Toxicology Flashcards
Management of paracetamol overdose, immediate release
> 10g or 200mg/kg. > 30 g or 500mg/kg = massive.
Charcoal if < 2 hrs post IR and cooperative. Or < 4 hrs if > 30 g.
< 8 hrs - APAP and +/- NAC
8-24 hrs - NAC, APAP & LFTs. Below nomogram and normal ALT - then stop
> 24 hrs - NAC, APAP & LFTs. Below 10 mg/L and normal ALT - stop.
NAC 200 mg / kg for 4 hrs, then 100 mg/kg (double if 2x nomogram) over 16 hrs.
- APAP and LFT 2 hrs prior to cessation.
Management of slow release paracetamol overdose
< 10g / 200 mg/kg - 2 levels, 4 hrs appart, start NAC if either above the line.
> 10g / 200 mg/kg - start NAC. APAP 4 hrs post ingestion and 4 hrs later. Complete NAC. If >2x nomogram, then dobule NAC.
> 30g / 500 mg/kg - start double dose NAC with 4 & 8 hr APAP.
APAP and LFTs prior to cessation
Paracetamol overdose, liver transplant unit referral criteria (kings college)
PH < 7.3 SBP < 80 BSL < 4 INR > 3.5 at 48 hrs, or > 4 at any time Renal failure, Cr > 200 Encephalopathy Plt < 50
Toxic dose risk assessment for salicylates
150-300 mg/kg - symptomatic
> 300 mg/kg - acid base abn, AMS, seizures
> 500 mg/kg - potentially lethal
Toxic dose risk assessment for iron (and max dose / tablet)
> 60 mg/kg - symptomatic
120 mg/kg - potentially lethal
Max dose / tablet = 110 mg/kg
Toxic dose risk assessment for TCA poisoning
5-10 mg/kg drowsy, anticholinergic
>10 mg/kg major toxicity possible
> 30 mg/kg severe toxicity, cardiotoxicity and coma
QRS > 100 = seziures
QRS > 160 = VT
Risk assessment - Colchicine anticipate lethal effects if dose more than:
> 0.8 mg/kg
Risk assessment - Isoniazid anticipate lethal effects if dose more than:
10 g
Risk assessment - Ibuporfen anticipate multiorgan failure if dose more than:
300 mg/kg
Risk assessment - Potassium anticipate lethal effects if dose more than:
2.5 mmol/kg (40 tablets)
Management of salicylate poisoning
Resus:
- intubation for coma, respiratory insufficiency or seizures.
- hyperventilate
- C - IVT for dehydration, urine output 1-2 mls/kg/hr
- D: IV benzodiazepines for seizures
Decontam: charcoal if > 150 mg/kg up to 8 hrs, via NG
Elim:
- urinary alkalinisation (if symptomatic) 1-2 mEq/kg bicarb, then infusion. Aim pH 7.5. IDC.
- haemodialysis: cant alkalinise, severe toxicity or rising salicylate level
Dispos: ICU
Management of tricyclic poisoning
Resus:
- Intubation for GCS <12 or seziure.
- Hyperventilate, target pH 7.5-7.55
- C: arrhythmia: Sodium bicarb for wide QRS or arrhythmia
- C: Hypotension: IV fluid, noradrenaline and bicarb.
- D: IV benzos and bicarb for seizures
D: Charcoal when intubated
A: Sodium bicarb, until pH 7.55, then 3% saline or lignocaine.
D: ICU
Management of calcium channel blocker toxicity
Resus:
- Airway: intubate if shock
- Bradycardia: atropine, adrenaline, CALCIUM, HIET
- Hypotension: IV fluid, CALCIUM, adrenaline, noradrenaline, HIET
—> Pacing, ECMO.
Decontam: Whole bowel irrigation if early and asymptomatic. Once hypotensive not possible.
Antidote: HIET. 1 unit/kg rapid acting insulin, 50 mls 50% dextrose. Then infusion 0.5 unit/kg/hr, 250 mls/hr 10% dextrose . Target MAP 60-65.
D: ICU
Anticipate complications: heart block/bradycardia, hypotension, arrest, hypokalaemia/hypoglycaemia with HIET
B-blocker
R:
- A/B: intubate if shocked or to hyperventilate (propranolol)
- C: atropine, adrenaline, external pacing. IV fluid bolus
- Elect: replace K, replace mag
S
I: ECG - long PR, heart block, wide qrs, TDP
D: charcoal < 2 hrs
A: HIET, intralipid, isoprenaline. ECMO.
Digoxin
R: lethal - K> 5.5, ingestion > 10g or level > 15 nmol/L.
R:
- C: bradycardia/tachycardia. Arrest. Hypotension. VT —> Lignocaine 1mg/kg.
—> atropine, adrenaline, fluid, pacing.
- Electrolytes: hyperkalaemia (insulin, sodium bicarb).
S
I: ECG - tachy/brady, conduction abnormalities (AV block, wide QRS, AF), increased automaticity: AE/VE, SVT
D: < 1 hr charcoal
E
A: Digoxin immune fab fragment. 5 stable, 10 unstable, 20 arrest.
Organophosphate poisoning - clinical exam
Muscarinic, Nicotinic & CNS features CNS: AMS, seizures, coma. Muscarinic: - Altered mental status (delirium) -Bradycardia, hypotension -Myrdiasis -Diaphoresis -Lacrimation -Salivation -Increased WOB, pulmonary crepitations (bronchorrhoea) -Vomiting / diarrhoea -Urinary incontinence Nicotinic - tremor, weakness, fasiculations - respiratory muscle paralysis - tachycardia / hypertension
Ethylene Glycol poisoning
R:
- A: intubate, sodium bicarb and hyperventilate.
- C: shock, IVT
- D: Seizures - benzos.
- Electrolytes: hyperK, hypomag. Calcium if refractory seizures, long QT
S
I: VBG, ECG. UEC (renal fcn), Calcum, EG level. Urine - calcium oxalate.
E: Haemodialysis - OG > 10, pH < 7.3, ARF
A: Ethanol, 8 mls/kg IV then 1-2 mls/kg/hr. Blood etoh 22-33 mmol/L. Or fomepizole.
Button battery ingestion
Iron overdose
R:
- C: Hypotension - IVT. GI losses & 3rd space.
S:
I: Iron level (4-6 hrs), metabolic acidosis, ECG, BSL, LFTs, UEC. AXR and count.
D: WBI (>60 mg/kg), endoscopy (WBI fails / impractical).
E:
A: Desferoxamine (shock, acidosis, AMS, or iron level > 90 micromol/L at 4-6 hrs). 15 mg/kg/hr.
D:
Lithium toxicity - acute overdose
Expected symptoms and priorities for care.
GI symptoms.
Rareful neurotoxicity.
Supportive care - avoid dehydration, hyponatraemia and renal impairment.
If significant renal impairment, then haemodialysis.
Doesn’t cause coma.
Carbon monoxide poisoning - effects
CNS: headache, nausea, confusion, ataxia, seizures
CVS: tachycardia, hypertension, myocardial ischaemia / infarction
Resp: pulmonary oedema
Metabolic: rhabdo, lactic acidosis
DIC
Management of CO poisoning
Resus: B - give O2. High flow.
S
Ix: CO level, correlates poorly with exposure / symptoms. CT brain - oedema.
D: remove from exposure
E: 100% O2 NRBM, until symptoms resolved & at least 8 hrs. 24 hrs if pregnant.
- hyperbaric O2, discuss. If pregnant.
A: nil
Cyanide poisoning
R:
- A/B: intubate and ventilate 100% O2 if severe poisoning.
- C: Shock
- D: Coma, seizures.
S
I: lactic acidosis, lactate > 10 - very suggestive if smoke inhalation victim without severe burns. Cyanide levels.
D: remove from exposure.
A: indications - AMS, seizures, hypotension, acidosis
- hydroxocobalmin 5g / 30 min.
Chronic poisoning with lithium
Neurological syndrome: tremor, hyperreflexia, agitation, ataxia. Rigidity, hypertonia, hypotension. Coma, seizures.
R: on lithium, with neurological signs/symptoms.
R:
- A/B & D: intubate if obtunded / seizures.
- C: rx hypotension with IVT. Target urine output 1 ml/kg/hr.
S
I: Cr (renal impairment), Na (low), dehydration, TSH. Lithium level.
E: haemodialysis if neurological dysfunction, and level > 2.5mmol/L.
Organophosphate poisoning management
Universal precautions. Solvent odour - headache.
R:
- A/B: High flow O2. Suction, adjuncts as required. Intubation for respiratory failure or seizures.
- C: bradycardia/hypotension —> atropine 1.2 mg, double every 5 min until drying of secretions and HR > 60.
- D: agitation - IV benzodiazepines.
D: remove clothes, wash skin with soap and water.
A: atropine. Pralidoxime - 2g IV then infusion, prevents aging in some exposures.
Box jellyfish envenomation - clinical syndrome, management
Long tentacles. Severe pain. Lattering whip marks.
Tachycardia, HTN, muscle spasms.
Wash skin with vinegar.
Give antivenom for reduced conscious state, arrest (3 vials), cardiac instability, respiratory failure or severe pain.
Other pain mx: opioids and MgSo4
Clinical syndrome and management of irukandji envenomation
Catecholaminergic syndrome
Muscle pain, sweating, agitation. Headache / weakness. Sense of impending doom.
Wash with vinegar.
Mx:
- opioid and benzodiazepines for pain and agitation.
- magnesium sulfate
- Antihypertensive (GTN) for APO or severe HTN
