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)