Endocrine

Question 1

Hyponatraemia investigations

Answer 1

U+E and urinary sodium

Question 2

Hyponatraemia, urinary sodium >20mmol, hypovolaemic

Answer 2

Sodium depletion, renal loss (patient often hypovolaemic)
diuretics: thiazides, loop diuretics
Addison’s disease
diuretic stage of renal failure

Question 3

Hyponatraemia, urinary sodium>20mmol, euvolaemic

Answer 3

SIADH (urine osmolality > 500 mmol/kg)

hypothyroidism

Question 4

Hyponatraemia, urinary sodium<20mmol, hypovolaemic

Answer 4

Sodium depletion, extra-renal loss
diarrhoea, vomiting, sweating
burns, adenoma of rectum

Question 5

Hyponatraemia, urinary sodium <20mmol, hypervolaemic and oedematous

Answer 5

Water excess
secondary hyperaldosteronism: heart failure, liver cirrhosis
nephrotic syndrome
IV dextrose
psychogenic polydipsia

Question 6

Hypernatraemia causes

Answer 6

dehydration
Osmotic diuresis e.g. hyperosmolar non ketotic diabetic state
diabetes insipidus
excess IV saline

Question 7

Hyponatraemia management (mild)

Answer 7

Fluid restriction

Loop diuretics

Question 8

Hyponatraemia management (moderate) 120-129

Answer 8

Hypertonic saline in first 3-4hours

Then fluid restriction

Question 9

Hyponatraemia management (severe) below 120

Answer 9

Bolus of hypertonic saline until symptom resolution

Conivaptan (Vasopressin analogue) can be used but not in hypovolaemic patients

Question 10

Osmotic demyelination syndrome/central pontine myelinosis

Answer 10

Overcorrection of low Na - only change 4-6mmol in 24hrs

Symptoms - irreversible seizures, confusion, dysarthria, dysphagia, locked in syndrome

Question 11

hypernatraemia treatment

Answer 11

Acute: 5% dextrose
Chronic: 4.5% saline if unable to tolerate water

Question 12

hyperkalaemia causes

Answer 12

acute kidney injury
drugs*: potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, heparin**
metabolic acidosis
Addison's disease
rhabdomyolysis
massive blood transfusion

Question 13

Hyperkalaemia management (3 elements)

Answer 13

1. Stabilize the cardiac membrane - calcium gluconate
2. Short term shift from intracellular to extracellular of potassium - IV insulin and glucose, nebulized salbutamol
3. Reduction of potassium - loop diuretics, calcium resonium, dialysis

Question 14

Hyperkalaemia ECG

Answer 14

Peaked or 'tall-tented' T waves (occurs first)
Loss of P waves
Broad QRS complexes
Sinusoidal wave pattern
Ventricular fibrillation

Question 15

Hypokalaemia causes (with alkalosis)

Answer 15

Thiazides and loop diuretics
Vomiting
Primary hyperaldosteronism (Conns)
Cushings syndrome

Question 16

Hypokalaemia causes (with acidosis - rarer)

Answer 16

Diarrhoea
Renal tubular acidosis
acetazolomide
Partially treated diabetic ketoacidosis

Question 17

Most common causes of hypercalcaemia

Answer 17

Two conditions account for 90% of cases of hypercalcaemia:

1. Primary hyperparathyroidism: commonest cause in non-hospitalised patients
2. Malignancy: the commonest cause in hospitalised patients. This may be due to number of processes, including; bone metastases, myeloma, PTHrP from squamous cell lung cancer

Question 18

Other causes of Hypercalcaemia

Answer 18

sarcoidosis*
vitamin D intoxication
acromegaly
thyrotoxicosis
Milk-alkali syndrome
drugs: thiazides, calcium containing antacids
dehydration
Addison's disease
Paget's disease of the bone**

Question 19

Hypercalcaemia treatment

Answer 19

Rehydration with normal saline
Bisphosphonates
Calcitonin
Loop diuretics