Pituitary Disorders - Cryar Flashcards
What are the main pituitary disorders
Hypopituitarism Hyperprolactinemia Acromegaly Cushings disease Diabetes insipid us
What is hypopituitarism?
Diminished or absent secretion of anterior pituitary hormones
What are two ways you can have hypopituitarism?
Primary disorder of anterior pituitary cells
Reduced stimulation by the hypothalamus
What is pan hypopituitarism?
Generalized loss of anterior pituitary hormones
What are the causes of hypopituitarism?
neoplasms infections or granulomas vascular infiltrative physical injury releasing hormone deficiencies
Clinical features of panhypopituitarism
weakness, malaise, nausea, vomiting amenorrhea, breast atrophy testicular atrophy absence of axillary and pubic hair waxy skin, fine periorbital wrinkling hypothermia hypotension, hypoglycemia
What features are not usually present in panhypopituitarism?
hyperpigmentation
aldosterone is less frequently involved
What causes the weakness, malaise, nausea and vomitting of panhypo pit?
adrenal insufficiency - lack of ACTH secretion from the ant pit
What is often the key diagnostic sign of panhypo pit?
absence of axillary and pubic hair
What causes the hypothermia of panhyp pit?
lack of thyroid hormones from the ant pit
What causes the hypotension and hypoglycemia of panhypo pit?
lack of glucocorticoids
What do the clinical features of Panhypo pit depend on?
the specific deficiencies
age
sex
How does age affect the clinical features of panhypo pit?
short stature and delayed puberty in children
How does sex affect the clinical features of panhypo pit?
impotence in men
ammenorrhea in women
What is pituitary apoplexy?
rapid hemorrhage into the pituitary gland
What is pituitary apoplexy characterized by?
sudden onset of excruciating headache
diplopia
hypopituitarism
What is the etiology of diplopia in apoplexy?
pressure on the oculomotor nerves
Hypopituitarism
sella has no way to expand
What is pituitary apoplexy often mistaken for?
stroke
What is the most important endocrine consideration for treatment with apoplexy?
Treatment of cortisol deficiency
How is pituitary apoplexy treated?
surgery for ocular consequences
treat cortisol def.
spontaneous improvement of both ocular and hormonal deficiencies can occur with time so milder cases can be watched and supported
What is Sheehan’s syndrome?
infarction after postpartum hemorrhage
How does severe sheehan’s syndrome present?
lethargy, anorexia, weight loss, failure to lactate
How does a mild case of Sheehan’s present?
failure to lactate and failure to resume menses
What eventually happens to the pituitary in Sheehan’s syndrome?
eventual development of small pituitary in a normal sized sella
What is Sheehan’s sometimes mistaken for?
empty sella syndrome
If Sheehan’s is suspected, what most be promptly assessed and treated?
adrenal insufficiency - the remaining deficiencies can be evaluated 4-6 weeks later
What deficiency from Sheehan’s is there no treatment for?
prolactin deficiency - which prevents lactation
What do you find on diagnosis of panhypo pit?
low levels of target organ hormones without a compensatory increase in pituitary hormones
What levels do you want to avoid measuring as the only screening for a possible hormone deficiency? and why?
anterior pituitary hormones - bc the levels may be low, normal or high - the key is how they are relative to end organ hormone levels
How do you treat panhypo pit?
the same way you would treat primary deficiencies
What do you need to be cautious of when treating hypothyroidism?
Be sure to recognize and treat any underlying adrenal insufficiencies first
How do pituitary neoplasms often present?
headache and visual disturbances (especially if non secretory)
excessive secretion or deficiency of ant pit hormones may be present
How is prolactin unique among the anterior pituitary hormones?
it is under tonic suppression
this means lesions in the hypothalamus or affecting the pituitary stalk cause increased prolactin secretion
What are some causes of hyperprolactinemia?
prolactin secreting pituitary adenoma
loss of dopaminergic suppression from the hypothalamus
nipple stimulation or chest wall injury
estrogen - increase is proportional to levels of estrogen
hypothyroidism
chronic renal failure
multiple drugs
What are one of the main classes of drugs causing hyperprolactenemia?
antipsychotics
How does hyperprolactermia present in women?
as a microadenoma
amenorrhea
galactorrhea
How does hyperprolacternemia present in men?
macroadenoma
impotence
visual disturbances
Differential of prolactin levels?
normal < 20
intermediate 21 - 150
tumor > 150
What is the treatment for hyperprolactinemia?
Dopamine Agonists
- bromocriptine - cabergoline
What is the major risk of treatment of hyperprolactinemia with cabergoline?
valvular heart disease seen in patients treated for parkinsons disease
What is MAINLY seen with acromegaly?
acral enlargement
soft tissue overgrowth
What are some other things seen with acromegaly?
headache vision loss hypopituitarism cardivascular disease visceral enlargement sleep apnea increased risk for malignancies (colon)
How do you clinically diagnos acromegaly?
fully developed syndrome is unmistakable
more commonly found in earlier, less pathognomonic stages
How do you diagnosis acromegaly with laboratory confirmation?
somatomedin-C (IGF-I) is the best screening test (GH levels are variable)
How do you treat acromegaly?
primary treatment is surgical - but it is often not curable
secondary therapy is - radiation of the sella or somatostatin analogues
What is cushings syndrome?
clinical manifestations of glucocorticoid excess (from any source)
What is cushings disease?
glucocorticoid excess specifically due to ACTH secretion from a pituitary adenoma
How do you determine the etiology of Cushing’s syndrome?
exogenous steroids or adrenal tumor = low ACTH
Cushing’s Disease = normal to high ACTH
ectopic ACTH = very high ACTH
How do you diagnos Cushing’s Disease?
Relies on the ability to suppress ACTH
dexamethasone - demonstrate suppressibility of endogenous cortisol production
What would a dexamethosone suppression test show on a patient with Cushing’s Disease?
No cortisol production suppression
Why is imagine problematic in cushing’s disease?
50% of patients have a “normal” pituitary on CT or MRI
How can you localize the source of ACTH to the pituitary when no adenoma is imaged?
Inferior petrosal sinus testing for ACTH
How is ADH secretion regulated?
very tightly regulated by osmolality
osmotic regulation is overridden by volume status
What is diabetes insipidus?
failure to appropriately concentrate the urine
What is central vs. nephrogenic DI?
central - inadequate ADH
nephrogenic - failure of kidney to respond to ADH
What is the etiology of central DI?
trauma, surgery, infiltrative or idiopathic
How do you diagnos DI?
polyuria and polydipsia
urine volumes > 3L per day
dilute urine with a serum osmolality > 295 (although some patients can compensate)
What is the water deprivation testing for DI?
water is withheld until urine osmolality stable
primary polydipsia - urine osmolality > serum
DI - urine osmolality remains low while serum osmolality increases
How do you tell the difference bw central or nephrogenic DI?
Administer DDAVP (AHD analogue) central DI - urine osmolality increase by 50% nephrogenic DI - no change
