Endocrine Cases

Question 1

Water deprivation test

Answer 1

Done while monitoring the patient’s weight, serum and urine osmolality, and serum electrolytes
ADH release should be stimulated and urine should become concentrated, while serum osmolality remains in the normal range

Question 2

How do you determine whether diabetes insipidus is central or nephrogenic?

Answer 2

Administer ADH (ddVAP) and measure the urine osmolality
If it increases, it is central
If the urine remains dilute it is nephrogenic

Question 3

What can cause nephrogenic diabetes insipidus

Answer 3

Congenital

Acquired (distortion of normal renal architecture, hypokalemia, hypercalcemia, Li, demeclocycline)

Question 4

What can cause central DI

Answer 4

Genetic
Tumor in the hypothalamus/pituitary
Trauma/surgery
Granulomatous infiltrative pituitary disease

Question 5

Who is at risk of becoming severely dehydrated and hypernatremic

Answer 5

Hospitalized patients
Elderly
Babies
Lack of water access

Question 6

Symptoms of GH excess

Answer 6

Acromegaly
Headaches
Sweating
Bone and soft tissue growth
Carpal tunnel
Elevated blood sugar (can lead to polyuria and polydipsia)

Question 7

Best test for GH axis

Answer 7

IGF-1

Longer half life and is not pulsatile like GH

Question 8

First line treatment for pituitary adenoma

Answer 8

Surgery

Question 9

Possible complications of pituitary surgery

Answer 9

Rarely serious complications: stroke, worsening vision
Transient or permanent DI
Damage to AP gland

Question 10

Options other than surgery for a GH tumor

Answer 10

Medical management with somatostatin analogue to suppress GH
DA agonist can be used
GH receptor agonist
Second surgery
Radiation (but takes years - only for patients who failed surgery and all medical options)

Question 11

Causes of secondary amenorrhea

Answer 11

Rule out pregnancy!
POI
Hypothalamuc amenorrhea
Increased androgens (PCOS, ovarian/adrenal tumor)
Hypopituitarism
Hypothalamic lesions
Hyperprolactinemia

Question 12

Causes of increased PRL

Answer 12

Pregnancy or breastfeeding
Prolactinoma
Mass compressing pituitary stalk
Drugs (DA antagonists)
Renal failure
Hypothyroidism
Physiological (breast stimulation)
Macroprolactin (Ig-PRL complex)

Question 13

First line treatment for prolactinoma

Answer 13

DA agonist

Lowers PRL and shrinks tumor

Question 14

Secondary vs primary amenorrhea

Answer 14

Primary: never has had a spontaneous period before