Endo - Pathology (Pituitary) Flashcards
Pg. 324-236 in First Aid 2014 Sections include: -Pituitary adenoma -Acromegaly -Diabetes insipidus -SIADH -Hypopituitarism
What is the most common pituitary adenoma? Is it benign or malignant?
Most commonly prolactinoma (benign)
What are the 2 general types of adenoma?
Adenoma may be functional (hormone producing) or nonfunctional (silent)
What is the main way in which nonfunctional adenomas present, and what are 3 effects that this presentation may have?
Nonfunctional tumors present with mass effect (bitemporal hemianopia, hypopituitarism, headache)
On what is the presentation of functional adenomas based? Give 2 examples of functional adenomas and their majors signs/symptoms.
Functional tumor presentation is based on hormone produced (e.g., Prolactinoma: amenorrhea, galactorrhea, low libido, infertility; Somatotropic adenoma: acromegaly)
What is the treatment for prolactinoma? What are 2 examples?
Treatment for prolactinoma: dopamine agonists (bromocriptine or cabergoline)
What defines Acromegaly? What typically causes it?
Excess GH in adults. Typically caused by pituitary adenoma
What are 5 signs/symptoms of Acromegaly?
(1) Large tongue with deep furrows (2) Deep voice (3) Large hands and feet (4) Coarse facial features (5) Impaired glucose tolerance (insulin resistance)
What are 3 ways in which Acromegaly can be diagnosed?
(1) High serum IGF-1 (2) Failure to suppress serum GH following oral glucose tolerance test (3) Pituitary mass seen on MRI
What is the first-line treatment for acromegaly? What are 2 options in the event that this does not work?
Pituitary adenoma resection. If not cured, treat with octreotide (somatostatin analog) or pegvisomant (growth hormone receptor antagonist)
What condition does excess GH in children cause, and why?
Excess GH in children => Gigantism (increased linear bone growth)
What is the most common cause of death in the context of gigantism?
Cardiac failure most common cause of death
What 3 major clinical findings characterize diabetes insipidus, and what are 2 causes of it?
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.
What are 6 possible etiologies of central DI?
(1) Pituitary tumor (2) Autoimmune (3) Trauma (4) Surgery (5) Ischemic encephalopathy (6) Idiopathic
What are 4 possible etiologies of nephrogenic DI?
(1) Hereditary (ADH receptor mutation), secondary to (2) hypercalcemia, (3) lithium, (4) demeclocycline (ADH antagonist)
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.
(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
Describe the method of diagnosis for diabetes insipidus. How is central versus nephrogenic DI distinguished in diagnosis?
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
What are treatments for central versus nephrogenic DI?
CENTRAL DI: (1) Intranasal DDAVP (2) Hydration; NEPHROGENIC DI: (1) HCTZ (2) Indomethacin (3) Amiloride (4) Hydration
What is SIADH? What are 3 major signs/symptoms that it causes?
Syndrome of inappropriate antidiuretic hormone secretion: (1) Excessive water retention (2) Hyponatremia with continued urinary Na+ excretion (3) Urine osmolarity > serum osmolarity
What causes the hyponatremia in SIADH? What 2 major effects can hyponatremia have? How must it be corrected, and why?
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.
What are 4 causes of SIADH?
Causes include: (1) Ectopic ADH (small cell lung cancer) (2) CNS disorders/head trauma (3) Pulmonary disease (4) Drugs (e.g., cyclophosphamide)
Give an example of ectopic ADH that may cause SIADH. Also, give an example of a drug that may cause SIADH.
Ectopic ADH (small cell lung cancer); Drugs (e.g., cyclophosphamide)
What is the treatment for SIADH?
Treatment: (1) Fluid restriction (2) IV hypertonic saline (3) Conivaptan (4) Tolvaptan (5) Demeclocycline
What is hypopituitarism? What are 5 causes of it?
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
What are 2 types of tumors that can cause hypopituitarism?
(1) Nonsecreting pituitary adenoma (2) Craniopharyngioma
What is Sheehan syndrome? How does it usually present? What condition does it cause?
Sheehan syndrome (ischemic infarct of pituitary following postpartum bleeding; usually presents with failure to lactate); Hypopituitarism
What defines empty sella syndrome? What often causes it? In what patient population is it common? What condition does it cause?
Empty sella syndrome (atrophy or compression of pituitary, often idiopathic, common in obese women)
What are 2 brain insults that can cause hypopituitarism? What is a specific name for one when it specifically pertains to pituitary?
Brain injury, hemorrhage (pituitary apoplexy)
What is the treatment for hypopituitarism?
Treatment: hormone replacement therapy (corticosteroids, thyroxine, sex steroids, human growth hormone).
