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IM Endo Pituitary USMLE 2

Terms

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Where is the anterior pituitary derived from?
Rathke's pouch
Where is the posterior pituitary derived from?
Hypothalamic neuronal axon terminals of the brain
what multiendocrine problem includes pituitary tumors?
MEN-1
(pituitary, pancreas, parathyroid)
where is the site of the primary tumors of the pituitary?
Anterior pituitary only
(none in posterior)
MC pituitary tumor, it presents w/ glactorrhea and amenorrhea

Tx?
Prolactinoma

Tx: Bromocriptine (DA agonist)
Dx:
pituitary tumor that presents w/ visual changes or slightly high prolactin levels

Tx?
Nonfunctioning Tumor

Tx: surgery
Definition:
MC tumor of the suprasellar region in children that arises from the remnants of Rathke's pouch and is solid or cystic; usually calcified
Craniopharyngioma
Dx:
HA, compression of optic chiasm "tunnel vision", signs of increased intracranial pressure
Craniopharyngioma
Dx Test for Craniopharayngioma
(3)
X-ray - shows enlarged sella

CT / MRI

Hormone studies: excess deficiencies
Tx for craniopharyngioma
(3 together)
1. Surgery

2. Hormone replacement

3. Dopamine agonist if prolactin-related Sx are noticed
specific Etiology of Acromegaly
pituitary Somatotrophic Adenoma secreting GH
Dx:
progressive enlargement of the peripheral body parts, particularly head, hands, and feet; decreased glucose tolerance; hyperphosphatemia
Acromegaly
Acromegaly in children
Gigantism
What hormone in excess is related to acromegaly?
GH
Dx tests that confirm Acromegaly
(3)
1. Serum GH levels - measured in bed in am

2. Lack of GH suppression by glucose

3. Elevated serum IGF-I levels
Aside from surgery and radiation, what is the medicine used to Tx Acromegaly?
GH receptor blocker:

Pegvisomant
(Somavert)
Dx:
29-yo woman w/ inability to lactate after childbirth. Delivery was complicated by blood loss and hypotension
Sheehan's syndrome
Etiology of Hypopituitraism
(3)
Tumors;

Medical/surgical destruction;

Sheehan's syndrome
Dx:
36-yo woman complains of amenorrhea for 1 year, increasingly bad HA, clumsiness and sporadic nipple discharge; beta-hCG levels are normal
Prolactinoma
Drugs that inhibit DA and as a result, cause hyperprolactinemia
(6)*
The Prolactin Has Magnified My C-cups:
TCAs;
Prochlorperazine;
Haloperidol;
Methyldopa;
Metoclopramide:
Cimetidine
Difference b/t Central DI and Nephrogenic DI w/ respect to ADH
Central DI:
inadequate pituitary secretion of ADH

Nephrogenic DI:
lack of renal response to ADH
Etiology of Central DI
(4, 3 are systemic)
PENS:

1. Posterior pituitary damage
(tumor, trauma, etc)

2. Encephalitis;

3. Neurosyphillis;

4. Sarcoidosis
Dx:
Psychiatric disorder of compulsive water drinking common in young to middle aged women; polyuria and dilute urine.

How is it distinguished from DI?
Psychogenic Polydipsia

difference w/ DI:
PP has a low plasma osmolality
Etiology of Nephrogenic DI aside from Drugs, renal Dz and electrolyte disorders
Sickle cell
(3) Drugs that can cause nephrogenic DI
"Liquid DM":

Lithium;

Demeclocycline;

Methoxyflurane
Dx:
polyuria (3-15 L/day); thirst; dilute urine (sp gravity < 1.005)
DI
Dx test for DI
(3)
1. plasma Osmolality: High

2. Exogenous ADH: leads to Water deprivation

3. Infusion of hypertonic saline: no response
Compare the urine osmolality before and after the infusion of exogenous ADH in:

1. Normal patient

2. Central DI patient

3. Nephrogenic DI patient
Normal:
High urine Osm -> high urine Osm

Central DI:
Low urine Osm -> high urine Osm

Nephrogenic DI:
Low urine Osm -> low urine Osm
Tx for Central DI
Desmopressin (DDAVP)
Tx for Nephrogenic DI
Thiazide Diuretics
Definition:
Excess production of ADH
SIADH
basic Etiology of SIADH
(3)
PIE:

Pharmacologic stimulation of hypo-pit axis;

Idiopathic overproduction of axis;

Ectopic production from tumors
what (2) tumors cause SIADH?
Small cell lung CA

Pancreatic CA
what are the Idiopathic causes of the overproduction of ADH in SIADH?
(5 in 2 categories)
CNS:
encephalitis, trauma, stroke

Pulmonary Dz:
TB, pneumonia

*any problem to Lungs or Brain (+ Pancreatic CA) can cause SIADH!
(4) Pharmacologic causes of SIADH
Carbamazepine;

Chlorpropamide;

Clofibrate;

Vincristine
(4)* other causes, aside from small cell and pancreatic cell cancer, of ADH secretion
Adrenal failure;

Renal failure;

Edema;

Fluid loss
Dx:
hyponatremia; low serum osmolality; high urinary sodium; urine osmolality > serum
SIADH
Tx for SIADH
(2 w/ fluids, 1 drug)
Fluid restriction;

Hypertonic saline in severe HypoN;

Demeclocycline
(lowers CD response to ADH)

Deck Info

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