Poisonings + OD Flashcards
In what time frame can activated charcoal be used?
Within 1 hour of ingestion
What dose of salicylates is considered poisoining?
> 125mg/kg needs assessment in hospital
Describe the presentation of salicylate poisoning
- Acid base disturbance: met acid (anion gap) + resp alk
- Electrolyte abnormalities: hypokalaemia
- CNS disturbance: confusion, seizures, coma
+ increased RR, tachycardia, sweating, warm peripheries, tinnitus
Describe the complications of salicylate poisoning
- Cerebral oedema -> coma
- Arrhythmias -> heart failure
- AKI
Describe the A to E in salicylate poisoning
A to E
- A: may be non-patent due if drowsy
- B: increased RR, ABG: resp alk + met acid (later)
- C: sweaty, warm, tachycardiac, hypertensive, possible ECG abnormalities. Get IV access and send bloods
- D: reduced GCS
Describe the important investigations for salicylate poisoning
- Obs
- ABG
- Urine: pH
- Bloods: FBC, U+Es, clotting, glucose, salicylate level (at 2 hours + 4 hours) + paracetamol level
- ECG
- CXR
Describe the management of salicylate poisoning
Medical:
Senior help, consider ITU/NIPS
1. IV fluids
2. Monitoring: cont cardiac monitor + pulse ox
3. Monitor bloods: glucose, salicylate level, ABG, U+Es
Consider: sodium bicarb (if serum >500mg/L), RRT
Psych:
- History + risk assessment
- Liaison psych referral
What dose of paracetamol is considered OD?
OD: >75mg/kg
Toxicity is more likely if: >150mg/kg
Describe the presentation of paracetamol OD
Often asymptomatic
- Nausea and vomiting
- > RUQ
- > Jaundice and liver dysfunction
- AKI
What is the most common drug used in OD?
Paracetamol
Describe the pathophysiology of paracetamol OD
OD results in excessive production of NAPQI (toxic metabolite normally degraded quickly)
- > overwhelms hepatocyte capacity to metabolise (conjugation with glutathione)
- > injury + hepatocyte death -> acute liver failure
Describe the investigations for paracetamol OD
- Obs
- Urine dip
- Bloods: FBC, U+Es, LFTs, clotting, glucose, VBG/ABG, paracetamol level (after 4 hours only)
- ECG
- Abdo USS if symptomatic RUQ
Which patients are at greater risk of toxicity in paracetamol OD?
Malnourished:
- Eating disorders
- Chronic illness eg. HIV
- Alcoholics
Drug Hx of enzyme inducers:
- Anti-epileptics
- Rifampicin etc
Describe the management of paracetamol OD
- Take history (details of OD, psych, PMH)
- Examination: for signs of acute liver failure
- Investigations: bloods, etc
- Senior help, consider ITU if needed
- Within 1 hour: act charcoal
- At 4 hours: take paracetamol level, use chart
- IV acetylcysteine infusion over 21 hours
- > monitor glucose. At end of infusion, repeat bloods
+ psych referral, 1-1 care etc
When can a patient with paracetamol OD be discharged?
No signs of liver failure
Normal creatinine
NAC stopped
Psych allows
Describe the NAC regimen
1st bag: 150mg/kg in 5% dex over 1 hour
2nd bag: 50mg/kg in 500ml 5% dex over 4 hours
3rd bag: 100mg/kg in 1L of 5% dex over 16 hours
What are some common side effects of NAC? What is the management?
Vomiting common. Can give anti-emetic
Rash. Don’t stop infusion, give chlorphenamine
Describe the signs of carbon monoxide poisoning
Non-specific
- Headache
- Nausea
- Dizziness
- Cardiac: MI, arrhythmia, cardiac arrest
- Neuro: confusion, focal neuro, drowsiness, coma
Describe the investigations for carbon monoxide poisoning
- History + examination
- Bloods: basic bloods (DDx) + VBG/ABG (gold standard), troponins
- ECG
- Imaging: CT head, CXR as indicated by symptoms
Which key test is elevated in CO poisoning?
Carboxyhaemoglobin
Describe the management of CO poisoning
Medical Mx:
- Call senior
- A to E approach
- High flow oxygen (100% at 15L), consider I+V if low GCS
Extras:
- Consider non-accidental exposure
- Ensure other people away from source
- Discharge to safe place
Describe the presentation of TCA OD
- Anticholinergic effects: dilated pupils, blurry vision, tachycardia, hyperthermia, drowsiness, ataxia
- Seizures, coma
- Arrhythmia (wide QRS, prolonged QTc), cardiac arrest
Describe the treatment of TCA OD
Supportive + monitoring
IV sodium bicarb
Describe the presentation of benzodiazepine OD
Drowsiness, coma
Hypotension, reduced RR
