Toxidromes:
Anticholinergic
Sympathomimetic /Stimulant
Sedative-Hypnotic (EtOH)
Opiate
Cholinergic
Organophosphates
Specific toxins: Salicylates, Acetaminophen
Anticholinergic
Features: – Blind as a bat (mydriasis, cycloplegia)
– Mad as a hatter (hallucination, confusion, agitation)
– Red as a beet (flushed)
– Hot as a pot (fever)
– Dry as a bone (dry mucous membranes and dry skin)
– Bowel and bladder lose their tone (ileus, urinary retention)
– Heart runs alone (tachycardia)
Toxins: anticholinergics, antihistamines, antispasmotics (i.e. Ditropan/ oxybutynin), Jimson weed, tricyclic antidepressants, phenothiazines, atropine and antipsychotics
Antidote: Physostigmine (1-2mg IV over 5 minutes)
Treatment: supportive
TCAs
-
- Death due to cardiac effects: tachycardia and EKG changes
- Charcoal, alkalinize the urine, supportive (fluids for hTN), benzos for seizure control
Sympathomimetic/Stimulant
Features:
– Agitation
– Diaphoresis*
– Hypertension
– Mydriasis
– Tachycardia
Toxins: amphetamines, cocaine, MAO inhibitors
Treatment: supportive and benzodiazepines
Sedative-Hypnotic
Features:
– CNS depression
– Respiratory depression
– Hypotension
– Bradycardia
– Hypothermia
Toxins: EtOH, barbiturates, benzodiazepines and GHB (i.e. date rape drug)
Antidote: For benzodiazepines use flumazenil
TOXIC ALCOHOLS
Ethylene glycol
- Antifreeze, solvents
- Antidote is fomepizole or EtOH IV, but must give thiamine 100mg and pyridoxine 100mg (minimalize oxalic acid)
Methanol
- May cause blindness or death
- Antifreeze, varnish, paint remover
- Urine may look fluorescent
- Antidote is fomepizole or EtOH IV, but must give folate 50mg first (minimalize formic acid)
Isopropyl alcohol (not really a toxic alcohol)
- Rubbing alcohol
Narcotic
Features:
– Coma/↓LOC
– Respiratory depression
– Miosis
Toxins: opioids, narcotics
Antidote: Naloxone (0.2-0.4mg IV)
Cholinergic (muscarinic)
Features: DUMBELS (or SLUDGE)
– Defecation
– Urination
– Miosis
– Bradycardia and bronchorrhea
– Emesis
– Lacrimation
– Salivation
– May be diaphoretic and tachycardic
Toxins: organophosphates
Antidote: For organophosphates use Atropine (0.5mg IV at a time to end point of dry secretions)
Cholinergic (nicotinic)
Features: MTWtHFS
– Muscle cramps
– Tachycardia
– Weakness
– Hypertension
– Fasciculations and paralysis
– Sugar (hyperglycemia)
Toxins: tobacco, black widow spider venom
Salicylates
Features:
– Acid-base (respiratory alkalosis → AG metabolic acidosis)
– CNS (confusion → coma)
– Electrolytes (pyrexia, ↑RR, and vomiting → fluid loss, dehydration and ↓K)
– GI (N/V, pain)
– Ototoxicity (tinnitus)
– Pulmonary edema
– Anticoagulation (inhibit vit K dependent synthesis – factors 2,7, 9, 10)
Notes: Minimum acute toxicity 150mg/kg. Affects CNS, Kreb’s cycle enzymes, and decouples oxidative phosphorylation. NaHCO3 is used to alkinalize urine (diuresis).
Acetaminophen
Features:
– Four phases of clinical presentations (children present early, adults present late)
– Stage 1: GI (mild)
– Stage 2: 24-48hr, may feel well but liver enzymes rise
– Stage 3: 3-4d, jaundice, coagulopathy, hepatic encephalopathy
– Stage 4: 5+d, recovery, LFT’s start to normalize
Notes: 140mg/kg or 7.5g over 24hr; mostly metabolized in the liver; NAPQI is the toxic metabolite (glutathione depletion) causing oxidative liver injury
Antidote: N-acetylcysteine based on acetaminophen levels 4 hr post ingestion (or initial presentation) = consult nomogram
Delirium Tremens
Features
– Occurs hours after heavy drinking
– Tremors
– Irritability
– Nausea/Vomiting
– Altered mental status (hallucinations, confusion, agitation)
– Seizures
Treatment: monitors, IV access, O2, C/S with dextrose if needed, benzodiazepines (Diazepam 5-10mg IV, or Librium 50-100mg IV, or Lorazepam 2-4mg SL/IV), labs (CBCD, electrolytes, Mg, LFTs, amylase, EtOH, CK if suspect rhabdomyolysis), IV fluids with multivits, thiamine 100 mg IV, referral for EtOH counselling (i.e. AADAC)
History
- Who? -coingesters (rave drugs)
- What?
- When? -peak effects, decontamination
- Where? -other exposures (CO)
- Why? -psych, peds
- How? -site, route, IV>inhaled>IM/SC>oral>dermal
- How much? Toxicity
Physical exam
- Rule out other injuries
- Look for toxidromes
Overdose approach
- As always start with ABCs and vitals (reassess frequently)
- Large bore IV with crystalloid
- Monitors
- Depending on LOC consider thiamine, dextrose, O2, naloxone
- Look for toxidromes… always consider that patient may have taken more than one drug
- Investigations:
- Basic bloodwork, serum osmolarity, serum betaHCG
- Tox screens: ASA, acetaminophen, EtOH, toxic alcohols
- EKG
- Xray
- Radiopaque toxins:
- Chloral hydrate
- Heavy metals
- Iodides
- Phenothiazines
- Enteric-coated pills (bezoar of pills)
- Solvents
- Body packers may have obvious findings on plain films
- Radiopaque toxins:
- ABG
- Management
- Supportive and monitoring
- Antidotes
- Decontaminate
- Ipecac – contraindicated depending on airway and in bowel perforation/obstruction
- Charcoal (1g/kg) – if w/i 30 minutes; ineffective for Li, Fe, Fluoride, alcohols, caustic acids/bases
- Osmotic lavage – OG, w/i 30 minutes, patent airway, contraindicated if <8yr
- Cathartics – magnesium citrate
- Whole bowel irrigation – Go Lytely, cocaine OD
- Enhanced elimination
- Dialysis – lithium, salicylates, ethylene glycol, methanol, Br, isopropyl alcohol
- Hemofiltration
- Digoxin poisoning – may use digibind
- Change pH of blood or urine
Osmolar gap
- Calculate the difference between the serum osmolarity and [2Na+ + BUN + Glucose]
- Normal = ~10
Anion Gap Metabolic Acidosis
- Methanol
- Uremia
- DKA
- Paraldehyde
- Isoniazide
- Lactic acid
- Ethylene glycol (and EtOH via ketoacidosis due to starvation)
- Salicylates
- Cyanide
- Arsenic
- Toluene
Calculation of Anion Gap
- Na – (Cl + HCO3)
- Normally 12 +/- 2 meq/L
notes that are concise and to the point