Pituitary Dysfunction Flashcards
when The loss of a target (peripheral) organ hormone is due to a defect at the level of the hypothalamus, this is referred to as a ______ endocrine disorder.
Tertiary
When The loss of a target (peripheral) organ hormone is due to a defect at the level of the pituitary gland, this is called a ___ endocrine disorder
Secondary
Secondary and tertiary disorders
are difficult to distinguish and are collectively called _____
central disorders.
Pituitary hormone deficiency is established by a low target hormone level in the setting of ______
inappropriately normal, or low, pituitary hormone level.
Pituitary hormone excess is established by a high target hormone level in the setting of an ________
inappropriately normal, or high, pituitary hormone level.
why are GH levels not a screening test for gigantism;
B/C GH levels fluctuate widely over 24 hrs and normal
values can overlap with GH-secreting tumors
why are GH levels not a screening test for acromegaly?
B/C GH levels fluctuate widely over 24 hrs and normal
values can overlap with GH-secreting tumors
Confirmatory testing (for equivocal IGF-1 level) in acromegaly includes a Oral glucose tolerance test: 75 gm oral glucose load, followed by growth hormone testing q 30 minutes for 2 hrs (abnormal GH response = \_\_\_\_\_\_\_\_).
> 1 ug/L or
>0.40 ng/ml with ultrasensitive GH assays
in aa Pituitary MRI- _____are detected in most cases of acromegaly (>80%).
macroadenomas
what is the clinical presentation of GH deficiency
increased central obesity, reduced lean body mass),
decreased bone mineral density,
increased insulin resistance/glucose inntolerance,
pro-atherogenic lipid profile/increased inflammatory markers (i.e., CRP, hypertriglycerides, IL-6),
fatigue and depression.
Describe Provocative testing for GH reserve in patients suspected of GH deficiency
Insulin induced hypoglycemia (gold standard). Insulin (0.1U/kg) to induce hypoglycemia (blood sugar <40 mg/dl). Normal GH response: > 3-5 ug/dl.
what are the Contraindications for using insulin induced hypoglycemia testing of GH reserves?
Elderly, h/o seizure disorder, coronary artery disease or cerebrovascular disease.
Hormone Excess is assessed by a _______
Suppression Test (e.g., Oral glucose tolerance test for GH suppression to confirm acromegaly)
Hormone Deficiency is assessed by a ______
Stimulation Test (e.g., insulin tolerance test to evaluate ACTH and GH reserves)
What is a Craniopharyngioma
WHO grade I, benign, slow-growing epithelial tumors, derived from ectopic remnants of Rathke’s pouch or craniopharyngeal duct
what is a Adamantinomatous Craniopharyngioma
It is a subtype of Craniopharyngioma that Occurs exclusively in children.
Calcifications on CT scan are pathognomotic
how does a Adamantinomatous Craniopharyngioma clinically present
Often present with growth failure and delayed puberty
what is the best diagnostic test for GH excess
Elevated IGF-1 level (age and gender matched)
what are some Physiological Etiologies of Hyperprolactinemia
Pregnancy, suckling, sleep, stress
What are some Pathological causes of Hyperprolactemia
Prolactinoma Pituitary Stalk Interruption (from any cause) Hypothyroidism, chronic renal/liver failure, seizure
what are some Pharmacological causes of Hyperprolactemia
Estrogens Antipsychotics , antidepressants (tricyclics, MAO-I), anti-emetics (i.e., reglan), anti-HTN (i.e., verapamil) Opiates
what is the clinical presentation of hyperprolactemia
Galactorrhea (rarely in males), irregular menses/amenorrhea (♀), erectile dysfunction (♂), infertility, osteoporosis and decreased libido.
Pituitary Macroadenomas (♂ > ♀) can cause Mass Effects that includes:
headaches, vision disturbances, cranial nerve palsies and pituitary hormone deficiencies
how do you diagnose hyperprolactemia
1) Random PRL level (use gender-based normative ranges), Levels usually >100-150 ng/mL with prolactinomas
2) Pituitary MRI
