Lecture 14: Pituitary Pathophysiology Flashcards
What types of diseases affect pituitary and hypothalamus?
- tumors
- infiltrative diseases
- hemochromatosis
- sarcoidosis
- meningitis
- trauma
What diseases cause HYPERsecretion of pituitary hormones?
Only pituitary ADENOMAS can hypersecrete hormones, or fragments thereof, normally made by pituitary cells
What diseases cause HYPOsecretion of pituitary hormones?
Any disease of the pituitary or hypothalamus can cause deficiency of any hormone made by anterior pituitary
Only a disease of the hypothalamus or infundibiulum can cause a deficiency of vasopressin and thereby cause diabetes insipidus
What are examples of somatotroph adenomas?
- Gigantism
- Acromegaly
Big hands and Neanderthal like jaw structure
What is somatotropin?
Growth hormone
What is somatostatin?
Shit that INHIBITS growth hormone lmao
How do you diagnose somatotroph adenoma?
- chemical confirmation
- lack of suppression of growth hormone from glucose
- elevated serum IGF-1
- pathologic confirmation
- histologic appearance of pituitary adenoma
- immunospecific staining for growth hormone
What are the consequences of somatotroph adenoma?
- Arthritis
- Cancer, especially of the colon, preceded by polyps
- Cardiovascular disease
- diabetes mellitus
- neuropathy, including carpal tunnel syndrome
- sleep apnea
- mortality
What is the treatment for somatotroph adenomas?
- surgical
- pharmacological
- radiation
What are the pharmacologic treatments for somatotroph adenomas?
- Dopamine agonists
- somatostatin analogs
- Growth Hormone receptor antagonists
What does somatostatin inhibit?
TSH and GH
What is octreotide/lanreotide do?
It is a somatostatin analog that inhibits TSH and GH
What is Cabergoline?
A drug used to reduce adenoma size
Dopamine agonist
What is Pegvisomant? EXAM QUESTION
A growth hormone receptor ANTAGONIST
Decreases IGF-1 volume
Used to treat somatotrophic adenomas
Does not decrease tumor size
What are the characteristics of lactotroph and somatotrophs?
They make people look funny
What are chracteristics of ACTH, LH, FSH?
They are undetected physically
What are the clinical syndromes associated with LACTOTROPH adenomas?
- Premenopausal women
- ammenorrhea or oligomenorrhea
- galactorrhea
- Postmenopausal women
- neurological symptoms
- Men
- decreased libido
- decreased fertility
- decreased potency
What are the causes of HYPERprolactinemia
- physiologic
- pregnancy
- nursing
- exercise
- physical and psychological stress
- Pathologic
- lactotroph adenomas
- dopamine receptor antagonists
- catecholamine inhibitors
- H2 antagonists
- estrogens
What can cabergoline be used for?
Dopamine agonist
To treat lactotroph adenomas (to inhibit prolactin)
To treat somatotroph adenomas (to inhibit GH)
What can bromocriptine be used for?
D2 agonist
To treat lactotroph adenomas (to inhibit prolactin)
To treat somatotroph adenomas (to inhibit GH)
How do you treat lactotroph adenomas?
Cabergoline
Bromocriptine
What are the clinical syndromes characteristic of CORTICOtroph adenomas?
- Cushing’s syndrome
2. Neurological symptoms
What is the pharmacologic treatment of thyrotroph adenomas?
Somatostatin analogs
1. Reduce TSH secretion (98%)
2. Decrease adenoma size (50%)
Example: Octreotide
What can octreotide be used for?
Somatostatin analog
Treat somatotroph adenoma
Treat thyrotroph adenoma
What is the most common visual abnormality associated with a pituitary mass? EXAM QUESTION
Bitemporal hemianopsia (or upper visual field deficit) Good kush and alcohol
What are the clinical presentations of gondatotroph adenomas?
- neurological symptoms
- visual field impairement (bitemporal hemianopsia)
- headaches
- Incidental finding on MRI
- Hormonal abnormality
- premature puberty in boy
- ovarian hyperstimulation in a premenopausal woman
How might you expect the size of the an adenoma to be affected by Pegvisomant?
Would not affect the SIZE of the tumor
Because it only decreases IGF-1 in blood circulation
