HIGHLIGHTS IN PEDIATRICS TOXICOLOGYDr. Manal Al MaskatiOct, 2011 - Kuwait

OBJECTIVES

Few words about poisoning in Pediatrics.

Key points in poisoning history and physical

examination.

Some important Toxidromes.

Common cases of poisoning in Pediatric age

group.

INTRODUCTION

Poisonings too common in pediatric world.

Around 6,000,000 children ingest potentially toxic substance each year nationwide.

Most frequently in children ages 1-5 years old.

Most common exposures are substances found around the house (makeup, household chemicals, over the counter medicines, and houseplants).

Substances either nontoxic or, if toxic, in insufficient amounts to cause significant problems.

Second peak of exposures in adolescent population, most are suicide attempts.

Drug or Poison Potentially Lethal Dose In 10 kg Child

Camphor 1 teaspoon of 20% oil

Chloroquine 1 tablet (500 mg)

Codeine 3 tablets (60 mg each)

Desipramine 2 tablets (75 mg each)

Hydrocarbons (e.g. gasoline)

One swallow (if aspirated)

Oral Hypoglycemics 2 Glyburide tablets (5mg each)

Imipramine 1 tablet (150 mg)

Iron 10 tablets (Full Adult Strength)

Lindane 2 teaspoons

Methyl Salicylate Less that 1 teaspoon of Oil of Wintergreen

Theophylline 1 tablet (500 mg)

Verapamil 1 tablet (240 mg)

HISTORY

Three key questions in all poisoning cases:

1) WHAT substance(s) was ingested?

2) WHEN did the ingestion occur?

3) HOW MUCH was ingested?

HISTORY Answers to questions will provide valuable

information about:

a) Severity of the ingestion.

b) Potential benefits/efficacy of GI

decontamination.

c) Whether or not therapeutic interventions

necessary.

d) Accurate interpretation of specific drug levels.

e) Disposition of the patient.

TOXICOLOGIC PHYSICAL EXAMINATIONa) Eyes: pupillary size, symmetry and response to light

presence of nystagmus (vertical or horizontal).

b) Oropharynx: moist or dry mucus membranes, presence/absence of the gag reflex, presence of any particular or distinctive odors.

c) Abdomen: presence/absence and quality of bowel sounds.

d) Skin: warm/dry, warm/sweaty or cool.

e) Neurologic: level of consciousness and mental status, presence of tremors, seizures or other movement disorders, presence/absence and quality of deep tendon reflexes.

TOXIDROMES Refer to specific constellation of signs and symptoms

specific class or type of toxic substance.

1. Anticholinergics (atropine, antihistamines, cyclic antidepressants):

Tachycardia, hypertension, tachypnea (red as a beet).

Mydriasis (blind as a bat).

Agitation, hallucinations/delirium, seizures, hypoactive bowel sounds( mad as a hatter).

Warm/dry skin, dry mouth (hot as a hare ,dry as a bone).

TOXIDROMES 2. Sympathomimetics (cocaine,

amphetamines, PCP, decongestants, beta-

agonists, theophylline):

Tachycardia, hypertension, tachypnea.

Mydriasis.

Agitation, hallucinations, delirium, seizures,

hypoactive bowel sounds.

Warm/sweaty skin.

TOXIDROMES

3.Cholinergics (organophosphate and

carbamate insecticides):

"D-U-M-B3-E-L-S"

Defecation, Urinary incontinence, Miosis.

Bradycardia/Bronchospasm/Bronchorrhea.

Emesis, Lacrimation, Salivation.

TOXIDROMES 4. Opioids (codeine, morphine, meperidine, heroin):

Bradycardia, hypotension, bradypnea.

Hypothermia, hyporeflexia, pinpoint pupils.

5.Sedative-hypnotics (ethanol, benzodiazepines,

barbiturates):

Bradycardia, hypotension, bradypnea.

Hypothermia, hyporeflexia, miosis.

PYRAMID OF TOXICOLOGY

A two year olds brought to the Pediatric Emergency Department by his mother following an ingestion of 20-22 cyproheptadine HCL tablets (4mg Periactin) 1-1.5 hours prior to presentation. According to his mother, the patient was acting "bizarre".

VS: BP:130/70 P :160 T :98.4

Skin: Warm, dry, not flushed

Neck: Supple

Lungs: CTAB

Heart: Tachycardic, otherwise WNL

Abdomen: soft, NT

Neurologic: Delerious. Patient grasping objects on the floor that were not present Unable to recognize mother, gait ataxic. DTR's normal, no focal findings.

 

CASE 1

ANTIHISTAMINE TOXICITY (ANTICHOLINERGIC TOXIDROME)Management

ABC's + supportive care.

Sedation with benzodiazepines.

Give false positive tricyclic immunoassay on

urine screen hamper accurate diagnosis.

Physostigmine not indicated unless

patient's condition deteriorated.

If hemodynamically stable, likely to respond

well to sedation.

A three year-old male is brought to the Emergency Department in severe respiratory distress. The mother states that she was polishing her dining room table and left to answer the phone. She subsequently found he child several minutes later drenched in the furniture polish solution. The child was noted to be coughing violently, and was anxious and irritable.

VS: BP :100/60 P :120 RR :30 T :101.2 rectally.

Gen: Anxious, dyspneic, crying infant, coughing violently. Mild cyanosis noted during coughing episodes. Use of accessory muscles and nasal flaring noted. Kerosene-like odor noted on patient's breath.

Lungs: Diffuse crackles bilaterally.

Heart: Tachycardia.

Abd: soft, NT.

Neuro: Unable to obtain adequate exam due to poor cooperation

CASE 2

HYDROCARBON ASPIRATIONManagement Most hydrocarbon ingestions of small volume. ABC's to prevent further aspiration, may need

intubation for airway protection and /or progressive respiratory distress.

Skin decontamination is needed, by removing his clothing and washing with gentle soap and water.

Observe for signs of pneumonia , aspiration cause aseptic chemical pneumonitis does not require antibiotics.

Secondary bacterial pneumonia may need treatment Prophylactic antibiotics NOT indicated.

Steroids also NOT indicated. Supportive treatment with oxygen and

bronchodilators to counteract bronchospasm.

Common CompoundsRisk of

Systemic Toxicity

Risk of Aspirati

onTreatment

No Systemic Toxicity, High Viscosity (Petrolatum Jelly, motor oil)

Low Low None

No Systemic Toxicity, Low Viscosity (Gasoline, kerosene, mineral seal oil, petroleum ether)

Low High

Observe for pneumonia;

do not empty stomach

Unknown of Uncertain Systemic Toxicity (Turpentine, pine oil)

Uncertain High

Observe for pneumonia,

Empty stomach if

ingestion is > 2 mL/kg

Systemic Toxins (Camphor, phenol, halogenated or aromatic compounds)

High High

Observe for pneumonia;

perform gastric

lavage or give AC or do

both

A 50 kg 14 year old female is brought to the Emergency Department in a comatose state. History, as obtained from the distraught parents, reveals that their daughter was very upset recently following the termination of her relationship with her closest friend. The child was found in a lethargic state when the parents returned home from the theater. An empty bottle of Darvocet N-100 was found in the bedroom near the patient. The mother confirms that the medication was prescribed by her family physician for back pain, and the prescription for 100 tablets had been filled one week ago. The parents last saw the patient approximately 5 hours ago.

VS: BP: 80/40 P: 110 R :8 T :98.6 rectally

Gen: Comatose female, responsive only to deep sternal pressure, vomitus on clothing, diaphoretic.

HEENT: Pupils equal at 3mm bilaterally, sluggish.

Lungs: CTAB

Heart: WNL

Abdomen: soft, NT

Neurologic: Absent DTR's

CASE 3

ACETAMINOPHEN TOXICITYOPIOID TOXICITY Darvocet N-100 is a combination analgesic that

contains propoxyphene, a synthetic opioid, and

650mg of acetaminophen.

Synthetic opioids that do not cause significant

miosis (others Demerol and Dextromethorphan)

Many of synthetic opioids do not show up on

routine urine tox screens.

This scenario carries high possibility of additional

unknown coingestants intentional

overdoses often polydrug ingestions.

ACETAMINOPHEN TOXICITYOPIOID TOXICITY

Management

Close attention to ABC's.

Intubation if there risk of aspiration.

For opioid toxicity:

Naloxone (Narcan) to be given at initial dose of 2mg.

Further doses given until adequate effect achieved.

Naloxone provide rapid (1-2 minutes) reversal of symptoms.

Due to short duration of naloxone action (60 minutes), re-dosing will likely be necessary ,if opioid symptoms persist.

Lack of response to narcan might point to coingestion of another CNS depressant (benzodiazepines or barbiturates).

ACETAMINOPHEN TOXICITYOPIOID TOXICITY For acetaminophen toxicity APAP level should be sent. 4 hour post ingestion level key in

determining need for treatment. If level is toxic based on nomogram ,treatment

with NAC should be initiated. If level is subtoxic, then to be repeated within

4 hours to confirm it . Initial loading dose of NAC within 8 hrs of

ingestion, good effect if given within 24 hrs of ingestion.

NAC Loading dose 140 mg, followed by 70 mg q4h X 17 doses.

Rumack-Matthew Nomogram

A 15 year old female is brought to the Emergency Department in a confused state by her sister. Following an argument, the patient ingested an unknown amount of medication during the early morning hours. Her sister who was, awakened in the morning to find the patient mumbling incoherently. She brought her to the Emergency Department and quickly left. The patient herself can give no additional history.

VS: BP:70/50 P:120 R:32 T:102.6

GEN: Disoriented, somewhat restless female

HEENT: NCAT, TM's clear bilat., Pt c/o "noise in her ears", PERRLA, Pt. complains of blurred vision.

Lungs: Crackles 2/3 of the way up bilat.

Heart: Tachycardia, otherwise WNL

Abd: 2+ Mid-epigastric tenderness with diminished bowel sound

Skin: Warm and moist

CASE 4

Sodium: 148Potassium: 3.2Chloride: 101Bicarbonate: 13ABG on Room AirpH: 7.21pCO2: 10pO2: 80UrinalysisU/O over 1st hour: 5ccSpecific Gravity: 1.029 with microscopic hematuriaRadiographicChest X-Ray: Bilateral hilar infiltrates

LAB WORK

SALICYLATE TOXICITY Elevated anion gap metabolic acidosis (AG=34). A combination of primary AG metabolic acidosis +

primary respiratory alkalosis highly suggestive of salicylate poisoning.

A serum salicylate level > 60, indicates major exposure.

Level > 100, indicates severe poisoning. Mental status + acid/base status more important

than serum concentration. Bedside, quick urine test ferric chloride

test. Presence of salicylates purple color change.

Click icon to add picture

10% Ferric Chloride Test

MANAGEMENT ABC's.

Activated charcoal should be administered.

Bicarbonate, both to correct the acidemia, and alkalinize

the urine facilitate excretion of salicylates.

Important to maintain serum potassium in normal range

hypokalemia hamper efforts to alkalinize the urine.

Dialysis to be considered for refractive acidosis or

severe hypokelemia.

TRICYCLIC ANTIDEPRESSANTS

Significant source of poisonings.

Toxic effects of TCA’s mediated through

anticholinergic, alpha1 blockade, and quinidine-like Na

channel blockade effects.

TCA’s have low therapeutic to toxic ratio, doses < 10

times therapeutic sufficient to cause toxicity.

Symptoms appear rapidly (within 1 hr of ingestion).

Asymptomatic person for 6 hrs post ingestion unlikely

to develop life-threatening events.

Mechanism Cardiovascular Effects CNS Effects Anticholinergic

Tachycardia Hypertension

Hyperthermia Agitation Delerium Coma

Alpha1 Blockade

Peripheral Vasodilation Flushing Hypotension (tends to predominate over HTN)

 

Na Channel Blockade

Membrane Depression Conduction Disturbances Prolonged PR, QRS Arrhythmias (tachy, VF)

Seizures (may be related to serotonin or norepinephrine mediated effects) 

 

DIAGNOSIS Urine screens can detect many of TCA’s, but a

negative screen doesn’t rule out exposure.

ECG key element to diagnose TCA toxicity.

QRS prolongation + seizures + lethargy or coma ,

highly suggestive of TCA poisoning.

Degree of QRS prolongation severity of CNS +

cardiovascular toxicity.

QRS >0.10 associated with seizures and >0.16

associated with arrhythmias.

MANAGEMENT ABC’s Activated charcoal. Unlike pure anticholinergic toxicity, physostigmine

should NOT be used  in TCA overdose worsen seizures + conduction disturbances + increased risk for asystole.

Most important therapy for TCA overdose sodium bicarbonate, QRS prolongation or hypotension.

Initial dose 1 mEq/kg, repeated as boluses to maintain QRS < 0.10.

 Asymptomatic pts monitored for at least 6 hours, symptomatics should be admitted to ICU for at least 24 hours.

BETA BLOCKERSCALCIUM CHANNEL BLOCKERS Beta Blockers

Have negative inotropic + chronotropic effects.

In toxic doses, myocardial depressant effects

predominate (hypertension, ventricular

arrhythmias).

Calcium Channel Blockers

Have negative inotropic + chronotropic effects ,

and/or vasodilation, depends on site of action.

Site of Action

Verapimil Diltiazem Dihydropyridines

Vascular Smooth Muscle

+ ++ +++

Cardiac +++ ++ +

Site of Action

MANIFESTATIONS Toxic doses for both classes varies from agent to

agent.

Both beta blockers and calcium channel blockers have very small therapeutic to toxic ratio.

Signs of toxicity within therapeutic range.

Most common features of overdose of both classes hypotension + bradycardia.

ECG's show simply sinus bradycardia, with vaiable PR prolongation.

Beta blockers QRS prolongation, but calcium channel blockers not.

MANIFESTATIONS

MANAGEMENT ABC’s Activated charcoal . Gastric lavage for significant

ingestions( within 1/2 -1 hr of ingestion). Sustained release preparations may need

whole bowel irrigation. No place for dialysis. Focused Therapy -- Beta Blockers Glucagon is antidote. Has positive inotropic

+ chronotropic. Given as bolus followed by continuous

infusion. Epinephrine also effective. QRS prolongation treated with sodium

bicarbonate.

MANAGEMENT Focused Therapy -- Calcium Channel

Blockers Calcium is antidote, helps to overcome the

blockade of calcium channels. Given either as calcium chloride or calcium

gluconate, repeated as needed. Calcium gluconate preferable (tissue

damage with calcium chloride) 30 mL of calcium gluconate approximately 1 gram of calcium.

Leads to rapid improvement in contractility, but no effect on conduction disturbances, sinus node depression or peripheral vasodilation.

Glucagon and epinephrine beneficial in treating severe hypotension and/or bradycardia.

TAKE HOME MESSAGE

Prevention is always better than treatment.

As early as the diagnosis and intervention as

better as the results.

Detailed history + Thorough examination +

Reliable source + Little knowledge about

toxicology Successful management.

Discussion