Toxicology (main): Difference between revisions
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**Motor response | **Motor response | ||
**DTRs | **DTRs | ||
*Skin Exam - moisture, temp | *Skin Exam - moisture, temp, evidence of injection drug abuse | ||
*Lung Exam | *Lung Exam | ||
*Bowel Sounds | *Bowel Sounds |
Revision as of 14:54, 31 August 2019
Background
Epidemiology
- In 2014, ~2.2million human exposures reported to US poison control centers
- Top 5 substance classes:
- analgesics (11%)
- cosmetics/personal care products (8%)
- household cleaning substances (8%)
- sedatives/hypnotics/antipsychotics (6%)
- antidepressants (4%)
- 1,835 human exposures resulted in death
Autonomic Nervous System Receptors and Their Effects
- Parasympathetic - ACh is transm
- Muscarinic
- receptors in heart, eye, lung, GI, skin and sweat glands
- Bradycardia
- Miosis
- Bronchorrhea / Bronchospasm
- Hyperperistalsis (SLUDGE)
- Sweating
- Vasodilation
- Nicotinic
- receptors in both sympathetic and parasympathetic nervous systems
- fasciculations, flaccid paralysis
- ?Mild bradycardia, hypotension
- Muscarinic
- Sympathetic
- Alpha effects (vessels, eye, skin)
- Mydriasis, hypertension, sweating
- Beta effects (heart, lungs)
- Tachycardia, bronchodilation
- Alpha effects (vessels, eye, skin)
Clinical Features
Toxidrome Chart
Finding | Cholinergic | Anticholinergic | Sympathomimetic | Sympatholytic^ | Sedative/Hypnotic |
Example | Organophosphates | TCAs | Cocaine | Clonidine | ETOH |
Temp | Nl | Nl / ↑ | Nl / ↑ | Nl / ↓ | Nl / ↓ |
RR | Variable | Nl / ↓ | Variable | Nl / ↓ | Nl / ↓ |
HR | Variable | ↑ | ↑ (sig) | Nl / ↓ | Nl / ↓ |
BP | ↑ | ↑ | ↑ | Nl / ↓ | Nl / ↓ |
LOC | Nl / Lethargic | Nl, agitated, psychotic, comatose | Nl, agitated, psychotic | Nl, Lethargic, or Comatose | Nl, Lethargic, or Comatose |
Pupils | Variable | Mydriatic | Mydriatic | Nl / Miotic | |
Motor | Fasciculations, Flacid Paralysis | Nl | Nl / Agitated | Nl | |
Skin | Sweating (sig) | Hot, dry | Sweating | Dry | |
Lungs | Bronchospasm / rhinorrhea | Nl | Nl | Nl | |
Bowel Sounds | Hyperactive (SLUDGE) | ↓ / Absent | Nl / ↓ | Nl / ↓ |
- ^Consider Sympatholytic when looking at Sedative OD or someone who doesn't respond to Narcan
- Withdrawal from substances have the opposite effect
Differential Diagnosis for Specific Signs
Hyperthermia
- Altered Metabolism
- Aspirin (Salicylate) Toxicity
- withdrawal states
- thyroid hormones
- dinitrophenols
- Increased Muscle Activity
- withdrawal, sympathomimetics
- MAOI Toxicity
- PCP, LSD
- Lithium
- Amoxapine
- Serotonin Syndrome
- Impaired Heat Dissipation
- anticholinergics
- antihistamines
- antipsychotics (TCAs)
- Malignant Hyperthermia
- anesthestics
- Neuroleptic Malignant Syndrome
- phenothiazines, Lithium, LevoDopa
Hypothermia
- Exposure
- Ethanol Toxicity
- Sedative hypnotics
- Opioids
- TCAs
- Phenothiazines
- Insulin (Hypoglycemia)
Increased Respiratory Rate
- Direct Stimulation
- Aspirin (Salicylate) Toxicity
- Metabolic Acidosis
- dintirophenol, pentachlorophenol
- hepatorenal failure
- CNS stimulants (cocaine, amphet, theophylline)
- Tissue Hypoxia
Respiratory Depression
- Central Depression
- antipsychotics
- Chlorinated hydrocarbons
- Sedative/Hypnotics (Ethanol Toxicity, glycols)
- Tricyclic (TCA) Toxicity
- Lomitil
- Muscle Failure
- Organophosphates
- Marine Toxins
- Nicotine
- strychnine
- botulinis
- Mojave rattlesnake, Cobra
Bradycardia
PACED
- Propranolol/ beta-blockers, poppies (opiates), propoxyphene,
physostigmine
- Anticholinesterases, antiarrhythmics
- Clonidine, calcium channel blockers
- Ethanol or other alcohols
- Digoxin, digitalis
Seizures
OTIS CAMPBELL
- Organophosphates, oral hypoglycemics
- TCA, theophylline, tramadol
- Isoniazid, Insulin
- Sympathomimetics, salicylates, strychnine
- Camphor, carbon monoxide, cyanide, chlorinated hydrocarbons, cocaine
- Anticholinergics (antihistamines), amphetamines, antidepressants (citalopram, TCAs, buproprion)
- Methanol, Methylxanthines (theophylline, caffeine), MAOI
- PCP, propranolol
- Benzo withdrawal, buproprion, botanicals (hemlock, nicotine), GHB
- EtOH withdrawal, ethylene glycol
- Lead, lithium
- Lidocaine, lindane (pesticide, scabies)
Evaluation
Toxicological Exam
- All vital signs (Temp, RR, HR, BP)
- Neurologic exam
- Level of consciousness
- Pupillary exam
- Motor response
- DTRs
- Skin Exam - moisture, temp, evidence of injection drug abuse
- Lung Exam
- Bowel Sounds
- ECG (ie. look for QT prolongation, QRS prolongation, etc)
Management
- Depends on agent
- See antidotes
- "Coma cocktail" when suspecting toxic ingestion (mnemonic = "DONT")
- Dextrose (50mg IV)
- Oxygen
- Naloxone (0.2-0.4mg IV/IM, repeat dose 1-2mg)
- Empiric opioid ingestion treatment
- Thiamine (50-100mg)
- Treat or avoid Wernicke encephalopathy
- Though some suggest giving thiamine prior to dextrose, do NOT let this delay treatment of hypoglycemia!
- Case reports of dextrose precipitating Wernicke's involved thiamine-deficient patients receiving prolonged course of IV glucose, NOT with single bolus[1][2]
Disposition
- Depends on agent