Toxicology Part 1: Approach to Ingestions



Toxicology Part 1: Approach to Ingestions


Shauna Jain



Introduction



  • Young children are at risk for accidental poisonings


  • Adolescents have higher morbidity and mortality because large amounts ingested and maybe multiple ingestants particularly in suicide attempts


  • Acetaminophen is the most common ingestion


  • Tricyclic antidepressants are the most common fatal ingestion








Table 55.1 Epidemiology






Children < 6 years ingest substances in small quantities. Most commonly ingest:




  • Cleaning products



  • Analgesics (acetaminophen most common)



  • Personal care products/cosmetics



  • Cough and cold preparations



  • Plants



  • Topical agents



  • Pesticides, hydrocarbons


Children > 6 years ingest toxins commonly involved in fatalities:




  • Analgesics



  • Antidepressants



  • Cleaning products



  • Hydrocarbons and pesticides



  • Minerals (iron most common fatal ingestion)


Toxins associated with adolescent fatalities:



  • Analgesics


  • Antidepressants


  • Sedatives, hypnotics, psychotics


  • Street drugs (especially stimulants)


  • Cardiac medications


  • Toxic alcohols



Approach to a Toxic Ingestion



  • ABCDs of toxicology:



    • Stabilize: Airway, Breathing, Circulation, Disability/dextrose


    • Consider: Decontamination/elimination/antidote


  • Complete history including amount and timing of ingestion, possibility of co-ingestants and significant past medical history


  • Key physical exam findings: vitals and evidence of toxidrome (level of consciousness, pupils, skin, bowel/bladder abnormalities)


  • Key laboratory tests: glucose, electrolytes, anion gap, osmolar gap, CBC, ECG, U/A, toxicology screen, drug level


  • Call poison control, consult Poisindex® or toxicologist for advice


The Toxicologic Exam


Toxidromes



  • May not be helpful in the face of multiple ingestions


  • All signs and symptoms may not be present in every toxidrome


  • Considerable overlap of all toxidromes









Table 55.2 Toxidromes


















Sympathomimetics




  • Fight or flight response



  • Hypertension, tachycardia, tachypnea, hyperthermia, diaphoresis, mydriasis, altered mental status



  • Risks: rhabdomyolysis, myocardial infarction, stroke



  • Management: benzodiazepines, cooling



  • Toxins: cocaine, PCP, XTC, amphetamines


Anticholinergics




  • Similar to sympathomimetic toxidrome except skin is dry



  • Tachycardia, hyperthermia, dry, hot flushed skin, mydriasis, altered mental status, urine and stool retention



  • Hot as a hare, dry as a bone, red as a beet, blind as a bat, mad as a hatter, plugged as a pig



  • Risks: arrhythmias, seizures, rhabdomyolysis



  • Toxins: TCA, jimsonweed, antihistamines, phenothiazines



  • Treatment: NaHCO3 for TCA


Cholinergics




  • Secretions from all sites



  • Clinical findings include: SLUDGE Salivation, small pupils, Lacrimation, Urination, Diarrhea, diaphoresis, GI cramps, Emesis And the B‘s: Bradycardia, Bronchorrhea, Bronchoconstriction



  • Toxin: organophosphate



  • Management:


    ○ Protective clothing


    ○ Decontaminate patient


    ○ Supportive treatment


    ○ Atropine, pralidoxime


Opioids




  • Depression of pulse, blood pressure, respiratory drive, miosis



  • Cause of death is respiratory arrest, risk of pulmonary edema



  • Treatment: naloxone, supportive care



  • Toxins: morphine, codeine


Sedatives




  • Depression of blood pressure, pulse, respiratory rate



  • Benzodiazepine clinical picture is of depressed mental status with normal vital signs



  • Treatment: supportive, flumazenil in some benzodiazepine cases but increased risk of seizures; contraindicated in multidrug ingestion










Table 55.3 Clues to the Toxins


















































































































Pupils and toxins


Miosis




Cholinergics, clonidine




Opiates, organophosphates




Phenothiazines, pilocarpine




Sedative-hypnotics



Mydriasis




Antihistamines




Anticholinergics




Antidepressants




Sympathomimetics


Skin findings and toxins


Diaphoresis (SOAP)



Sympathomimetics




Organophosphates




ASA




PCP



Red skin: carbon monoxide



Blue skin: methemoglobinemia


Bradycardia/hypotension and toxins


Antihypertensives:



β-blockers and Ca channel blockers




Digoxin, narcotics


Seizures and toxins


(OTIS CAMPBELL)



Organophosphates



Tricyclic antidepressants



Isoniazid



Sympathomimetics



Camphor



Amphetamines



Methylxanthines



PCP, phenol, propanolol



Benzodiazepine withdrawal



Ethanol withdrawal



Lithium



Lidocaine, lead, lindane

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Jun 22, 2016 | Posted by in EMERGENCY MEDICINE | Comments Off on Toxicology Part 1: Approach to Ingestions

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