Endo - Pathology (Pituitary)

Question 1

What is the most common pituitary adenoma? Is it benign or malignant?

Answer 1

Most commonly prolactinoma (benign)

Question 2

What are the 2 general types of adenoma?

Answer 2

Adenoma may be functional (hormone producing) or nonfunctional (silent)

Question 3

What is the main way in which nonfunctional adenomas present, and what are 3 effects that this presentation may have?

Answer 3

Nonfunctional tumors present with mass effect (bitemporal hemianopia, hypopituitarism, headache)

Question 4

On what is the presentation of functional adenomas based? Give 2 examples of functional adenomas and their majors signs/symptoms.

Answer 4

Functional tumor presentation is based on hormone produced (e.g., Prolactinoma: amenorrhea, galactorrhea, low libido, infertility; Somatotropic adenoma: acromegaly)

Question 5

What is the treatment for prolactinoma? What are 2 examples?

Answer 5

Treatment for prolactinoma: dopamine agonists (bromocriptine or cabergoline)

Question 6

What defines Acromegaly? What typically causes it?

Answer 6

Excess GH in adults. Typically caused by pituitary adenoma

Question 7

What are 5 signs/symptoms of Acromegaly?

Answer 7

(1) Large tongue with deep furrows (2) Deep voice (3) Large hands and feet (4) Coarse facial features (5) Impaired glucose tolerance (insulin resistance)

Question 8

What are 3 ways in which Acromegaly can be diagnosed?

Answer 8

(1) High serum IGF-1 (2) Failure to suppress serum GH following oral glucose tolerance test (3) Pituitary mass seen on MRI

Question 9

What is the first-line treatment for acromegaly? What are 2 options in the event that this does not work?

Answer 9

Pituitary adenoma resection. If not cured, treat with octreotide (somatostatin analog) or pegvisomant (growth hormone receptor antagonist)

Question 10

What condition does excess GH in children cause, and why?

Answer 10

Excess GH in children => Gigantism (increased linear bone growth)

Question 11

What is the most common cause of death in the context of gigantism?

Answer 11

Cardiac failure most common cause of death

Question 12

What 3 major clinical findings characterize diabetes insipidus, and what are 2 causes of it?

Answer 12

Characterized by intense thirst and polyuria with inability to concentrate urine due to lack of ADH (central) or insensitivity to ADH (nephrogenic). Has a central or nephrogenic cause.

Question 13

What are 6 possible etiologies of central DI?

Answer 13

(1) Pituitary tumor (2) Autoimmune (3) Trauma (4) Surgery (5) Ischemic encephalopathy (6) Idiopathic

Question 14

What are 4 possible etiologies of nephrogenic DI?

Answer 14

(1) Hereditary (ADH receptor mutation), secondary to (2) hypercalcemia, (3) lithium, (4) demeclocycline (ADH antagonist)

Question 15

Distinguish central versus nephrogenic DI in terms of the following lab findings: (1) ADH levels (2) Urine specific gravity (3) Serum osmolarity (4) Volume contraction.

Answer 15

(1) CD: low ADH; ND: normal ADH levels (2) CD & ND: urine specific gravity < 1.006 (3) CD & ND: Serum osmolarity > 290 mOsm/L (4) CD & ND: Hyperosmotic volume contraction

Question 16

Describe the method of diagnosis for diabetes insipidus. How is central versus nephrogenic DI distinguished in diagnosis?

Answer 16

Water restriction test: No water intake for 2-3 hr followed by hourly measurements of urine volume and osmolarity and plasma Na+ concentration and osmolarity. DDAVP (ADH analog) is administered if normal values are not clearly reached; CENTRAL DI - Water restriction test: > 50% increase in urine osmolarity; NEPHROGENIC DI - Water restriction test: no change in urine osmolarity

Question 17

What are treatments for central versus nephrogenic DI?

Answer 17

CENTRAL DI: (1) Intranasal DDAVP (2) Hydration; NEPHROGENIC DI: (1) HCTZ (2) Indomethacin (3) Amiloride (4) Hydration

Question 18

What is SIADH? What are 3 major signs/symptoms that it causes?

Answer 18

Syndrome of inappropriate antidiuretic hormone secretion: (1) Excessive water retention (2) Hyponatremia with continued urinary Na+ excretion (3) Urine osmolarity > serum osmolarity

Question 19

What causes the hyponatremia in SIADH? What 2 major effects can hyponatremia have? How must it be corrected, and why?

Answer 19

Body responds to water retention with low aldosterone (hyponatremia) to maintain near-normal volume status. Very low serum sodium levels can lead to cerebral edema, seizures. Correct slowly to prevent central pontine myelinolysis.

Question 20

What are 4 causes of SIADH?

Answer 20

Causes include: (1) Ectopic ADH (small cell lung cancer) (2) CNS disorders/head trauma (3) Pulmonary disease (4) Drugs (e.g., cyclophosphamide)

Question 21

Give an example of ectopic ADH that may cause SIADH. Also, give an example of a drug that may cause SIADH.

Answer 21

Ectopic ADH (small cell lung cancer); Drugs (e.g., cyclophosphamide)

Question 22

What is the treatment for SIADH?

Answer 22

Treatment: (1) Fluid restriction (2) IV hypertonic saline (3) Conivaptan (4) Tolvaptan (5) Demeclocycline

Question 23

What is hypopituitarism? What are 5 causes of it?

Answer 23

Undersecretion of pituitary hormones due to: (1) Nonsecreting pituitary adenoma, craniopharygioma (2) Sheehan syndrome (ischemic infarct of pituitary following postpartum bleeding; usually presents with failure to lactate) (3) Empty sella syndrome (atrophy or compression of pituitary, often idiopathic, common in obese women) (4) Brain injury, hemorrhage (pituitary apoplexy) (5) Radiation

Question 24

What are 2 types of tumors that can cause hypopituitarism?

Answer 24

(1) Nonsecreting pituitary adenoma (2) Craniopharyngioma

Question 25

What is Sheehan syndrome? How does it usually present? What condition does it cause?

Answer 25

Sheehan syndrome (ischemic infarct of pituitary following postpartum bleeding; usually presents with failure to lactate); Hypopituitarism

Question 26

What defines empty sella syndrome? What often causes it? In what patient population is it common? What condition does it cause?

Answer 26

Empty sella syndrome (atrophy or compression of pituitary, often idiopathic, common in obese women)

Question 27

What are 2 brain insults that can cause hypopituitarism? What is a specific name for one when it specifically pertains to pituitary?

Answer 27

Brain injury, hemorrhage (pituitary apoplexy)

Question 28

What is the treatment for hypopituitarism?

Answer 28

Treatment: hormone replacement therapy (corticosteroids, thyroxine, sex steroids, human growth hormone).