Class 4 (02|01|22) Toxicology - Overdose & Poisonings Flashcards
What are toxidromes?
What do they help with?
Is it a perfect science?
a group of clinical signs and symptoms associated with a toxic ingestion or exposure (often with overdosage)
Help with the identification of common signs and symptom pt are presenting with which help HCP determine the class of drugs uses Combination of specific signs and symptoms that reflect drug class effects on particular neuroreceptors
Imperfect because symptoms from multiple toxins can overlap, clouding the clinical picture
Toxidormes Classication
Downers
opioid
Sedative-Hypnotic
Cholinergic
Fast & Furious
Anticholinergic
Sympathomimetic
Downers — OPIOIDS
examples
Morphine, Codine, Tramado, Heroin, Meperidine, Diphenoxylate, Hydromorphone, Fentanyl, Methadone, Propoxyphene, Pentazocine, DXM, Oxycodone, Hydrocodone
Downers — OPIOIDS
pathophysiology
stimulate three receptors in the CNS and PNS
Downers — OPIOIDS
main use
MAIN USE: analgesic properties — inhibits nociceptive information in the nervous system (prevents transmission of pain to the brain
Euphoria — increases dopamine release
Anxiolysis — lower anxiety
Downers — OPIOIDS
s/s
Heart Rate: decrease Resp Rate: decrease Temp: decrease Pupils: pinpoint/constricted Bowel sounds: decrease Skin: normal Mental status: depressed
Downers — OPIOIDS
management
ABCDE approach
Naloxone-: block effect of opioid
Blood Glucose:hypoglycemia can present similarly
GI decontamination: risk for aspiration so a later resort
Downers — OPIOIDS
significant clinical findings
resp rate > 12 is usually the best indicator
Look for tach marks
Downers — SEDATIVE-HYPNOTIC
examples
Anti-anxiety agents, muscle relaxants, antiepileptics and preanesthetic medications -Barbiturates - Benzodiazepines
Downers — SEDATIVE-HYPNOTIC
treatment/managment
ABCDE approach — focusing on the life threatening aspects (cardio, resp depression)
Dialysis in order to clear the toxins
Flumazenil: Benzo - antagonist: blocks the effects of the benzodiazepines
Downers — SEDATIVE-HYPNOTIC
s/s
Heart Rate: decrease Resp Rate: decrease Temp: decrease Pupils: no change Bowel sounds: decrease Skin: normal Mental status: depressed
Downers — SEDATIVE-HYPNOTIC
useages
Choral hydrate: sedation in hospital
Rohypnol: date-rape-drug (gamma hydroxybutyrate)
Downers — SEDATIVE-HYPNOTIC
patho
enhance the effect of the GABA transmitter that blocks impulse nerve cells and brain
Increase GABA/blockage, they can improve mood and anxiety
When taxes in excess, end up with toxidrome: sedative and hypnotic
Downers — SEDATIVE-HYPNOTIC
what present similarly
signs and symptoms of the over dose can look like alcohol usage
What is Flumazenil?
Flumazenil: Benzo - antagonist: blocks the effects of the benzodiazepines (Downers — SEDATIVE-HYPNOTIC)
Antagonsis
Downers — CHOLINERGIC
examples
Organic Phosphorous Compounds: Carbamates, Arecholine, Pilocarpine, Urecholine (Betanechol), Carbachol, Choline, Metacholine, Mushrooms
Downers — CHOLINERGIC
common uses
found in agriculture and chemicals
Included in medications
Downers — CHOLINERGIC
patho
increase levels of acetylcholine at the neuromuscular junction due to the inactivity of the acetylcholine enzyme which would normally break down acetylcholine
Results with increase levels and longer duration at the receptor of acetylcholine
Symptoms arise when the receptors found: smooth muscle of GI, bronchi, heart, salivary & sweat glands, and ciliary body of eye
Downers — CHOLINERGIC
“classic” set of s/s
SLUDGE
Increase salivation and sweating increase lacrimation increase urinary incontinence increase diarrhea increase GI cramps increase emesis
Downers — CHOLINERGIC
s/s
Heart Rate: no change - decrease Resp Rate: no change Temp: no change Pupils: pinpoint/constricted Bowel sounds: increase Skin: diaphoresis Mental status: depressed, confused, seizures
Downers — CHOLINERGIC
treatment/management
- anticholinergic medications: atropine (IV) | diazepam: treat seizures
Fast & Furious — ANTICHOLINERGIC
examplese
Anticholinergics - Atropine, scopolamine, glycopyrrolate benztropine, trihexyphenidyl
Antihistamines - chlorpheniramine, cyproheptadine, doxylamine, hydroxyzine, dimenhydrinate, diphenhydramine, meclizine promethazine
Fast & Furious — ANTICHOLINERGIC
common uses
Tricyclic antidepressants, muscle relaxants, anti-psychotics, antimuscarinic agents for an overactive bladder (Oxybutlnin)
Plants
Fast & Furious — ANTICHOLINERGIC
patho
inhibition of the muscarinic cholingeric neurotransmission: block the acetylcholine from blinding to receptors (blocks parasympathetic nervous system and body will enter fight to flight mode with no regulation)
Reports can be found on the smooth muscle on the Gi tract, bladder, heart, sweat glands, ciliary of eye, salivary glands
Fast & Furious — ANTICHOLINERGIC
s/s
Heart Rate: increase Resp Rate: no change Temp: increase Pupils: dilated Bowel sounds: decrease Skin: normal - dry Mental status: depressed, confused, hallucinations, seizures
Fast & Furious — ANTICHOLINERGIC memorization technique (5)
Mad as a hatter - altered mental status blind as a bat - mydriasis red as a beet - flushed skin hot as a hare - skin dry dry as a bone - dry mucous membranes
Fast & Furious — ANTICHOLINERGIC
significant clinical findings
body cannot sweat so it regulates body temp by becoming hyperthermic
Tachycardia: earliest and most reliable s/s
Fast & Furious — ANTICHOLINERGIC
treatment
ABCDE approach:
Gastric decom. : activated charcoal
Diazepam: calm, treat seizures
Physostigmine salicylate: antidote for anticholingeric toxicity
What is physostigmine salicylate?
Physostigmine salicylate: antidote for anticholingeric toxicity
Fast & Furious — SYMPATHOMIMETIC
examples
where is it found in medication?
Caffeine, cocaine, amphetamines, methamphetamines, ritalin, LSD, Theophylline, MDMA
Medication: E, NE, dopamine
Fast & Furious — SYMPATHOMIMETIC
patho
CNS stimulation increase because increased circulating levels of catecholamines (E/NE and dopamine)
Causes reduced catecholamine re-uptake at the pre-ganglionic synapse (body in fight or flight and unable calm itself down)
Fast & Furious — SYMPATHOMIMETIC
s/s
Heart Rate: increase Resp Rate: increase Temp: increase Pupils: dilated Bowel sounds: increase Skin: diaphoresis Mental status: alert, agitated, seizures
Fast & Furious — SYMPATHOMIMETIC
significant clinical findings
hyperthermia here can result in rhabdomyolysis and brain injury acidosis and essentially disseminated intravascular coagulation — life-threatening cerebral hemorrhage
Agitation, psychosis, seizures, responsive dilated pupils
Can lead to excited delirium
COMMON causes of death: intracerebral haemorrhage, hyperthermia and arrhythmias (VIA acidosis, tachycardia and hypertension)
Fast & Furious — SYMPATHOMIMETIC
treatment
ABCDE approach
Hyperthermic: cool, ice packs, fans, Cooling blanket
Hypertension: nipride- potent vasodilator (IV)
Diazepam: slow body down and help control seizures
Using toxidromes, what should be assessed/affect the airway?
Look for signs of inability to protect airway (secretions, vomiting)
LOC decreased to the extent of unable to protect airway
GCS comma scan <8
Implement interventions if needed
Using toxidromes, what should be assessed/affect the breathing?
(Rate, Depth)
- intervene: beg valve mask ventilation, O2
Using toxidromes, what should be assessed/affect the circulation?
Careful attentions to colour of skin and diaphoresis/dryness
Using toxidromes, what should be assessed/affect the disability?
GCS: responsive, unresponsive
Pupils
Movement of extremities
Glucose: s/s can mimic hypoglycaemic
Using toxidromes, what should be assessed/affect the Elimination/Exposures?
Remove clothing Transdermal patches External contaminants: substance on clothing or personal Measure temp Look for tack marks Skin infections
What does the following diagnostic testing indicate?
blood glucose
CBC, electrolytes
BUN/Cr
Blood glucose: baseline, rule out hypoglycaemia
CBC, electrolytes: baseline, risk of arrhythmias with certain toxins, fluid balance
BUN/Cr: evaluate the kidney function and the risk of rhabdomyolysis
What is rhabdomyolysis?
rhabdomyolysis: when the skeletal muscle fibres begin to break down and the muscle content leak into circulations (can happen in certain toxin overdoses
What does the following diagnostic testing indicate?
liver enzymes
INR/Ptt
Serum osmolality
liver enzymes: want baseline for liver function, determine if there abnormalities to make it difficult to excerpt toxin
INR/Ptt: asses risk increase risk of bleeding
Serum osmolality: what substance are dissolved in our blood; sodium glucose and urea are primary substance
What does the following diagnostic testing indicate?
Lactate
Urinalysis
Beta-HCG
Lactate: acidotic determine through arterial blood gas
urinalysis: aspirin overdose - help determine treatment to affect the alkalinization of the urine
Beta-HCG: pregnant
What does the following diagnostic testing indicate?
Troponin
CK
Tox Screen
Troponin: myocardial damage
CK (creatinine kinase: skeletal muscle damage
Tox screen: Serum (ASA, alcohol, acetaminophen etc) and urine — help determine how much is in the system or how much has been eliminated
Using toxidromes, what should be done for management for airway?
- intubate if not protecting airway (GCS >8)
Using toxidromes, what should be done for management for breathing?
provide oxygen and respiratory support as needed
Respiratory support: mechanical ventilation, beg valve mask ventilation
Using toxidromes, what should be done for management for circulation?
vascular access: IV
IV fluids/pressors as needed: rehydrate to clear toxins, if BP is low
Insert folet
Using toxidromes, what should be done for management for Disability?
treat hypo/hyperglycemia if present
Using toxidromes, what should be done for management for Elimination/exposures?
- remove clothing transdermal patches, external contaminants
What can be done to manage to reduce absorption with drug toxicity?
Gastric decontamination
Describe Gastric decontamination
REDUCING ABSORPTIOM
activated charcoal is a special form of carbon that can bind other substances on its surface
Used to absorb drugs in the GI tract to reduce absorption (VIA drink or nasal gastric tube)
Advers effects: nausea, vomiting
what can be done to manage to reduce metabolism with drug toxicity?
examples (4)
Antidote or competitive inhibitors
Narcan (Naloxone)
Flumazenil (benzodiazepine antagonist/antidote: sedative-hypnotic)
Physostigmine (anticholinergic antidote)
Atropine (cholinergic antidote)
Describe the mechanism of action of the competitive inhibitor Narcan (Naloxone).
Opioid antagonist (VIA competes the receptor site so opioid cannot but uptake) - nasal spray or injection (IM/SC) Only works w opioids
Describe the mechanism of action of the competitive inhibitor Flumazenil (benzodiazepine antagonist/antidote)
Flumazenil (benzodiazepine antagonist/antidote): compete for the receptors
Describe the mechanism of action of the competitive inhibitor Physostigmine (anticholinergic antidote)/
reverse the effects of the anti-cholinergic by increase the level of acetylcholine at the site of transmission (IV, IM)
Describe the mechanism of action of the competitive inhibitor Atropine.
competitive antagonist of muscarinic receptors - competitive inhibition of the postganglionic acetylcholine receptors which leads to the parasympathetic inhibition of the acetylcholine receptor in the smooth muscle
IV, subQ, endotracheal tube, IM
Using toxidromes, what examples for management for elimination? (4)
Alkalinization of the blood or urine
Hydration (IV fluids)
Hemodialysis
saline diuresis
In management of drug toxicity, how does Alkalinization of the blood or urine work?
Alkalinization of the blood or urine: alter the urine pH to increase excretion
Sodium bicarbonate: pH >7.5 allows more drug to be excrete through the urine (used in aspirin OD’s)
In management of drug toxicity, how does Hydration (IV fluids) work?
Hydration (IV fluids): increases volume of urinary fluids
In management of drug toxicity, how does
When is hemodialysis commonly used?
Common: alcohol, ethylene glycol methanol OD’s, lithium, acetaminophen, aspirin, dilantin
In management of drug toxicity how does saline diuresis work?
patient dehydrated where admin of fluid will increase excretion of the toxin/substance
How are Antihypertensives used to manage overdoses?
Pt presenting with sympathomimetic toxidromes - hypertension is common
Nipride
What are the s/s of the first phase of Acetaminophen Overdose?
1st 24 hours S/s not specific n/a unwell asymptomatic
What are the s/s of the second phase of Acetaminophen Overdose?
24-72 hours (1-3 days)
Elevation in liver function test: AST & ALT, billrium, prothrombin time
Right upper qua pain
What are the s/s and time period of the third phase of Acetaminophen Overdose?
72-96 hours (3-5 days)
Liver becomes necrotic: s/s liver dysfunction
Hepatic encephalopathy: VIA ammonia level increasing
Bleeding
Hypoglycemia
What are the s/s and time period of the fourth phase of Acetaminophen Overdose?
5-7 days
Complete resolutions if damage cause is reversible OR
Liver transplant
What is the treatment of Acetaminophen Overdose?
Treated with NAC (w in 8 hours)
N-acetylcysteine (Parvolex/Mucomyst)
Administered intravenously
Not an antidote but interferes with the binding to reduce absorption and metabolism of the drug
Describe Acetaminophen Overdose — Pathophysiologic Effects.
Acidic environments (stomach) allow for more drug absorption compared with tissue at a hight pH May cause spasm of pyloric sphincter Small amount excreted unchanged in urine
What significant parts of the body does Salicylate Overdose affect?
It is an acid to when there is an overdosage, it ends up effecting the cardiac myocardial function which contributes to toxicity
Acid environment of stomach aids absorption (food delays absorption)
What are the early symptoms of a Salicylate Overdose?
Nausea
Vomiting
Dizziness
Tinnitus: ringing in ears
What symptoms indicate moderate toxicity in Salicylate Overdose? (>250mg/kg)
tachypnea Hyperpyrexia Sweating Dehydration Agitation Ataxia Restlessness
What symptoms indicate severe toxicity in Salicylate Overdose? (>500mg/kg)
hypotension Metabolic acidosis Cerebral edema Oliguria Renal failure Coma Seizure Acidosis can cause cardiac dysrhythmias and cardiac failure
Describe the impact Salicylate Overdose has on the body. (resp, blood glucose, cerebral edema, cardiac, kidneys)
respiratory: respiratory alkalosis
Glucose homeostasis affected: interference of the KREB’s cycle (glycogen depleted results with low serum glucose levels)
Cerebral edema: increase
Myocardial depression and hypotension from the increasing acidic
Kidneys eliminate HCO3-, Na+ and K+: bc of increase acidosis
Need to admin electrolytes to stabilize ^
What are the 6 phases of a basic approach to a poisoned patients?
(1) immediate assessment and stabilization
(2) laboratory assessment,
(3) decontamination,
(4) administration of an antidote,
(5) elimination enhancement of the toxin, and
(6) disposition
What are the 5 basic intervention/management of a poisoned patient?
high flow oxygen for pt w suspected poisoning or ingestion and exhibit resp compromise
Blood glucose taken - hypoglycaemic 50mL of 50% dextrose
100 mg thiamine for Wernicke’s encephalopathy or alcohol use
Naloxone max 2 mg @ 0.1mg/kg
Seizure control - benzodiazepines & pyridoxine (vit. B6)
