ED - Toxicology Flashcards
What do you want to know in the history of overdose
How much? What they took? More than one drug? Accurate timing? Staggered or all together? With alcohol or water? - alcohol worsens Do bloods and blood gas TRAKCARE for drug Hx Collateral
How do you assess
ABCDE Check BM as reversible cause of low GCS before intubate ECG Check vitals, temp, pupil size, IV access Bloods
What else should you do
Risk assess
Do they have capacity
Do they need psychiatry / police
What is good source of information
TOXBASE
Look up drugs to see what they cause and form management
Always suspect possibly overdose if patient with abdominal pain / vomit
What is a toxidrome
Signs and symptoms that suggest a specific type of poisoning as patient may not be able to tell you
How do you examine
ABCDE A+B = RR and HR C = pulse and BP D = GCS, pupils, reflex, any seizures E = temp, skin, mucous membrane
What drugs cause sympathomimetic / adrenergic toxidrome
Cocaine Amphetamine Theophylline Decongestants Legal highs
What drugs cause sedative / hypnotic toxidrome
Benzodiazepine
Zopiclone
Barbiturates - phenobarbital (CNS depressant)
Alcohol
What drugs cause opioid toxidrome
Heroin
Methadone
Codeine
MST
What drugs cause anti-cholinergic toxidrome
TCA
Anti-histamine
Anti-psychotics
Oxybutin / tolterodine - incontinence
What do sympathomimetic drugs do
Stimulate A and B adrenergic receptors
Prevent uptake of Noradrenaline, dopamine and serotonin
Release Na
How do they present
Chest pain - MI can develop Aortic dissection Arrythmia- QT prolonged High HR High BP - can cause bleed High RR Sweating Fever Dilated pupils Brisk reflexes HYpertonia Seizure Metabolic acidosis Rhabdomyolysis Excessive speech and motor Restless Agitated Insomnia Hallucination Ischaemic colitis
How do you treat
IV fluid + cooling ECG to look for arrhythmia Control agitation - diazepam / benzo Check CK Control BP - GTN infusion (Na nitroprusside) If chest pain = GTN and PCI if MI develops - Treat as MI Anti-pyretic to lower temp Treat arrythmia Treat metabolic acidosis
How do you treat acidosis / raised CK
IV fluid and sodium bicarb
What do you NOT give
BB
leads to unopposed alpha antagonism and HTN crisis
How do sedative drug overdose present
Braydcardia Respiratory depression Hypotension Slurred speech Ataxia Reduced reflex Normal skin / membrane Pupil size normal May have blurring / diplopia / nystagmus Hallucination Delerium Coma
How do you manage sedative overdose
Protect airway
Support ventilation if reduced GCS
Correct hypo - may need vasopressor
What drug can be used to manage Benzo OD
Flumazenil
When do you use
If 100% confident isolated Benzo OD Iatrogenic Severe or would otherwise require ventilation HIGH RISK OF SEIZURE Not dependent as risk of withdrawal
When do you consider opioid overdose
If person on opioids regularly on drug chart
What does opioid toxidrome look like
Resp depression Bradycardia Hypotension Pin point pupil - miosis Reduced GCS Hypothermia Seizure Normal skin and mucous
How do you treat
Nalaxone (competitive antagonist) up to 2mg
Start with 400 microgram
IM or IV
Lasts 45 minutes so may have to keep doing it as opiate will have longer half life
What suggests anti-cholinergic overdose
Hot as hare
Dry as bone
Mad as hatter
What are ECG changes
Sinus tachycardia Widen QRS Long PR Long QT Arrythmia
What is toxidrome of anti-cholinergic overdose
Hypertension Tachycardia Dilated pupil Brisk reflexes then absent - myoclonus Pyrexia Flushed dry skin / dry mouth Urinary retention Restless Arrythmia Metabolic acidosis Seizure Confused Later drowsy then coma
How do you manage
Repeated doses of charcoal if within 1 hour
Check CK
Correct acidosis
IV bicarb = 1st line to reduce risk of seizure
Glucagon if severe hypo / HF or cariogenic shock
Many anti-arrythmics CI as prolong QT
What do you do if CK raised
Fluid
When do you give sodium bicarb
Metabolic acidosis
QRS prolonegd
Arrythmia
Hypo not responding
How does paracetamol overdose present
N+V Coma Severe metabolic acidosis Abdo pain = late sign After 2-3 days hepatic necrosis = RUQ pain, jaundice, renal failure, coma
Where is paracetamol conjugated and broken down
What puts you at increased risk of hepatotoxicy
Liver by p450 enzyme
Patients taking p450 inducers
Malnourished patient as enzyme to break down depleted
Acute alcohol therefore may be protective as p450 inhibitor
How do you investigate paracetamol overdose
Do levels 4 hours after overdose
LFT as well + clotting (PT bad)
Bloods - FBC, U+E, LFT, clotting, INR
Do VBG for acid base balance / pH - gives instant result
- Abnormal LFT, acidosis, hypoglycaemia, coag abnormalities
Get paracetamol level after 4 hours to see if need NAC
If present >8 hours take straight away and give NAC immediate
This allows you to decide if patient needs NAC
Mental health referral
How do you treat
Activated charcoal if <1 hour
N-acetylcysteine (NAC)- Allows safe metabolism of toxin
Liver transplant
When should NAC be commenced
Within 8 hours to be fully effective
21 hour infusion
What do you do if staggered overdose (not all taken within 1 hour)
Level in blood not helpful
Just work out if toxic overdose >150ml/kg and give nAC
What is liver transplant indicated / referral to liver unit
King’s College Criteria
- pH <7.3 24 hours later OR
All 3 of
- PT >100 or INR >6.5
- Creatinine >300
- Grade 3 -4 encephalopathy
How does CO poisoning present
Headache = 90% N+V Malaise FAtigue Flu like symptoms Chest pain Confusion Vertigo Weakness Diarrhoea Drowsy
Severe
Bizarre neuro / extra-pyramidal if severe
Pink mucosa
Arrhythmia
How do you Dx
ABG or VBG showing elevated HbCO
Pulse oximetry can read high as similar to HbO
What else should you do
ECG + cardiac biomarkers to look for ischaemia
What other tests
CK / urine myoglobullin - rhabdo in severe cases FBC U+E - hypokalaemia LFT Glucose - hyperglycaemia Blood lactate - severity Toxicology - if suspect suicide Urinanalysis - +ve albumin / glucose in chronic
How do you Rx
100% O2 non rebreather mask
Continue till symptoms resolved but minimum 6 hours
Intubate if coma
Cardiac monitoring + pulse oximetry
Pathophysiology behind
CO has high affinity for oygen
Shifts oxo-haemoglobin curve to the left resulting in hypoxia
Indications for Hyperbarci oxygen
LOC
Neuro signs
Arrhythmia
Pregnancy
How do you manage BB overdose
Atropine if Brady
Glucagon if resistant
How do manage heparin overdose
Protamine sulphate
What are features of Salicylate overdose (Aspirin)
Tinnitus Lethargy Sweating Pyrexia N+V Hyper or hypoglycaemia More severe = hyperventilation and resp alkalosis AKI Confusion Seizure Coma
What acid base
Respiratory alkalosis due to early stimulation of resp = late
Metabolic acidosis due to AKI / direct effect = early
How do you Rx
ABC
Charcoal if acute
Urinary alkalisation with sodium bicarbonate
Haemodialysis
What are indications for dialysis
High concentration Resistant acidosis AKI PUlmonary oedema Siezure Coma
How does ecstasy poisoning present
Neuro - agitation, confusion, ataxia CVS - tachy + HTN Hyponatraemia Hyperthermi Rhabdomyolysis
How do you Rx
Supportive
Dantrolene for hyperthermia if fails
What is activated charcoal used for
Reduce absorption and accelerate excretion following overdose
Give 50g within 1 hour of overdose
Binds free drug
Can cause vomiting
Lithium toxicity
IV saline
Dialysis if severe
Theophylline toxiciity
Activated charcoal
Dialysis
Antitode to opiate
Nalaxone
Antitotde to BB
Glucagon
Antitode to Iron
Desferroxamine
Antitode to CO
Hyperbaric O2
Antitode to digoxn
Digiband
