Stuff Flashcards
How to work out anion gap in metabolic acidosis?
Na - (Cl+HCO3), normal range = 4-12
OR
(Na+K) - (Cl+HCO3), normal range = 10-18
Causes of anion gap metabolic acidosis?
MUDPILES CAT
Methanol Urea DKA Paraldehyde Iron/Isoniazid Lactate Ethanol Salicylates
Carbon monoxide
Aminoglycosides
Theophylline
Causes of normal anion gap metabolic acidosis?
HARDASS
Hyperalimentation (TPN feeds) Addison's disease Renal tubular acidosis Diarrhoea Acetazolamide Spironolactone Saline infusion
7 P450 enzyme inducers?
Phenytoin Carbamazepine Rifampicin Phenobarbitone St John's Wort Chronic alcohol intake Smoking (smokers need to take more aminophylline)
12 P450 inhibitors?
Ciprofloxacin and erythromycin Isoniazid Cimetidine Omeprazole Amiodarone Allopurinol -azole antifungals Fluoxetine and Sertraline Valproate Acute alcohol intake
Drugs which can cause SIADH?
Carbamazepine Sulfonylureas SSRI's Tricyclics Vincristine
Causes of hypernatraemia?
Management?
Dehydration
Osmotic diuresis (e.g. HHS)
Diabetes insipidus
Excessive saline
Correct hypernatraemia slowly and cautiously, can predispose cerebral oedema and seizures
General rate is no greater than 0.5mmol/hour
Raised ALP and raised Ca?
Bone mets
Hyperparathyroidism
Raised ALP and low Ca?
Osteomalacia
Renal failure
Generally, what is reabsorbed in kidney?
Na, Ca, Cl, Mg H2O HCO3 Glucose AA
Generally, what is excreted in kidney?
K, H, urea
Creatinine
Hyponatraemia causes with urinary Na >20mmol/L?
Sodium depletion/renal loss (often hypovolaemic):
- diuretics: thiazides, loops
- Addison’s
- renal failure
If patients euvolaemic:
- SIADH (urine osmolality often >500mmol/kg)
- Hypothyroidism
Hyponatraemia causes with urinary Na <20mmol/L?
Sodium depletion/extra-renal loss:
- diarrhoea, vomiting, sweating
- burns
- rectal adenoma
Water excess (often hypervolaemic and oedematous):
- secondary hyperaldosteronism (HF, cirrhosis)
- nephrotic syndrome
- IV dextrose
- psychogenic polydipsia
Management of chronic (>48 hrs) hyponatraemia if:
- hypovolaemic cause (renal failure, diuretics, addison’s)?
- euvolaemic cause (SIADH)?
- hypervolaemic cause (HF, liver failure, nephrotic syndrome)?
Hypovolaemic: 0.9% saline
Give as trial initially, if Na falls then likely alternative diagnosis such as SIADH
Euvolaemic: fluid restrict to 500ml/day. Consider demeclocycline/vaptans
Hypervolaemic: fluid restrict to 500ml/day. Consider loop diuretics/vaptans
When is a 150ml bolus of 3% NaCl typically given?
Acute hypovolaemia Na <120
