ACUTE POISONING -MANAGEMENT

Ayman M. Kamaly, MDProfessor of Anesthesiology

Ain Shams University

kamaly3@hotmail.com

INTRODUCTION

• Acute poisoning is a common medical emergency in any country.

• The exact incidence of this problem in our country remains uncertain.

For effective management of an acutely poisoned victim, 5 steps are required:

I. Resuscitation and initial stabilizationII. Diagnosis of type of poisonIII. Nonspecific therapyIV. Specific therapyV. Supportive care

I. Resuscitation and Initial Stabilization

Initial management: ABCDs

• Airway• Breathing• Circulation

Lessons from History...

• A young princess ate part of an apple given to her by a wicked witch

• She was found comatose and unresponsive, as if in a deep sleep,

• Airway positioning and mouth to mouth ventilation were performed,

• and she was fully

recovered.

Lessons:

• Best Antidote = Good Supportive Care(Love’s first kiss)

• Airway issues is a still the major cause of morbidity in toxicology as in other aspects of emergency.

Circulation = Plumbing

• Pump working? Inotrope

• Enough volume (is it primed)? Hypovolemia?

IV fluid challenge

• Adequate resistance (no leaks)? Inadequate vascular resistance?

Norepinephrine, phenylephrine

Initial management: ABCDs

Treat problems as you find them!!• Airway,• Breathing,• Circulation,• Drugs, • Decontamination, • Detoxication,• Disability – GCS/AVPU and Pupils,• DON’T EVER FORGET GLUCOSE.

Don’t forget GLUCOSE

“A stroke is never a stroke until it’s had 50 of D50”

• Empiric administration of dextrose??!• Check the blood sugar using a reliable bedside

test• Administer dextrose ONLY if the RBS is <80

mg/dl.

II. Diagnosis of Type of Toxin

• What?• When?• How much? (mg/kg)• What else?• Why?

A) History Be a Detective

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

Look for Clues

B) Examination

Investigations• All Patients

– Glucose– Paracetamol & Salicylate

• As indicated– LFT– RFT, Lytes– Co-ag / INR– CK– ABG / VBG

• Urine toxicology screen

Investigations• Urine toxicology screen

– Pinkish urine --->>> phenothiazine,

– Chocolate colored --->>> met-hemoglobinaemia,

– Oxalate crystals --->>> ethylene glycol,

– Ketonuria (without metab. changes) --->>> Salicylate

Investigations• Abdominal X-Ray (Radiopaque Toxins)

– Chloral hydrate, iodides,

– Heavy metals, iron,

– Sustained release pills,

– Solvents (Chloroform, CCL4)

• Aim:

– Reduce absorption of poison from the gut,

– Increase excretion of absorbed poison.

III. Non-Specific Therapy

1) Emesis

• Syrup of Ipecac• Amount of recovered toxin is highly variable • Effective within ONE hour• Contraindicated:

– Comatose/Convulsing– Ingested corrosive or hydrocarbon*

A. Reducing absorption

2) Gastric Lavage

• Lt Lat Position + head down • to prevent aspiration & ↓ pushing lavage into

duodenum.• If unconscious ETT• Effective within 1-2 hours• Contraindicated:

– Strong corrosive or – Volatile hydrocarbons

3) Activated Charcoal

• Small particle size & enormous surface area,• Bind most drugs & toxins,• Dose: 1 g/kg• Exceptions:

– Iron, Lithium, Metals,– Methanol, Ethanol, Hydrocarbons,– DDT

Activated Charcoal (cont.)

• More effective than Ipecac, Gastric Lavage• First choice for most Over Doses

4) Whole Bowel Irrigation

• Isotonic soln. of Polyethylene glycol (2 L/hr)• Not absorbed from intestine (mechanical

flush)• Good for:

– Iron, Lithium,– Sustained-release pills,– Foreign bodies,– Drug “packets”

1) Forced Alkaline Diuresis• Principle: Renal tubular epith is impermeable toionized (+) molecules. If the urinary pH is changedso as to produce more of ionized form, it is trapped in the tubular fluid & is excreted in the urine.

• Useful in: – Salicylates, – Phenobarbital,– Lithium

B. Increasing Excretion

Forced Alkaline Diuresis (Cont.)

• Method: – D5% - ½ NS + bicarbonate 20-35 mEq/L to produce

a urine output of 3-6 ml/kg/hr & a urine pH 7.5-8.5.

– Diuretics are often needed to maintain high urine flows.

– KCl is added to prevent ↓K+,

• Contraindications: – Shock,– Hypotension, CHF,– Renal failure

2) Multiple-Doses Activated Charcoal• 1 g/kg/1-4 hrs• To maintain intestinal toxin conc. near-zero

(Gastrointestinal Dialysis).• Indicated in toxins with :

– Long ½ life,– Enterohepatic circulation ( Digoxin, Phenobarbitals,

Theophylline),– Sustained-release preparations,– Massive toxin dose to be effectively adsorbed by

single charcoal dose

3) Dialysis (Peritoneal/Hemo)

• For H2O soluble & Low MW compounds.

• Useful in: – Ethanol, Methanol,– Salicylates, – Theophylline, – Ethylene glycol,– Phenobarbital – Lithium

IV. Specific Therapy

• Try to maintain functions of CNS, CVS, Renal, …

• Care for coma, seizures, hypotension, arrhythmias, hypoxia, …

V. Supportive Therapy

• Exposure to toxins could be through routes other than ingestion (Cutaneous, Ocular)

• Antidotes are NOT available for every toxin

• However; when Antidote is Present the effect is Dramatic

• The 1st sample of gastric lavage should be collected in “clean” container (Contamination !!).

• Container should be sealed using a glue paper before sending for toxicological screening.

Legal Aspects

• After sealing Blood & Urine collection tubes and bottles, pt’s information should be written on the labels & affixed @ the juncture between the cap & the bottle.

• POLICE should be informed !!

Clinical Scenarios

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

Prescott Nomogram

Paracetamol metabolism• Metabolised by:

– Glucuronidation (60%),– Sulphation (35%) – Oxidation (10%) by Cytochrome p450

produces NAPQI (toxic hepatocellular necrosis)

• NAPQI detoxified by conjugation with glutathione.

High Risk pt.

• Increased oxidation pathway (enzyme induction)– 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– Other accompanying overdose.

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

after 4 hrs.

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

• High risk patient• Level above the high risk line

Patient 3• 17 year old

epileptic• 25 tab Panadol 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• Level is above the treat-line in context to time• Need to monitor Liver function, clotting and renal

function• May need discussing with Liver Unit if abnormal

26836674 24823314 26840902

Some Famous Historic Poisonings

Thank You .. !!