KC Tox Flashcards
*What drugs cause false positives on urine drug screens?
Dextromethorphan (opiates/PCP)
Diphenhydramine (opiates/PCP)
Labetalol (amphetamines)
Tramadol (PCP)
NSAIDs (PCP/THC)
PPI (THC)
Quinolones (opiates)
Ranitidine (amphetamines)
Basically all the antidepressants
*2 properties of meds that make them able to be dialyzed
- Low molecular weight
- Low protein binding
- Low volume of distribution
- Low plasma clearance
- Low dialysate concentration
- High water solubility
*7 toxicologic causes of seizure besides alcohol and withdrawal states (different categories)
Seizures (OTIS CAMPBELL)
O organophosphates, oral hypoglycemics
T tricyclic antidepressants
I isoniazid, insulin
S sympathomimetics, strychnine, salicylates
C camphor, cocaine, carbon monoxide, cyanide, chlorinated hydrocarbons
A amphetamines, anticholinergics
M methylxanthines (theophylline, caffeine), methanol
P phencyclidine (PCP), propranolol
B benzodiazepine withdrawal, botanicals (water hemlock, nicotine), bupropion, GHB
E ethanol withdrawal, ethylene glycol
L lithium, lidocaine
L egad, lindane
*List 4 indications for emergent hemodialysis (drugs)
Dialyzable toxins
STUMBLED
S salicylates
T theophylline
U uremia
M metformin/methanol
B barbiturates
L lithium
E ethylene glycol
D Depakote (valproic acid—in massive overdose)
*List 3 reasons favouring GI decontamination
Early presentation, no antidote, deadly poisoning
*3 methods you could use to decontaminate (PO ingestion CCB)
Gastric lavage, charcoal, WBI
*2 contraindications to GI decontamination in an overdose patient
Delayed presentation, effective antidote
*List 3 potential adverse consequences of GI decontamination
Aspiration, perforation, laryngospasm, bradycardia (vagal), lytes disturbances, bradycardia, epistaxis
*List 3 toxic mechanisms of theophylline
PDEi, beta-agonist, alpha-agonist
*List 5 major clinical manifestations of severe theophylline toxicity
Seizures, dysrhythmias, N/V/D, hypotension, coma
*What is the most common cause of death in theophylline toxicity?
Dysrhythmias
*What is the definitive treatment of choice in theophylline toxicity?
Dialysis
List 3 tox agents that cause miosis and 3 that cause mydriasis
Miosis COPS:
Cholinergics, clonidine, carbamates
Opioids, organophosphates
Phenothiazines (antipsychotics), pilocarpine, pontine hemorrhage
Sedative hypnotics
Mydriasis SAW:
Sympathomimetics
Anticholinergics
Withdrawal syndromes
List 5 agents that can cause coma or seizures
LETHARGIC
Lead, lithium
Ethanol, ethylene glycol
Tricyclic antidepressants, thallium, toluene
Heroin, hemlock, hepatic encephalopathy, heavy metals, hydrogen sulfide
Arsenic, antidepressants, anticonvulsants, antipsychotics, antihistamines
Rohypnol, risperidone
GHB
Isoniazid, insulin
Carbon monoxide, cyanide, clonidine
List the toxins associated with each of the following smells
Bitter almonds
Carrots
Fruity
Garlic
Mothballs
Pears
Oil of wintergreen
Rotten eggs
Bitter almonds = cyanide
Carrots = water hemlock
Fruity = DKA, isopropanol
Garlic = organophosphates, arsenic
Mothballs = camphor
Pears = chloral hydrate
Oil of wintergreen = methylsalycylate
Rotten eggs = sulfur
List ingestions associated with bradycardia
PACED
Propranolol, poppies (opioids), physostigmine
Anticholinesterase drugs, antiarrhythmics
Clonidine, calcium channel blocks
Ethanol or alcohols
Digoxin
List ingestions associated with tachycardia
FAST
Free forms of cocaine
Anticholinergics, antihistamines, antipsychotics, amphetamines, alcohol withdrawal
Sympathomimetics (cocaine, caffeine, amphetamines, PCP)
Theophylline, TCAs, thyroid hormones
List ingestions associated with hypothermia
COOLS
Carbon monoxide
Opioids
Oral hypoglycemics, insulin
Liquors (alcohol)
Sedative-hypnotics
List ingestions associated with hyperthermia
NASA
NMS
Antihistamines, alcohol withdrawal
Salicylates, sympathomimetics, serotonin syndrome
Anticholinergics, antidepressants, antipsychotics
List ingestions associated with hypotension
CRASH
Clonidine, calcium channel blockers
Rodenticides
Antidepressants, antihypertensives
Sedative-hypnotics
Heroin or other opioids
List ingestions associated with hypertension
CT SCAN
Cocaine
Thyroid supplements
Sympathomimetics
Caffeine
Anticholinergics, amphetamines
Nicotine
List ingestions associated with tachypnea
PANT
PCP, paraquat, pneumonitis
ASA
Noncardiogenic pulmonary edema, nerve agents
Toxin induced metabolic acidosis
List ingestions associated with slow respirations
SLOW
Sedative-hypnotics (barbiturates, benzos)
Liquor (alcohol)
Opioids
Weed (marijuana)
List substances that can cause a wide anion gap metabolic acidosis
A CAT MUD PILES
Alcohol ketoacidosis
Cyanide, CO, colchicine
Acetaminophen
Toluene
Paraldehyde, phenformin
Isoniazid, iron, ibuprofen
Lactic acidosis
Ethylene glycol
Salicylates
Methanol, metformin, massive ingestions
Uremia
Diabetic ketoacidosis
How do you calculate anion gap
Na - (HCO3 + HCL)
Elevated if >12
List causes of metabolic acidosis without an anion gap
Loss of bicarb (diarrhea, renal tubular acidosis)
Gain of chloride (ammonia, calcium chloride)
HARDUP
Hyperalimentation
Acetazolamide
RTA
Diarrhea
Ureteroenterostomy
Pancreatoenterosomites
List potentially lethal toxins where activated charcoal should be used
Killer Cs
Cyanide, colchicine, calcium channel blockers, cyclic antidepressants, cardio glycosides, cyclopeptide mushrooms (amanita phalloides), cocaine, cicutoxin, salicylates
List substances that do not bind to activated charcoal
PHAILS
Pesticides, hydrocarbons, heavy metals, acid/alkalis, iron, lithium, solvents
List substances amenable to multidose activated charcoal
ABCDQ (drugs with significant enterohepatic circulation)
Aminophylline/theophylline
Barbiturates
Carbamazepine, concretion forming drugs ex. Salicylates
Dapsone
Quinine
List 3 substances amenable to serum alkalinization
Salicylates, methotrexate, phenobarbital
List 3 mechanisms for intravenous fat emulsion
Lipid sink
Enhance cardiac metabolism of free fatty acids
List drugs amenable to lipid emulsion
Refractory beta blocker overdose, calcium channel blocker overdose, bupropion, cocaine toxicity
List the antidotes for each of the following
Acetaminophen
Methanol/ethylene glycol
Organophosphates
Iron
Arsenic
Isoniazid
Acetaminophen = N-acetylcysteine
Methanol/ethylene glycol = fomepizole
Organophosphates = atropine/pralidoxime
Iron = deferoxamine
Arsenic = Dimercaprol (BAL)
Isoniazid = pyridoxine
How do you calculate serum osmols
2*Na + BUN + glucose
List 4 causes of al elevated osmolar gap
ethylene glycol, methanol, acetone, mannitol, polyethylene glycol (IV lorazepam), ketosis (diabetic, alcoholic), renal failure, multi-organ failure, IVIG, pseudohyponatremia, uremia
List 3 causes each of Type A and Type B lactic acidosis
Type A: poor perfusion: sepsis, mesenteric ischemic, hemorrhage
Type B: no hypoperfusion
- Metformin, DKA
- Seizure
- Alcohol: liver dysfunction, alcoholic ketosis, toxic alcohols
- Mitochondrial defects
- Drug s/e: Ventolin, propofol
- Tox: salicylate poisoning, carbon monoxide, cyanide, massive Tylenol
List 4 toxins that are radio-opaque
CHIPES: Calcium carbonate, heavy metals (Fe), iodized toxins (thyroxine), packer/potassium/psychotropics, enteric coated pills (ASA, slow K), solvents (halogenated hydrocarbons)
List 3 methods of GI decontamination
orogastric lavage, charcoal, whole bowel irrigation
What is the dose of activated charcoal
1g/kg PO (usually 50g) or 10g AC per 1g of toxin in a single dose
What is the dose of whole bowel irrigation
PEG 100ml/hr titrated up to 1-2L/hr until rectal effluent is clear
You are 100-1000% going to shit your pants
For what toxins is decontamination with water contraindicated
metals (potassium, magnesium, sodium) as these can ignite on contact with water
List 3 methods of elimination
Urine alkalinization, MDAC, dialysis
What is the dose for multi dose activated charcoal
loading dose (10:1) followed by 50% of initial dose every 4-6 hours for 24 hours
List 4 ingestions associated with wide complex QRS
TCAs, type 1a and 1c antidysrhythmic, cocaine, diphenhydramine
List 5 ingestions associated with hypoglycemia
Oral hypoglycemic agents, sulfonylureas, insulin
Beta blockers, isoniazid, salicylates, ethanol
List 5 one pill can kill ingestions
ABC GET MOM
A - ASA
B - BBs
C - CCBs, clonidine, cardiac glycosides, colchicine, camphor
G - glucose lowering (sulfonylureas)
E - EG
T - TCAs, Theophylline
M - methanol
O - opioids
M - MAOIs, metals (iron, lead)
List 3 side effects of levamisole
agranulocytosis, leukoencephalopathy, cutaneous vasculitides
List 4 causes of a double gap
methanol, ethylene glycol, diabetic ketoacidosis, alcoholic ketoacidosis, uremia, septic shock, multiorgan failure
*What are the 4 stages of Ethylene Glycol toxicity?
1 - acute neurologic stage, 30 min - 12 hours
2 - cardiopulmonary stage, 12 - 24 hours
3 - renal stage, 24 - 72 hours
4 - delayed neurologic stage, bulbar palsy, 5 - 20 days
*What are the 3 toxic metabolites of ethylene glycol?
- Glycolic acid
- Glyoxylic acid
- Oxalic acid
*What are the 3 highly effective treatments for ethylene glycol toxicity and how do they work
- Sodium bicarbonate: Correcting metabolic acid may increase urinary excretion of EG and delay calcium oxalate- induced AKI
- Fomepizole/Ethanol: ADH blockade prevents metabolism of EG into toxic metabolites
- Dialysis: Removal of EG in the setting of acidosis (pH < 7.3)/renal failure/serum EG level > 8.1 mmol/L (level taken from Toxinz)
*What are the 2 vitamins that you can also give in ethylene glycol toxicity?
1) Pyridoxine
2) Thiamine
How do you adjust your anion gap for albumin
Albumin corrected anion gap = anion gap +2.5*(normal albumin-measured albumin)
Albumin is a negative charged protein. AG will be lowered in the presence of hypoalbuminemia, thereby masking an elevated AG - a normal AG may actually represent a metabolic acidosis
What is an abnormal anion gap
12
Normal gap 6-14, elevated if >12
How do you calculate your osmolar gap?
Osmolar gap = measured serum osmolarity – calculated serum osmolarity
Calculated serum osmolarity = 2Na + Glucose + BUN + 1.2EtOH
What is an abnormal osmolar gap
> 10
What is the delta gap?
Delta gap = (change in anion gap) - (change in bicarb)
Delta gap = (AG-12)-(24-HCO3-)
Determines if the anion gap is accounted for by the change in Bicarb
Positive delta gap = delta AG > delta bicarb = metabolic acidosis + metabolic alkalosis
No delta gap = delta AG = delta bicarb = pure AGMA
Negative delta gap = delta AG < delta bicarb = AGMA + non anion gap metabolic acidosis
What is Winter’s equation and when is it used?
PaCO2 = (1.5*serum HCO3-) + (8 +/- 2)
Used to calculate the expected arterial PCO2 for the serum bicarbonate level
Tells us if there is a mixed picture
Which two alcohols are toxic alcohols
Methanol and ethylene glycol
For methanol describe 1) common substances containing it 2) metabolism 3) clinical presentation 4) lab findings 5) management
1) Contained in windshield wiper fluid, de-icing products, paint removers, antifreeze, camping stove fluid
2) Methanol -> formaldehyde -> formic acid
3) Neurologic symptoms including optic neuritis, parkinsonism, ataxia, confusion
4) Labs show elevated osmolar gap and acidosis
5) Treated with fomepizole, folic acid 50mg, dialysis
For ethylene glycol describe 1) common substances containing it 2) metabolism 3) clinical presentation 4) lab findings 5) management
1) Found in radiator fluid, antifreeze, metal cleaners
2) Ethylene glycol -> glycolaldehyde -> glycolic acid -> oxalic acid
3) Stage 1 CNS, mimics alcohol intoxication. Stage 2 cardiopulmonary with myocardial dysfunction. Stage 3 renal failure with ATN from calcium oxalate crystals. Stage 4 late neurological sequelae i.e. bulbar palsy
4) Labs show elevated osmolar gap and acidosis. Typically high lactate. Hypocalcemia with calcium oxalate in the urine
5) Treated with fomepizole, pyridoxine 100mg, thiamine 100mg, dialysis
For isopropyl alcohol describe 1) common substances containing it 2) metabolism 3) clinical presentation 4) lab findings 5) management
1) Found in rubbing alcohol, hand sanitizer
2) Isopropyl alcohol -> acetone -> acetol
3) Intoxication, more prolonged than EtOH, fruit odor on breath
4) Ketosis and elevated osmolar gap without acidosis
5) Supportive care. No fomepizole as the metabolite is no more toxic than isopropyl alcohol itself. Fomepizole will only prolong CNS depression
How fast does ethanol metabolize
5.5 mmol/hr
What are the treatment goals in toxic alcohol
1) correction of acidosis 2) inhibition of the production of toxic metabolites 3) elimination of parent alcohol and its toxic metabolites
Is there a role for GI decontamination in toxic alcohol?
No; quickly absorbed
What are the indications for fomepizole
Methanol concentration > 6.2 mmol/L,> 3.2 for ethylene glycol
Hx of methanol or EG ingestion with an osmol gap >10
Suspected methanol or EG ingestion with at least 2 of: pH <7.3, Co2 level <20, urinary oxalate crystals present, osmolar gap >10
What is the dose of fomepizole
15mg/kg over 30 mins, then 10mg/kg over 30 mins q12 for the first 48 hours (x 4 doses) then 15 mg/kg q 12
List indications for hemodialysis in toxic alcohol
*Elderly man with alcohol use, memory impairment, wide based gait, nystagmus, ataxia. What is the likely diagnosis and treatment?
Wernicke-Korsakoff syndrome
Treatment: Thiamine and magnesium repletion
*Ddx Wernicke’s (6)
Stroke
Hepatic encephalopathy
Encephalitis
Intox
Brain tumour
Dementia
*What single lab test would be most likely to predict severe liver dysfunction in chronic EtOH use?
- AST/ALT ratio > 2 – MOST SPECIFIC TO ALCOHOL
*List three physical exam findings of Wernicke’s encephalopathy
Classic triad:
- Altered mental status
- Oculomotor dysfunction
- Gait ataxia
*List 10 side effects of ETOH withdrawal, as per the CIWA score
- Nausea or vomiting
- Tremor
- Paroxysmal sweats
- Anxiety
- Tactile disturbances
- Auditory disturbances
- Visual disturbances
- Headache
- Agitation
- Orientation and clouding of sensorium
*4 mechanisms of seizures related to alcohol use
- Withdrawal (alcohol or drugs)
- Neuro Exacerbation of idiopathic or post-traumatic seizures
- Infectious (meningitis, encephalitis, brain abscess)
4.Trauma (intracranial hemorrhage) - Metabolic (hypoglycemia, hyponatremia (Beer potomania), hypernatremia, hypocalcemia, hepatic failure)
*5 specific treatments that address the specific pathophysiology of alcohol withdrawal
- benzo: ativan, diazepam (1mg ativan = 5mg diazepam), switch to other agent after 400mg
- propofol
- phenobarb
- dexmedetomidine (for refractory)
- ketamine (for refractory)
- Thiamine (+magnesium)
*ETOH user. Dx AKA. What are the calculations for AG and DG
AG: [Na+] - ([Cl−] + [HCO − ])
Delta gap = (change in anion gap) - (change in bicarbonate) … (Anion gap - 12) - (24 - bicarbonate)
*What are FOUR causes of a double-gap acidosis (anion gap with osmolar gap)?
- Alcoholic/starvation ketoacidosis
- Diabetic ketoacidosis
- Ethylene glycol toxicity
- Methanol toxicity
*Describe the pathophysiology of alcoholic ketoacidosis.
1 - Long-standing ethanol user abruptly stops drinking (acute starvation on top of malnutrition)
2 - Ketones are generated (ketogenesis blocked by drinking) and accumulation of β-hydroxybutyrate and the inhibition of gluconeogenesis
*Treatment of AKA
- Fluids (D5NS)
- Thiamine
- Electrolyte replacement
- Correction of acidosis (should correct with above)
*In AKA, serum levels of which of the following would be elevated or depressed? Insulin, Ketones, Catecholamines, Lipolysis
Insulin - down
Ketones - up
Catecholamines - up
Lipolysis - up
What is the metabolism of alcohol
Alcohol by AHD -> alcohol dehydrogenase -> acetaldehyde -> acetyl coenzyme A _ CO2 + H20 (acetate)
What is the legal limit of alcohol
17 mmol/L
What is the pathophysiology of alcohol withdrawal
Decrease in GABA with the cessation of alcohol. Low GABA and high glutamate cause CNS excitation
What are the stages of alcohol withdrawal
Stage 1 (12-18hrs onset): shakes, sweating, agitation, anorexia, anxiety
Stage 2 (12-24): seizures
Stage 3 (12-24, often later): hallucinations
Stage 4: (3-5 days): delirium tremens
What is delirium tremens
Life threatening form of alcohol withdrawal characterized by altered sensorium (confusion, delusions) + autonomic hyperactivity (fever, tachycardia, hypertension)
Describe an approach to manage alcohol withdrawal
Diazepam 10-20mg PO or IV q15 until tachycardia is resolved and patient is comfortable. Phenobarbitals 5-10mg/kg (~65mg, can double each dose) as a second line agent
Alternatives would be to follow the CIWA protocol and give benzos if score >10
List 3 medications that can be used as anti relapse drugs in alcohol withdrawal
Naltrexone, gabapentin, disulfiram, acamprosate
List 10 long term effects of alcohol use
Neurological: withdrawal seizures, polyneuropathy, tremor, cerebellar dysfunction, ataxia, Wernicke’s, Korsakoff
Cardiovascular: increased HR/HTN, contribute to CAD and arrhythmias ex. Holiday heart
Resp: increased pneumonia, often concurrent smoking
GI: esophagitis, GERD, GI bleeding from varices, alcoholic hepatitis (AST/ALT >2), cirrhosis, pancreatitis
ID: immunosuppression
Heme: anemia, leukopenia, thrombocytopenia
Metabolic: hypoglycemia (likely due to starvation and depletion of liver glycogen stores) electrolyte deficiencies
List the components of the CAGE questionnaire
desire to cut back, annoyed when people ask, guilty about drinking, eye opener in the morning
What are the safe drinking guidelines
2023 Canadian guidelines
0 - health benefits, sleep benefits
1-2 - likely avoid harms
3-6 - increase CA risk (breast and colon)
>7 - increase MI and stroke risk
Don’t have more than 2 on one day per week
0 in pregnancy
List the components of SBIRT
Screening, brief intervention, referral to treatment
*Table of 4 stages of APAP toxicity
Stage 1 = Pre – Injury (<24hrs – 36hrs)
Asymptomatic
Possible N/V/Abdo Pain
Stage 2 = Liver Injury (8 – 36hrs)
N/V/Abdo Pain
Elevated AST/ALT
Stage 3 = Maximal Liver Injury (2-4 days)
Fulminant hepatic failure (enceph / coagulopathy / acidosis etc)
Stage 4 = Recovery (> 4 days)
Death or recovery
*4 criteria for liver transplant (APAP toxicity)
Kings College criteria:
pH < 7.30
INR > 6.5 (PT > 100 sec)
Creatinine 300 µmol/L
Grade III or IV hepatic encephalopathy
*Patient meets Kings College transplant criteria on BW. 6 things to do in the ED while waiting.
- IV crystalloid resuscitation
- IV NAC
- Intubation
- Consult transplant service
- Consult nephrology service regarding hemodialysis
- Regular monitoring of CBC/INR/PTT/VBG/glucose/LFT
*APAP level is zero. 2 reasons to still give NAC
For delayed, chronic, or supratherapeutic toxicity, NAC therapy should continue until acetaminophen is undetectable in the serum (<10 mcg/mL) AND:
- Any signs of liver injury have resolved (ie, encephalopathy has cleared, normalization of the coagulation profile, resolution of metabolic acidosis)
- AST is less than 1000 IU/L with demonstration of a downward trend
*If APAP is zero (pre-Tx) how is NAC still useful?
Decreases rates of cerebral edema, hypotension and death
*Describe the metabolism of APAP
Glucuronidation (50% range 40-67%)
Sulfation (30% range 20-46%)
CYP (~10%); this is what produces NAPQI
Direct Renal Clearance (~10%)
*What drug is used as an antidote to acetaminophen toxicity? List 3 ways in which it works.
Decrease toxic / free NAPQI
Glutathione precursor
Glutathione substitute
Direct reduction of NAPQI-APAP
Increase Sulfation route
Free radical scavenger
Hepatocyte stabilizing effect
*Describe the Rumack Matthews nomogram. What are 2 situations in which it is inapplicable? Describes level at which hepatic injury is likely.
Reference graph plotting serum APAP level and time in hours.
At 4h - levels greater than 1000 umol/L toxic
8h - greater than 500
12h - greater than 250
Not to be used in chronic ingestions, extended release preparations, co-ingestions etc.
*Acute EtOH ingestion increases the risk of Tylenol ingestion (T/F)
Chronic EtOH ingestion increases the risk of Tylenol ingestion (T/F)
False - CYP inducer is busy so less NAPQI is produced
True - more NAPQI is produced
*Concomitant ingestion of cimetidine is likely to worsen Tylenol toxicity (T/F)
10‐15% of Tylenol is metabolized by CYP450 pathway (T/F)
False (CYP450 inhibitor)
True
*Glucuronidation exceeds sulfonation metabolic pathway for Tylenol metabolism in adults (T/F)
Sulfonation exceeds glucuronidation as the dominant pathway in kids (T/F)
True
True
What is a massive Tylenol ingestion
> 500mg/kg or >50gm or acetaminophen ingestion + rapid onset of lactic acidosis, hyperthermia, hyperglycemia, altered mental status
List 4 risk factors for severe Tylenol toxicity
chronic use, chronic EtOH, pre-existing liver disease, malnourished, other CYP meds (ex. Rifampin, phenobarbital, phenytoin)
When should acetaminophen levels be measured
4 hours after ingestion and q4 hours until peaked
What Tylenol ingestion is likely toxic
200mg/kg or ~ 10-12g [OPC]
List indications for NAC
Acetaminophen level about the treatment line, chronic acetaminophen toxicity with signs of toxicity (clinical symptoms, elevated AST x2 limits, elevated APAP), clinical suspicion for massive ingestion, unable to get APAP level back within 8 hours of ingestion, acetaminophen ingestion + elevated liver enzymes
What is the dose for NAC
Will vary based on local poison control protocol
3% NAC 60mg/kg/hr for 4 hours + 6mg/kg/hr (max 600mg/hr) until stopping criteria reached
What is the stopping criteria for NAC
Tylenol level is undetectable AND
N-acetylcysteine has been given for at least 12 hours AND
AST/ALT <100 and falling and INR <2
What are the indications for dialysis in Tylenol poisoning
APAP >1000mg/L or 6620 umol/L without NAC
APAP >700mg/L or 4630 umol/L with altered mental status, acidosis, elevated lactate and without NAC
APAP >900mg/L or 5960 umol/L with altered mental status, acidosis, elevated lactate with NAC
*List 3 reasons why the elderly are at increased susceptibility to ASA toxicity.
Decreased liver blood flow limits biotransformation of salicylate
Decreased renal function reduces salicylate clearance
Chronic ingestion decreases albumin binding, increasing the free salicylate that can enter the cell, and allows salicylates more time to pass through the blood-brain barrier.
*Explain why serum level of ASA is incongruent with degree of symptoms
Falling concentration may reflect redistribution rather than clearance
List 4 products that contain salicylates
ASA, oil of wintergreen methyl cold products, bismuth (pepto bismol)
What is a toxic dose of ASA
200mg/kg or ASA 10-30g
List 4 clinical signs of asa toxicity
Tachypnea, hyperpnea, hyperthermia
Resp: pulmonary edema
GI: Abdo pain, nausea/vomiting
Neuro: altered mental status, irritability, ototoxicity
Heme: coagulopathy
Describe the progress of the acid base status in a patient with salicylate toxicity
Respiratory alkalosis 0-4 hrs - tachypnea from stimulation of the medulla.
Neutral 2-12 hours - metabolic acidosis from uncoupling of oxidative phosphorylation + metabolic alkalosis from vomiting
Metabolic acidosis 6-12 hours - respiratory acidosis if preterminal due to respiratory muscle fatigue
Why can chronic salicylate toxicity present with lower serum levels
serum levels may underestimate the severity of the intoxication because salicylate has already accumulated in the brain
List 6 management priorities in ASA toxicity
- GI decontamination
- IV fluids
- Urine alkalinization
- Glucose supplementation
- Potassium correction
- Dialysis if refractory
Describe the process for urinary alkalinization with targets
1-2 mEq/kg bicarb bolus then bicarb drip (3 amps of sodium bicarb in 1L D5 with 40mEq at 2.5*maintenance)
Target urine pH 7.5-8.0 and serum pH of 7.55
What are the indications for urinary alkalinization
Acute ASA level >3.5 [OPC]
Chronic ASA level >2.9
ASA ingestion + clinical symptoms
How does urinary alkalinization work
Salicylate are acidic and readily ionize in an alkali environment
Only the non ionized state can traverse cell membrane and cause toxicity. The non ionized state is the one that causes clinical harm
Once ionized in the urine they are ’trapped’ there
Alkaline urine traps the salicylate on and increased excretion
Reduces reabsorption of salicylate molecules and encourages secretions down a concentration gradient
List indications for dialysis in salicylate toxicity
Salicylate >7.2 mmol/L or >6.5 mmol/L in the presence of impaired kidney function
Salicylate toxicity + altered mental status, hypoxia,
Failure of standard therapy (ex. urine alkalinization)
In general, lower threshold for chronic ingestions
Discuss an approach to intubation a patient with salicylate toxicity
Caution as it is difficult to match the patient’s ventilation. If intubation is necessary:
- VBG beforehand
- Bicarb boluses before hand
- Intubation without paralysis
- Bag during the apneic period
- Match pt’s pre intubation RR on the vent
Describe the physiology of an anticholinergic overdose
Anticholinergic ingestions antagonize the muscarinic receptors (ex. Salivary glands, SA node, pupils, skin)
Do not affect the nicotinic receptors at the neuromuscular junction