Untitled Quiz

• Poisoning is exposure to chemicals or agents that negatively affect functioning of an organism.

• Exposure circumstances can be intentional, accidental, environmental, medicinal, or recreational.

• Exposure routes are ingestion, injection, inhalation, or cutaneous exposure.

• Essentially, any substance can be a poison, depending on the dose.

• Poisons include prescription or over-the-counter medicines taken in high doses.

• Other poisons are overdoses of illegal drugs, carbon monoxide, household products, pesticides, indoor/outdoor plants, lead, and mercury.

• Poisoning effects range from short-term illness to brain damage, coma, and death.

• Pediatric exposures are mostly unintentional in preschool age groups because of tendency to put virtually anything in their mouths.

• Most toxic exposures involve only a single substance.

• The vast majority of exposures are through ingestion.

• About 50% of cases involve non-drug substances: cosmetics, personal care items, cleaning solutions, plants, and foreign bodies.

• Pharmaceutical preparations, such as analgesics, topical preparations, cough/cold medications, and vitamins, are commonly reported.

• A second peak in pediatric exposures occurs in adolescence.

• Adolescent age group exposures are primarily intentional from suicide attempts, abuse, or substance misuse.

• These exposures often result in severe toxicity.

Approach to the Poisoned Patient

• The initial approach to a poisoning patient should be the same as for any sick child.
• Begin with stabilization and rapid assessment of the airway, breathing, circulation, and mental status.
• A serum dextrose concentration and naloxone administration should be considered for any patient with an altered mental status.
• A targeted history and physical examination builds the foundation for differential diagnosis, refined by lab testing and diagnostic studies.

Important History

• Obtain an accurate, problem-oriented history.
• Note the child's age: toddler or adolescent?
• Consider cases with acute onset of symptoms without prodrome.
• Consider sudden mental status alteration, multiple system organ dysfunction, or household stress.
• Description of the exposure is important.
• Names (brand, generic, chemical) and specific ingredients, along with their concentrations, can often be obtained from product labels.
• Clarifying where the child was found (garage, kitchen, etc.) can generate a potential toxin list for unknown exposures,.
• Clarify when the ingestion occurred and estimate the amount of substance ingested. In these cases, overestimate the amount ingested.

Past Medical History

• Underlying diseases can make a child more susceptible to a toxin’s effects.
• Concurrent drug therapy can also increase susceptibility because certain drugs may interact with the toxin.
• Psychiatric illness history can make patients prone to substance abuse/misuse, intentional ingestions, and polypharmacy complications.

Social History

• Understanding the child's social environment can identify potential exposure sources: caregivers, visitors, grandparents, recent parties.
• Environmental stressors like a new baby, parent's illness, or financial stress might have contributed to the ingestion.
• Some poisonings occur in the setting of serious neglect or intentional abuse, unfortunately.

Physical Examination

• A targeted physical exam identifies the potential toxin and assesses exposure severity.
• Assess and stabilize airway, breathing, circulation, and mental status.
• Once the airway is secure and the patient is stable from a cardiopulmonary standpoint, a more extensive physical exam helps identify characteristics of specific toxins/toxin classes,.
• Key features of the physical exam include vital signs, mental status, pupils, nystagmus, skin, bowel sounds, and odors.
• These can suggest a toxidrome that then guides differential diagnosis and initial management.
• A toxidrome is a syndrome caused by a dangerous level of toxin often from a drug overdose or systemic infection.

Clinical features to note

• Tachypnoea can be caused by aspirin or carbon monoxide.
• Slowed respiration rates can be caused by opiates or alcohol.
• Hypertension can be caused by Amphetamines or cocaine.
• Hypotension can be caused by tricyclics, opiates, B-blockers, or iron.
• Convulsions can be caused by tricyclics or organophosphates.
• Tachycardia can be caused by Cocaine, antidepressants, or amphetamines.
• Bradycardia can be caused by B-blockers.

Pupil Dilation

• Large pupils can be caused by tricyclics, cocaine, cannabis, or amphetamines.
• Small pupils can be caused by opiates or organophosphates.

Lab Evaluations

• Quantitative blood concentrations are for select intoxications such as salicylates, some anticonvulsants, acetaminophen, iron, digoxin,methanol, lithium, ethylene glycol, carbon monoxide, and lead.
• All intoxicant levels must be interpreted in conjunction with the patient's history.
• Both urine drug-of-abuse screenings and more comprehensive drug screenings vary widely in their ability to detect toxins and generally add little information to the clinical assessment.
• Serum osmolality is only helpful as a surrogate marker for toxic alcohol exposure.
• An electrocardiogram (ECG) is a quick, noninvasive bedside test that can yield important clues to diagnosis and prognosis.
• Abdominal x-rays are most helpful in screening for lead-paint chip presence or other foreign bodies.
• Upper endoscopy may be useful for prognosis after significant caustic ingestions.

Decontamination

• Regardless of the decontamination method used, the intervention's efficacy decreases with time since exposure.

• Decontamination shouldn't be routine for every poisoned patient.

• Begin with removing contaminated clothing and particulate matter, followed by flushing the affected area using tepid water/normal saline.

• Use proper protective gear when performing irrigation.

• A minimum of 10-20 minutes of flushing is recommended for most exposures.

• Some chemicals, alkaline corrosives, may require much longer periods of flushing.

• Dermal decontamination, especially after exposure to adherent or lipophilic agents, should include thorough cleansing with soap and water.

• Water shouldn's be used after exposure to elemental sodium, phosphorus, calcium oxide, and titanium tetrachloride.

• Decontamination for inhalational exposure involves moving the patient to fresh air and giving supplemental oxygen.

Preventing Absorption

• Activated Charcoal (single or multiple doses)

• Cathartics

• Whole Bowel Irrigation

• Enhancing Excretion

• Emesis

• Gastric Lavage

• Diuresis

• Dialysis

• Hemoperfusion

• Gastric lavage involves placing a tube into the stomach to aspirate contents, followed by flushing with aliquots of fluid, usually water or normal saline.

• This used to be done for many years, but objective data do not document or support its clinical efficacy.

• This is particularly true in children, in whom only small-bore tubes can be used.

• Lavage is time-consuming and painful, and can induce bradycardia via a vagal response.

• Can delay administration of more definitive treatment (activated charcoal), and, under the best circumstances, only removes a fraction of gastric contents.

• In most clinical scenarios, the use of gastric lavage is no longer recommended.

Activated Charcoal

• This decreases or prevent the intestinal absorption of drugs and toxins and enhance drug elimination that are already absorbed into the systemic circulation.
• It should be specially prepared to have a very large adsorptive surface area.
• Many, not all, toxins are adsorbed.
• Some toxins, heavy metals like iron and lithium, hydrocarbons, cyanide, and low molecular weight alcohols, are not significantly bound.
• Dose is 10-50 g (≈1 g/kg) administered to a child.
• Airway reflexes must be preserved or protected via endotracheal intubation.
• It should only be considered for phenobarbital, theophylline, phenytoin, carbamazepine, and dapsone poisonings.

Cathartics

• Cathartics (sorbitol, magnesium sulfate, magnesium citrate) may be used in conjunction with activated charcoal to prevent constipation and accelerate evacuation of the charcoal-toxin complex.
• However, they should be used with care in young children and never be used in multiple doses because of risk of dehydration and electrolyte imbalance.

Whole-Bowel Irrigation

• Large volumes are instilled (35 mL/kg/hr in children or 1-2 L/hr in adolescents) of a polyethylene glycol electrolyte solution to "wash out" the entire Gl tract.
• Careful attention should be paid to airway and abdominal exam assessment.
• Should never be given to patients without bowel sounds or signs of obstruction/ileus or without a protected airway.

Emulsion Therapy

• Intralipid Emulsion Therapy is useful for sequestering fat-soluble drugs and decreasing their impact at target organs.

Hydrocarbons

• In determination of risk, low viscosity values (kerosene, gasoline, lighter fluid, turpentine, mineral seal oil, mineral spirits) have the highest risk for aspiration.
• Viscous hydrocarbons (petroleum, lubricating oil, paraffin) have a lower risk.
• A low surface-tension chemical will have high ability to creep or spread.
• For volatility, a more volatile agent is more likely to have adverse central nervous system effects.

Hydrocarbon Clinical Management

• Primary clinical effect is pneumonitis.
• Pathophysiologically, these chemicals interfere with surfactant and directly irritate respiratory epithelium.
• This results in alveolar collapse, bronchospasm, direct damage to the airway epithelium and endothelium, and interstitial pneumonitis. Ultimately leads to ventilation perfusion mismatch, hypoxemia and hypercapnia.

Clinical Presentation of Kerosene Ingestion

• Patient may note burning, nausea, belching, and diarrhea related GIT effects.
• Patient may note cough, tachypnoea, tachycardia, cyanosis, pulmonary crepitations, rhonchi, chocking, gagging and grunting through respiratory effects.
• CXR >6 hrs later may show pulmonary infiltrates or peri-hilar densities, pneumatoceles (2-3 weeks), pleural effusion / pneumothorax and bacterial super-infection.
• Resolution can take 2-7 days.
• Central nervous system effects: lethargy (25% of cases), semi-coma, coma, and convolutions.

Other effects

• Bone marrow toxicity and hemolysis are not particularly common.
• Clinicians must be aware of the possibility of heart rhythm problems (atrial/ventricular fibrillation).
• Also look for hepatic and renal failure.
• Contact of hydrocarbon with skin and mucous membranes may cause variable irritation degrees and bullae formation.

Managing Hydrocarbon exposure

• Remove the child from the source of poisoning and ensure the airway is open and functional.
• Remove any contaminated clothing and soap and water wash the child.
• Perform a pulse oximetry and give supplemental oxygen.
• In severe cases (hypoxia, respiratory distress, lower consciousness), perform an intubation and mechanical ventilation.
• Do avoid gastric lavage.
• Administer Antibiotics and steroids (controversial).
• If there are early symptoms or signs of respiratory problems, admit the patient.

Important Points

• Do not encourage vomiting due to risk of inhalation.
• CXR should be carried before 6 hrs for assessment.
• Steroid/antibiotic use is controversial.

Chronic environmental poisoning

• Lead is one of the most known pollutants.
• Some low to middle-income countries have water/environmental contamination from mining and factories.

Symptoms of Chronic Lead Exposure

• While non-specific, symptoms include behavioral changes, hyperactivity and/or reduced physical activity, developmental milestone delays, lead nephropathy.

• Severe symptoms can include abdominal pain, vomiting, constipation, headache, ataxia, lethargy, seizures and coma.

• In treatment of lead exposire, prevent further exposure to lead.

• Chelation therapy can be useful however the treatment is complicated due to the complexity of lead deposition in bone.