Toxicology Flashcards
Anticholinergic Syndromes
i.e. Atropine overdose
Signs:
-Tachycardia
-Dry flushed hot skin
-elevated temp
-urinary retention
-agitated delirium
Causes:
-Atropine
-scopolamine
-antihistamines
-anti-parkinsons
-anti-psychotics
Tx: Physostigmine
Sympathomimetic Syndromes
i.e. Cocaine
Signs:
-Tachycardia
-Hypertension
-Seizures
-Increased temp
-mydriasis(pupil dilation)
-Delirium
-Paranoia
Causes:
- Cocaine
- amphetamines
-OTC decongestants
-caffiene
-thophylline
Tx: benzodiazepines for seizures,
-Lidocaine for Tachycardia and v fib
Opiates
i.e. Heroin
Signs
-Hypotension
-Bradycardia
-coma
-respiratory depression
-miosis, pupil constrict
-hyporeflexia
-CNS depression
causes:
-Narcotics
Tx: Naloxone (narcan)
- symptomatic
Non-opiates
i.e. Alcohol
Signs:
Same as opiates
causes:
-Barbituates
-Benzodiazepines
-other sedatives
-ethanol
Tx: Flumazenil for benzodiazepine
-IV saline for ethanol
-symptomatic tx
Cholinergic Syndromes
i.e. Insecticides, Nerve agents
Signs:
-confusion
-weakness, paralysis
- CNS depression
- Miosis
-SLUD
Causes:
-Organophosphates
-carbamates
-physostigmine (AchE inhibitor)
-insecticides
Tx: Cholinergic Antagonist: Atropine
-Pralidoxome: (organophosphates only)
Non-specific Tx
Determine nature of poison first (lab test, poison control,etc.)
-Activated Charcoal, nonspecific chelator, limits absorption if agent isn’t fast absorbing. only effective up to 4 hours after poisoning.
-Gastric lavage-for caustic liquids ingestion
-Syrup of ipecac-vomit inducer, rarely used
-whole bowel irrigation Poly ethylene glycol in balanced electrolyte solution
(for Fe, Li)
Insecticides
-Organophosphates
-Chlorinated Insecticides
-Pyrethrins
Organophosphates
AchE inhibitors:
Irreversible:
Organophosphates
-VX nerve agent
- methyl parathion
(2-PAM can “reverse”)
Reversible: Carbamates
Signs:
-Headaches, nausea, dizzy
-cholinergic complaints, SLUD
Mechanism:
Extreme toxic, diaphragm muscle paralysis, respiratory failure,
-CNS depression respiratory centers, bronchoconstriction
Tx:
-Atropine for both
-Pralidoxome (2-PAM) for organophosphates only
Chlorinated Insecticides
DDT, methoxychlor, chlordane
can accumulate in food
DDT ok in africa
Less tox than AchE Inhibitors (poor absorption)
MOA: inhibit VG Na channels -seizures
signs: seizures, weakness, numbness, twitches, tremors
Tx:
-Activated charcoal
-gastric lavage
-DO NOT induce vomiting (risk seizure onset)
-Anticonvulsants (phenobarbital, diazepam) slow infusion for seizures
Pyrethrins
from chrysanthomum plant, for tx of parasite in farm animals
rapid metabolism in humans
-low toxicity
signs:
-bronchospasm
-skin burning
-irritant
seizures or coma if large amounts (200-500mL concen.)
MOA:Inhibit VG Na channels
Tx: Activated Charcoal
- NO vomitting
give o2 and bronchodilator
Alcohols
-Methanol
-Ethylene Glycol
-Diethylene Glycol
Methanol
Wiper Fluid, pain removers, hand sanitizer
Signs:
-CNS depression like ethanol
Toxic metabolites: Formaldehyde and Formate
-cause blindness and metabolic acidosis
Tx: ADH Inhibitors (or ethanol outcompete)
- Fomepizole
-Na bicarbinate IV
Ethylene Glycol
Antifreeze
metabolized to oxalic acid
-hypocalcemic tetany
-oxalic acidurea (crystals in urine)
-CNS depression
Tx: Ca IV
-ADH inhibitor
-Fomepizole
-pyridoxine, folate, thiamine
Diethylene Glycol
Toothpaste in china
subtitute for propylene glycol
signs:
-Anuric renal failure
-Hepatitis
-pancreatitis
Tx:
- symptomatic tx
- supportive for organ failure
Metals
Body has natural defense mechanisms:
-Cellular chelators
-antioxidant system for metal induced oxidative stress
Lead
Inorganic form is toxic
-contaminated food (utensils for prep)
-chocolate candy processing
-ingestion of paint chips/dust
-contaminated drinking water (10-20%)
-toys, gasoline, occupational
Lead Symptoms
-Hypochromic Microcytic anemia
-PNS weakness (wrist extensors
-CNS weakness- lead encephalopathy
fatal in children
Children absorb 40% ingested Lead, 10% in adults
Deteriorates BBB easily in children
Low IQ, ADHD, aggresive behavior if childhood exposure
Lead Tx
Lead replaces Ca,Zn,Mg in enzymes and bone
-inhibits hemoglobin synthesis
take action if 5ug/dL
Severe-45 in children, 50 in adults, should use oral chelator:
Succimer
Arsenic
Most toxic is elemental trivalent and pentavalent
Organic Arsenicals: least toxic, in seafood
elemental in rural water supplies
MOA: oxidative stress
-affinity for -SH groups on proteins
Arsenic signs
signs: (acute) hemorrhagic gastroenteritis
-rice-water diarrhea
-garlic odor breath
Chronic intoxication: more common and insidious
-hyperkeratosis, exfoliative dermatitis on feet
-vasodilation, fatty liver, cancer
Tx: metal chelator
- Dimercaprol given IM
MethylMercury
Organic form is most dangerous, inorganic Hg can be biotransfered into methylmercury by aquatic organisms
-Inorganic Hg poorly absorbed (dental, thermometers, inorganic salts(preservatives), less toxic)
Ethyl mercury- antibacterial/fungal, not correlated with autism in children from vax
Methylmercury highly absorbed in GI
-readily passes BBB
- in fish,
-grain fungicide (seeds, in Iraq)
-Minamata Disease (Minamata bay)
Methylmercury signs/tx
Signs:
-loss of balance
-ataxia
-sensory defect
-deafness
-dysarthria
All irreversible, kills neurons
MOA: Increases intracellular Ca
Tx: chelator therapy if high levels, levels can rebound
Metal chelators
only reduces readily accessible pool, can rebound. for severely elevated
-Dimercaprol (BAL)-for Arsenic, Hg, sometimes lead
-EDTA-severe Lead (kidney tox at high dose), AE: chills, fever, nausea, vomiting
- Deferoxamine- for Iron, AE: allergy
-Succimer- for Lead
oral
CO
from burning/combustion
high O2 demand organs suffer first
-Headache
-Increased HR
outcompetes O2 for Hemoglobin
Tx: hyperbaric O2
Cyanide
plastic smoke, wool burning, cigarettes
signs: bitter almond breath
-tachypnea(low levels)
-apnea (high levels)
MOA: inhibits cytochrome oxidase in ETC in mitochondrial for ATP
Tx: cyanokit
better than 2 step method( which is also bad for CO poisoning at same time)
Asbestos
filamentous silica
mesothelioma lung cancer after 15-20 years
migrate to form pleural plaques/effusions(5-10yrs
No Tx
PCBs and Dioxin
Flame retardants, plasticizers, insulating material in elecric transformers
PCB in farm raised Salmon
signs: Dermal erruptions, Chloracne
-nausea, vomitting, headache
Dioxin-Agent orange byproduct
contaminant of industrial processes(not intentionally produced
No Tx
