Pituitary Disease Flashcards
Reivew: hormones of anterior v. posterior pituitary
Anterior: FSH, LH, ACTH, GH, prolactin, TSH
Posterior: ADH, oxytocin
What are the possible pituitary diseases?
- *Pituitary tumors** - can be hormone secreting or non-hormone secreting
- note that this is distinct from pituitary hyperplasia i.e. lactotroph hyperplasia during pregnancy
Non-pituitary lesions: benign tumors (craniopharyngioma, meningioma)
Cysts
Malignant tumors (chordoma, metastatic tumors-breast, lung)
Lymphoma
Granulomatous i.e. sarcoidosis, TB
Lesions of hypothalamus i.e. craniopharyngiomas, germ cell tumors, infiltrative lesions i.e. sarcoid, langerhans cell, TB
Vasculary lesions - aneurysm
Pituitary apoplexy: hemorrhage/infarction
Sheehan syndrome: pituitary infarction
Head trauma
Genetic dz: PROP1, PROU1F1 mutations
Empty sella syndrome: CSF into pituitary area
Genetic mutations that can cause pituitary disease?
- *PROP1 mutation**: most common familial/sporatic congenital combined pituitary hormone deficiencies
- autosomal recessive
- it’s mutation encoding TF’s necessary for differentiation of the diff cell types –> deficiency of almost all the hormones
PROU1F1 mutation: autosomal recessive/dominant
- mutaiton of TF necessary for differentiation of somatotroph, lactotroph, thyrotroph cells –> deficiency of these hormones
Craniopharyngioma
Benign cell rest tumors (displaced cells)
Arise from remnants of Rathke’s pouch anywhere from hypothalmus to stalk to pituitary gland
Colid or mixed solid/cystic
Bimodal distribution of occurrence: half kids, half adults
Typically present with vision loss, signs/sx of pituitary hormone insufficiency
Treat with surger/radiotherapy
* You’re often deciding between pituitary tumors and craniopharyngioma
Signs and sx of pituitary mass lesions/disease
Visual & neuro abnormalities
Signs and sx of hypopituitarism
Signs & sx of hormone hypersecretion syndrome from a hormone-secreting pituitary tumor
Can be incidentally noted on head imaging study done for another reason
- MRI = gold standar
Visual & neuro abnormalities in pituitary dz
Headache: common but not specific
- *Visual field deficit**: bc lesion compresses optic chiasm
- bitemporal hemianopsia (blindness on lateral halves of vision)
Cranial nerve dysfunction: CN III, IV, VI; more likely with sudden expansion
Secondary adrenal insufficiency
Pituitary ACTH deficiency –> decreased adrenal cortisol production
Lethargy, weakness, anorexia, nausea, weight loss, postural dizziness, hypotension, hyponatremia
Tx: oral hydrocortisone
Secondary hypothyroidism
Abnormal pituitary TSH secretion –> TH deficiency
Fatigue, dry skin, constipation, bradycardia, cold intolerance, delayed relaxation of deep tendon reflexes, puffiness
Tx: oral thyroid hormone
Secondary hypogonadism
Women: oligo-amenorrhea, infertility, estrogen deficiency, osteopenia
Men: decreased libido, erectile dysfunction, gynecomastia, infertility, osteopenia
Tx: women: estrogen/progesterone replacement if premenopasual
- *men**: testosterone
- *both**: gonadotropin or HCG therapy to restore fertility
Growth hormone deficiency (in adults)
Mild: increased fat mass, decreased lean body mass, increased cholesterol, increased CV risk markers i.e. CRP, decreased bone density
Tx: controversial; daily injections of rhGH to normalize serum IGF-I level
Vasopressin deficiency
Reduced ability to concentrate urine –> huge volume of dilute urine, thirst
Check urine volume, osmolarity, specific gravity, serum sodium (hypernatremia), dehydration test (for dilute urine despite dehydration)
Tx: DDAVP nasal spray or pills
Benign neoplasms that are monoclonal in origin- options?
Lactotroph = prolactin secreting
Somatotroph = GH secreting
Corticotroph = ACTH secreting
Thyrotroph = TSH secreting
Gonadotroph = usually clinically nonfunctioning; may secrete FSH/LH/alpha-subunit
Rarely lacto/somatotroph: GH/prolactin
Rarely pluri-hormone secreting
What are most clinically non-functioning pituitary tumors derived from?
Gonadotroph cells
Usually don’t produce a clinical hypersecretion syndrome
Usually large at presentation –> signs of mass lesion/ s&sx of hypopituitarism
Tx: transphenoidal surgery + radiotherapy if recurrence
RARELY: LH –> increased testosterone, early puberty in males
FSH –> ovarian hyperstim in females
Acromegaly: etiology
Lots of GHRH –> stimulates GH secretion from pituitary in pulsatile fasion –> produciton of IGF-1 which goes into circulation
In acromegaly, GH comes out in pulsatile fashion but bsln is high –> high GH, high IGF-1
Cushing’s disease
Corticotroph pituitary adenoma
ACTH from pituitary –> cortisol production in adrenal gland –> neg feedback to stop ACTH release from pituitary (normally)
In tumor, ACTH is high, cortisol is high, neg feedback is turned off
Clinical: central obesity, facial fullness, thin skin, bruising, proximal muscle weakness, diabetes, htn
Mostly females, 20-40 years old
Check for high urine free cortisol, normal/high ACTH, localization to confirm pituitary source
Treat with transsphenoidal surgery & radiation if recurrence
TSH producing pituitary tumor: signs, testing, tx
Signs of hyperthyroidism: tremor, sweating, smooth skin, stare, palpitations, weight loss, goiter
Elevated free thryoxine (T4) levels
TSH normal or elevated
Tx: transphenoidal surgery, radiation, somatostatin analog therapy (inhibits TSH release)
Hyperprolactinemia: what can cause it?
Prolactin secreting tumor = prolactinoma
Also: anything that interrupts the tract between pituitary/hypothalamus & disrupts dopamine going to pituitary to suppress prolactin
- Acromegaly
- Other sellar masses
- Infiltrative disorders
- Hypothalmic & pituitary stalk dz or damage
Other: primary hypothyroidism, seizures, PCOS, neurogenic causes (chest wall trauma, surgery, herpes zoster), renal insufficiency, cirrhosis, meds
Which meds can cause hyperprolactinemia?
Most commonly:
Antipsychotics: phenothiazines, butyrophenones, atypicals
Antidepressants: tricyclics, MAO inhibitors, SSRIs
Also:
Antihypertensives: verapamil, methyldopa, reserpine
GI meds: chloropromazine, metoclopramide, doperidone, H2 blockers
Clinical manifestations of hyperprolactinemia?
Prolactin suppresses gonadotropins –> low LH/FSH –> gonadal dysfunction
Women: oligo-amenorrhea, infertility, galactorrhea, estrogen deficiency, acne hirsuitism (excess hair growth), osteopenia
Men: decreased libido, erectile dysfunction, gynecomastia, galactorrhea, infertility, osteopenia
Treatment of hyperprolactinemia?
- *Dopamine agonist therapy**: it suppresses prolactin levels, shrinks tumor
- Bromocriptine, cabergoline
- for small tumors, you can taper the meds off
Surgery & radiation thrapy occasionally used
Careful follow up w/out treatment is an option for patients if they don’t have macroadenoma, are asymptomatic, normal gonadal function, not seeking fertility
Treatment goals: restore gonadal function, resolve galactorrhea, reduce/stabilize tumor, normalize prolactin level
