Interpretation Of UE's

Question 1

Hypovolaemic hyponatraemia

Answer 1

Urinary NA >30- diuretics, Addisons, kidney injury, osmotic diuretics (losing it in the urine)

Urinary NA <30- diarrhoea, vomiting, burns (lost elsewhere)

Question 2

Euvolaemic hyponatraemia

Answer 2

Urinary NA >30, urinary OSM >100- SIADH, hypothyroidism, glucocorticoid insufficiency

Urinary NA <30, urinary OSM <100- water intoxication

Question 3

Oedematous hyponatraemia

Answer 3

Congestive cardiac failure

Hypoalbuminaemia (cirrhosis, nephrotic syndrome)

Question 4

Euvolaemic hypernatraemia

Answer 4

Iatrogenic eg. Excess IV Na containing fluids

Question 5

Hypovolaemic hypernatraemia

Answer 5

Dehydration, diabetes insipidus, osmotic diuresis eg. DKA

Question 6

Hypokalaemia causes

Answer 6

Increased renal loss- NPS diuretics, steroids, cushings, hyperaldosteronism (conns) hyponagnesaemia

Intestinal loss- vomiting, diarrhoea

Increased cellular uptake- salbutamol, insulin, alkalosis

Question 7

Hyperkalaemia causes

Answer 7

Reduced renal excretion- AKI/ CKD, PS diuretics, ACE-I, NSAIDS, Addison’s disease

Excess K- iatrogenic, massive blood transfusion

Release from intracellular fluid- acidosis, tissue breakdown eg. Burns, crush injury

NB- pseudohyperkalaemia= EDTA contamination, haemolysis of sample

Question 8

Management of hyperkalaemia

Answer 8

ECG and 3 lead cardiac monitoring 
Calcium gluconate to stabilise cardiac cell membrane 
Actrapid insulin 
Calcium resonium 
Treat cause 
Haemodualysis if all else fails

Question 9

Hypocalcaemia symptoms

Answer 9

CATS GO NUMB 
Convulsions 
Arrhythmia 
Tetany 
Numbness (periorbital, oral, hands, feet)

Question 10

Hypocalcaemia causes

Answer 10

PTH deficiency- hypoparathyroidism, hypomagnesia, cinacalcet

Vit D deficiency

Increased deposition in bones- bisphosphanates

Others- CKD, rhabdomyolysis

Question 11

Hypercalcaemia symptoms

Answer 11

Painful bones, renal stones, abdominal groans (nausea and vomiting), general moans (malaise, fatigue and lethargy), time on the thrones (polyuria and constipation) and psychiatric overtones (confusion, depression, ataxia, delirium, psychosis)

Question 12

Hypercalcaemia causes

Answer 12

PTH excess- primary hyperparathyroidism, ectopic PTH secretion eg. Squamous cell lung cancer

Vitamin D excess- excessive intake, sarcoidosis

Increased release from bones- bony metastasis (high ALP), myeloma (normal ALP), thyrotoxicosis

Others- thiazide diuretics, dehydration

NB- can give a bisphosphanate to reduce Ca

Question 13

Hypomagnesia causes

Answer 13

Reduced intake- poor nutrition, malabsorption, alcoholism

Excess loss- diarrhoea, vomiting, PPI, hyperaldosteronism, diuretics, ketoacidosis

Question 14

Hypophosphataemia causes

Answer 14

Reduced intake/ absorption- vitamin D deficiency, poor nutrition, alcoholism, malabsorption

Shift into IC space- refereeing syndrome, insulin therapy, alkalosis

Excess renal loss- primary hyperparathyroidism

Question 15

Increased urea

Answer 15

Dehydration, GI bleeding, increased protein breakdown (trauma- bleeding, infection, malignancy), high protein intake

Question 16

Decreased urea

Answer 16

Malnutrition, liver disease, pregnancy

Question 17

AKI

Answer 17

Rise in serum creatinine >50% from baseline, or urine output <0.5ml/Kg/hour for 6 hours

Question 18

Calculate anion gap

Answer 18

Sodium and potassium - bicarbonate and chloride

Basically positives - negatives

Considered in patients with metabolic acidosis

Question 19

Normal anion gap metabolic acidosis

Answer 19

GI loss eg. Diarrhoea
Renal tubular acidosis 
Acetazolamide 
Addison’s disease
Ammonium chloride injection

Question 20

Raised anion gap metabolic acidosis

Answer 20

Lactate (shock, hypoxia)
Ketones (DKA, alcohol)
Urate (renal failure)
Acid poisoning eg. Salicylates, methanol
Chronic paracetamol use