Transcript Toxicology for Medical Students Dr Kent Robinson Emergency Staff

Toxicology for Medical
Students
Dr Kent Robinson
Emergency Staff Specialist
Liverpool and Campbelltown Hospital's
OBJECTIVES
• Understand basic approach to the poisoned
patient.
• Recognose the major toxidromes.
• Apply your knowledge to clinical cases.
Approach to Poisoned Patient
• Supportive care is the mainstay of therapy.
• Decontamination of the patient is now rarely
indicated.
• In specific situations, antidotes may used in
the management of the poisoned patient.
Case 1
• 21 year old female - found down at home
• Drug paraphenalia found next to patient
• Pinpoint pupils, GCS 3, cyanotic
Case 1
• Naloxone 2 mg x 2 dose intravenous - no
response
• O2 therapy, IPPV
• How would you manage this patient?
Case 1
• Assess and manage ABC's
• Disability - check BSL
• Reading "low on glucometer"
• Treated with dextrose 25 g iv, GCS to 15/15
Teaching Point
• In any patient with altered mental
status, always check a BSL
Case 2
• 41 year old male brought in from police cells
• Patient states he has taken overdose of
diazepam
• Ataxic and drowsy
• Vital signs T 39, P 140 (ST), BP 90/60
• Pupils fixed and dilated
• Dry, warm skin, urinary retention
Case 2
• Is this presentation consistent with the stated
overdose?
• What toxidrome is the patient exhibiting?
• What drugs are likely to cause this problem?
• How would you manage the patient?
Anticholinergic Toxidrome
• Antihistamines
• Antipsychotics
• Anticonvulsants
• Antidepressants
• Antispasmodics
• Antimuscarincs
• Plants - Datura, Mushrooms
Case 2 - Management
• Assess and manage ABC's
• Sedation - benzodiazepines
• One to one nursing care
• Intravenous fluids for tachycardia and
hypotension
• Insertion of IDC
• Consider physostigmine if pure anticholinergic
overdose.
Teaching Point
• In patients who present with a drug overdose,
always assume that they may have taken
drugs other than what they have volunteered.
Teaching Point
• Patients who present with any overdose make every attempt to get collateral
information.
Case 3
• 18 year old female
• Paracetamol overdose (50 x 500 mg tablets)
• Observations; T 37, P 90, BP 120/60, GCS 15
• Management?
Case 3
• Assess and manage ABC's
• Toxic dose considered to be 150 mg/kg.
• Baseline bloods (FBC, EUC, LFT, Coag's,
Paracetamol level)
• Repeat paracetamol at 4 hours
• Start NAC infusion.
Teaching Point
• NAC is the "antidote" for paracetmol toxicity
• In the setting of potentially hepatotoxic
ingestion, start NAC early.
• Decision for ongoing therapy should be based
on the 4 hour paracetamol level.
Case 4
• 45 year old male
• Chronic alcohol dependence
• Alcohol intoxication, presents aggressive and
agitated.
• Vital Signs; T 37, P 100, BP 110/60, RR 16,
GCS 14/15
• Management?
Case 4
• Assess and manage ABC's (Intravenous fluids
for HR and BP)
• Check BSL
• Give dextrose 25 g and thiamine 300 mg
• If no response, will need chemical restraint what agent will you choose to sedate, and
why?
Teaching Point
• Alcohol and benzodiazepines are sedativehypnotic agents.
• Giving a BDZ to an agitated alcoholic will
make the problem worse - use an
antipsychotic.
• Always think of the possibility of intracranial
pathology in an agitated alcoholic - low
threshold for CT Brain.
Summary
• Management of poisoned patient is largely
supportive
• Decontamination is rarely indicated (seek
senior advice)
• In specific situations, an antidote may be of
benefit.