15.1,2 Pituitary, anterior + posterior

Question 1

How much of pituitary tissue has to be lost before hypopituitarism symptoms occur?

Answer 1

75% parenchyma lost

Question 2

GH pituitary adenoma

-symptoms (4)

Answer 2

gigantism–before puberty

acromegaly–after puberty

1. enlarged bones in hands, feet, jaw
2. growth of visceral organs, leading to dysfunction (eg cardiac failure)
3. enlarged tongue
4. Secondary diabetes mellitus (GH induces liver gluconeogenesis)

Question 3

Pituitary adenoma

-common hormones secreted (3)

Answer 3

1. Prolactin
2. GH–acromegaly, gigantism
3. ACTH–cushing’s disease

Question 3

Prolactinoma

• symptoms–female (1)
• symptoms–male (2)
• Tx

Answer 3

1. galactorrhea, amenorrhea
2. decreased libido, headache

Tx: DA agonist (bromocriptine), surgery

Question 4

Sheehan syndrome

-clinical presentation (3)

Answer 4

1. poor lactation (no prolactin)
2. loss of public hair (low LH/FSH)
3. fatigue

Question 7

SIADH

• most common cause
• other causes (3)

Answer 7

• ADH secreting tumor (eg small cell carcinoma)
  1. CNS trauma
  2. pulmonary infection
  3. drugs–eg cyclophosphamide

Question 7

SIADH

• clinical symptoms (2)
• Tx (2)

Answer 7

1. hyponatremia, low serum osmolalilty
2. seizures, mental status changes. (hyponatermia causes intracerebral swelling)
3. demeclocycline (induces nephrogenic diabetes insipidus–blocks ADH effect on nephron)
4. free water restriction

Question 8

Empty sella syndrome

Answer 8

• herniation of arachnoid and CSF into sella, compressing and destroying pituitary.
• causes hypopituitarism

Question 9

Central diabetes insipidus

• how to dx
• Tx

Answer 9

• water deprivation test (if central diabetes insipidus, urine osmolarity remains low)
• Desmopressin (ADH analog)

Question 10

Oxytocin

-effects (2)

Answer 10

1. labor during pregnancy
2. stimulates lactation (release of breast milk)

Question 11

GH Pituitary adenoma

• how to diagnose (3)
• Tx

Answer 11

1. elevated GH
2. elevated IGF-1
3. lack of GH suppression with oral glucose
   - octreotide (somatostatin analog)

Question 12

Nephrogenic diabetes insipidus

-etiology

Answer 12

-due to inherited mutations or drugs (eg lithium, demeclocycline)

Question 13

Hypopituitarism

-most common causes (adults, children)

Answer 13

mass effect or apoplexy

1. pituitary adenoma (adults)
2. craniopharyngioma (children)

Question 14

demeclocycline

Answer 14

• acts on nephron to block effect of ADH
• induces nephrogenic diabetes insipidus
• Tx for SIADH

Question 15

Sheehan syndrome

-mech

Answer 15

• pregnancy related infarct of pituitary gland
• pit gland doubles in size during pregnancy but blood supply remains the same. Bleeding during pregnancy causes infarct

Question 16

Pituitary adenoma, nonfunctional

-symptoms (3)

Answer 16

mass effect

1. bitermporal hemianopsia
2. hypopituitarism–compression of normal pituitary tissue
3. headache