ACUTE POISONING

Major C J Porter RAMC Army Medical Directorate Emergency Medicine Registrar Bristol Royal Infirmary

Outline of lecture

• Epidemiology • Toxidromes • History, examination and detective work • General management • Specific management • Antidotes • Scenarios

EPIDEMIOLOGY

• 4000 UK deaths per year (1/3 CO) • Most deaths outside hospital • 100,000 Hospital admissions (12%) • Not just overdoses: Illicit drugs, Alcohol

EPIDEMIOLOGY

• Self poisoning: • F>M • 1/3 >one drug • Taken with alcohol: F: 40% M: 60% • Repeated self-poisoning: 11% of admissions

SUICIDE

• 2% of male deaths • 1% of female deaths • Method: • Female: • Male: Poisoning 40% Gas / Hanging / Suffocation • Self-harm parasuicide: • 1% dead after 12 months • 3-5% dead after 5-10 years

Toxidromes

• Patterns of signs and symptoms • Useful to help in diagnosis and treatment of unknown poisons

Opiates

• Respiratory depression • Cardiovascular depression • Reduced level consciousness • Pinpoint pupils • Pulmonary oedema • Hypothermia • (Rapid response to Naloxone)

Common causes

• Opiates – heroin, morphine etc

Sympathomimetics / Stimulants

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

Common causes

• Cocaine • Amphetamines • Decongestants • Ecstasy

Anticholinergic

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

Anticholinergic signs

• Hot as a hare • Blind as a bat • Dry as a bone • Red as a beet • Mad as a hatter

Common causes

• Antidepressants-

Tricyclics

• Antihistamines • Atropine • Antipsychotics • Antispasmodics

Serotonin Syndrome

• Similar to anticholinergic syndrome – loss of consciousness: – sweating and tremor: uncommon common • Agitation • Delirium • Hypertonia / myoclonus • Tachycardia • Tachypnoea

Common Causes

• SSRIs • MAOIs (Hyperpyrexia / Hypertensive crisis)

Cholinergic

• Brady/tachycardia • Confusion/reduced GCS • Pinpoint pupils • Seizures • Weakness • SLUDGE • Pulmonary oedema

SLUDGE

• • • • • •

S L U D G E

sweating salivation lacrymation urinary frequency diarrhoea urgency gastrointestinal discomfort eyes pinpoint

Common causes

• Organophosphates • Physostigmine • Some mushrooms • Nerve agents

Salicylism: Aspirin

• Impaired hearing • Tinnitus • Sweating • Warm skin • Hyperventilation • Cinchonism: Quinine (salicylism + blindness)

MANAGEMENT

Management Overview

• History & assessment of vital signs • ANY concerns: move patient to RESUS

A B C DEFG D

• Supportive care (O 2 , IV Fluids) • Prevent absorption • • Increase elimination • Antidotes

PSYCHOLOGICAL ASSESSMENT

History

• What?

• When?

• How much? (mg/kg) • What else?

• Why?

Collateral history

• Paramedics • Family / friends • Notes • Look in pockets – carefully!!!

Detective work

• BNF • Toxbase • Tablet identification aids: TICTAC • Poisons advice: NPIS • Plant identification books • National teratology information service

Initial examination

• • • • • • Treat problems as you find them!!

A

irway

B C

reathing irculation

D

isability – GCS/AVPU and Pupils

D

ON’T

E

VER

F

ORGET

G

LUCOSE

Observations

• Saturations and respiratory rate • Pulse and blood pressure • GCS • Pupils • Temperature • GLUCOSE

Investigations

•

All Patients

–

Glucose

– –

U&E Paracetamol & Salicylate

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

Reduce absorption

• Emesis – No role • Activated charcoal within 1 hour • Gastric lavage – rarely • Whole bowel irrigation - rarely

Increase elimination

• Urinary alkalinisation • Multi-dose Activated Charcoal • Haemodialysis • Haemoperfusion • Plasma exchange • Forced alkaline diuresis (no longer recommended)

Paracetamol

• 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 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 Nomogram

High Risk

• Increased oxidation – Chronic alcohol use – Drugs • Reduces glutathione stores – Malnutrition – Eating disorders – Chronic liver disease

N-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?

Patient 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 treat

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

Patient 2

• 70 year old man • Takes 20 paracetamol 6 hours before presenting • Alcoholic • No drug history • Blood level 100mg/l

Treat

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

Patient 3

• 17 year old epileptic • 25 codydramol 2 hours before attendance • Taking carbamazepine • Blood level at 4 hours is 120mg/l

Treat

• High risk patient • Level above the high risk line

Patient 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

Treat

• 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

PARACETAMOL

DEADLY PITFALLS

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

Tricyclics

• Antidepressants • Dangerous: US 60-70% fatal ODs • UK commonest fatal OD per prescription • 10% unconscious patient will fit – Treat fits with diazepam/lorazepam

Tricyclic effects

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

Tricyclics 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

Tricyclics

• ABG – Hypoxaemia – Metabolic acidosis – Respiratory acidosis

Tricyclics

• Management: – EARLY ITU REFERRAL – SODIUM BICARBONATE • If hypotension resistant to fluid challenge • Dysrhythmias • Convulsions – Consider IV Magnesium for resistant dysrhythmia

Salicylate

• Salicylism • Dehydration • Confusion /coma • Seizures • Haemetemesis • Hypoglycaemia

Salicylate

• 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

Salicylate

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

Salicylate 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 management

• <350mg/L: • >350mg/L: oral fluids urinary alkalinisation • >700mg/L: haemodialysis • DISCUSS WITH NPIS

Salicylate

DEADLY PITFALL

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

Opiates

• 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

Antidotes

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

Scenario 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?

• A – Give naloxone • B – Check airway • C – Take history • D – Give flumazenil

Check airway

• Check airway patent • Give oxygen • Call for senior help • Check glucose • Give naloxone IM and IV

Scenario 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?

• 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 bloods

• Early treatment is essential in paracetamol overdose • Need to know what her levels are as soon as possible

Scenario 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 fish

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!

Toxbase

• 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

Summary

• Common • Approach using:

A B C D DEFG

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

Questions

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