17 - Clinical tox Flashcards
(23 cards)
Supportive care (ABC..)
- Airway - positioning, remove foreign objects, intubation
- Breathing - oxygen, ventilation
- Circulation - IV fluids, ECG, vital signs monitoring
- Deal with social/psychiatric issues ASAP
Self-poisoning
Presentation of underying psych or personality problem
* A little bit of this, but mostly that
* Taking risks
Substance use and risk of death
↑ risk of suicide, attempts and accidental poisoning
* Previous inpatient psych treatment is a risk factor
Most common drugs in delibrate or self poisoning overdoses
- TCAs
- SSRIs
Most common drugs in recreational ODs
- Opioids
- Dextropropoxyphene
- Amphetamines
- Anticholinergic drugs
- GHB
Symptoms of opioid overdose
- Sedation
- Vomiting
- Decreased bowel sounds
-
Small pupils
5.** Hypo**tension, bradycardia - Respiratory arrest and airway obstruction
Diagnosis (investigations)
- ECG
- Oximetry and arterial blood gases
- Drug levels
- Urine drug screen
- Ask yes or no Qs
Antidotes for drug overdose
Only 2 antidotes are SAFE (Paracetamol and TCAs)
* Most are effective but problems with antagonists (put someone in withdrawal)
Naxolene
Higher affinity for opioid receptor (antidote for opioid overdose)
Problems with naloxone
- Acute opioid withdrawal
- Does not reverse some drug effects
- Short duration of effect
Flumazenil
Naloxone of benzos
Problems with flumazenil
- Acute benzo withdrawal
- Unmasking other toxins
- Short duration
Typical satisfactory pharmacological outcome
(naloxone & flumazenil)
- Rapid, rude awakening
- Aggressive, uncooperative
- Sedated w/ morphine and midazolam
- Ventilated overnight
Ipecac
Gastric emptying (via vomiting)
* Less effective than other interventions
How is charcoal “activated”?
Heated to high temp in presence of gas or by reacting with steam
* typically made from wood, coconut shells, coal
How can activated aid in overdose?
Abs ingested toxins within the GI tract preventing the systemic abs.
* Only adsorbs toxins that are in the dissolved liquid phase via direct contact
Activated charcoal - complications
- Aspiration (Sorbitol pneumonitis)
- Bowel obstruction
- Hyponatraemia (electrolyte imbalance)
When should different antidote treatments be implemented?
- Doing nothing (low tox)
- Ipecac (never)
- Charcoal (severe poisonings, within 1-2h
- Gastric Lavages (< 1h, serious poisoning)
Methanol in alcohol
Methanol has lower boiling point than ethanol
* Need 2 step distillation
* In spirits in foreign countries
Pathophysiology of methanol
Broken down into formaldehyde then formic acid
* Inhibits mitochondrial oxidative metabolism
* ↑ lactic acid
* Lactic and formic acid ➔ high anion gap metabolic acidosis
Clinical features of methanol toxicity
- CNS (e.g. Vertigo, lethargy)
- Ocular (e.g. blurred vision, blindness
- GIT (e.g. vomiting)
- Kidney (e.g. myoglobinuria)
Treatment for methanol poisoning
Ethanol as they compete
ABC or 3Rs of antidotes mechanism/actions
- Absorption (REDUCE dose)
- Block/bypass (RESTORE function)
- Control consequences (RESCUE and support)
