Poisons and Environmental Toxins Flashcards
Kids are at increased risk for manifestation of what toxicity effects over the course of their lifetime as compared to adults?
Latent toxicity effects
What toxin does the placenta specifically block?
Cadmium
Can lead transfer across the placenta?
Yes
What toxin does the placenta enhance the passage of?
Mercury
What 2 toxins can cross the placenta easily due to their lipophilic nature and low molecular weight?
PCBs and insecticides
What 3 toxins could you see in water?
- E. coli
- Cryptosporidium
- Mercury
What common thing ingested can contain many toxins, especially if not handled correctly?
Food
What is the appropriate dosing of activated charcoal?
0.5 to 1 g/kg, up to an adult dose range of 25 to 100 g
What can be given to expedite exit of an ingested substance (toxin) and reduce enterohepatic excretion?
Cathartics (magnesium citrate and sorbitol)
What is always an incorrect treatment for toxin ingestion on boards?
Syrup of ipecac
What are some reasons kids are at an increased risk from toxic exposures compared to adults?
In utero, smaller size means more vulnerable to an equivalent toxic exposure. Kids put more non-food items in mouth, increased risk for exposure to toxic agents in environment.
If you are giving activated charcoal to a patient at risk for respiratory depression (like phenobarbital overdose), what else should you do?
Intubation, then give charcoal with an NG tube
What can’t you give activated charcoal with?
Antidotes (it would interfere with the absorption of the antidote)
What is the one antidote you can give with activated charcoal and why?
N-acetylcysteine (since it is given in such large quantities)
What are the toxic substances that are “calmly” removed without charcoal?
Cyanide
Alcohol
Lithium
Heavy Metals
Charcoal is a poor choice for these
When would you do gastric lavage?
Use is reserved for potential life-threatening ingestions that have occurred within 60 minutes of seeking medical attention
*Gastric lavage is no longer recommended for most infections…risk outweighs benefits
With toxin ingestion what should you do first?
Address ABCs and search for the specific cause later
Most treatment for toxins is supportive
If you are presented with an unstable patient, what is the correct answer?
Secure the airway
When do the initial manifestations of acetaminophen toxicity occur?
First 24 hours
What are the initial symptoms of acetaminophen toxicity?
Anorexia, nausea, vomiting
In cases of significant acetaminophen toxicity, what happens during the latent phase and how long does this last?
Liver enzyme levels rise significantly, lasts 1-4 days
With severe acetaminophen toxicity, what happens after the latent phase (1-4 days where liver enzyme levels rise)?
Jaundice and liver tenderness
What is the most important predictor of outcome regarding acetaminophen toxicity?
Level taken 4-10 hours post ingestion
Why is immediate discharge from the ED when the person is asymptomatic following acetaminophen ingestion always the wrong answer?
It is very common to be asymptomatic initially, with liver toxicity presenting later on
What is done for someone with acetaminophen ingestion when it has been less than 4 hours since ingestion?
Give activated charcoal to reduce absorption
What is done after giving someone with acetaminophen ingestion activated charcoal?
Get an acetaminophen level 4-24 hours post ingestion and plot level on published nomogram to determine risk for hepatotoxicity
You give N-acetylcysteine without obtaining acetaminophen levels when?
If it is determined that more than 140 mg/kg has been ingested
*Especially if it would delay initiation of treatment longer than 10 hours after ingestion
What does N-acetylcysteine do?
Prevents the accumulation of toxic metabolites of acetaminophen
How is acetaminophen overdose diagnosed?
By a history of ingestion of 140mg/kg or more
How is acetaminophen toxicity diagnosed?
By the level in the nomogram
How late can the transaminase levels rise in acetaminophen overdose?
3-4 days after ingestion (LFTs can be normal 2-3 days after ingestion, even in cases of severe overdose)
“Wintergreen” odor on breath is clue to what ingestion?
Salicylate
What can cause salicylate toxicity?
ASA ingestion along with medications that contain salicylates
What is initial management of salicylate ingestion?
Activated charcoal
What is given to correct metabolic acidosis in salicylate ingestion?
Sodium bicarbonate (alkalinize the urine)
What causes metabolic acidosis in salicylate ingestion?
Not directly caused by salicylates, but typically by respiratory alkalosis and by a build up of organic acids as a result of salicylate action in cells
What two electrolytes should you worry about in salicylate ingestion?
Hypokalemia and low glucose (consider glucose even if not hypoglycemic)
What should be calculated when presented with acidosis and values for sodium, potassium, chloride, and bicarbonate?
Anion gap
What is the formula for anion gap?
Sodium - (Chloride + Bicarbonate)
What happens to the anion gap in salicylate poisoning?
It is elevated
Do kids with salicylate toxicity get fever?
Yes…don’t just assume sepsis if you have other clues consistent with salicylate toxicity
What are symptoms of ibuprofen ingestion?
Usually asymptomatic, but for boards at least nausea and vomiting
What is management of ibuprofen overdose?
Primarily supportive
If you get steen who ingested ibuprofen for a suicide attempt who is physically stable, what is the best next step?
Go after risk for co-ingestion and choose the answer that is a level for another drug (salicylate or acetaminophen)
Don’t choose ipecac, gastric lavage, or ibuprofen level (it doesn’t exist)
How might ethanol toxicity be presented on boards in kids?
- Adolescent who is having a seizure and is hypoglycemic
2. Toddler who got hold of drinks left over after a party the night before and parents found him unresponsive
What constitutes a mild blood alcohol level?
What are symptoms of mild blood alcohol levels?
Euphoria, lowered inhibitions, and impaired coordination
How do you treat mild ethanol toxicity?
Watch them
What is a moderate blood alcohol level?
> 0.2 g/dL, 200 mg/dL, 0.2% BAC
Clinical presentation of moderate blood alcohol level?
Slurred speech, ataxia, impaired judgement, mood swings
Management for moderate ethanol toxicity?
Monitor until sober
What is a severe blood alcohol level?
> 0.3 g/dL, 300 mg/dL, 0.3% BAC
Symptoms for severe ethanol toxicity?
Confusion and stupor
What ethanol level is potentially lethal causing coma, respiratory depression, and death?
Greater than 0.4 g/dL, 400 mg/dL, 0.4% BAC
What is important to monitor in a patient with ethanol toxicity?
Hypoglycemia and electrolyte imbalance
What can ethanol intoxication mask?
Toxicity of other drugs
Where an you find ethyl alcohol?
Mouthwash, cough and cold preparations, elixirs, colognes, perfumes
*Presentation of ethanol toxicity might not be obvious…
Where is methanol found?
Rubbing alcohol, windshield washer fluid, cooking fuel, perfumes, antifreeze
Abdominal pain and vomiting, inebriation, severe metabolic acidosis, increased anion gap, CNS depression
Methanol toxicity
Does methanol ingestion cause immediate signs of toxicity?
Not necessarily (same with situation of a child acting drunk after ingesting ethanol)
What does methanol get broken down into?
Formic acid and formaldehyde
What horrible things can formic acid and formaldehyde (methanol toxicity) cause?
Havoc on liver and optic nerve (blurred vision, “snow field” vision, and edema of the optic disc)
What can be given for methanol toxicity?
- Ethanol…serves as an alcohol dehydrogenase antagonist and slows conversion of methanol to formaldehyde
- 4-methypyrazole (4-MP)…only approved in Europe right now, but it does the same thing as ethanol with less toxicity
- Sodium bicarbonate (helps counter formic acid)
What BAC is considered legally under influence in most states?
0.08%
What is a BAC of 0.08% equivalent to in g/dL or mg/dL?
0.08 g/dL or 80 mg/dL
Toddler who is lethargic, in respiratory distress, sweating, wheezing, kid was in a backyard shed….
Organophosphate poisoning (hinting at insecticide exposure)
Muscle twitching, salivary secretions, urination, GI cramps
Organophosphate poisoning…(“Overstimulated person playing the organ”)
What routes can someone get organophosphate poisoning?
Ingestion, inhalation, absorbed through skin
What is the mechanism of action for organophosphate poisoning?
Organophosphates inhibit acetylcholinesterase…so the effects are due to acetylcholine overload- Cholinergic effects
What are cholinergic symptoms?
“Fight or flight” … In a rush, you create slush (SLUDGE)
- Salivation
- Lacrimation
- Urination
- Defecation/Diarrhea
- Gastrointestinal
- Emesis
What is the other pneumonic to remember cholinergic side effects besides SLUDGE)?
DUMBBELS
- Diarrhea
- Urination
- Miosis
- Bronchospasm
- Bradycardia
- Emesis
- Lacrimation
- Salivation
What effects can long term insecticide exposure have on a child’s health?
Issues with brain development
What is one big source of insecticide exposure for kids?
Unwashed fruit and vegetables…kids are more likely to be exposed in general due to behavioral factors
What are the 2 categories of cholinergic effects?
Muscarinic and nicotinic
What are the cholinergic muscarinic effects?
Salivation, lacrimation, diarrhea, wheezing, bradycardia
What do you give to manage muscarinic cholinergic effects?
Atropine
“Muskrat”: “Musc”arinic effects need “at”ropine
What are the nicotinic cholinergic effects?
Primarily neuromuscular…weakness, paralysis, muscle fasciculations
How do you treat nicotinic cholinergic effects?
Pralidoxime
What medications can cause anticholinergic side effects?
TCAs, mydriatic agents, antispasmodics
*Watch out for household members taking one of these…suggests accidental ingestion of one of these medications
What are anticholinergic signs?
Dry mouth, dry mucous membranes, mydriasis (dilated pupils)
*Same symptoms for antihistamine overdose…blind as a bat, red as a beet, hot as a hare, dry as a bone, mad as a hatter, bowel and bladder lose their tone, heart runs alone
What are the three C’s of managing TCA toxic ingestion?
- Charcoal decontamination
- Measuring levels are not indicated
- Cardiac is where the money is
If you get a patient with anticholinergic signs who you suspect ingested TCAs, what do you need to watch out for?
Dysrhythmias (can develop within 24 hours)…tachycardia and HTN are other diagnostic signs
How do you treat a patient with a dysrhythmia from TCA ingestion?
Alkalinization of urine…dysrhythmias don’t typically lead to V-fib and shouldn’t be treated with cardiac medications
When do you measure TCA levels?
You don’t, measurement of TCA levels isn’t clinically useful
What is the most important parameter to measure with TCA overdose?
EKG, looking for widened QRS complex
What do you use for decontamination for TCA overdose?
Activated charcoal
How do you treat a widened QRS complex from TCA overdose?
Sodium bicarbonate blouses…keep giving until QRS duration is less than 100msec
You have a kid who gets allergy testing that is all negative…what medication could the patient be taking that would cause this?
TCA…they render allergy testing unreliable because they interfere with the histamine response, so allergy testing isn’t valid with a patient taking TCAs
Kid with depressed sensorium, bradycardia, hypotension, disphoresis…
Ingested beta blocker
How to manage a kid who ingested a beta blocker?
Observe on a monitor
What is gasoline, kerosene, and lighter fluid?
Hydrocarbons
Non-specific signs of hydrocarbon ingestion?
Oropharyngeal and gastric irritation, nausea, vomiting
History of choking and/or gagging with cough, wheezing, and/or tachypnea
Hydrocarbon ingestion
What are labs and imaging consistent with hydrocarbon ingestion?
Labs show hypoxemia, film shows diffuse bilateral infiltrates
What can hydrocarbon ingestion lead to?
Acute respiratory distress syndrome (ARDS)
If a kid ingested hydrocarbons and is symptomatic, what do you do?
Oxygen, bronchodilators, supportive care (intubation)
If a kid ingested hydrocarbons, but is asymptomatic, what do you do?
Observation for 6 hours, no other intervention (even CXR)
Sudden flu-like symptoms in a patient who is afebrile, with a supple neck
Carbon monoxide toxicity
What are other clues to carbon monoxide toxicity?
Symptoms in other family members, or recent death of a small family pet
Signs and symptoms of carbon monoxide poisoning?
Vague…fatigue, headache, dizziness, nausea, dyspnea, weakness, confusion
Someone in a house fire who has singed nasal hairs, charcoal-stained clothes, and carbonaceous sputum, or hacking and heaving…
Carbon monoxide toxicity
What is a crucial initial first step with suspected carbon monoxide poisoning?
Obtaining carboxyhemoglobin levels
What is the correlation between symptoms and carboxyhemoglobin levels with carbon monoxide poisoning?
They don’t always correlate
Are cherry red mucous membranes an important diagnostic criteria for carbon monoxide toxicity?
No…used to be believed to be a key factor in making diagnosis, but it is now too insensitive of a sign…don’t choose this when asked about important diagnostic criteria
What is oxygen saturation in carbon monoxide poisoning?
It can be normal, so oxygen saturations are completely unreliable in this setting…oxygen saturation doesn’t distinguish between carboxyhemoglobin and oxygenated hemoglobin
When do you use hyperbaric oxygen for carbon monoxide poisoning?
Severe cases…
- Pregnancy
- Acidosis
- Signs of cardiac involvement
- Sign of neurological involvement
For routine carbon monoxide poisoning, what do you do?
Administer high flow oxygen through a nonrebreather mask
Presented with a patient who is lethargic, confused, respiratory distress, normal pulse ox…treatment?
100% oxygen…don’t be fooled by normal pulse ox if it suggests carbon monoxide poisoning… 100% oxygen is still correct answer
If you give someone with suspected carbon monoxide poisoning 100% O2 and they don’t improve, what should you consider?
Cyanide poisoning (if no improvement, carbon monoxide poisoning isn’t the correct answer)
What’s the difference between presentation of cyanide poisoning and carbon monoxide poisoning?
They present in a similar fashion, but cyanide poisoning fails to respond to O2
What can cause cyanide poisoning?
Any smoke exposure
What smell is associated with cyanide poisoning?
Almonds
What are 3 treatment options for cyanide poisoning?
- Hydroxocobalamin (most recently approved)
- Sodium thiosulfate (old)
- Nitrate (old)
How many phases to ethylene glycol toxicity?
3
Patient who has drunken appearance, no odor of alcohol on breath, and large anion gap
Ethylene glycol poisoning
What happens in phase 1 of ethylene glycol toxicity?
Nausea, vomiting, tachycardia, hypertension, metabolic acidosis, and calcium oxalate crystals in urine (leads to hypocalcemia )
What phase of ethylene glycol toxicity causes coma and cardiorespiratory failure due to acidosis and hypocalcemia?
2
What happens during phase 3 of ethylene glycol toxicity?
Renal failure due to acute tubular necrosis, with the patient needing dialysis (lasts 1-3 days)
What is it always important to ask about with weird symptoms?
Intake of complementary or alternative medicines in the investigation of potential ingestions
What do you do for a kid who ingested chlorine (household bleach, Clorox)?
May not require much intervention…discharge from the ER can be the correct answer since the concentration of hypochlorous acid is low
Kid who is lethargic, ataxic, and vomited. Labs show low serum bicarb and elevated anion gap. Is it ethanol or ethylene glycol toxicity?
Look for clues… Like if the kid was in the garage (likely not a bar in the garage)
Anything about crystals in the urine, ethylene glycol is the answer
If you are given a serum sodium, bicarb, and chloride, what should you do?
Calculate anion gap
First step with ingestion of multiple agents or unknown agent?
ABCs…stabilize patients
Once ABCs are done, what do you do for someone with multiple ingestions or unknown ingestions?
- Look at history for environmental exposures or family members taking medications
- Labs (acid/base status, glucose concentration, anion gap), drug testing
- Acetaminophen and salicylate levels (multiple agents, unknown agents, intentional ingestion)
Coughing, crying, drooling, difficulty swallowing, chest pain
Ingestion of a caustic substance
Why isn’t the ingestion of a crystalline substance alarming?
The kid often spits it out ASAP
When do you do gastric lavage for a caustic substance ingestion?
You don’t, gastric lavage is contraindicated
What do you do for a patient who is symptomatic after ingesting a caustic substance?
Endoscopy (in less than 24 hours) to determine the presence and severity of esophageal function
Is the presence or absence of oral lesions predictive of esophageal injury in caustic ingestions?
No
Where do alkali substances tend to injure?
The esophagus (they may even lead to esophageal perforation)
Where do acidic substances tend to injure?
The esophagus and stomach (they are not neutralized as alkali substances are)
For a caustic substance…what should you look for in question stem as a clue!
Description of child who was exposed to a common household cleaning substance that could be mistaken by a child as food (scented floor cleaners, foam oven cleaner spray bottles)
What are 2 common alkaline ingestions?
Dishwasher detergent or drain cleaner
What happens with alkaline ingestions?
Immediate impact, leading to burns of exposed tissue, or oral/esophageal burns
Presentations of alkaline ingestions?
Drooling, dysphasia, or emesis
Additional findings include vomiting (with hematemesis), stridor, wheezing, burns on face, hands, or chest
What is the affect on tissues from alkaline ingestions?
Deep liquefaction necrosis of affected tissues…leads to ulceration and perforation as potential complications
Why are systemic signs rarely a part of the presentation for alkaline ingestions?
The toxicity is primarily via direct contact with skin and mucosa…why even a small amount of alkali substance can cause significant damage
Why don’t you use activated charcoal for alkaline ingestions?
It won’t absorb alkali and will inhibit endoscopic examination
When do you do endoscopy in someone with an alkaline ingestion?
- If asymptomatic, endoscopy isn’t indicated (even though esophageal burns can be present in an asymptomatic patient)
- Observe for 6 hours to await presentation of symptoms…if asymptomatic after 6 hours, no endoscopy
Patient with alkaline ingestion presents with wheezing and/or stridor, what do you do?
Airway stabilization and/or protection
What lead levels can result in cognitive deficit?
As low as 10mcg/dL (should be followed)
What lead levels would require chelation therapy?
70mcg/dL or higher
What are signs and symptoms for lead levels of 10-20mcg/dL?
Mild cognitive delay
What do you do for lead levels of 10-20mch/dL?
Education on lead exposure, environmental control measures, and continued lead level monitoring
What are signs and symptoms of lead levels over 70mcg/dL?
Severe toxicity/headaches, encephalopathy, lead lines on gingiva, and/or anemia
What do you do for lead levels over 70mcg/dL?
Chelation
What type of blood sample is needed to base treatment for lead exposure on?
Venous sample…capillary sample is adequate for screening purposes, but is isn’t acceptable to base treatment on this
15 month old, elevated lead level, parents doing kitchen, bathroom, and home equity loan renovations…most likely cause of lead poisoning?
Household dust…lead can be absorbed through GI and respiratory tract…kids are at high risk for absorption of lead through household dust during home renovations
Don’t pick pica or lead plumbing
What is the most important current source of lead exposure?
Lead based paint in older houses (kids either eat the paint chips or are exposed to house dust or soil)
Name some sources of lead exposure besides lead based paint.
Glazed ceramics, storage battery casings, bullets, cosmetics, leaded glass, jewelry, farm equipment
What are two home remedies that can lead to elevated serum lead levels?
Amarcon or greta
Name some symptoms and signs of lead poisoning.
Headache, irritability, constipation, lethargy, microcytic anemia
What is considered a toxic ingestion of iron?
40mg/kg of elemental iron
Who do you treat for iron ingestion?
Toxic levels (40mg/kg), but symptomatic patients with even lower ingestions should be treated
What happens on phase 1 of toxic iron ingestion?
Within 6 hours, vomiting (often hemorrhagic), diarrhea, and abdominal pain
What happens during phase 2 of iron ingestion?
Decreased GI symptoms and deceptive improvement for next 6-24 hours
What happens during phase 3 of iron ingestion?
Multi-system effects: Metabolic acidosis, coagulopathy, cardiovascular collapse
What happens during phase 4 of iron ingestion?
GI obstruction due to scarring and strictures
When do you check serum iron levels with ingestion?
4 hours post ingestion
What is the iron, WBC, and glucose levels associated with severe iron ingestion?
Serum iron > 350
WBC > 15000
Glucose > 150
What studies do you want for a symptomatic patient with iron ingestion?
Abdominal film (identify iron tablets that haven’t been absorbed), electrolytes, aminotransferases, CBC, and coagulation studies
What are indications for chelation with iron ingestion?
- Severe symptoms
- Anion gap acidosis
- Serum iron over 500mcg/dL (89.5 mcmol/L)
- Significant number of pills visible on abdominal film
What is used for iron chelation treatment?
Deferoxamine
What chelation treatment turns the urine a pink-red color?
Deferoxamine…urine turns pink-red when serum iron level exceeds the serum iron binding capacity
When can you stop treatment with deferoxamine for iron ingestion?
When there is adequate clinical improvement and/or the urine is no longer pink
Can you use activate charcoal for iron ingestion?
No, it absorbs iron poorly and isn’t indicated for iron ingestion (syrup of ipecac isn’t indicated either)
What can iron deficiency and lead toxicity cause with the blood?
Microcytic anemia…check iron and lead levels if you see this
Where can kids get exposed to mercury?
Environmental exposures…it can be inhaled or ingested, primarily through consumption of fish and drinking contaminated water
*Thermometers no longer contain mercury
Is mercury exposure a high risk during home renovations?
No
What are PCBs?
Synthetic hydrocarbons that are pervasive in the environment and can be concentrated in certain foods
High exposure to PCBs during fetal development can lead to what?
Low birthweight, dark pigmentation of the skin, early eruption of teeth, acneiform rash, can ultimately be fatal
*PCB can cause Pigmentation and rash, Cutting teeth prematurely, and Birthweight that is low…also long term neurodevelopmental consequences
Where do smallpox lesions begin?
Face and extremities
Where do varicella lesions begin?
Centrally and spread peripherally
Which lesions leave scars…smallpox or varicella?
Smallpox
Which has lesions in varying stages of development?
Varicella
What can smallpox present with?
General signs of fever and headache, along with delirium
What form does anthrax usually present in (for boards)
Cutaneous
What is the incubation period for anthrax?
Less than 2 weeks
Describe the lesion of anthrax.
Starts as a pruritic papule (similar to a routine insect bite), that progresses to a central bullous lesion that becomes necrotic, forming a central black painless eschar. Surrounding tissue is swollen and red. No associated tenderness.
How long until the eschar falls off from anthrax?
1-2 weeks
What are some systemic signs for anthrax?
Adenopathy, fever, malaise, headache…all very vague, so rely on the cutaneous signs
What is the most commonly ingested foreign body?
Coins
What % of ingested coins will pass and how many days does this take?
95%, 4-6 days
When do you remove an ingested coin by endoscopy ASAP?
Anything in the proximal esophagus
What do you do for a coin in the middle-lower esophagus?
Observe for 12-24 hours if asymptomatic, then do endoscopy if the coin doesn’t pass beyond that point
When an object reaches what point can you just observe it for passage?
Stomach
What is usually the shape of a coin in the esophagus on X-Ray?
Face forward on PA film, from the side on lateral film
What is usually the shape of a coin in the trachea on X-Ray?
Face forward on lateral film, from the side on PA film
What are the 3 really bad ingestions?
- Button disc batteries
- Sharp and pointed objects
- Magnets
Kid playing with a calculator or hearing aid who is suddenly having difficulty swallowing or is throwing up?
Swallowed button disc battery
Kid that you think might have swallowed a button disc battery but is asymptomatic?
Immediate endoscopy to remove the battery if still in esophagus, observation ONLY if it has passed into stomach or below
-Don’t be fooled and choose watching and waiting, charcoal, repeat CXR in a week, or sifting through stool
What does swallowing a sharp and pointed object pose a risk for?
Perforation
If a swallowed object that is sharp and pointy is longer than how many cm does it especially pose a risk for perforation?
4-6cm
For a sharp and pointed object that has been swallowed, what should you do?
Endoscopic removal (most likely the correct answer whether in esophagus or further)
How can a swallowed magnet cause perforation?
If more than one is ingested and they attract to each other across bowel walls
*Super important if they note that a child ingested 2 or an unknown number of magnets
What is the correct answer for all magnet ingestions?
Inpatient observation (stay away from airport security check, stay away from MRI suite)
