Toxicology Flashcards
What are some ways of reducing absorption of drugs following overdose?
Activated charcoal if attend within one hour of ingestion.
Multi-dose charcoal
Kleen-prep whole bowel irrigation,
Gastric lavage is rare and induced emesis is NEVER.
What is the anticholinergic toxidrome and a cause?
Dry as a bone, red as a beet, mad as a hatter and hot as a hare.
Seen in TCA overdose!
Flushing,
Dry skin and membranes,
Mydriasis,
Confusion,
Hyperthermia,
Hypotension,
Metabolic acidosis,
Convulsions.
What is the management of anticholinergic toxidrome?
A-E exam,
Activated charcol if within one hour.
IV Sodium bicarbonate (aim for pH of 7.5).
Cholinergic toxidrome?
SLUDGE - cholinergic
Salivation,
Lacrimation,
Urination,
Defecation,
GI cramps,
Emesis
MTWTF - Muscarinic symptoms
Muscle cramps,
Tachycardia,
Weakness,
Twitching,
Fasciculations.
Killer Bs
Bradycardia
Bronchorhea,
Bronchospasm
causes of cholinergic toxidrome
Cholinergic insecticides,
Alzheimer’s meds,
OD of myasthenia gravis meds.
Nerve agents.
Treatment of cholinergic poisioning?
Atropine - mainstay. Titrated to secretions
Pralidoxime - role unclear.
Sympathomimetic toxidrome?
Tachypnoea,
HTN
Tachyarrythmias,
Mydriasis, seizure, psychosis,
Hyperthermia
Causes of sympathomimetic toxidrome?
Cocaine,
Caffeine,
Ecstasy,
MDMA,
Theophylline.
Management of sympathomimetic management?
First do bloods - CK, myoglobin, potassium.
Mainstay of treatment - benzodiazepines.
If very hyperthermic then use IV Dantrolene 1mg/kg
Severe sympathomimetic toxidrome - Serotonergic crisis
Rigid jaw and airway compromise,
CV collapse,
Acidosis,
Hypertonicity and clonus,
Confusion and agitation,
Refractory hypoglycaemia,
Rhabdomyolysis
Hyperkalaemia,
Malignant hyperthermia
Management of serotinergic crisis
Intubation - without fentanyl.
Benzodiazepines,
Aggressive cooling,
Cyprohepatdine (oral or NG),
Chlorpromazine
Differences between anticholingeric and sympathomimetic toxidromes?
Anticholingeric - skin is dry and red. hypoactive bowel sounds and urinary retention.
Sympathomimetic - skin is wet, hyperactive bowel sounds and no urinary retention
Opioid toxidrome and its management
Hypoventilation and hypoxia,
Hypotension and bradycardia,
Reduced GCS and pinpoint pupils,
Hypothermia.
Give NALOXONE
Benzodiazepine overdose toxidrome and management?
Airway loss,
Resp compromise,
Hypotension,
Bradycardia,
Dizzy,
Dysarthric,
Drowsy,
Ataxic.
Management - mainly supportive but can use flumazenile
What are the risk factors for a paracetamol overdose?
Patients already taking enzyme inducing drugs
Malnourished patients
What should NAC be given in paracetamol OD?
- Elevated plasma concentration,
- Staggered OD,
- Patients presenting within 8-24hr who have taken >150mg/kg even if plasma conc not available yet.
- Patients presenting >24hr after ingestion with jaundice, raised ALT, INR > 1.3 or hepatic denderness.
What to do if a patient presents with ingestion of paracetamol OD <4hr ago?
Wait until 4 hours to take a level and then treat with NAC based on level
What to do if a patient presents with ingestion of paracetamol OD 4-8hrs ago?
Take level.
If taken over 150mg/kg and there will be a delay of 8+ hours in attaining level then start NAC immediately.
Risk of N-acetylcysteine.
Presentation of calcium channel blocker overdose?
Sinus bradycharida,
Hypotension,
Prolonged QT inverval.
High potassium and low glucose.
Cardiogenic shock which cen develop into VF/VT
Management of calcium channel blocker?
IV calcium chloride - high conc of ionised calcium.
Best treatment - hyperinsulinaemic euglycaemia.
Sodium bicarbonate if very acidotic.
Intralipid.
Iontropes.
ECMO.
Presentation of digoxin overdose?
QT prolongation, bradycardia and ‘reverse tick’ on ECG.
Metabolic acidosis,
Hyperkalaemia,
N+V,
Confusion
Treatment of digoxin toxicity
Charcoal
8.4% sodium bicarb.
Insulin/dextrose for hyperkalaemia (dont give calcium gluconate in this case of hyperkalaemia)
Atropine.
Digibind.
Overdose of iron presentation
Direct caustic gut action - N+V, abdominal pain, diarrhoea, haematemesis, acidosis, hepatic necrosis.
