introduction to the poisoned patient department of emergency medicine the ottawa hospital

59
Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Upload: morgan-holmes

Post on 17-Jan-2016

220 views

Category:

Documents


0 download

TRANSCRIPT

Page 1: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Introduction to the Poisoned Patient

Department of Emergency Medicine

The Ottawa Hospital

Page 2: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Outline

• Directed toxicology history

• Toxidromes

• Cases/Treatment

Page 3: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Toxicology - Objectives-Determine whether poisoning has occurred, the substance involved, how severe the exposure was, how toxic it is likely to become, and the causticity of substance.-Perform supportive care, decontamination or prevention of further absorption, give antidote where indicated, and enhance elimination of the poison.- Discuss special considerations in the management of poisoning with aspirin, acetaminophen, tricyclic antidepressants, and methanol.

Page 4: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Clinical Timeline

History Toxidrome Treatment

Confirm or refute

Reassess

Laboratory

Page 5: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Directed Tox History• When (most NB)• What • How

– How much?

– Method?

• Whose? – Compliance

• Coingestants?– Access

– Specifics

• Self treatment?– Ipecac

– Induced emesis

– Ethanol

• Intent?• Symptoms

Work hard to get it, then be suspect!

Page 6: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Toxidrome

What it is:– a clustering of symptoms and/or signs– consistent with a class of drugs/medications

What it isn’t:– a way to identify a specific substance– a way to discriminate well among

“contradictory agents” until repeated over time

Page 7: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Common Toxidromes

• Narcotic (coma resp depression, miosis)• Anticholinergic (mad as a hatter …)• Cholinergic (DUMBELS)• Sedative/Hypnotic (pupillary rxn spared)• Stimulant or Sympathomimetic• Hallucinogens • Extrapyrimidal• Serotonergic

Page 8: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Anticholinergics

• TCA’s, atropine, scopolamine, antihistamines– Mad as a hatter (delerium)– Hot as a hare (fever)– Blind as a bat (mydriasis)– Dry as bone (dry mucous membrane, urinary retention,

decreased BS)– Red as beet (flushing)– Bowel and bladder lose tone and heart goes on alone)

• Difference with adrenergics =– Bowel sounds present– Diaphoresis

Page 9: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Cholinergics

• Pheostigmine, organophosphtes (insecticides), and nerve gas (DUMBELS)– Diaphoresis, diarrhea, decreased BP

– Urination frequent

– Miosis

– Bronchospasm, bronchorrhea, bradycardia

– Emesis, excitation of skeletal muscle

– Lacrimation

– Salivation / seizures

Page 10: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Sympathomimetics

• Amphetamine, cocaine– Resemble paranoid schizophrenic– CNS stimulation– Seizures– Psychosis– Increased BP, pulse, Temp

Page 11: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Hallucinogens:

• Hallucinations

• May be oriented to time / place / person

• Tachy

• HTN

• mydriasis

Page 12: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Opioids

• Coma

• Resp depression

• Miosis (not with demerol)

Page 13: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Sedatives

• Barbituarates, ethanol, benzo’s, ethanol, GHM (gamma hydroxybutyric acid)– CNS depression– Resp depression– Coma– Pupil rxn usually spared

Page 14: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Extrapyramidal

• chlorpromazine, stemetil, halodol, metocloperamide– Dystonia (occulogyric crisis, laryngospasm,

torticollis)– Akithesia– Parkinson like sx (tremor, ridgidity, akinesia,

postural instability)– Dyskinesia (tic, spasm, chorea, myoclonus)

Page 15: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Seratonergic

• Mimics NMS (neuroleptic malignant syndrome) of increased BP, increased pulse, increased temp, increased resp rate (onset within 24 hours, hyperactive, clonus, hyperreflexic, clonus)

• NMS (due to massive dopamine blockade) (FARMERS)– Fever– Autonomic changes (increased bp, pulse, sweating) / acidosis (rare)– Rigidity of muscles / rhabdomyolyis – Mental status changes (eg. Confusion)– Elevated BP, HR, pulse, RR– Rhabdomysolysis– Seizures– Onset days to weeks

Page 16: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

CaseA 78 yo F presents with agitation and confusion. BP 180/105, P 110 RR 16 T 38.2 C. Physical exam reveals an

acutely agitated pt, pupils 6 mm, CVS/resp normal except tachycardia.

Is a toxidrome present?

What are the treatment priorities?

What tests do you want to order?

Page 17: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Investigations• Serum levels

– acetaminophen (4 hour level)

– ASA

– Ethanol

– ingestion specific (eg phenytoin, digoxin level)

• Electrolytes, BUN/Cr• EKG• Serum osmolarity

Page 18: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

What about a “Tox Screen”?• Urine immunoassays

– lab determines which tests to include on the “screen”

• Often clinically irrelevant– confuse the clinical picture

• positive cocaine in a patient with an opioid toxidrome

• “toxic” TCA level in a cyclobenzaprine (Flexeril) overdose

Treat the patient, not the test!

Page 19: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

CaseA 78 yo F presents with agitation and confusion. BP 180/105, P 110 RR 16 T 38.2 C. Physical exam reveals an

acutely agitated pt, pupils 6 mm, CVS/resp normal except tachycardia.

Is a toxidrome present?

What are the treatment priorities?

What tests do you want to order?

Page 20: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Supportive treatment of the poisoned patient is the

cornerstone of management

Page 21: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

A 20 yo F comes to the ED saying she just took a whole bottle (1.5 grams) of Elavil (amitriptylline). Her vital signs are normal. She is alert and exam is

normal.

Treatment considerations?

Page 22: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

TreatmentElimination:

-Activated Charcoal

-Whole Bowel Irrigation

Removal:

-Gastric Lavage

Antidotes

Page 23: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

TreatmentElimination:

-Activated Charcoal

-Whole Bowel Irrigation

Removal:

-Gastric Lavage

Antidotes

Page 24: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Activated Charcoal• Ingestion < 1 hr

– upto 2 hrs if delayed emptying, bad toxin

• 1 g/kg or 10 g for each gram of OD drug• Ineffective

– Pesticides– Hydrocarbons– Alcohols– Iron– Lithium– Alkali’s / acids (contraindicated)

Page 25: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Activated Charcoal• CX

– Aspiration • Gastric content aspiration worse than charcoal

aspiration

• But a lot worse if dump charcoal into lungs

– Perforation if bowels not moving

Page 26: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Cathartics

• Sorbitol– available premixed with charcoal

• can use for first dose

– contraindicated if < 2 years• electrolyte problems

– Used with charcoal to counteract its constipating effect

Page 27: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

An alert 36 year old M 2 hours post accidental ingestion of antifreeze

Page 28: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

A: Not indicated; 2hrs is too late (esp for liquid) and alcohols bind poorly

An alert 36 year old M 2 hours post accidental ingestion of antifreeze

Page 29: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

A somnolent 45 yo F with ingestion of olanzapine (Zyprexa) and venlafaxine

(Effexor) at an undetermined time.

Page 30: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

A somnolent 45 yo F with ingestion of olanzapine (Zyprexa) and venlafaxine

(Effexor) at an undetermined time.

A: Not indicated; undetermined time (likely greater than 1 hr for toxicity to develop from these agents) and risk of aspiration given altered mental status.

Page 31: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

An intubated 37 yo F 30 min after collapsed after metoprolol OD.

Page 32: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

To Give or Not to Give...

An intubated 37 yo F 30 min after collapsed after metoprolol OD.

A: Indicated; recent ingestion, (very) bad drug and airway is protected.

Page 33: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

TreatmentElimination:

-Activated Charcoal

-Whole Bowel Irrigation

Removal:

-Gastric Lavage

Antidotes

Page 34: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Decontamination

• Gastric Lavage– recent (< 1hr)– Life threatening ingestion– no antidote– not adsorbed by AC– sustained release– concretions– no emesis EasyLav

Page 35: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Gastric Lavage

• Large hose with blunt end (need this for tablets to pass)

• LL decubitus position with pylorus pointing upwards

• Has to have airway protected either intubated of fully conscious

• Have bucket of warm water and bucket on floor

Page 36: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Gastric Lavage

• Give warm water through funnel / tube above pt … Percuss stomach … move tube below level of head to drain into bucket … repeat

• Prevents drug from getting into small intestine as drain directly from stomach

Page 37: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

TreatmentElimination:

-Activated Charcoal

-Whole Bowel Irrigation

Removal:

-Gastric Lavage

-Dialysis

Antidotes

Page 38: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Whole Bowel Irrigation

• Polyethylene glycol (eg. Golytely)– 1-2 L/hr via NGT until clear effluent– Do for 4 to 6 hours until clear effluent via rectal

tube

• SR preps, Lithium, iron, sustained release drugs

• Body packers/stuffers

Page 39: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

A 20 yo F comes to the ED saying she just took a whole bottle (1.5 grams) of Elavil (amitriptylline). Her vital signs are normal. She is alert and exam is

normal.

Treatment considerations?

Page 40: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Tricyclic Antidepressants - Sx

• Block sodium channels• Neuro:

– mental status changes– anticholinergic toxicity– seizures

• Cardiac:– (lethal) arrhythmias– AV blocks– hypotension

• QRS > 120 ms and ‘R” in aVR > 3mm predicts seizures/ arrhythmias

Page 41: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Tricyclic Antidepressants - Mgmt

• Activated Charcoal (no role for dialysis)

• Alkalinization of blood (7.45 – 7.50) with sodium bicarbonate– Abolishes dysrhythmias and improves

hypotension– Use if QRS > 100 msec– Administer as 1 – 2 mEq/kg IV push then 20

mEq / hr drip

Page 42: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Enhanced Elimination

• Diuresis– Alkaline

• 3 amps NaHCO3 in 1 L D5W with 40 mmol KCl at 250 mL/hr

• goal: urine pH 7.5-8

• E.g Salicylates, Phenobarbital

– Neutral• Lithium

Page 43: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Tricyclic Antidepressants - Mgmt

- Seizure mgmt:- avoid dilantin (increases dysrhythmias)- Diazepam/lorazepam/ phenobarbitol

- Hypotension- Crystalloid and alkalinization- Vasopressors if no response

- Dysrhythmias unresponsive to bicarb- Lidocaine- Consider pacemaker insertion for blocks

Page 44: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

A 34 yo M presents 4 hours after ingesting 100 regular ASA pills.

He complains of tinnitus, is vomiting and has an ASA level of 6 mmol/L. His vital signs are BP

132/78 P 85 RR 28 T 37.5° C

Decontamination?

Other treatment considerations?

Page 45: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Commonly Dialysable Drugs

• Isopropanol

• Salicylates

• Theophylline

• Uremia

• Methanol

• Barbiturates

• Lithium

• Ethylene Glycol

Page 46: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Salicylates - Symptoms

• Causes metabolic acidosis .. Initially resp alkalosis as stimulates resp centre

• Mild = ototoxicity (tinnitis, vertigo)

• Severe = CNS stimulation followed by depression (confusion, delerium, seizures_– Cardiac dysrhythmias, noncardiogenic

pulmonary edema, renal failure, hemorrhage

Page 47: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Salicylates – Treatment

• Treatment is not dependant on specific serum level; it is a CLINICAL diagnosis

• Done nomogram USELESS

• Draw levels to ensure declining

Page 48: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Salicylates – Evaluation

• Decontamination with Activated charcoal• Consider gastric lavage if < 60 min• Alkaline diuresis with bicarb increases elimination

of ASA (goal of urine pH 5 – 8)– See TCA OD for bicarb dosing

• Hemodialysis is most effective means– Indications include renal failure, severe cardiac tox,

rising ASA levels despite alkalinization, pulm edema, severe acidbase imbalance

Page 49: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

CaseA 42 yo M presents after ingesting 30 grams of acetaminophen. He is asymptomatic. A serum level 4 hours after ingestion is 1625 mol/L.

Page 50: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

AntidotesAcetaminophen N-acetylcysteine

Atropine Physostigmine

Carbon monoxide oxygen

Cyanide Amyl nitrite + sodium nitrite + sodium thiosulfate

Ethylene glycol /

Methanol

Ethanol / fomepizole

Iron Deferoxamine

Lead EDTA (calcium disodium edetate)

Page 51: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Antidotes

Nitrites Methylene Blue

Organophosphate Atropine

Opiods Naloxone

Isoniazid Pyridoxine

Digoxim Digibind

Benzodiazepines Flumazenil

Page 52: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Acetaminophen

• Delayed hepatoxicity• Consider activated charcoal• Rumack-Matthew nomogram

– predicts toxicity 4 hrs after acute ingestion– No use less than 4 hours before

• N-acetylcysteine antidote– Minimum 300 mg/kg IV over 20 hrs

• Goal of therapy is administration of NAC within 8 hrs of ingestion

Page 53: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital
Page 54: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Methanol

• Found in windshield washing fluid, paint thinners, solvents

• Converted by alcohol dehydrogenase to formaldehyde (liver) to formic acid– Formic acid – toxic product– Causes high anion gap and osmole gap– Affects optic nerve fxn causing papillitis and

retinal edema – “blind drunk”

Page 55: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

High Anion Gap

• C (carbon monoxide, cyanide)• A (Arsenic)• T (toluene)• M (methanol, metformin)• U (uremia)• D (DKA)• P (paraldehyde, phenformin)• I (INH, iron) • L (Lactic acidosis)• E (ethylene glycol (antifreeze), everything • S (salicylates, strychtnine)

Page 56: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Anion and osmole gap

– AG = Na – Cl – HCO3

– Osmole Gap = 2Na + BUN + glucose + ETOH( 1.25)

• Osmole gap causes:– Ethanol, Isopopanol, Methanol, Ethylene glycol,

Acetone, Glycerol, Mannitol, Uremia, Ketocacidosis

• Isopropanol causes high osmole but not anion gap• Peraldehyde and isoniazide cause high AG but not

high osmole gap

Page 57: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Methanol

• 8 hour – 30 hour latent period followed by onset of abdo pain, nausea, vomiting, blurred vision, metabolic acidosis– Often dilated pupil with photophobia

• High anion gap acidosis– Na – Cl – HCO3

• Osmole gap may be high but can be normal– 2Na + BUN + glucose + EtOH (1.25)– Normal is 280 – 295 mosm

Page 58: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

Methanol

• Supportive measures• Consider bicarbonate with severe acidosis• ADH inhibitor

– Fomepizole – inhibits alcohol dehydrogenase– Ethanol (BEER!) – ethanol infusion as alcohol

dehydrogenase preferentially metabolizes ethanol (keep at 22 – 33)

• Hemodialysis– If symptomatic or methanol level > 8 mmol / L – Severe acidosis

Page 59: Introduction to the Poisoned Patient Department of Emergency Medicine The Ottawa Hospital

TOXICOLOGY AXIOMS• The most important aspect of the history is the time

of ingestion and coingestants• The most critical therapy varies with the time course

of the patient’s presentation• No evaluation is complete until repeated over time• Toxidromes can help identify classes of drugs• It is often not important to determine the exact drug

taken within a class• Supportive tx is the cornerstone of tx