Toxicology Flashcards
A patient presents with an overdose metabolic acidosis, dilated pupils, tachycardia with widening of QRS on ECG. They are known to have a background of depression and hypertension. What is the likely drug and treatment?
Tricyclic Antidepressant overdose e.g amitriptyline
Treatment is IV bicarbonate
A car mechanic presents after a divorce with confusion, slurred speech and dizziness. ECG shows sinus tachycardia. Bloods show metabolic acidosis with a high anion gap and high osmolar gap. What is the cause and treatment?
Cause - Ethylene Glycol Toxicity (found in anitfreeze)
Treatment - Fomepizole (inhibits alcohol dehydrogenase)
What are the features of heparin induced thrombocytopenia?
50% reduction in platelets
thromobosis
Skin allergy
Treatement is to switch to either danaparoid or a direct thrombin inhibitor such as argatroban
A patient is being treated for depression presents with rigidity, sweating, confusion, hyperreflexia and monoclonus. He admits to taking st johns wort over the counter. What is the diagnosis and treatment?
Likely serotinin syndrome
Management - IV fluids + benzodiaxepines
severe cases - cyproheptadine and Chlorpromazine
A patient with known schizophrenia presents with raised temperature, sweating, rigidity and reduced reflexes. What is the diagnosis and treatment?
Neuroleptic malignant syndrome due to antipsychotics
IV fluids and benzodiazepines
Sever cases treated with Dantrolene
What drugs can prescipitate lithium toxicity?
Thiazides e.g. Indapamide
ACE inhibitors / ARBs
Metronidazole
NSAIDs
What are the features of lithium toxicity?
coarse tremor
hyperreflexia
acute confusion
polyuria
seizure
coma
How is lithium toxicity managed?
IV fluids
haemodialysis in severe toxicity
Sodium bicarbonate increases the alkalinity of urine promoting lithium excretion.
What is the King’s College criteria for liver transplantation following a paracetamol overdose?
- Arterial pH < 7.3 24 hours after ingestion
OR all of the following:
- prothrombin time > 100s
- creatinine >300
- grade 3 or 4 encephalopathy
What are the cardiovascular adverse effects of cocaine?
Cardiovascular - coronary artery spasm (MI), tachycardia / bradycardia, HTN, QRS widening, Qt prolongation, aortic dissection
What is the mechanism of action of cocaine?
blocks uptake of dopamine, noradrenaline and serotonin
What is the treatment for cocaine toxicity?
benzodiazpeines
Chest pain - benzos and GTN
HTN - benzos and sodium nitroprusside
What are the neurological features of cocaine toxicity?
seizures
mydriasis
hypertonia
hyperreflexia
A farmer presents with diarrhoea, excess salivation and hypotension. On examination he is bradycardia, with small pupils and muscle fasciculations.
What is the diagnosis and treatment?
Organophosphate poisoning.
Treated with atropine
Which tuberculosis medication requires visual acuity checks before and during treatment and why?
Ethambutol can cause optic neuritis
Which TB drug can cause hepatitis?
Rifampicin, Isoniazid, Pyrazinamide
Which TB drug can cause orange secretions?
Rifampicin
Which TB drug can cause gout?
Pyrazinamide - can cause hyperuricaemia and gout.
Which TB drug can cause agranulocytosis, peripheral neuropathy, hepatitis
Isoniazid
What channels does flecainide block to slow down cardiac conduction?
Nav1.5 sodium channels
What are the contraindications to flecainide?
- post MI
- structural heart disease e.g. HF
- sinus node dysfuction e.g. second degree AV block
- Atrial flutter.
What are the inducers of the P450 system?
CRAP GPS
Carbamazepine
Rifampicin
Alcohol (chronic)
Phenytoin
Griseofulvin
Phenobarbitone
St Johns wort / smoking
What are the inhibitors of the P450 system?
SICK FACES.COM
Sodium Valproate
Isoniazid
Cimetidine
Ketoconazole
Fluconazole
alcohol (acute) and grapefruit juice
Chloramphenicol
Erythromycin
Sulfonamides
Ciprofloxacin
Omeprazole
Metronidazole
What are the indications for haemodialysis in salicylate overdose?
Indications for haemodialysis in salicylate overdose
serum concentration > 700mg/L
metabolic acidosis resistant to treatment
acute renal failure
pulmonary oedema
seizures
coma
