Vol.3-Ch.8 "Toxicology and Substance Abuse" Flashcards
Since the treatments for poisoning and overdoses are always changing it is recommended that a poison control center always be called so that you can get the most updated treatment plan.
What are 3 specific reasons that it is a good idea to always call a poison control center?
- they can help you immediately determine potential toxicity based on the type of agents, amount of time exposed, and physical condition of the pt
- they can direct the most current and definitive field treatment
- they can notify the hospital of the current treatment and recommendations even before arrival of the patient
What are the 4 routes of Toxic Exposure?
- Ingestion:
MOST COMMON and usually include cleaning
agents, cosmetic, drugs, foods, household products,
petroleum based products, and plants. There can be
immediate damage from things like acids and bases
to the mouth, tongue, throat etc, but actually ingestion
mostly takes place in the small intestine. Some drugs
such as Aspirin tablets can even form together and
make a bolus that is hard to pass in the stomach and
therefore remain there for a while. - Inhalation:
Causes damage to the respiratory tract such as
edema, alveolar/capillary damage, tissue death and
once absorbed can travel to far parts of the body.
These include things like ammonia, CO, Chorine,
Cyaide, Tear gas, ect. - Surface Absorption:
Anything that gets absorbed through the skin or
mucous membrane and usually involves plants like
poison ivy/oak/sumac or Organophosphates used in
pesticides - Injection:
These usually cause immediate reactions (localized to
the immediate tissue touched) AND delayed reactions
once it gets into the system and spreads. This can
include drugs put in veins and muscles as well as
stings and bites from insects (Hymenoptera) or
animals like snakes
What are 2 obvious scene hazards when a toxic substance is involved?
- if it is a toxic substance abuser they may be agitated and dangerous, NEVER put your hand in a pocket b/c it could have used needles in it
- if there is a toxic substance or material spilled you must ensure you have the right protection to enter the area
Do not delay immediate needed care or transport while waiting for _____
Do not wait for contact or information with a poison control center! Transport and treat as needed, then get advisement on route for advances help
After basic supportive treatment have been started, next start to address the specific toxicologic emergency. The first step of this is _____ and is done via what 3 way steps?
After basic supportive treatments you should next DECONTAMINATE. This is done by:
- Reduce Intake:
This involves removing the pt from the toxic
environment or removing a stinger/needle - Reduce Absorption:
Once used was the Syrup of Ipecac or Gastric lavage
(using a tube to fill the stomach with water) but both
are not recommended as much. Ipecac made the toxic
both involved getting the pt to throw up which risks
aspiration or perforation. Very rarely does gastric
lavage work and it must be done within an hour of
ingestion. ACTIVATED CHARCOAL is the only
recommended treatment for this. - Enhance Elimination:
CATHARTICS such as Sorbitol are used to help
increase gastric motility but it is used with caution in
peds who may have a severe electrolyte shift. WHOLE
BOWL IRRIGATION is rising in popularity where a
rectal tube is used to flush the colon with a
polyethylene glycol electrolyte solution at 1-2L/hour to
clear the bowels and ensure electrolyte shifts don’t
occur
PG 330 HAS A LIST OF ANTIDOTES
PG 330 HAS A LIST OF ANTIDOTES
What information is just as important as WHAT was ingested?
What and WHEN are very important to know when dealing with an absorbed toxin (ingested may take a while where injected can be immediate)
What are the 2 main purposes of a physical exam on these pts?
- provide physical evidence of intoxication
- find any underlying illnesses that may account for symptoms or that may affect the outcome of the poisoning
What is in a “speedball”?
Heroin and cocaine
Apart from maintaining ABCs what is the second most common complication that must be maintained/prevented?
ASPIRATION (pts will have increased likelihood of vomiting and usually a decreased gag reflex, you can use advanced airways or RSI as needed)
An IV of lactated ringers or normal saline should always be administered but some departments have a “coma cocktail” of ______(x3). Should this be used for unconscious toxic patients?
NO! The solution normally has D50W, Naloxone, and Thiamine but do NOT USE just because they are asleep, use each separately as needed
What old technique for ingested toxins is no longer used?
Induces Vomiting should never be used!
It risks aspiration or for toxic substances can cause further damage on its way out
What is the main reason inhaled toxins such as “huffers” (paint or propellants, especially if in plastic or paper bags) cause irreversible brain damage?
What are the three main systems that are effected by inhaled toxins?
It mainly causes injury b/c it displaces O2 and causes hypoxia
- Central Nervous System (dizzy, headache, confusion, seizures, hallucinations, coma)
- Respiratory (tachypnea, cough, hoarseness, stridor, dyspnea, retractions, wheezing, chest pain/tightness, crackles (rales) or rhonchi)
- Cardiac (arrhythmias)
TOXIC SYNDROMES ON PG.334
TOXIC SYNDROMES ON PG.334
Toxidromes are toxins with similar _____?
Signs and symptoms
What is the #1 cause of poisoning?
Carbon Monoxide. A tasteless odorless gas that comes from the incomplete combustion of fossil fuels, charcoal, and wood. It is a very STABLE molecule
What are the 3 primary classes of sources of CO?
- ENDOGENOUS:
small amounts of CO are normally produced from
Heme Catabolism (the break down of hemoglobin) and
the normal range of this is 0.4-0.7%
(smoking will increase this significantly from 5-9
depending on how much) - EXOGENOUS:
The more common CO exposure and includes things
like house fires, automobile exhaust, or propane
fumes, etc - HYDROCARBON METHYLENE CHLORIDE:
Methylene Chloride (an organic hydrocarbon ; H2Cl2C)
is a hydrocarbon hat is often used in industrial solvents
and paint thinner. When inhaled it is converted into CO
in the liver and can cause Carboxyhemoglobinemia
that has similar signs and symptoms of CO poisoning
How does CO effect the release of NO in the body and how does that play a role in the brain and vasculature?
CO stimulates an increase in circulating NO levels. NO is a smooth muscle relaxer that causes vasodilation. After systole NO get released to cause the vasodilation of diastole to allow the blood to pass. When there is too much NO b/c there is too much CO, it CAUSES the SYNCOPE and HEADACHES related to CO poisoning.
How does CO effect O2 saturation of hemoglobin?
What is carboxyhemoglobin?
What is oxyhemoglobin?
Hemoglobin has a 200-250x higher affinity for CO than O2. It binds to the heme (iron containing complex on hemoglobin) to form CARBOXYHEMOGLOBIN causing an early release of the O2 also on that hemoglobin in the tissues and the inhibition of other O2 molecules to be taken up.
Oxyhemoglobin is what the hemoglobin is called when it is carrying O2.
How does CO effect O2 saturation of Myoglobin, and what does myoglobin usually do?
Myoglobin is an iron containing protein similar to oxygen but it is found in selected tissues (especially muscle) used for O2 storage, and is especially important in the heart
CO can displace the O2 found in myoglobin which can lead to ischemia, or arrhythmias in the heart
What is the normal half life of Carboxyhemoglobin?
How can it be reduced?
Normally Carboxyhemoglobin will be naturally destroyed and removed within 240-360 minutes (4-6hours)
100% O2 administration can reduce that to 80 minutes
Hyperbaric O2 can reduce it to 22 minutes
What are 2 main body systems that are affected by CO
The CNS and the cardiovascular system, this is b/c they are very dependent on aerobic metabolisms to which CO reduces.
CO causes DEPRESSIVE reactions in both
** as a bonus it also usually causes PULMONARY EDEMA
Ultimately what are the 7 major effects of CO?
- Limits O2 transport
- Inhibits O2 transfer
- Causes tissue inflammation
- Causes reduced cardiac function
- Increases NO levels
- Causes Vasodilation
- Induces free-radical formation
TABLE 8-4 ON PG 337 HAS SIGNS AND SYMPTOMS OF CO POISONING BASED OFF % OF COhb
TABLE 8-4 ON PG 337 HAS SIGNS AND SYMPTOMS OF CO POISONING BASED OFF % OF COhb
CO detectors made before _____ should not be used?
1998
A CO-oximeter can measure for _____?
They use a finger probe similar to on pulse-ox but instead of measuring 2 waves of light it can measure ____ waves.
A CO-oximeter can measure SpO2, SpCO, SpMet (methemoglobin %), and pulse rate.
They use a finger probe similar to on pulse-ox but instead of measuring 2 waves of light it can measure 8 waves.
At what level of SpCO should you begin to treat?
Begin treating for SpCO at 10-12% via high flow O2 and consider CPAP.
Watch out for complications of CO poisonings such as seizures, cardiac arrhythmias, and cardiac ischemia
Cyanide is the triple bond of ____ and ____.
It can be a gas or powder depending on what it is combined with. But ultimately it inhibits an enzyme called _____ which causes _____.
Cyanide is a colorless, sometimes odorless gas (60% can smell a faint bitter almond smell). It is a C and N triple bonded. It is a common gas biproduct of the burning of plastics, wool, silk, synthetic rubber, polyurethane, and asphalt. It has permitted levels of 10ppm as an 8 hour time-weighted average. It can also be a white powder as sodium cyanide or potassium cyanide.
It ultimately inhibits the enzyme called CYTOCHROME C OXIDASE (aa3) found in the 4th complex of the electron transport chain. When it is inhibited it effectively stops the production of ATP and causes a shift from aerobic metabolism to anaerobic metabolism
and as already learned the CNS and cardiovascular system heavily rely on aerobic metabolism
The older version of Cyanide antidote was the Lilly or Pasadena cyanide antidote kit that had 3 things, what were they and what did they do?
Why is it no longer used?
It had AMYL NITRITE(1) ampules (that can be immediately inhaled while IV access is started) that would induce the formation of methemoglobin (MetHb). Cyanide has a greater affinity for methemoglobin over cytochrome oxidase, which allows for it to go back to being used for cellular energy production.
After the amyl nitrite is given, SODIUM NITRITE(2) should be admin via IV access
Lastly SODIUM THIOSULFATE (3) is given which binds to cyanide to form thiocyanate which is must less toxic and can be secreted by the kidneys.
It is no longer recommended b/c methemoglobin cannot carry O2 and it changes the state of the iron on the heme molecule. It changes it from Ferrous (Fe2+) to Ferris (Fe3+). O2 can only bind to Ferrous (Fe2+)
What is the more preferred antidote for cyanide poisoning?
HYDROXOCOBALAMIN (Cyanokit) is a precursor for cyanocobalamin (vitamin B12). It combines to the Cyanide ion (chelates from cytochrome oxidase) to form cyanocobalamin. Vitamin B12 can then be eliminated harmlessly through the kidneys
How do cardiac medications usually effect the heart? (3)
What are the antidotes for:
- Calcium channel blockers
- Beta Blockers
- Digoxin
Usually they affect the heart through decreasing heart rate, suppressing automacity, and or reducing vascular tone
What are the antidotes for:
- Calcium channel blockers = Give Calcium
- Beta Blockers = Give Glucagon
- Digoxin = Give Digoxin-Specific Fab (Digibind)
Acids VS Bases
Acids:
- pH less than 2
- Causes immediate severe pain but does not spread deep b/c it causes coagulation and necrosis with the production of an Eschar at the burn site that prevents further penetration
Bases:
- pH greater than 12.5
- Causes delayed pain which usually causes the damage to go deeper before it is noticed. Also it causes liquefaction necrosis so no Eschar or coagulation is formed, also allowing the damage to go deeper
If ingested, there is usually not much damage done to the esophagus b/c it passes through quickly. Activated charcoal DOES NOT HELP b/c caustic substances do not bind with it
Why is Hydrofluoric Acid so dangerous even though it only causes minor burns on skin contact?
Apart from removing clothing and irrigating thoroughly, what else can be done to help treat a Hydrofluoric Acid exposure?
HF penetrates deeply into the tissues and is only inactivated when it comes into contact with cations such as calcium ion. Calcium fluoride is formed by this inactivation and settles in the tissue as a salt. The removal of calcium from cells causes a total disruption of cell functioning and can even cause bone destruction as calcium is leached out of the bones
Immerse the affected limb in iced water with MAGNESIUM SULFATE, CALSIUM SALTS, and BENZETHONIUM CHLORIDE.
What are hydrocarbons found in? How serious are they?
What works and doesn’t work for this?
Hydrocarbons are an organic compounds of mostly carbon and hydrogen. They are found in things like lighter fluids, paint, solvents, aerosol proellants, etc.
If the pt knows what the toxin was and is asymptomatic the pt may be allowed to stay home; however, if the pt does NOT know what the toxin was, and is symptomatic or who has ingested hydrocarbons into the GI system they need to be treated with normal toxicology protocol.
Activated charcoal DOES NOT WORK
This is one of the rare instances that a Gastric Lavage may actually be useful!
What are Tricyclic Antidepressants and how should you treat an overdose?
Tricyclic Antidepressants were once commonly used for depression but were dangerous b/c they have a very NARROW THERIPUTIC INDEX, meaning just a little increase in dose can have large effects.
The most common cause of death is cardiac arrhythmias.
Sodium Bicarbonate may be useful and 100% cardiac monitoring should be used. If you suspect a mix with benzos DO NOT USE FLUMAZENIL as it may precipitate seizures
What are MAO inhibitors and how should you treat an overdose?
Monoamine Oxidase Inhibitors (MAOs) were once rarely used to treat depression and OCD. But they also have a very NARROW THERAPUTIC INDEX, as well as have multiple drug interactions and serious interactions with food containing tyramine (certain red wines and cheese). HOWEVER, there are newer versions that are more easily reversible and do not have as severe reactions with drugs and food
They inhibit the breakdown of neurotransmitters such as norepinephrine and dopamine while increasing the availability of other components to make even more neurotransmitters. Symptoms may not arise for up to 6 hours.
What is Serotonin Syndrome?
Serotonin Syndrome is an overdose on a newer version of antidepressants called Selective Serotonin Reuptake Inhibitors (SSRIs). SSRIs prevent the reuptake of serotonin, but when taken in excess and overdosing it causes Serotonin Syndrome which is largely in part due to an excessive stimulation of the serotonin receptors in the nervous system.
It can have varying degrees of symptoms:
- Mild:
tachycardia, shivering, diaphoresis, mydriasis,
intermittent tremor or myoclonus, and overreactive
reflexes - Moderate:
hypertension, hyperthermia, hyperactive bowel
sounds, hypervigilance or agitation - Severe:
Shock, agitated delirium, muscular rigidity, metabolic
acidosis, rhabdomyolysis, seizures, renal failure
Often described as having a clinical triad of abnormalities:
- Cognitive:
confusion, hypomania, hallucinations, agitation,
headache, coma - Autonomic:
shivering, sweating, fever, hypertension, tachycardia,
headache, coma - Somatic:
myoclonus/clonus (muscle twitching), hyperreflexia,
tremor
What is lithium used to treat?
Bipolar Disorder (Manic-depressive).
It also has a very narrow therapeutic index and charcoal DOES NOT work with this either. For high toxicity dialysis is usually required
What is a common Salicylate used over the counter that can be OD’d on?
Aspirin. It usually takes 300mg/kg to achieve toxicity.
They will eventually inhibit normal energy production and acid buffering and lead to metabolic acidosis
Definitely USE activated charcoal
At what dosage is acetaminophen dangerous?
At 150mg/kg it becomes toxic and once the natural defenses are down, it causes hepatic necrosis (renal tissue death).
Symptoms appear in 4 stages:
- Stage 1: 30min-24hrs
nausea, vomiting, weakness, fatigue - Stage 2: 24-48hrs
abdominal pain, decreased urine, elevated liver
enzymes - Stage 3: 72-96hrs
liver function disruption - Stage 4: 4-14 days
Gradual recovery or progressive liver failure
ANTIDOTES:
- N-Acetylcysteine (NAC, Mucomyst)
- Cimetidine (Tagamet)
What is Theophylline?
It is a drug used in asthma or COPD b/c of its bronchodilation and mild anti-inflammatory effects but it has a NARROW THERAPEUTIC WINDOW.
This is one of the few drugs that are apart of the Enterohepatic Circulation class which means that repetitive Activated Charcoal will help remove more and more from circulation
At what dose does IRON become toxic?
20mg/kg; usually kids will do this because they eat too many candy flavored vitamins.
This will often lead to gastrointestinal injury and possible shock from hemorrhaging due to the fusing of the tablets or vitamins creating a CONCRETION (lumps of iron formed when tablets fuse together)
DEFEROXAMINE is a chemical agents that binds to iron so that it wont be absorbed as much by the body. (activated charcoal does not work with iron nor other heavy metals like lead and mercury)
What is the only bug in the Hymenoptera class that leaves a stinger?
The honey bee, also remember that only FEMALES sting with any of the Hymenoptera
Hymenoptera stings are usually how severe?
Not severe (redness, pain, edema, or wheels at injection) UNLESS there is an anaphylactic reaction
What are Africanized Honey Bees aka “Killer Bees” more dangerous?
They are way more aggressive and can leave up to 8-10 times more stingers.
They can be immobilized and killed with wetting surfactants like dishwashing detergents
Brown Recluse VS Black Widow
BROWN RECLUSE:
- Sothern and Midwestern states
- Lives in dry and dark places
- Besides the fiddle they also only have 6 eyes in a
semicircle - Bites are PAINLESS and start out with just a small
erythematous macule surrounded by a white ring.
They will progress over the next 8 hours into localized
pain, redness, and welling. Over days it will cause
tissue necrosis, Erythema often becomes wide spread
over days. - Treat with antihistamines for systemic reactions, NO
ANTIVENOM, may need surgery to remove necrotic
tissue
BLACK WIDOW:
- Found in wood piles and brush all over US
- Females are responsible for majority of bites and they
are the ones with an hourglass on the abd(not males) - Venom causes excessive neurotransmitter release at
the synaptic junctions - Immediate pain, redness, and swelling. Will progress
to muscle spasms. - IV muscle relaxants may be required for severe
spasms. Diazepam 2.5-10mg IV. ANTIMENOM IS
AVAILABLE
What is the main scorpion that can cause fatalities?
What does the venom do?
How do you treat?
The Bark Scorpion
Venom is stored in bulb at end of tail and it acts on the nervous system producing burning and tingling without much indication of injury. Gradually progresses to numbness and eventually slurred speech and restlessness
Apply constriction band above wound site but no tighter than a watch, just to occlude lymphatic flow
ANTIVENOM IS AVAILABLE but should be used only for severe cases
Crotalidae = Pit Vipers VS Elapidae = Coral Snakes
Crotalidae = Pit Vipers:
- Cotton Mouths (Water Moccasins), Rattlesnakes, &
Copperheads - Pit b/w the eyes and nostrils on each side of the
head, elliptical eyes, two well-developed fangs,
triangular head - Venom contains hydrolytic enzymes that destroy
proteins and most other tissue components like RBCs
and other clotting factors - Will produce infarction and tissue necrosis
- Most deaths are via shock over 6-30 hours but can
occur as quick at 30minutes - 25% of all rattlesnake bites are “dry” aka don’t release
toxins - ANTIVENOM IS AVAILABLE (American Crotalid
envenomation) but should only be used for severe
cases - Keep PT SUPINE, splint limb, maintain extremity in
neutral position. DO NOT apply cold packs,
tourniquet, or use electrical stimulation
Elapidae = Coral Snakes:
- Round eyes, narrow head, no pit, yellow banded red
and black rings - “red touch yellow, kill a fellow. Red touch black,
venom lack” - Venom primarily acts on nervous system causing
respiratory and muscle paralysis - Wash the wound, apply compression bandage, keep
extremity at heart level, immobilize limb with splint.
DO NOT apply cold packs, incise the wound, or use
electrical stimulation
Marine animal injections usually occur _____?
How do you treat?
What is something that should always be considered with marine animal injections?
They usually occur on land
Venom is unstable and usually produces pain out of proportion to the actual wound.
Apply constriction band above wound site but no tighter than a watch, just to occlude lymphatic flow. RELIEVED BY HEAT (110-113F), inactivate and or remove stinger
Fresh and Saltwater contain considerable bacterial and viral pollution (Vibrio species) so ALWAYS CONSIDER SECONDARY INFECTION
What is Ciguatera Poisoning?
Illness caused by eating fish that contain toxins produced by marine microalgae called Gambierdiscus toxicus. It usually occurs in predatory reef fish at the top of the food chain, mostly noticed with BARRACUDA.
Begins with GI probs (nausea, vomiting, diarrhea, Abd pain) within 2-6 hours. Within 3 hours it can elevate to neuro probs such as weakness, paresthesia (tingling), tooth pain, pain on urination , and birred vision
No diagnostics exist for this other than looking at the symptoms and history of recent fish meal (if part of the meal is saved they can check for ciguatoxin in the meal)
They are colorless, odorless, and tasteless, and cannot be eliminated by cooking or freezing
Has NO CURE, can only be treated for symptoms
Antidote or treatment for Alcohol?
May require thiamine and D50W for hypoglycemia
Antidote or treatment for Amphetamines/stimulants?
Benzodiazepines for seizures and in combo with haloperidol for hyperactivity
Antidote or treatment for Barbiturates?
Forced diuresis and alkalization of the urine improve elimination of barbiturates from the body
Antidote or treatment for Benzodiazepines?
Flumazenil can counter adverse effects, but be careful not to incite a seizure fueled withdrawal
Antidote or treatment for Cocaine?
Benzodiazepines (diazepam) may be needed for sedation and to treat seizures. Beta-blockers are absolutely contraindicated b/c unopposed alpha-receptor stimulation can cause cardiac ischemia, hypertension, and hyperthermia
Antidote or treatment for Hallucinogens?
Use Benzodiazepines for seizures and in combination with haloperidol for hyperactivity
Antidote or treatment for Narcotics/Opiates?
Naloxone is effective in reversing respiratory depression and sedation, be careful as it may trigger a withdrawal reaction in chronic opiate abusers
