Toxicology/Poisonings Flashcards
Name some one-pill killers
One dose can be life threatening
Clonidine Oil of wintergreen (methylsalicylate) Camphor Toxic alcohols (methanol, ethylene propyl) TCAs Benzocaine CCBs Sulfonylurea Propanolol Buprenorphine Chlorpromazine Chloroquine Hydroxychloroquine Lomotil Methadone (and other opioids) Quinidine Quinine
What three treatments/antidotes should be considered in all comatose patients?
Oxygen
Glucose
Naloxone
Describe the following toxidrome: SYMPATHOMIMETIC
UPPERS
Agitation, Delirium, Psychosis, Seizure Tachycardia Hypertension Fever/Hyperthermia Mydriasis (increased pupil size - reactive) Sweaty
Describe the following toxidrome: ANTICHOLINERGIC
Blind as a bat, hot as a hare, dry as a bone, red as a beet, mad as a hatter
The bowels and bladder lose their tone and the heart beats on alone
Delirium, Psychosis, Seizure, Coma/somnolence
Tachycardia
Hypertension
Fever/Hyperthermia
Mydriasis (increased pupil size - sluggish)
Decreased bowel sounds
Flushed/Dry skin
Describe the following toxidrome: CHOLINERGIC (ORGANOPHOPHATES)
Pouring with secretions
SLUDGE And the 3 killer B’s
DUMBELS
Salivation Lacrimation Urination Diarrhea GI Distress Emesis Bronchorrhea Bradycardia Bronchospasm
Diarrhea Urination Miosis Bradycardia/Bronchorrea/Bronchospasm Emesis Lacrimation Salivation
Fasiculations Seizures Can have tachycardiac (nicotinic) and bradycardia (muscarinic) Normal or hypertension Tachypnea Miosis Sweaty
Describe the following toxidrome: OPIATES (CLONIDINE)
DOWNERS
Somnolence/Coma Tachycardia Hypotension Hypothermia Bradypnea Significant MIOSIS Decreased bowel sounds
Describe the following toxidrome: SEDATIVE-HYPNOTICS (BARBITUATES)
ALSO DOWNERS
Somnolence/Coma Hypotension Hypothermia Bradypnea Bullae on skin (IV drug use)
Describe the following toxidrome: SALICYLATES
Coma/Somnolence, Seizures Normal or tachycardia Hyperthermia Tachypnea Sweaty skin
Name 3 differences between Sympathomimetics and Anticholinergics
Skin - Sweaty (SYM), Dry/flushed (ANTICHOL)
Pupils - Reactive (SYM), Sluggish (ANTICHOL)
Bowel sounds - No impact (SYM), Decreased (ANTICHOL)`
Bitter almond smell in your coffee - what toxin?
Cyanide
Name the toxins with characteristic smells
Cyanide - almonds Arsenic, thallium, organophosphates, selenic acid - garlic Chloral hydrate, paraldehyde - pears Hydrogen sulfide - rotten eggs Methyl salicylate - wintergreen
List the toxins that are poorly absorbed by activated charcoal
Heavy metals (Lithium, iron)
Alcohols
Hydrocarbons
List the possible indications for Whole Bowel Irrigation (WBI)
Body packers/stuffers Ingestion of metals, lithium Ingestion of sustained release preparations Ingestion of pharmaceutical patches Massive overdoses Concretions of pills
List the possible indications for hemodialysis
Ethylene glycol Lithium Methanol Salicylate Theophylline
List some drugs that may lead to delayed expression of clinical toxicity
Sulfonylurea (oral hypoglycemics) Acetaminophen Iron Sustained release drug formulations MAOIs Thyroid hormones Warfarin
Toxic level for acetaminophen
150 mg/kg
Pathophysiology of acetaminophen poisoning
Acetaminophen saturates the hepatic metabolism pathways
Depletes glutathione
Causes increased production of NAPQi (N-acetyl-p-benzoquinone imine) - which binds to liver hepatocytes and causes necrosis
What are the 4 stages of acetaminophen poisoning?
STAGE 1 (30 min - 24 hours) Asymptomatic, occasionally N/V, diaphoresis, pallor
STAGE 2 (24 - 48 hours) N/V, RUQ abdo pain, elevates liver enzymes
STAGE 3 ( 72 - 96 hours)
Fulminant hepatic failure with jaundice, thrombocytopenia, increased INR, hypoglycemia, hepatic encephalopathy
Renal failure and cardiomyopathy may occur
STAGE 4
If patient survives - resolution of Sx
When do you draw an acetaminophen level?
at 4 - 24 hours post ingestion
Plot on the Rumack-Matthew nomogram to determine if antidote is required
What is the antidote for acetaminophen toxicity? How does it work
NAC N-acetyl-cysteine Replenishes glutathione in the liver Detoxifies the toxic metabolite - NAPQi Alleviates existing hepatotoxicity through antioxidant and pro-circulatory properties
Effective when initiated within 8 hours of ingestion
Given IV over 21 hours (can be given PO - old regimen)
SE - anaphylactic reaction, reaction with pts with asthma
Describe the treatment for salicylate poisoning?
ABCDEF
Activated charcoal - in < 1-2 h post ingestion
IVF
Urine alkalinization - if peak level > 35 mg/dL (350 mg/L)
- reduces salicylate access to the brain
Hemodialysis - if patient meets these criteria: unremitting metabolic acidosis, pulmonary edema, severe renal impairment, coma, seizures, liver impairment, salicylate level > 70 mg/dL (700 mg/L)
What hazard is associated with intubation of salicylate poisoned patients?
Tend to have profound respiratory alkalosis
Abrupt reversal with a sedative and paralytic - causes significant acidemia which may increase salicylate entry to the brain and cause seizures
How does iron produce toxicity?
Iron acts on the GI mucosa
Inhibits oxidative phosphorylation in the mitochondria
Body has no mode of excretion of excess iron
What are the toxic levels of iron?
Ingestion levels: Mild: 20 - 60 mg/kg Moderate: 60 - 100 Serious: 100-200 Lethal : > 200
Serum levels roughly correlate with toxicity:
< 350 mcg/dL – minimal
350-500 mcg/dL – mild
>500 mcg/dL – serious
Check serum iron levels 4-6 hours post ingestion
AXR - can sometimes show iron pills that have not been absorbed yet
What are the stages of Iron toxicity?
STAGE 1 (up to 6 hours)
GI Symptoms, N/V, GI bleed
If severe - shock due to volume loss, coma
STAGE 2 (6 - 24 hours)
GI Symptoms resolve, patient looks relatively well
Transient phase
STAGE 3 (>24 hours) Metabolic acidosis, hepatocellular injury, elevated transaminases, jaundice, intractable shock, seizures, coma
STAGE 4 (4-6 weeks) Resolution of symptoms, patients who survive can get gastric scarring and cause pyloric stenosis
What is the antidote for iron poisoning?
Deferoxamine
An iron chelator
Dose: 5-15 mg/kg/hour (up to 6g/day) IV
Stop it for 6 h q24h - to prevent ARDS or pulmonary fibrosis
Causes vin-rose urine
What reasons would you stop deferoxamine?
Clinical improvement:
Urine runs clear
Metabolic acidosis resolves
Iron level returns to normal
Adverse effects: Anaphylactic reaction ARDS Pulmonary fibrosis Cramps Neuropathy
What gastrointestinal decontamination is helpful and what is not helpful in iron toxicity?
Helpful - WBI - if undissolved tabs on AXR, or massive overdose
Not- helpful - activated charcoal
