Poisoning and Overdose Flashcards
50% of poisonings are in ___
kids younger than 6 years
**Rare for poisoning to cause death in a child, but suicide attempts are more likely to cause death
Some patient factors for poisoning
- Age (bad to be very young or very old)
- Dose (the dose makes the poison)
- Timing (just took it or took it 3 days ago)
- Co-ingestion (additive effects)
Describe the systemic approach to poisoning
- Sick or not sick?
- If they are sick start resuscitating them - If they are not sick you have time
- Treat symptoms
- Try and figure out what is likely to happen
- Try and prevent later complications
What is in tox. resuscitation
- manage airway early!
- Breathing
- Circulation-hypotension
The most common cause of poisoning death is ___
loss of airway or breathing
*Airway management will prevent most poisoning deaths
Many poisonings cause a ___
Patients compensate with a __
metabolic acidosis
respiratory alkalosis
If you are controlling ventilation, you need to maintain ____
metabolic compensation
*So hyperventilate the patient (a little) until you see their blood gas
Most poisoned patients circulatory status
- hypovolemic
- Decreased oral
- Vomiting
- Vasodilation
tx for circulation resuscitation
- Give fluids unless clear volume overload
- Peds 20 ml/kg saline
- Adults 2L - If no response, begin adrenergic vasopressor
- Dopamine, epinephrine, norepinephrine
Complication of poor circulation
- arrhythmias (slow or fast and narrow)
* fixing rate does not fix BP
Tx of slow rhythm from poor circulation
- Atropine, Pacing
- Digoxin Fab?
Tx of fast and narrow rhythm from poor circulation
- Most commonly caused by hypovolemia or CNS stimulation
- Give fluids, sedation with benzodiazepines
tx of fast and wide rhythm from poor circulation
- Most common in medical cases due to heart disease
- Amiodarone and shock - Most common in poisoning due to sodium channel blocking
- Hypertonic sodium bicarbonate (1-2 meq/kg) push
* *Won’t improve by shocking
What most commonly causes:
- fast and narrow rhythm:
- fast and wide rhythm:
- fast and narrow rhythm:hypovolemia or CNS stimulation
- fast and wide rhythm: Na channel blocking or heart dz (MI, electrolyte abnormality)
What drugs block potassium channels
- Antipsychotic medications
- Haloperidol
- Antidepressants- venlefaxine
- Cardiac drugs- Propafanone, quinidine, sotalol
What is the ECG manifestation of potassium channel blocking?
prolonged QT–> can lead to Torsades (polymorphic VT)
What is the ECG manifestation of Na channel blocking?
Wide QRS
When does Torsades typically happen
- uncommon w/ meds
2. usually only w/ bradycardia
TX of torsades
- Defib
- Magnesium 2g iv
- Cardiac pacing to rate >100 BPM
Complications of CNS depression and CNS excitation
CNS depression- manage airway
CNS excitation- agitation or seizure
TX of CNS deficits
- Benzodiazepines- 2-5 mg lorezepam repeated as needed
- If not responding consider paralysis and propofol or other general anesthetic
- Cool patients if hyperthermia develops*
How do you tx the sx of CNS effects, CV, and vomiting
- Monitor for CNS effects
- Intubate for severe sedation
- Sedate for severe agitation - Monitor for CV effects
- Fluids/pressors for hypotension
- Treat dysrhythmias as discussed - Antiemetics for vomiting
Most common manifestation of poisoning
vomiting
How can you predict what sx might happen?
- Extension of therapeutic effect
- Hypotension after ingestion of a anti-hypertensive
- Coma from a sedative overdose - Extension of side effect
- Sedation from antipsychotic
- Seizure from ADD medication - Other effect– Use your resources or call the PC
Treat the patient not the poison!!
Most of the time you don’t need to know the exact poison- just treat the __
symptoms
*However, sometimes you can figure out the poison from the symptoms
What are toxidromes
*Collection of symptoms that are caused by a specific exposure
Toxidromes are usually due to a xenobiotic that acts at a wide spread receptor type including
- Opioid
- Adrenergic
- Anticholinergic
- Muscarinic cholinergic
- Serotonergic
Presentation of Opioid toxidrome (oxycodone, heroin)
- CNS depression
- Respiratory depression
- Miosis=small pupils
- Decreased bowel sound (ileus)
- Bradycardia
Presentation of Sympathomimetic toxidrome
- Agitation and extremely paranoid/Vigilant
- Tachycardia
- fever
- HTN
- Tachypnea
- Hyperactive bowel sounds
- Sweating
- Dilated pupils
Examples of Sympathomimetics
- Cocaine
- Methamphetamine
- “Bath Salts”
- Ecstasy
- Ephedrine
Presentation of Anticholinergic toxidrome (benadryl, atropine, jimsonweed)
- *Red as a beet, dry as a bone, mad as a hatter, hot as a hare, blind as a bat
1. Agitated and confused/delirium
2. Fever
3. Dry flushed skin
4. huge pupils/dilated= mydraisis
5. Urinary retention
6. Dry mouth
Presentation of Cholinergic crisis / toxidrome (organophosphate, nerve gases)
SLUDGE
- Salivation
- Lacrimation
- Urination
- Defecation
- GI upset (diarrhea)
- Emesis
- pulm. edema wheezing/cough/rales
- miosis (constricted pupils)
- muscle fasciculations*
Other managements of poisonings
resuscitation, sx managment
- Decontamination
- Antidotes
- Drug screens
- Poison Center
presentation of Serotonin toxidrome
hx: PCP changed from paroxetine to venlafaxine 3 days ago
1. Hyperreflexia
2. Fever
3. Tachycardia
4. Flushed skin
5. confusion/mental status changes
6. seizure
7. Tremor/shakey
*Clinical Dx
Tx of Serotonin toxidrome
- Benzos- to sedate
- Give Cyproheptadine
- admit
- +/- cool patiet
Common after OD or adding new serotonergic med
- Effects vary from mild-severe
- mild-tremor anxiety
- Severe- delirium hyperthermia rigididy
Serotonin toxicity
Describe the use/concept of decontamination
- Concept- keeping the poison from being absorbed will prevent the toxicity
2 Reality-
- Most poisons don’t cause severe symptoms
- Many patients present with symptoms because the poison is already in their system
- Decontamination methods are not very effective (decrease ~30-60% absorption)
- Used selectively (if ever!)
What are ways to decontaminate
- *never induce vomiting!!
1. activated charcoal**
2. Gastric lavage (pumping of the stomach- rarely used)
3. Whole bowel irrigation (Huge doses of polyethylene glycol to push bowel contents through- rarely used)
Complications of activated charcoal
Can cause severe pneumonitis if aspirated
*do not give if they are at risk of aspiration– very sleeping, vomiting,
When are antidotes used
(Drugs that reverse or attenuate a specific poison)
- Most poisoned patients do not need an antidote
- Used WITH SUPPORTIVE CARE to treat a poisoned patients
Most pharmaceutics are bound by charcoal but activate charcoal must be given __
BEFORE the drug is absorbed
-Huge doses of polyethylene glycol to push bowel contents through- rarely used
Commonly done w/ drug smuggling or extended release med
Whole bowel irrigation
How do drug screens affect management?
- Drug screens rarely change management
- If the drug screen is positive and the pt has no symptoms you don’t treat them
- If the drug screen is negative and the patient has symptoms you still treat them
*Presence does not mean intoxication!
When do you use urine or blood for drug screens
- For screening use urine**
Drugs are concentrated for excretion- easier to detect - For quantitative concentrations use blood
Serum concentrations correlate best with effects
*also use for renal failure with no urine production
*more likely to detect the drug in urine bc it concentrates there and blood also has more things in it– use urine to screen
Most common drug screen is __
an immunoassay that looks for specific drugs
- Cocaine, amphetamines, opioids, benzos, marijuana
- Don’t order if you are interested in something else
What are some common drugs that are missed on drug screen
- Methadone- can hide opioids
- Fentanyl
- Clonazepam
*And (rarely) false positives occur in general
What are some other methods of drug screens that may detect more drugs
Gas chromatography/Mass spectrometry can detect >1000 drugs
- These tests are generally done in reference labs and not rapidly available
- For medical-legal cases (e.g. deliberate poisoning) you need to preserve chain of custody (contact your lab)
What is the bottom line for drug screens
- Bottom line- Order the test but understand the limits
1. Treat the patient not the test
2. You wont find what the immunoassay doesn’t look for
3. If you really need to know you can order a reference test- but it will take a while
___ overdoses are common but rarely serious
___ ingestions account for most deaths
Accidental pediatric
Deliberate adult
Most common OD that results in hospitalization in US
acetaminophen
Describe the management and tx of acetaminophen OD
- Calculate if exposure is potentially toxic (>150mg/kg)
- Need a tylenol level FOUR HRS after exposure
- Tx w/ acetylcysteine (NAC) 150 mg/kg –> repeat dosing until acetaminophen no longer detected in serum
*if the 4 hour tylenol level is greater than 150microgram/ml, treat
NAC is most effective if given w/in ___
8 hrs, but even delayed administration is helpful
27 year old ingests 3 gms amitriptyline
What are the expected symptoms?
What are the target organs?
- CV and neuro toxicitiy
Cardiac: wide complex tachy
What is the primary tx for QRS prolongation or dysrhythmia
- 1-2 meq/kg IV bolus
- Infusion not really effective
- Hypertonic saline if alkalemia present
what is the tx of adrenergic vasopreesors/ hypotension
Norepi considered pressor of choice for hypotension
Describe the presentation and tx of TCA OD
- Sedation-seizure
- EKG: Prolonged QT (wide, fast)
Tx:
- Bicarbonate
- tx seizure w/ benzos
Describe the evaluation ASA OD
- Confusion, pulmonary edema?
- BMP
- Renal function
- ? Acidosis and anion gap - Blood gas (venous)
- Mixed acid base disorder
- ? Compensation - Serum salicylate concentration
- Urine pH
SX of ASA OD
- N/V
- Tinnitus
- Increase respiration (Respiratory alkalosis)
- +/- renal failure
- Mixed acid/base disturbance
* anion gap acidosis causes a mixed A/B disorder - Pulmonary edema
- Mental status change/Cerebral edema
tx of ASA OD
- Calculate a potentially toxic ingestion (150-300mg/kg) or salicylate level of >30
- Tx w/ fluids, urine alkilinazation w/ bicarc
- dialysis prn
Who needs dialysis for ASA OD
- NOT JUST A CONCENTRATION
- Failure of medical management
- Metabolic
- Increasing levels - Fluid overloaded/Pulmonary edema
- Renal failure
- Altered mental status
Enteric coating ASA overdose may not peak for __, which requires __
24 hours
*Intubation and standard ventilator settings may lead to respiratory acidosis so adjust their minute ventilation (increase)
*Anion gap not always as high as you think
Probably true in mild/early cases
How do you calculate if an acetaminophen ingestion is a toxic dose?
Toxic dose is 150mg/kg
Do a calculation: 30 tablets x500mg – 1500 mcg/weight…; also talk about a serial tylenol level if concerned
SX of carbon monoxide poisoning
- Nonspecific Sx
1. HA
2. N/V
3. Dizzy
4. Mental status
5. Consider it seasonally- spring and fall when heating system start to work
6. Ataxia
Describe the evaluation of CO poisoning
- Send a venous CO/ Carboxyhemoglobin
* O2 sats are NOT helpful
Consider:
- Brain injury- Syncope, mental status test, ataxia
- Cardiac injury- CP, ecg, trops
Describe the tx of CO posioning
** high flow o2 (all symptomatic patients)
-hyperbaric oxygen (no consensus on efficacy)
clues to CO poisoning
- spring and fall when heating system start to work
- working w/ a generator in basement/garage
- N/V/HA but no fever
**Key is making dx to avoid reexposure
SX of spice OD/ingestion (K2)
- N/V
- coma
- bradycardia
- hypotension
**not detected on drug screens
TX of spice OD/ingestion
- Treat supportively
2. Some become agitated and may have seizures–Treat with benzodiazepines
Substituted amphetamines
Sold as “not for consumption”
bath salts
SX of Bath salt ingestion/smoked
- Moderate stimulant similar to MDMA
- sympathomimetic toxicity,
- psychosis and
- rhabdomyolysis
SX of GHB intoxication
- Initial intoxication/euphoria
- May progress to profound coma
- Patients seen to wake up with airway management attempts
- Symptoms usually resolve over 4-6 hours
Tx of the following toxidromes:
- Opioid:
- Sympathomimetics:
- Cholinergic:
- Anticholinergic:
- Opioid: Naloxone or supportive
- Sympathomimetics: benzo, hydration, cooling
- Cholinergic: atropine, airway
- Anticholinergic: benzo, cooling, Physostigmine prn
Presentation of sedative/hypnotic OD (benzos, barbiturates)
- Decrease LOC
- slurry speech
- ataxia
- Bradycardia
- Bradypnea
tx of sedative/hypnotic OD (benzos, barbiturates)
ventilatory support prn otherwise just time
Presentation of EPS OD (haldol, phenergan, reglan)
- Dystonia
- Muscle rigidity
- restlessness
Tx of EPS OD (haldol, phenergan, reglan)
Benadryl
benzo
What can cause Methemoglobinemia
- pyridium
2. Oragel/benzocaine
Describe the presentation and tx of Methemoglobinemia
- cyanosis
- cyanosis that is unresponsive to supplemental O2
Tx: Methylene blue
