Endocrine

Question 1

Name two conditions where there is thirst (polydipsia) and polyuria (increased urine output).

Answer 1

Diabetes insipidus

Psychogenic polydipsia

Question 2

What is psychogenic polydipsia?

Answer 2

Increased thirst and urine output related to psychiatric or psychological excess water consumption. ADH levels and function are normal.

Question 3

How is DI differentiated from psychogenic polydipsia?

Explain this test.

Answer 3

Water deprivation test.
The psychogenic patients urine output will reduce in line with their decreased consumption whereas the patient with DI will become more dehydrated.

Question 4

How are the two forms of DI clinically differentiated (tested)?

Answer 4

Give synthetic ADH (desmopressin).

Cranial will resolve with the analogue while nephrogenic will not.

Question 5

What is desmopressin?

What does it test for?

Answer 5

Synthetic ADH

Differentiate b/w cranial (responsive) and nephrogenic DI.

Question 6

Name two forms of DI (diabetes insipidus).

Describe each.

Answer 6

Cranial (insufficient ADH from posterior pituitary)

Nephrogenic (sufficient ADH but kidneys don’t respond to it)

Question 7

Name EIGHT diagnostic criteria for SIADH.

Describe generally what SIADH causes.

Answer 7

Water retention (dilute blood and concentrated urine)
Isovolaemic
Normal PART (pituitary, adrenal, renal & thyroid)
No diuretics
Low SERUM osmolarity
High URINE osmolarity

Question 8

What condition is raised GH?
What is the most common cause?
How is this diagnosed? (What test)
What result confirms this condition?
Explain what this result means.

Answer 8

Acromegaly
Pituitary tumour
Via measurement of GH in a GTT or IGF1 (both increased)
GH > 1 mU/L is diagnostic
GH is too variable to measure directly.
GH and BGL are linked.
In hyperglycemia GH is secretion is INHIBITED. In acromegaly autonomous GH secretion means it either persists or increases during OGTT.

Question 9

Name five common causes of hyperprolactinaemia.

Answer 9

Physiological (pregnancy and lactation)
Tumour (secreting ProL)
PCOS
seizure 
Primary hypothyroidism
Drugs (dopamine antagonists: antipsychotics & antiemetics)

Question 10

Name three types of HYPONATREMIA

Answer 10

hypervolaemic, euvolaemic, hypovolaemic.

Question 11

What clinical signs suggest hypervolaemic hyponatremia?

What is the treatment?

Answer 11

Oedema; weight gain

Fluid restriction; diuresis (diuretics)

Question 12

What clinical signs suggest euvolaemic hyponatremia?
Name the three subtypes.
What serum osmolarity demarcates them?

Answer 12

Weight gain; NO oedema
Hypotonic, isotonic, hypertonic
290 mmol / kg

Question 13

What is the serum osmolarity in hypotonic euvolaemic hyponatremia?
On what basis is this condition further categorized ?
What is the value?

Question 14

What is the cause of a low urine osmolarity in hypotonic euvolaemic hyponatremia ?
How is it treated?

Answer 14

Excess water intake (water overload)

Fluid restriction

Question 15

Name THREE causes of euvolaemic hyponatremia where the urine osmolarity is > 100 mmol / kg.

Answer 15

SIADH
excess fluids
Thiazide diuretics

Question 16

Consider euvolaemic hyponatremia where serum osmolarity is >= 290 mmol / kg:
Where the osmolarity gap is LESS than 10 mmol / kg …
What is the likely cause?
How is it treated?

Answer 16

High BGL

Control DM

Question 17

Consider euvolaemic hyponatremia where serum osmolarity is >= 290 mmol / kg:
Where the osmolarity gap is GREATER THA OR EQUAL TO than 10 mmol / kg …
What is the likely cause?
How is it treated?

Answer 17

Non-glucose solute

Correct the cause.

Question 18

What name is given to a tumour causing excess catecholamines?
How is this diagnosed?
If this is equivocal, what other test

Answer 18

Phaeochromocytoma
Free metanephrines (plasma) or fractional metanephrines (urine)