ACUTE POISONINGACUTE POISONING

Major C J Porter RAMCArmy Medical Directorate

Emergency Medicine Registrar

Bristol Royal Infirmary

Outline of lectureOutline of lecture

• Epidemiology

• Toxidromes

• History, examination and detective work

• General management

• Specific management

• Antidotes

• Scenarios

EPIDEMIOLOGYEPIDEMIOLOGY

• 4000 UK deaths per year (1/3 CO)

• Most deaths outside hospital

• 100,000 Hospital admissions (12%)

• Not just overdoses: Illicit drugs, Alcohol

• Self poisoning:• F>M • 1/3 >one drug• Taken with alcohol: F: 40% M: 60%

• Repeated self-poisoning: 11% of admissions

EPIDEMIOLOGYEPIDEMIOLOGY

SUICIDESUICIDE

• 2% of male deaths• 1% of female deaths

• Method:• Female: Poisoning 40%• Male: Gas / Hanging / Suffocation

• Self-harm parasuicide:• 1% dead after 12 months• 3-5% dead after 5-10 years

ToxidromesToxidromes

• Patterns of signs and symptoms

• Useful to help in diagnosis and treatment of unknown poisons

OpiatesOpiates

• Respiratory depression

• Cardiovascular depression

• Reduced level consciousness

• Pinpoint pupils

• Pulmonary oedema

• Hypothermia

• (Rapid response to Naloxone)

Common causesCommon causes

• Opiates – heroin, morphine etc

Sympathomimetics /Sympathomimetics / StimulantsStimulants

• Agitation/delusions/paranoia• Fight/Flight response• Tachycardia• Hypertension• Arrhythmias• Dilated pupils• Seizures• Hyperpyrexia

Common causesCommon causes

• Cocaine

• Amphetamines

• Decongestants

• Ecstasy

AnticholinergicAnticholinergic

• Tachycardia• Arrhythmias• Pupils: mid-point or dilated / divergent• Confusion / drowsiness / coma• Seizures• Dry flushed skin• Urine retention• Hypertonia, Hyper-reflexia, Myotonic jerks

Anticholinergic signsAnticholinergic signs

• Hot as a hare

• Blind as a bat

• Dry as a bone

• Red as a beet

• Mad as a hatter

Common causesCommon causes

• Antidepressants-Tricyclics

• Antihistamines

• Atropine

• Antipsychotics

• Antispasmodics

Serotonin SyndromeSerotonin Syndrome

• Similar to anticholinergic syndrome– loss of consciousness: uncommon– sweating and tremor: common

• Agitation• Delirium• Hypertonia / myoclonus• Tachycardia• Tachypnoea

Common CausesCommon Causes

• SSRIs

• MAOIs (Hyperpyrexia / Hypertensive crisis)

CholinergicCholinergic

• Brady/tachycardia

• Confusion/reduced GCS

• Pinpoint pupils

• Seizures

• Weakness

• SLUDGE

• Pulmonary oedema

SLUDGESLUDGE

• S sweating salivation

• L lacrymation

• U urinary frequency urgency

• D diarrhoea

• G gastrointestinal discomfort

• E eyes pinpoint

Common causesCommon causes

• Organophosphates

• Physostigmine

• Some mushrooms

• Nerve agents

Salicylism: AspirinSalicylism: Aspirin

• Impaired hearing

• Tinnitus

• Sweating

• Warm skin

• Hyperventilation

• Cinchonism: Quinine (salicylism + blindness)

MANAGEMENTMANAGEMENT

Management OverviewManagement Overview• History & assessment of vital signs

• ANY concerns: move patient to RESUS

AA BB CC DDDEFGDEFG

• Supportive care (O2, IV Fluids)• Prevent absorption• Increase elimination• Antidotes• PSYCHOLOGICAL ASSESSMENT

HistoryHistory

• What?

• When?

• How much? (mg/kg)

• What else?

• Why?

Collateral historyCollateral history

• Paramedics

• Family / friends

• Notes

• Look in pockets – carefully!!!

Detective workDetective work

• BNF

• Toxbase

• Tablet identification aids: TICTAC

• Poisons advice: NPIS

• Plant identification books

• National teratology information service

Initial examinationInitial examination

• Treat problems as you find them!!

• Airway

• Breathing

• Circulation

• Disability – GCS/AVPU and Pupils

• DON’T EVER FORGET GLUCOSE

ObservationsObservations

• Saturations and respiratory rate

• Pulse and blood pressure

• GCS

• Pupils

• Temperature

• GLUCOSE

InvestigationsInvestigations• All Patients

– Glucose– U&E– Paracetamol & Salicylate

• As indicated– LFT– Co-ag / INR– CK– ABG / VBG– ECG– CXR

• Urine toxicology screen

Reduce absorptionReduce absorption

• Emesis – No role

• Activated charcoal within 1 hour

• Gastric lavage – rarely

• Whole bowel irrigation - rarely

Increase eliminationIncrease elimination

• Urinary alkalinisation

• Multi-dose Activated Charcoal

• Haemodialysis

• Haemoperfusion

• Plasma exchange• Forced alkaline diuresis (no longer recommended)

ParacetamolParacetamol

• Very common: 40% poisons admissions

• Often asymptomatic

• Can be lethal – 200-300 deaths/year

• Check blood level at 4 hours

• Two treatment lines normal and high risk

• Given IV N-acetylcysteine

Paracetamol metabolismParacetamol metabolism

• Metabolised by glucuronidation (60%),

Sulphation (35%) and oxidation (10%)

• Cytochrome p450 produces NAPQI

• NAPQI toxic causes hepatocellular necrosis – irreversible binding

• NAPQI detoxified by conjugation with glutathione

Prescott NomogramPrescott Nomogram

High RiskHigh Risk

• Increased oxidation– Chronic alcohol use– Drugs

• Reduces glutathione stores– Malnutrition– Eating disorders– Chronic liver disease

N-acetylcysteineN-acetylcysteine

• Most effective within 8 hours

• Precursor for glutathione production

• Can cause anaphylactoid reactions

• Consider starting before paracetamol result if:– Presenting > 8 hrs & >150mg/kg taken– Staggered overdose

To treat or not to treat?To treat or not to treat?

Patient 1Patient 1

• 20 year old woman who takes a handful of paracetamol tablets

• No drug history• No alcohol use• Fit and well• Blood level is 80mg/l

No need to treatNo need to treat

• Patient is not high risk• Level at 4 hours is below even the high risk

line

Patient 2Patient 2

• 70 year old man• Takes 20

paracetamol 6 hours before presenting

• Alcoholic• No drug history• Blood level 100mg/l

TreatTreat

• Patient is high risk• Level is above the high risk line• Delayed presentation means need to act fast

Patient 3Patient 3

• 17 year old epileptic• 25 codydramol 2

hours before attendance

• Taking carbamazepine

• Blood level at 4 hours is 120mg/l

TreatTreat

• High risk patient• Level above the high risk line

Patient 4Patient 4

• 35 year old man who presents after taking 24 paracetamol over a period of 24 hours

• No drug history• Fit and well• Blood level 20mg/l

TreatTreat

• Staggered overdoses are difficult• Poisons advice is to give IV acetylcysteine• Levels are not that helpful• Need to monitor Liver function, clotting and

renal function• May need discussing with Liver Unit if

abnormal

PARACETAMOLPARACETAMOL

DEADLY PITFALLSDEADLY PITFALLS• The Prescott Nomogram High Risk Line• Staggered Overdoses• Management of late presentation• Recheck U&E, LFT, INR after N-acetylcysteine

TricyclicsTricyclics

• Antidepressants

• Dangerous: US 60-70% fatal ODs

• UK commonest fatal OD per prescription

• 10% unconscious patient will fit– Treat fits with diazepam/lorazepam

Tricyclic effectsTricyclic effects

• Anticholinergic toxidrome

• The 3 C’s– Coma– Convulsion– Cardiac

Tricyclics cardiac effectsTricyclics cardiac effects

• Quinidine effects lead to arrhythmias• ECG

– Sinus tachycardia– Broad QRS: RBBB– Prolonged QT interval– Right axis deviation

• Severe poisoning – VT, bradycardia, heart block• QRS > 160mS = ↑↑risk of seizures and cardiac

toxicity

TricyclicsTricyclics

• ABG– Hypoxaemia– Metabolic acidosis– Respiratory acidosis

TricyclicsTricyclics

• Management:

– EARLY ITU REFERRAL

– SODIUM BICARBONATE• If hypotension resistant to fluid challenge• Dysrhythmias• Convulsions

– Consider IV Magnesium for resistant dysrhythmia

SalicylateSalicylate

• Salicylism

• Dehydration

• Confusion /coma

• Seizures

• Haemetemesis

• Hypoglycaemia

SalicylateSalicylate

• Metabolic and acid-base disturbance

• Complex

• Respiratory alkalosis – direct stimulation to over breathe

• Metabolic acidosis- acid, impaired normal metabolism, production of lactic acid

• Check ABG / VBG

SalicylateSalicylate

• Severity of ingested dose:• >150 mg/kg: mild• >250 mg/kg: moderate• >500 mg/kg: severe

Salicylate managementSalicylate management

• Tailor treatment to symptoms• Fluids• Reduce absorption:

• Activated charcoal• Gastric lavage (>500 mg/kg and <1 hour)

• Increase elimination:• Urinary alkalinisation

• Cooling• Glucose if hypoglycaemic

Salicylate managementSalicylate management

• <350mg/L: oral fluids

• >350mg/L: urinary alkalinisation

• >700mg/L: haemodialysis

• DISCUSS WITH NPIS

SalicylateSalicylate

DEADLY PITFALLDEADLY PITFALL

• Salicylate levels can continue to rise following admission (10% of cases)– Repeat levels every until peaked

OpiatesOpiates

• Common

• Act on μ-receptors

• Reversible with Naloxone

• Naloxone pure opioid antagonist

• Naloxone• Short half life: may need repeated doses

• Give IV +/- IM & may need IVI

AntidotesAntidotes

• Opiates – naloxone• Paracetamol – acetylcysteine/methionine• Beta-blockers – glucagon• Insulin – glucose• Iron – desferrioxamine• Carbon monoxide – oxygen• Methanol - ethanol• (Benzodiazepines – flumazenil)

Scenario 1Scenario 1

• 20 year old IVDU found by ambulance crew unconscious

• Needle lying by side

• Resp rate 6, Sats 94% on air

• 60bpm BP 100/55

• Responds to pain

What next?What next?

• A – Give naloxone

• B – Check airway

• C – Take history

• D – Give flumazenil

Check airwayCheck airway

• Check airway patent

• Give oxygen

• Call for senior help

• Check glucose

• Give naloxone IM and IV

Scenario 2Scenario 2

• 30 year old woman

• Taken some white tablets 4 hours earlier

• Feels completely well

• Felt depressed after argument with partner

• Usually fit and well

What next?What next?

• A – Start N-Acetylcysteine

• B – Discharge as she is obviously well

• C – Find out what the tablets are

• D –Take blood for paracetamol levels

Take bloodsTake bloods

• Early treatment is essential in paracetamol overdose

• Need to know what her levels are as soon as possible

Scenario 3Scenario 3

• 45 year old man works in local aquarium

• Put right hand into tank and got stung by a lion fish

• Respiratory rate 16 sats 100% on air

• Pulse 100 bpm 160/80

• Fully conscious

• Extreme pain in hand

Lion fishLion fish

What next?What next?

• A – Panic you know nothing about lion fish!

• B – Look on Toxbase

• C – Ring local zoo

• D – Ask a senior who also knows nothing about Lion fish!

ToxbaseToxbase

• Patient needs cardiovascular monitoring• Analgesia• Hand in water as hot as can tolerate• Lion fish toxin is heat labile• Carefully remove spines if present

• Few hours later patient feels much better goes home

SummarySummary

• Common• Approach using:

A B C DA B C DDEFGDEFG

• Consider the toxidromes• Early senior help / Early ITU referral• Supportive Care• Antidotes• Psychological assessment

QuestionsQuestions

?