The Poisoned Patient: Notes

Key Questions:
- What should I look out for?
- How should I treat the patient?
- What tests should I order?
- Where can I get more info?
- When can the patient be safely referred?

Known Substance:
- Primary Survey
- Sample History
- Secondary Survey
- Definitive Diagnostic Tests
- Definitive Treatment
- Disposition
Unknown Substance:
- Primary Survey
- Sample History
- Screening Diagnostic Tests
- Empirical Interventions/Supportive Care
- Disposition once stable and the substance identified or dangerous toxins excluded.

Realize that any intentional self-harm is a call for help.
Remember a biopsychosocial approach.
Do not only treat the toxidrome but extend help beyond the antidotes (Disposition planning).

	HR+BP	RR	TEMP	PUPILS	BOWEL SOUNDS	DIAPHORESIS
Anticholinergic	↑	↓	↑	↑	↓	↓
Cholinergic	↓	↑	N	↓	↑	↑
Opioid	↓	↓	N	↓	↓	N
Sympathomimetic	↑	↑	↑	↑	N	↑
Sedative-Hypnotic	↓	↓	N	N	N	N

Xenobiotic	ECG Findings	Physiology	Treatment
Beta-blocker	Sinus bradycardia	Blockage of cardiac beta receptors	Glucagon, high dose insulin and glucose, Pressors
Ca2+ Channel Blocker	Sinus bradycardia, wide QRS	Prolongation of phase 0 of nodal action potential, slowing rate of depolarization and thus heart rate	High dose insulin, Pressors, glucagon, and phosphodiesterase inhibitors, calcium
Na+ Channel Blocker	Wide QRS, negative deflection of terminal R wave in aVR	Prolongation of phase 0 of myocyte action potential, prolonging depolarization phase of cardiac myocytes	Sodium bicarbonate to pH
K+ Channel Blocker	Long QT	Prolongation of phase 3 of action potential, prolonging time for repolarization	Magnesium to treat or prevent Torsades de pointes
Na/K/ATPase Blocker	Biphasic QRS, Increased automaticity with AV block	Increased calcium in cardiac myocytes increasing sensitivity to multiple signals and increasing automaticity	Digoxin Immune Fab

Decontamination
- Terminate topical exposure
Consider decreased absorption:
- Activated Charcoal
- Gastric Lavage
- Whole Bowel Irrigation
- Endoscopy
Increased elimination
- Multi-dose Activated Charcoal
- Alkalinisation of Urine
- Extracorporeal Elimination

23-year-old female presents to the emergency department following an overdose.
She has been feeling depressed after not passing a module at university.
She had an alcohol binge, after which she ingested 10 grams of Paracetamol, 4 hours ago.
She had one episode of vomiting but is otherwise asymptomatic.
Questions:
- What is your approach?
- What diagnostics would you perform and when?
- What is the antidote?
Consider N-Acetyl-Cysteine (NAC) for all patients with toxic exposure (>7,5g or >150mg/kg).
Paracetamol levels only pulled at 4 hours.
Treat ALL patients with serum paracetamol levels above the nomogram treatment line.

A 35-year-old male presents following an intentional overdose of his mother’s sleeping tablets.
He is drowsy, confused, warm to the touch, and his skin and mucosa are dry.
He is noted to have a GCS of 11, HR 140, and a BP of 140/90.
TCA is known for its 2 A's and 2 C's:
- Coma
- Convulsion
- Acidosis
- Arrhythmia
Treatment goals involve increasing drug excretion, narrowing QRS, and neutralizing the weak acid.
Antidote is Sodium Bicarbonate. The target pH is 7.50 - 7.55