Toxicology
Dr Jacqueline Maplesden
Listen in to Jacqueline discuss an approach to managing the toxicology patient.
Case Study
Imagine that the next patient you are going to see is a Cat 3, with the triage note stating ‘26 year old female. Overdose of antidepressant medications and a bottle of wine 1 hour ago, appears drowsy.’ The patient is tachycardic, hypotensive, and has a GCS of 14.
Once you have had a go answering the below questions, click on them for answers.
1) What are the immediate life threats and how will you manage them?
ABCs – in this case, the GCS is 14, so airway and breathing need rapid assessment but should not require support unless the GCS drops, which is possible. The main concern is the circulation - hypotension, so IV access and obtaining an ECG are the first priorities, then supporting the circulation starting with a fluid bolus.
2) What investigations will you immediately?
ECG, blood glucose, and paracetamol level, (and in this case ethanol level).
3) After your immediate resuscitation, the patient’s obs are RR 18 sats 96% RA, P100 BP 100/60, GCS 13 - E3M6V4. What information do you need to make a risk assessment?
Toxins or medications/doses/timing/patient factors/clinical features
4)The ambulance crew have found a number of empty packets of tablets near the patient. These are: Quetiapine 25mg x 60 tablets, Diazepam 5mg x 6 tabelts and Paroxetine 20mg x 14 tablets. How will you determine your risk assessment based on all the facts? Where or from whom can you seek further advice?
Without going into too much detail (see risk assessment below), the quetiapine (antipsychotic), benzodiazepines and alcohol will all add to the effect on her conscious state which will need to be observed, and are likely to lead to mild hypotension. Quetiapine toxicity is dose dependent and at this dose she might have some mild but not life- threatening toxicity. We would look for sedation, hypotension, tachycardia and a long QTi on her ECG. Paroxetine is a SSRI so serotonin toxicity should be examined for – altered conscious state, fever, autonomic instability, brisk reflexes, increased tone, clonus, but again at this dose I would not be too concerned.
We would have a look at one of the databases, eTG or Austin Tox Guidelines, and determine that we should observe the patient for at least 6 hours or until her clinical state normalises. If we need specialist advice we would call the PIC on 13 11 26.
If we use the RRSIDEAD:
R – fluid resus
RA – we know the drugs, doses (25mg quetiapine is IR), timing, we need more information about the patient but at least we know she is on psychiatric medications, and we have a the clinical picture, so we can make predictions, as above.
S – supportive care has commenced and we will continue to observe
I – ECG, paracetamol, glucose, alcohol level, consider VBG or electrolytes if ECG abnormal
D – too drowsy to decontaminate
E – n/a with these drugs
A – diazepam is an antidote for mild serotonergic toxic so she is already fine here, and flumazenil (antidote to benzodiazepines) is (almost) never indicated in an ED patient, so no
D – High acuity cubicle initially, resus if BP falls further or GCS falls, aiming for ED short stay admission once stable, at least 6 hours but likely longer, and referral for mental health assessment
This is a complex case and you would not be expected to know all the details, but it should give you an idea of how the RRSIDEAD principle can be applied, and what information you need to make an informed risk assessment.