Toxicology Flashcards
(39 cards)
1
Q
Name of toxic metabolite from acetaminophen
A
NAPQI (N-acetyl-p-benzoquinoneimine), overdose causes depletion of GSH and accumulation of NAPQI
2
Q
Clinical effects/stages of acetaminophen overdose
A
- 0-24 hours - nausea, vomiting, malaise, pallor - normal AST/ALT and INR
- 12-72 hours - hepatotoxicity, RUQ pain - rising AST/ALT and normal or rising INR
- 72-96 hours - fulminant hepatic failure, encephalopathy, coma - AST/ALT > 10,000, elevated INR, elevated Cr, acidosis, lactemia
- > 96 hours - recovery with normalization of labs
3
Q
Diagnosis of acetaminophen overdose
A
- Obtain serum APAP level 4 hours after ingestion
- Most important predictor of outcome is level taken at 4-10 hours post ingestion
- “Overdose” is taking 140 mg/kg or more
4
Q
Clinical effects of aspirin (salicylate) overdose
A
- Vomiting, tinnitus, tachypnea, tachycardia, hypoxia, pulmonary edema, fever
- “Wintergreen” odor on breath
5
Q
Diagnosis/management of salicylate overdose
A
- Labs: mixed respiratory alkalosis and metabolic acidosis
- Treatment with activated charcoal
- Aspirin level > 30 requires treatment with urinary alkalinzation (sodium bicarb), > 90 requires hemodialysis
6
Q
Drugs that prolong QRS
A
- Bupivacaine, bupropion, carbamazepine, cocaine, diphenhydramine, lamotrigine, quinidine, TCAs
- Prolonged is > 100
- Tx with sodium bicarbonate
7
Q
Drugs that prolong QTc
A
- Antipsychotics, fluoroquinolones, macrolides, methadone, ondansetron, SSRIs and SNRIs
- Prolonged is > 500 (but age specific)
- Tx with electrolyte correction (and mag)
8
Q
Drugs that cause hypoglycemia
A
HOBBIES:
- Hypoglycemics (sulfonylureas, meglitinides)
- Other (unripened fruit, IV quinine)
- B-Blockers
- Insulin
- Ethanol
- Salicylates
9
Q
Activated charcoal uses
A
- Dose is 0.5-1 g/kg
- If ingestion can cause respiratory depression, need to intubate before giving activated charcoal
- Don’t give charcoal with antidotes (interferes with absorption of the antidote), only acception is NAC
10
Q
Toxins that don’t require activated charcoal
A
CALM
- Cyanide
- Alcohol/alkaline ingestion
- Lithium
- heavy Metals
11
Q
Treatment of acetaminophen overdose
A
- Often asymptomatic initially so immediate ER discharge is never the right answer
- If < 4 hours since ingestion, give activated charcoal
- Treat with NAC if level is above nomogram (wait until 8 hours after ingestion to begin treatment)
- NAC works by protecting liver and body from oxidative stress of NAPQI and regnerates GSH
12
Q
Anion gap equation
A
Sodium - (Chloride + bicarb)
13
Q
Ibuprofen ingestion signs/symptoms and treatment
A
- Nausea and vomiting (on boards), asx in real life
- Treatment is supportive
- Should check for other drug ingestions though
14
Q
Alcohol toxicity symptoms/levels
A
- Mild: BL 100 - euphoria, lowered inhibitions
- Moderate: BL 200 - slurred speech, ataxia, impaired judgement
- Severe: BL 300 - confusion and stupor, seizures
- Electrolyte disturbances: hypogylcemia
- Alcohol is also present in mouthwash, cough/cold meds, cologne, perfume
15
Q
What is methanol found in
A
Windshield washer fluid, cooking fuel, perfumes, antifreeze
16
Q
Clinical presentation/labs of methanol toxicity
A
Abdominal pain, vomiting, inebriation, severe metabolic acidosis, increased anion gap, CNS depression
- Gets broken down into formic acid and formaldehyde and can cause huge issues with the liver and optic nerve
17
Q
Methanol toxicity treatment
A
- Administration of ethanol - alcohol dehydrogenase antagonist (slowing conversion of methanol to formaldehyde)
- Also can use 4-methypyrazole
- Soduium bicarb - counters formic acid
18
Q
Ethylene glycol toxicity (3 phases)
A
- Phase 1: drunken appearance with no alcohol odor, large anion gap metabolic acidosis, hypocalcemia d/t crystals in the urine, hypertension, N/V
- Phase 2: coma and cardiorespiratory failure
- Phase 3: 1-3 days, renal failure due to ATN
19
Q
Organophosphate toxicity
A
- SLUDGE: salivaiton/sweating, lacrimation, urination, defecation/diarrhea, gastrointestinal, emeesis
- Can be lethargic and have respiratory distress
- Insecticide ingestion, unwashed fruits and veggies
- Mechanism of action: inhibiting acetylcholinesterase (cholinergic effects)
20
Q
Muscarinic cholinergic effects and treatment
A
- Salivation, lacrimation, diarrhea, wheezing, bradycardia
- Tx: atropine
21
Q
Nicotinic cholinergic effects
A
- Neuromuscular, weakness, paralysis, muscle fasciculations
Tx: pralidoxime
22
Q
Tricyclic antidepressants toxic ingestion
A
- Anticholinergic effects: Blind as a bat (mydriasis, dilated pupils), 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
- Need to monitor EKG for widening QRS complex (treat iwth sodium bicarb until QRS is < 100)
- Tx: activated charcoal
23
Q
Beta blocker ingestion side effects
A
- Bradycardia, hypotension, sweating
- Monitoring is all thats needed
24
Q
Hydrocarbon ingestion
A
- Gasoline, kerosene, lighter fluid
- Gastric irritation, nause, vomiting, choking/gagging, cough, wheezing
- Labs with hypoxemia and CXR with diffuse bilateral infiltrates –> can lead to ARDS
- Tx is symptomatic
25
Carbon monoxide toxicity symptoms
- Sudden flu like illness in an afebrile patient (headache, vomiting, weakness, fatigue)
- Symptoms in other family members or recent death of a small family pet
26
Carbon monoxide toxicity workup/treatment
- Carboxyhemoglobin levels
- Oxygen saturations are unreliable
- Give high flow 100% oxygen
27
Cyanide poisoning
- Presents like carbon monoxide poisoning but failure to respond to oxygen therapy
- Smell of almonds
- Tx: hydroxocobalamin
28
Treatment for ingestion of caustic substance
- Endoscopy within 24 hours to determine extent of esophageal injury
- No gastric lavage with caustic ingestion
29
Alkaline ingestion
- Alkali substances tend to injure the esophagus and can lead to esophageal perforation
- Ingestion of dishwasher detergent or drain cleaner
- Also watch for signs of burns on the face/hands/chest
30
Lead screening and levels
- > 27% of housing built before 1950
- Level 5-14: report, venous sample in 3 months, do environmental history/screening
- Level 15-44: report, venous sample in 4 weeks, consider xray if pica
- Level 45-70: report, venous sample in 48 hours
- Level > 70: report, venous sample immediately
31
Lead toxicity treatments
- Level as low as 10 can lead to cognitive deficit
- Level 45-70 give outpatient chelation if symptomatic (oral succimer)
- Level > 70 need hospitalization and IV chelation (edetate)
- Need a venous sample to base treatment (not capillary)
32
Lead sources
- Lead based paint in older homes
- Household dust, soil
- Glazed ceramics, storage battery casings, bullets, cosmetics, leaded glass, jewelry, farm equipment
33
Toxic iron ingestion amount and phases
- 40 mg/kg of elemental iron is "toxic"
- Phase 1: within 6 hours - vomiting, diarrhea, abd pain
- Phase 2: slight improvement for 6-24 hours
- Phase 3: metabolic acidosis, coagulopathy, cardiovascular collapse
- Phase 4: GI obstruction due to scarring and strictures
34
Management and treatment of iron toxicity
- Lead level 4 hours post ingestion
- Labs/imaging: abdominal film, electrolytes, liver function, CBC, coagulation
- Tx: indications for chelation with deferoxamine are anion gap acidosis, serum iron > 500, significant iron on abdominal film
- Deferoxamine turns the urine pink/red when serum iron level exceeds serum iron binding capacity - can stop when urine is no longer pink
35
PCB exposure in utero
Low birthweight, dark pigmentation, early eruption of teeth, acneiform rash --> can be fatal
36
Anthrax
- Cutaneous form, incubation period is less than 2 weeks
| - Lesions are pruritic papules --> central bullous lesion --> necrosis --> central black painless eschar
37
Coin ingestion treatment
- Proximal esophagus should be removed by endoscopy immediately
- Middle to lower esophagus can be observed for 12-24 hours if asymptomatic, if in stomach it can just be observed for passage
- Coins in the esophagus usually face forward on the PA film and from the side on the lateral film (opposite if in trachea)
38
Three ingested objects that can't be ignored
- Button batteries, sharp/pointed objects, magnets --> all high risk for perforation so need immediate endoscopy
39
Discoloration of blood, normal PaO2, clinical evidence of cyanosis
Methemoglobinemia
| - Exposure to exogenous oxidizing drugs: amyl nitrite, butyl nitrite, isobutyl nitrite
