Pituitary

Question 1

Ant. Pit Adenoma (Prolactin)

Answer 1

• Most common=Hyperprolactemia _{^{(over 200)}}-Micro that can progress to macro=mass effect
• Associated w/MEN 1 _{^{(pit, parathyroid, Pancreas)}}
• Treat w/Bromocriptine _{^{(dopamine agonist)}}
• Symptoms (micro):
  
  • _{^{Amenorrhea, galactorrhea, loss of libido <u><strong>(low GnRH)</strong></u>}}
• Symptoms (macro):
  
  • _{^{Bitemp hemianopsia press on optic chiasm}}
  • _{^{Increased intracranial pressure=papilledema herniation (optic disc swelling)}}

Question 2

Stalk Effect (hyperprolactinemia)

Answer 2

• Compression syndrome (stalk syndrome)
  
  • _{^{Complete trans-section/compression of stalk}}
  • Delivery of dopamine is blocked _{^{<u><strong>(antagonist of prolactin)</strong></u>}}
• “Empty Sella Syndrome”-Obese women abnormal lactation-CT scan “Fluid density in Sella turnica”
• ALL ant. pit hormones LOW except prolactin
  
  • _{^{lvls less than 200 BUT still higher than normal}}
  • _{^{Same condition seen in <u>craniophryngiomas &amp; Rathke's cleft cysts</u>}}

Question 3

Ant. Pit adenomas (GH)

Answer 3

• _Adult=Acromegaly _
• High-Gh & IGF-1 = High Insulin _{^{(impaired Oral glucose tolerance test)}}
• Secondary diabetes-^{_{GH <strong>decreases</strong> glucose uptake into cells}}
• After closure of epiphysis
• Large hand/feet & prominent jaw _{^{(proganthism)}}
• IGF-1 _^(liver) Large internal organs & CHF _{^{(cardiac failure common)}}
• Adolescent=Gigantism
• Lab values same
• Before closure of epiphysis _{^{<strong>(less than 25 years)</strong>}}
• Tall w/long extermities
• Associated w/McCune-Albright syndrome
• Treat: Octreoride ^{_{(somatostain analogue)}} block GnRH

Question 4

McCune-Albright Syndrome

Answer 4

• Female pt-common
• Polyostotic fibrous dysplasia _{^{(normal bone replace w/fibrous growth)}}
• Cafe au lait spots
• Precocious puberty _{^{(menstrual periods begin early)}}
• Arises from endocrine abnormality (Gigantism, hyperthyroidism & Cushing syndrome)
• Genetics:
• Mutation in GNAS gene (G-protein) = overactivation of **adenylate cyclase enzyme **
  
  • _{^{<strong>Overproduction of several hormones</strong>}}

Question 5

Ant. Pit adenomas (others)

Answer 5

• Corticotroph cell adenoma=Cushing’s DISEASE
• NON-active=**Null cell adenoma **(non-secretory)
  • No Hormone production
  • Mass effect & possible “Stalk effect”
  • Hypopitutarism & diabetes incip _{^{(def of vasopressin)}}
  • Hypernaturemia=Water intox w/excessive ADH

Question 6

Craniopharyngioma

Answer 6

• Tumor from remnants of Rathke’s pouch/Pharynx
• Supra-sellar mass _{^{<strong>(above sella-turcica)</strong>}} lead to mass effect
• Interfere w/somatic & sexual development (Dwarf)
• Can compress on optic chiasm (bi-temp)
• Histo:
• Solid or cystic _{^{(calcified)or<u>(cholesterol crystals)</u>}}
• Squamos & columnar cells
• Dentigenous/Odotogenic tissue _{^{(Make teeth)}}

Question 7

Hypopituitarism (Sheehan’s)

Answer 7

• Diagnosis = greater than 75% of ant pit destroyed
• “Empty sella syndrome”
• Ischemic coag necrosis of pit = Sheehan’s Syndrome
  
  • _{^{Immediate symptoms-low prolactin<strong> (baby cannot feed)</strong>}}
• Symptoms:
  
  • _{^{Cold sensitivity (low TSH)}}
  • _{^{Weakness, hypotension, & low blood sugar <strong>(low ACTH)</strong>}}
  • _{^{Secondary adrenal insuff w/NORMAL Na}}
  • _{^{Amenorrhea & sterility (low sex steroid adrenal) - loss of pubic hair}}
• Non-secretory adenomas (“null cell”)-_{^{Compression leads to atrophy}}

Question 8

Post. Pit (Central Diabetes Insipidus)

Answer 8

• Neurogenic (def production of ADH):
• Causes=Null cell adenoma, craniopharagioma, hypothalamic lesion
• Serum=Hypernatremia w/High osmolarity
• Urine=Low spec gravity w/Low osmolarity
  
  • Nephrogenic _{<strong>^{(Renal tubules are unresponsive to ADH)}</strong>}
• Both present w/Polyuria, Thrist-Polydopsia
• Desmopressin/vasopressin effect on ADH-neuro _{^{<strong>(greater than 50% increase)</strong>}}
  
  • nephro _{^{(less than 10% increase)}}
• Water deprivation test taken @ _{^{9am, 12pm, 3pm, 4pm}}

Question 9

SIADH

Answer 9

• Excess of ADH
• Most common cause=Small cell carcinoma lung
• Serum: Low Na+ & low osmolarity
• Urine: High specific gravity _{^{(greater than 1.04)}}w/High osmolarity _{^{(greater than serum)}}
• Symptoms:
• Oliguria
• Cerebral edema _{^{<strong>(hyponatremia=Swelling of nerves)</strong>}}
• Treat: Demelocyline _{^{(blocks ADH)}} & restict water intake