Toxicology

Question 1

What are some ways of reducing absorption of drugs following overdose?

Answer 1

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.

Question 2

What is the anticholinergic toxidrome and a cause?

Answer 2

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.

Question 3

What is the management of anticholinergic toxidrome?

Answer 3

A-E exam,
Activated charcol if within one hour.
IV Sodium bicarbonate (aim for pH of 7.5).

Question 4

Cholinergic toxidrome?

Answer 4

SLUDGE - cholinergic
Salivation,
Lacrimation,
Urination,
Defecation,
GI cramps,
Emesis

MTWTF - Muscarinic symptoms
Muscle cramps,
Tachycardia,
Weakness,
Twitching,
Fasciculations.

Killer Bs
Bradycardia
Bronchorhea,
Bronchospasm

Question 5

causes of cholinergic toxidrome

Answer 5

Cholinergic insecticides,
Alzheimer’s meds,
OD of myasthenia gravis meds.
Nerve agents.

Question 6

Treatment of cholinergic poisioning?

Answer 6

Atropine - mainstay. Titrated to secretions
Pralidoxime - role unclear.

Question 7

Sympathomimetic toxidrome?

Answer 7

Tachypnoea,
HTN
Tachyarrythmias,
Mydriasis, seizure, psychosis,
Hyperthermia

Question 8

Causes of sympathomimetic toxidrome?

Answer 8

Cocaine,
Caffeine,
Ecstasy,
MDMA,
Theophylline.

Question 9

Management of sympathomimetic management?

Answer 9

First do bloods - CK, myoglobin, potassium.
Mainstay of treatment - benzodiazepines.
If very hyperthermic then use IV Dantrolene 1mg/kg

Question 10

Severe sympathomimetic toxidrome - Serotonergic crisis

Answer 10

Rigid jaw and airway compromise,
CV collapse,
Acidosis,
Hypertonicity and clonus,
Confusion and agitation,
Refractory hypoglycaemia,
Rhabdomyolysis
Hyperkalaemia,
Malignant hyperthermia

Question 11

Management of serotinergic crisis

Answer 11

Intubation - without fentanyl.
Benzodiazepines,
Aggressive cooling,
Cyprohepatdine (oral or NG),
Chlorpromazine

Question 12

Differences between anticholingeric and sympathomimetic toxidromes?

Answer 12

Anticholingeric - skin is dry and red. hypoactive bowel sounds and urinary retention.

Sympathomimetic - skin is wet, hyperactive bowel sounds and no urinary retention

Question 13

Opioid toxidrome and its management

Answer 13

Hypoventilation and hypoxia,
Hypotension and bradycardia,
Reduced GCS and pinpoint pupils,
Hypothermia.
Give NALOXONE

Question 14

Benzodiazepine overdose toxidrome and management?

Answer 14

Airway loss,
Resp compromise,
Hypotension,
Bradycardia,
Dizzy,
Dysarthric,
Drowsy,
Ataxic.
Management - mainly supportive but can use flumazenile

Question 15

What are the risk factors for a paracetamol overdose?

Answer 15

Patients already taking enzyme inducing drugs
Malnourished patients

Question 16

What should NAC be given in paracetamol OD?

Answer 16

1. Elevated plasma concentration,
2. Staggered OD,
3. Patients presenting within 8-24hr who have taken >150mg/kg even if plasma conc not available yet.
4. Patients presenting >24hr after ingestion with jaundice, raised ALT, INR > 1.3 or hepatic denderness.

Question 17

What to do if a patient presents with ingestion of paracetamol OD <4hr ago?

Answer 17

Wait until 4 hours to take a level and then treat with NAC based on level

Question 18

What to do if a patient presents with ingestion of paracetamol OD 4-8hrs ago?

Answer 18

Take level.
If taken over 150mg/kg and there will be a delay of 8+ hours in attaining level then start NAC immediately.

Question 19

Risk of N-acetylcysteine.

Question 20

Presentation of calcium channel blocker overdose?

Answer 20

Sinus bradycharida,
Hypotension,
Prolonged QT inverval.
High potassium and low glucose.
Cardiogenic shock which cen develop into VF/VT

Question 21

Management of calcium channel blocker?

Answer 21

IV calcium chloride - high conc of ionised calcium.
Best treatment - hyperinsulinaemic euglycaemia.
Sodium bicarbonate if very acidotic.
Intralipid.
Iontropes.
ECMO.

Question 22

Presentation of digoxin overdose?

Answer 22

QT prolongation, bradycardia and ‘reverse tick’ on ECG.
Metabolic acidosis,
Hyperkalaemia,
N+V,
Confusion

Question 23

Treatment of digoxin toxicity

Answer 23

Charcoal
8.4% sodium bicarb.
Insulin/dextrose for hyperkalaemia (dont give calcium gluconate in this case of hyperkalaemia)
Atropine.
Digibind.

Question 24

Overdose of iron presentation

Answer 24

Direct caustic gut action - N+V, abdominal pain, diarrhoea, haematemesis, acidosis, hepatic necrosis.

Question 25

Management of iron OD

Answer 25

No place for activated charcoal!
Gastric lavage + endoscopy,
Antidote - Desferroxamine.
Dialysis

Question 26

Describe features of cannabinoid hyperemesis

Answer 26

Relieved by hot water >41 degrees.
Standard antiemetics tend not to work. Haloperidol used instead.

Question 27

What are the adverse affects of cocaine?

Answer 27

CV - Coronary artery spasm, tachycardia/bradycardia, HTN, aortic dissection.
Neurological - Seizures, mydriasis, hypertonia, hyperreflexia.
Psychiatric effects - Agitation, psychosis, hallucinations
Others - ischaemic collitis, hyperthermia, metabolic acidosis, rhabdo.

Question 28

What is the management of cocaine toxicity

Answer 28

Mainstay - benzodiazepines.
Chest pain - Benzodiazepines and GTN.
HTN - Benzos and sodium nitroprusside

Question 29

Clinical features of ecstasty/MDMA poisoning?

Answer 29

Neuro - agitation, anxiety, confusion, ataxia.
CV - tachycardia, HTN,
Hyponatraemia - SIADH or excess water consumption while taking MDMA.
Hyperthermia
Rhabdomyolysis

Question 30

Treatment of ecstasty poisoning?

Answer 30

Supportive and dantrolene for hyperthermia if simple measures fail

Question 31

Presentation of LSD intoxication?

Answer 31

Psychoactive symptoms - impaired judgement, euphoria/dysphoria, agitation, drug induced psychosis.
Somatic symptoms - Nausea, headaches, palpitations, dry mouth, drowsiness.
Signs - tachycardia, HTN, mydriasis, paresthsia, hyperreflexia, pyrexia.