Abnormal Blood Tests

Question 1

Define chronic hyponatraemia

Answer 1

Na <135 for over 48 hrs

Question 2

Three types of hyponatraemia

Answer 2

hypovolaemia
euvolaemia
hypervolaemia

Question 3

example of hypovolaemic hyponatraemia

Answer 3

diuretics, adrenocortical failure, vomiting, diarrhoea, burns

Question 4

example of euvolaemic hyponatraemia

Answer 4

polydipsia
IV fluids
SIADH

Question 5

example of hypervolaemic hyponatraemia

Answer 5

heart failure
cirrhosis
CKD

Question 6

SIADH

Answer 6

(too much) ADH causes excessive water retention (and dilution of Na) without a physiological cause = hyponatraemia
(tumours, CNS, lung/drugs, thiazide, carbamezipines, tricyclics)

Question 7

where does the water go if plasma osmolality falls (hyponatraemia)

Answer 7

into cerebral cells = swelling (nausea, confusion, headache, coma)

Question 8

define hypernatraemia

Answer 8

> 145 mmol/L

represents a deficit in water relative to sodium

Question 9

common causes of hypernatraemia

Answer 9

free water loss eg. osmotic diuretic, diaahoea, sweating, diabetes insipidus

Question 10

what challenge test can you do for hypernatraemia

Answer 10

desmopressin

Question 11

causes of hyperkalaemia

reduced what could cause it x3

Answer 11

reduced GFR (AKI/CKD)
reduced aldosterone (Addison's, ACE-I, ARB, spironolactone)
renin inhibition - NSAIDs/beta blockers
Tubulo-interstitial disease

Question 12

ECG changes in hyperkalaemia

Answer 12

tented T waves

QRS broadening

Question 13

Emergency hyperkalaemia management 3 things to do

Answer 13

stabilise cardiac membrane (IV calcium gluconate)
shift K into cells (salbutamol, IV insulin/dextrose, bicarb)
Remove K from body (ion-exchange resin PR/PO, dialysis)

Question 14

Signs of hypercalcaemia

Answer 14

BONES (MSK pain)
MOANS (depression)
GROANS (abdo pain)
STONES (renal colic)

Question 15

hypercalcaemia with normal or high PTH main

Answer 15

primary hyperparathyroidism