mg in addition
93
Sodium valproate toxicity
Tox >200mg/kg
- >1g/kg lethal
CNS + MOF
1. CNS
- Sedation and coma
- Resp depression
2. CVS
- Depression + hypotension
3. Hepatotoxicity
4. Bone marrow suppression
5. Metabolic
- Acidosis, lactataemia
- HyperNa
- High ammonia
- HYPO glycaemia
- HypoCa
Ix:
- Valproate level
- VBG
- ECG
- CMP
- Ammonia
Treatment
1. AC if >200mg/kg
- MDAC if >500mg/kg
2. Dialysis if:
- pH <7.1
- Cerebral oedema
- Shock
3. Antidote:
- Carnitine 100mg/kg IV + 50mg/kg q8hrly
- until coma and metabolic acidosis resolve
94
Carbamazepine toxicity
Delayed toxicity, can be >48 hours after ingestion
>20mg/kg - sedation
>50mg/kg - CSN depression, CVS and GI tox
1. CNS:
- Nystagmus, ataxia, sedation
- Coma seizure
2. CVS
- Na-channel blockade --> QRS prolongation
3. Anticholinergic
- GI intermittent ileus prolongs absorption
Decontamination
- MDAC if >50mg/kg
CVS support
- Cardiac monitoring if >50mg/kg
Treat QRS prolongation (bicarb, hyperventilation)
Seizure control with benzos
Dialysis if severe
95
Phenytoin toxicity
Toxic >20mg/kg, severe >100mg/kg
*Saturatable metabolism* -> zero order kinetics prolonging half-life, may take weeks to resolve
CNS: cerebellar tox - ataxia, nystagmus, movement disorders
- Sedation, coma, seizures
Nil cardio effects
Decontaminate
AC if <2hrs, >20mg/kg
- Consider MDAC if >100mg/kg
Dialysis (however poor evidence)
A - intubate + ventilate if unable to protect airway
C - IVF for hypotension
96
NSAID toxicity
V safe
Ibuprofen tox >400mg/kg (1 tab/kg)
1. GI
- N+V, GI irritation
2. Metabolic acidosis
3. Renal
- AKI w/ hyperkalaemia
- RTA with life-threatening hypoK
4. CNS
- Seizures, coma (>1g/kg ibuprofen)
Rx:
AC (rarely required)
PPI, antacids
97
Warfarin toxicity
Toxic >0.5mg/kg
INR rises 12-24 hours post-ingestion
INR at baseline, q6hrly
FBC + G+H
AC + consider MDAC
Stop CYP2C9 inhibitors
Vit K (phytomenadione)
- 10-20mg PO/IV if INR >2
- Adjusted if taking warfarin therapeutically
If active bleeding:
- Beriplex 25-50u/kg IV
- FFP 15mL/kg (2-4U)
Monitor INR daily on vit K + 24 hours after cessation
Admit for monitoring 48 hours if:
- Deliberate
- >0.5mg/kg ingestion
- Raised INR
- Any bleeding
98
Caustic/corrosive toxicity
Airway burns
UGI erosion/perf/peritonitis
Alkali higher risk than acid
Ix: CT + endoscopy for perf
No role for AC
Limited role for steroids/PPI to prevent strictures
High risk: refer surg
Low risk: monitor 6 hours
99
Essential oil toxicity
1. CSN
- Sedation, coma, seizures
2. Respiratory
- Aspiration pneumonitis
3. GI
- N+V
4. CVS
- If severe: hypotension, tachycardia
Oil of Wintergreen -> salicylate poisoning++
Clove/pennyroyal oil -> hepatotoxic, use NAC
Rx:
Don't give AC
Rx bronchoconstriction with dilators
NAC 200mg/kg for clove or pennyroyal oil
100
Hydrocarbon ingestion
Essential oils + solvents etc.
1. GI
- N+V+D
- Perianal burns if hydrocarbon in diarrhoea
2. CNS
- Euphoria, coma, seizures
3. Resp
- Aspiration pneumonitis
4. Liver failure
5. CVS
- Catecholaminergic arrhythmias
Rx:
Don't give AC
Manage airway
Treat bronchoconstriction with dilators
NAC for liver injury prevention
Discharge at 6hr if:
- Asymptomatic
- Normal SO2
101
Volatile hydrocarbon inhalation
Often recreational: 'sniffing' (e.g. glue, markers, pens, petrol, paint thinners) or 'chroming' (e.g. aerosols, paints)
1. CNS
- Disinhibition, euphoria, headache, agitation, delirium
- Drowsiness, collapse, seizures, coma
2. CVS
- Hypotension, ventricular arrhythmias, "sudden sniffing death"
3. Renal
- RTA w/ chronic misuse (esp. toluene)
- Rhabdo
4. Metabolic
- Metabolic acidosis
- Electrolytes: hypo K, Ca, phos, glycaemia
5. Respiratory
- Hypoxia, aspiration
Toluene can cause VF
Adrenaline may make worse - increased sensitisation to endogenous catecholamines
- AVOID IN RESUS
- Consider lignocaine, amiodarone, BBlockers
102
Volatile hydrocarbon inhalation: associated syndromes w/ varying agents
Nitrites - methemoglobinaemia
Leaded gasoline - lead poisoning
NO - polyneuropathy and megaloblastic anaemia
Toluene - Muscle weakness, hypoK, metabolic acidosis
- VF
Methylene chloride - CO poisoning
103
Body packer management
Conservative:
- AC 50g
- WBO w/ macrogol/PEG
Surgical if:
- Unstable
- Evidence of toxicity
- Bowel obstruction
Happy when:
- All packets passed within 5 days
- Then: 2 normal BO + normal AXR
104
Body stuffer management
Don't image
Monitor for 6hr or until asymptomatic
105
Antimalarial toxicity: signs and symptoms
Rapid-onset, life-threatening tox
- "One pill can kill" paeds
1. HYPOkalaemia
2. CVS
- Hypotension, CVS collapse
- LQT, wide QRS
3. Seizures
4. Retinal and ototoxicity
- irreversible (quinine)
Hydroxychloroquine - Na + K channel blocker -> wide QRS + long QT
Chloroquine - MetHb
Quinine - Retinal and ototoxicity
106
Antimalarial toxicity: management
AC if <2hr
MDAC for quinine
Continuous ECG monitoring
Supper CVS
- IVF
- Inotropes
- Sodium bicarb if refractory (inotropes less effective in acidosis)
K+ replacement
May require intubation
Note:
Quinine: ototox + retinotox + MDAC
- 2 eyes, 2 ears, 2+ doses AC
107
Isoniazid toxicity
1. Metabolic acidosis (HAGMA)
2. Seizures + coma (likely due to GABA deficiency
Also weak MAO-I
- Serotonergic toxidrome if co-ingestion w/ serotonergic drug
- Tyramine reactions w/ food
AC
IV pyridoxine 5g
- Only if seizures or metabolic acidosis
Supportive care
108
Thyroxine toxicity
Majority asymptomatic
Mild-mod symptoms for 2-7 days
Hyperthyroid symptoms
109
Caustic ingestions: assessment and treatment
Symptoms may be delayed
Consider early intubation
NG insertion only on endoscopy
Decontamination contra-indicated
If asymptomatic:
- Observe
- Trial of PO intake 4 hours post-exposure (or earlier)
If any symptoms:
- Admit for oesophagoscopy/endoscopy (with 24 hours)
- NBM
- IV PPI
If skin contact:
- Remove clothing
- Low pressure irrigation until pH normal (~pH 7)
- Check pH every 15-20 mins
- Then treat as per thermal burns
110
Hydrogen peroxide ingestion
As per caustic injury +
- Direct corrosive injury
- Systemic gas embolism
- Distension of hollow viscera
111
Lead poisoning: acute symptoms and investigations
Chronic more common than acute, however...
Acute:
1. CSN
- Fatigue, weakness, headaches
- Encephalopathy -> coma, seizure
2. GI effects
- N+V, abdo pain
3. Hepatitis
4. Haemolytic anaemia
Ix:
Whole blood lead
- >100microg/dL = CSN symptoms
Chest + abdo xray
- Confirm and locate ingested lead objects
112
Lead poisoning: management
Locate and remove lead object
- C+AXR <48 hours
* In stomach, repeat in 48 hours and monitor for passing
* Beyond, wait to pass
- C+AXR >48 hours
* In stomach -> endoscopy
* Beyond, wait to pass
Chelation if:
- Lead conc. >70microgs/dL + symptoms
- Lead conc. >45microgs/dL if children and pregnant
PO - Succimer 10mg/kg PO TDS for 5 days -> 10mg/kg BD for 14 days
IV - DMPS (dimercaptopropane-1-sulfonate) 5mg/kg q6hrly for 5 days
113
ACE-I toxicity
Typically benign
Mild hypotension - responds to IVF +/- norad
Severe tox if co-ingested with CCB/BB
No role for AC
Can cause catecholamine resistance
Consider BRASH syndrome (separate flashcard)
114
BRASH syndrome
BRASH
Bradycardia
Renal failure
AV blockade
Shock
Hyperkalaemia
Contributory drugs:
ACE-Is/ARBs
BB
CCB
Digoxin
115
Nitrous oxide toxicity
1. CNS/PNS
- Subacute combined degeneration of the cord
- Peripheral neuropathy
2. Haem
- Bone marrow suppression
- Macrocytic anaemia
3. Resp
- ARDS
4. Psych
- Depression, psychosis
Ix
Low B12
Elevated homocysteine
MRI - dorsal column pathology - inverted V sign
Rx
Hydroxocobalamin IM injection
Oral methionine
116
Arsenic toxicity: sources, signs and symptoms
Inhalation - semiconductor and metal refining
Ingestion - older pesticide and insecticides (termites or ants)
Organic arsenic in seafood relative non-toxic
Early:
1. GI
- Severe N+V+D, dehydration, abdo pain
2. CVS
- Hypotension, ventricular arrhythmias, heart failure, collapse LQT
3. Heamolysis
4. Metabolic acidosis
5. MOF
Delayed:
Occur days to weeks if survive acute effects
1. Bone marrow suppression
2. Hepatitis
3. CNS
- Encephalopathy
- Ascending sensorimotor peripheral polyneuropathy
4. Hyperkeratotic lesions
117
Arsenic toxicity: investigations and management
Specific Ix:
Urinary arsenic concentration - 24 hour urine collection
WBI (not AC)
CVS support
Treat LQT
NAC for hepatotoxicity
Chelation therapy
- PO succimer 10mg/kg PO TDS
- IV DMPS 5mg/kg IV QID
118
Oral potassium overdose
High risk in impaired renal function
1. CVS
- Arrhythmias
- Myocardial deppression
- ECG abnormalities as for hyperK
2. CNS
- Resp depression, paraesethesias, flaccid paralysis
3. GI
- N+V, abdo pain
Ix:
Abdo xray - radio-opaque tablets
Mx:
As per hyperK
- + single dose PO fruse
Continuous cardiac moniroring
Consider:
- WBI if tablets of XR
- Dialysis (if renal impairment or instability)
119
Methotrexate toxicity
1. GI
- N+V+D
- Stomatitis, ulcers, mucositis
2. Hepatotoxicity
3. Haem
- Bone marrow suppression: neutropaenia, agranulocytosis, anaemia, thrombocytopaenia
- most commonly 7-14 days after onset of tox
Rx:
Calcium folinate 15mg PO QID
120
Paraquat poisoning
Weed killer, extremely toxic
Pulmonary tox + MOF
If MOF -> palliation
If survives acute phase, progressive pulm fibrosis, hypoxia and death
>15mL
- AKI
- Liver necrosis
- Myocardial necrosis
- Acute pnuemonitis
- Internal haemorrhage
Decontamination
- AC
NAC
Steroids
Haemodialysis
No antidote
121
Cinchonism
Caused by OD quinine (antimalarial) and quinidine (class 1A anti-arrhythmic)
1. Tinnitus and hearing loss
2. Visual disturbance
3. Confusion and delirium
4. Psychosis
122
Chlorine gas exposure
Skin + eyes + lungs
Mild:
- Lacrimation
- Rhinorrhoea
- Cough
- Headache
Severe:
- Bronchial epithelial sloughing
- Purulent exudate
- Pulm oedema
- Burning of eyes
- Chemical burns to skin w/ blisters
Mx:
Remove from source
Airway management
Warmed, humidified O2
Bronchodilator nebs
?Neb steroids/bicarb
123
Theophylline toxicity: signs and symptoms, RFs for same
Susceptibility depends on individual
Can cause life-threatening seizures and arrhythmias
RFs:
- HypoK
- Hyperglycaemia
- Age >60
Sympathomimetic-like toxidrome
1. GI
- N+V
2. CVS
- Tachyarrhythmias
- Hypotension, MI
3. CNS
- Agitation, tremor, seizures
4. Metabolic
- Hyperglycaemia, hypoK, metabolic acidosis
5. Resp
- Hyperventilation
124
Theophylline toxicity: investigation and management
Ix:
Theophylline levels
ECG
Electrolytes
Mx:
Decontamination - AC
Sedation - benzos
Seizure control - benzos
CVS support
Replace K
Enhanced elimination: MDAC + dialysis if severe, unstable
125
Nicotine toxicity: early vs late symptoms
1. Early phase
Nicotinic stimulation --> cholinergic toxidrome
- CNS: agitation, fasciculations, confusion, seizures
- CVS: tachy, HTN
- Resp: bronchoconstriction
- GI: N+V+D, abdo pain, hypersalivation
2. Late phase
Prolonged inhibition of nicotinic cholinergic receptors (looks like organophosphate tox)
- CNS: mydriasis, weakness, paralysis, lethargy, depression, coma
- CVS: Hypotension + brady
- Resp: Resp depression, resp muscle paralysis
126
Nicotine toxicity: management
AC for ingested dose
Supportive
Atropine 600mcg 3-5 min, max 3mg
Benzos for seizures (usually not required)
127
Baclofen toxicity
1. CNS
- Loss of brainstem reflexes - mimics brainstem death
- Delirium (prolonged)
- Sedation, coma, seizures
2. CVS
- Brady or tachycardia
3. Resp depression
- Risk of hypoxic encephalopathy
Mx:
Decontamination with AC
Intubation + ventilation
Benzos for seizures
Most patients recover within 72 hours if not developed hypoxic encephalopathy
128
Cannabinoid toxicity
1. CNS
- Confusion, psychomotor agitation, cognitive impairment
- CNS depression: drowsiness to coma
- Seizures
- Psychiatricz; anxiety, paranoia, psychotic symptoms
2. CVS
- Tachyarrhythmias, LQT, MI, CVA
3. Hyperthermia
4. Renal
- Rhabdo, AKI
Mx:
Control behavioural disturbance w/ sedation
Identify and treat severe hyperthermia
Treat complications as they arise
Paediatrics:
Significant CNS depression, hypotonia, hyporeflexia
129
Toxic mushrooms poisoning - amanita phalloides: presentation, signs and symptoms
Usually in ACT
Cooking does not inactivate the amatoxin (heat stable)
Contain cyclopeptides
Most ingestions by children and small and benign
Presentation triphasic:
1. 6-24 hrs: DELAYED GI upset (dysentery phase)
2. 12-72 hours: False recovery
3. 4-9 days: Hepatorenal phase
- Hepatic necrosis + liver failure
- Coagulopathy + GI bleeding
- Hepatic encephalopathy
- Renal impairment
130
Toxic mushrooms poisoning - amanita phalloides: management
Send photos to PIC for identification
AC + MDAC
- Give even days after ingestion due to long enterohepatic recirculation
Supportive
- IVF, treat hypoglycaemia
Possible antidotes:
- NAC for liver protection
- Silibinin IV
- Rifampicin IV
- Benzylpenicillin IV
If no GI symptoms and normal LFTs at 24 hours, can be discharged
131
Acute radiation syndrome: phases
Prodromal -> latent -> manifest/onset -> convalescent or death
1.Prodromal phase - 0-48hrs
- 1 Gy: N+V
- 4 Gy: Headache
- 6 Gy: Diarrhoea, fever
- 8 Gy: AMS, LOC
2. Latent phase 0-3 weeks
- No symptoms
3. Onset/Manifest phase
- 3 Gy: skin injury, heamatopoietic disorders (lymphocytes first)
- 8 Gy: GI tract disorder
- 10 Gy+: CNS, nerve and blood vessel disorders
132
Acute radiation syndrome: Dose, expected symptoms and potential management
1-2 Gy: NVD syndrome
- N+V+D, anorexia
2-6 Gy: Haematopoietic syndrome
- Loss of cellularity in bone marrow, spleen, thymuc
- Death between 10-30 days without intervention
- ABx, cytokines, BMT, stem cell therapy
8-15 Gy: GI syndrome
- Damage to crypt cells -> loss of absorption of nutrients, dehydration -> weight loss, severe electrolyte disturbance, hypotension
- Death in 3-5 days without intervention
- ABx, anti-emetics, IVF, electrolytes, stem cell therapy, BMT
>25 Gy: CNS syndrome
- Irritability, hyper-excitability, seizures, coma -> death
- Symptoms irreversible; no treatment
