Poisoning & Environmental Exposures Flashcards
Diphenhydramine
Anti-histamine with anti-cholinergic properties
Anticholinergic excess
Treatment
Dry mouth/dry skin (“dry as a bone”)
Blurry vision/mydriasis (“blind as a bat”)
Hyperthermia from impaired heat dissipation (“hot as a hare”)
Urinary retention (“full as a flask”)
Decreased bowel sounds
Cutaneous vasodilation (“red as a beet”)
Delirium or hallucinations (“mad as a hatter”)
Manage with physostigmine, a cholinesterase inhibitor
Salicylate intoxication
Signs
Treatment
Signs: Tinnitus, nausea/voming, fever
Treatment: Alkalization of urine with sodium bicarbonate
Serotonin syndrome signs
Autonomic hyperactivity (tachycardia, increased bowel sounds, hyperthermia, hypertension)
Mental status changes
Dilated pupils
Neuromuscular findings (clonus, hyperreflexia)
Theophylline overdose
Seizures
Hyperthermia
Cardiac arrhythmias
Tachycardia
Hypotension
Clinical features & management of tricyclic antidepressant overdose
- Clinical presentation
- Management
Benzodiazepines for seizures
Sodium bicarbonate for cardiac toxicity (QRS > 100 ms, ventricular arrhythmias)
Caustic ingestion
- Clinical features
- Management
- Complications
Delayed endoscopy increases perforation risk
Any intervention that may cause vomiting is contraindicated
Approach to childhood lead poisoning
Capillary (fingerstick) blood specifimens are widely used for initial screening but can have false-positive results.
Major toxins produced by combustion (fire) in closed spaces
Hydrogen cyanide (HCN)
Carbon monoxide (CO)
Treatment overview for suspected cyanide poisoning
- Decontamination
- Respiratory support
- Cardiovascular support
Clinical Presentation of Methemogloninemia
- History
- Clinical examination
- Laboratory findings
4. Treatment
- Treatment: Methylene blue
Caused by oxidation of ferrous (Fe2+) to ferric (Fe3+) iron in hemoglobin
Left shift in oxygen dissociation curve
Functional anemia due to reduced oxygen delivery to dissues
Arterial blood gas testing measures unbound oxygen
Frostbite
- Clinical findings
- Managment
Arsenic poisoning
- Mechanism
- Sources
- Manifestations
- Treatment
Diagnosis is confirmed with elevated urine arsenic levels
Sulfhemoglobinemia
Occurs after exposure to an oxidative sulfur-containing medication (e.g., sumatriptan, sulfasalazine).
Patients have a blue-green discoloration of blood and mucocutaneous surfaces
Co-oximetry testing
Analyzes hemoglobin absorption wavelengths and can identify hemoglobin, methemoglobin, and carboyxhemoglobin.
Treatment for lead poisoning
Dimercaprol: Chelating agent
Increases urinary and fecal excretion of lead
Treatment of ethylene glycol or methanol ingestion
Fomepizole
Inhibits alcohol dehydrogenase, preventing metabolism of alcohols to their toxic metabolites
Treatment for beta blocker or calcium channel overdose
Glucagon
Activates adenylate cyclase, increasing intracellular calcium and improving cardiac contractility
Antidote for acetaminophen poisoning
N-acetylcysteine
Restores glutathione, which metabolizes acetaminophen’s toxic metabolite, N-acetyl-p-benzoquinone (NAPQI), to nontoxic metabolites
Treatment for cholinergic toxicity (with acetylcholinesterase inhibitors)
Pralidoxime: reactivates cholinesterase enzyme
Atropine
Complication of circumferential, full-thickness (third degree burns)
Eschar formation that restricts venous and lymphatic drainage, leading to acute compartment syndrome
Iron poisoning
- Clinical features
- Diagnostic findings
- Treatment
Features of benzodiazepine overdose
Slurred speech
Unsteady gait
Drowsiness
Can be distinguished from opioid overdose by lack of severe respiratory depression and lack of pupillary constricton.
Distinguished from alcohol or phenytoin overdose by lack of nystagmus.
Carbon monoxide poisoning versus Cyanide poisoning versus methemoglobinemia
Carbon monoxide is emitted by automobiles, furnaces, charcoal grills.
Cyanide is released by burning of rubber or plastic.
Pinkish-red skin hue for both.
Methemoglobinemia presents with cyanosis and bluish discoloring of skin.
Treatment of iron poisoning
Deferoxamine
Binds ferric iron, allowing urinary excretion
