Chapter 7: Toxicology Flashcards
What are some clinical instances to order a toxicology screen?
1) Coma/AMS
2) Hypoventilation
3) HAGMA
4) Seizures
What impt points should be covered in the history?
1) What drug was taken? Taken with alcohol? Polydrug DO?
2) How much was taken? dose and formulation etc
3) what route was it taken by?
4) What time was it taken?(determines Rx and clinical presentation)
5) Any Rx already instituted?(eg. vomiting/drink ‘antidotes’)
6) PMHx? (Esp Cirrhosis, ESRF, CCF, Seizures, Old Age)
7) Any meds? (depends on whether its P450 inducer or inhibitor)
8) Psych hx (Suicide attempts? 1st time? Any hx of depression/psychosis)
9) LMP if female of child-bearing age
What do you look for in the Vitals?
1) Temperature:
-High
Neuroleptic Malignant Syndrome, nicotine
Anti-histamines
Salicylates, Sympathomimetics
Anti-depressants, Anticholinergics
-Low:
CO
Opiates
OHGA, insulin
Liquor
Sedative hypnotics-barbiturates
2) BP
-High: Cocaine, amphetamines, ecstasy
Low: Barbiturates and opioids
3) RR
High: Salicylates
Low: TCA, Barbiturates, Opioids
4) HR High: Free base(Cocaine) Anticholinergics, amphetamines, antihistamines Sympathomimetics Theophylline
Low: Propanolol Anticholinesterase CCBs Ethanol Digoxin
What do you look out for in PE?
1) Breath smell(Fruity, camphor etc)
2) Skin findings
- Needle tracks and pseudoaneurysms?(opioids, IVDA)
- Diaphoresis(Sympathomimetics, Organophosphates, Salicylates)
- Dry(anti-cholinergic)
- Jaundice?
3) Respi(APO in young person-Cocaine)
4) CVS (Dysrhythmias)
5) CNS (AMS, pupils)
What invg will you carry out?
Bloods:
1) FBC-elevated total whites(infxn, iron, theophylline)
2) U/E/Cr-renal fn and anion gap
3) ABG-Metab acidosis
4) Toxicology screen for drug levels
5) CBG-check osmolality
6) LFTs-Hepatotoxic drugs
7) PT/aPTT-Hepatotoxic drugs
Imaging:
CXR-APO?
AXR-Radio-opaque tablets-iron, phenothiazines, salicylates, heavy metals
Others:
ECG, Urine HCG?
What is Cholinergic syndrome?
Muscarinic effects:(DUMBBELS) in 12-24hr Diarrhea Urination Miosis Bradycardia Bronchospasm/bronchorrhea Emesis Lacrimation Salivation
Nicotinic effects: (rmb the days of week) Muscle cramps Tachycardia Weakness tHypertension Fasiculations Sugar(Hyperglycemia)
What is the main culprit for cholinergic syndrome?
Organophosphate insecticides(in farms) Pyridostigmine(for MG pts)
What is anti-cholinergic syndrome?
Hot as a hare-Fever,tachy, HTN
Red as a beet-Flushed skin
Dry as bone-dry skin, dry mucous membrane
Blind as a bat-dilated pupils
Mad as a hatter-Delirium, Psychosis, seizures
Full as a tick-Urinary retention
What are the main causes of anti-cholinergic syndrome?
TCA antidepressants
Atropine
Anti-histamines
Anti-spasmodics
What is the sedative-hypnotic syndrome?
CNS Depression Resp Depression Coma Hypotension Vesicle/Bullae
What is it usually due to?
Barbiturates
BZD
Ethanol
What is sympathomimetic syndrome and what are the causes?
1) HTN
2) Tachycardia
3) Mydriasis
4) Hyperpyrexia
5) Anxiety and Delirium
Drugs-Cocaine and Amphetamines
What are some mgmnt options in a suspected DO?
1) ABC especially the airway
2) Coma Cocktail
3) Decontamination
4) Gastric Decontamination
- Activated Charcoal: Binds toxic agent and prevents absorption. Best if given within 4h) Give with anti-emetic and sorbitol. It does not bind to lithium, alkali/acids and heavy metals/iron. Multi-dose use not sorbitol version.
- Gastric Lavage: If toxin ingested within 1 hr. Intubate prior to lavage, left lat Trendelenburg.
- Cathartics
- Whole Bowel Irrigation(Polyethylene Glycol, pt must be alert to go toilet on their own)
5) Enhancement of Elimination
- Forced Alkaline Diuresis
- Hemoperfusion
- Hemodialysis-for dialysable drugs only(Lith, ethylene glycol, methanol, salicylates)
- Specific Antidotes
Which toxins cause cardiac dysrhythmias?
1) QTc Prolongation: Lithium, phenothiazines, quinidines
2) Wide QRS: TCA(tachy), B Blockers, CCB, Cocaine, Quinidine
What is the toxic dose of paracetamol?
> 150mg/kg =15 Tab
