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
what is the Etiology of PRL Deficiency
Severe lactotrope destruction from any cause (e.g., pituitary tumors, infiltrative diseases, infectious diseases, infarction, neurosurgery or irradiation)
what is the Clinical Presentation of PRL deficiency
Failed lactation in post-partum females, no effect in males.
how is the Diagnosis Prolactin deficiency made?:
low random PRL level
what are the Specific features of Cushing’s disease (Hypercortisolism)
facial plethora,
easy bruising, wide (>1 cm) violaceous striae and
proximal muscle weakness
what are some of the General signs/symptoms (poor specificity) of hypercortisolism
weight gain/obesity, diabetes, hypertension, irregular menses, dorsocervical hump, acne, low libido, depression or hirsutism
what are the 3 Initial Screening Tests for cushing’s disease:
1) 24 hour urinary cortisol,
2)11-12 p.m. salivary cortisol test,
3) 1 mg dexamethasone suppression test (1 mg
dexamethasone given at 11-12 p.m., followed by ~8
a.m. serum cortisol level. Normal cortisol
suppression <1.8 ug/dl).
what can cause a false-positive screening test for cushing’s disease?
“Pseudo-Cushing’s” disease caused by depression, alcoholism, extreme stress
what are some Secondary/Tertiary causes of Cortisol Deficiency
Supraphysiologic exogenous glucocorticoid use (most common).
S/p tumor resection for Cushing’s Syndrome (pituitary, ectopic or adrenal).
Drugs: Opioids and megace .
if you suspect cushings and the MRI comes back negative what other procedures/tests can you do
Inferior petrosal sinus sampling (IPSS)
What is the Clinical Presentation of secondary/tertiary adrenal insufficiency (AI)
Fatigue
Anorexia, nausea/vomiting and weight loss
Generalized malaise/aches
Scant Axillary/Pubic hair (DHEA-S dependent in females)
Hyponatremia and Hypoglycemia
how do you diagnose adrenal insufficiency.
Random a.m. cortisol level, <3 ug/dl.
Cosyntropin (synthetic ACTH 1-24) stimulation test-valid for assessing HPA axis only if prolonged (several weeks-months) loss of pituitary signaling and resulting adrenal atrophy.
what are Clinical Features of Hypogonadism in females
anovulatory cycles (varying degrees of menstrual intervals and the absence of ovulation and a luteal phase),
oligo/amenorrhea,
infertility,
hot flashes,
vaginal dryness/atrophy,
dyspareunia (difficult or painful sexual intercourse)
reduced bone mineral density (BMD
what are Clinical Features of Hypogonadism in males
Reduced libido, erectile dysfunction, oligospermia or azoospermia, testicular atrophy, infertility, decreased muscle mass and low BMD. Hot flashes with acute and severe onset of hypogonadism
The majority of FSH/LH tumors are ______
clinically silent
What is the presentation LH/FSH (Gonadotropin) Excess?
Rare presentation (from functionally-intact FSH/LH molecules) include: ovarian hyper-stimulation syndrome (females) or macro-orchidism (males).
This type of pituitary tumor is very rare (<1% of pituitary tumors)
Thyrotropin secreting pituitary tumor
what is the Clinical Presentation of Thyrotropinoma (TSHoma) AKA central hyperthyroidism
similar clinical presentation to primary hyperthyroidism
(i.e., goitre, tremor, weight loss, heat intolerance, hair loss, diarrhea, irregular menses)
but also with associated mass effects (i.e., headaches, vision loss) from macroadenoma
how is a diagnosis for central hyperthyroidism made?
Elevated Free T4 and a non-suppressed TSH. Pituitary MRI (>80% macroadenomas
what is the clinical presentation of Central TSH Deficiency
similar to primary hypothyroidism (e.g., fatigue, weight gain, cold intolerance, constipation, hair loss, irregular menses). Possible mass effects
what is Panhypopituitarism
loss of all pituitary hormones
what is apoplexy?
Clinical syndrome of headache, vision changes, ophthalmoplegia and altered mental status caused by the sudden hemorrhage or infarction of the pituitary gland.
what is primary empty sella syndrome (ESS)
due to arachnoid herniation through a congenital diaghragmatic defect. Hyperprolactinemia in ~10% of cases, but hypopituitarism is very uncommon
_______ deficiency is common with metastatic tumors (e.g., breast, lung or GI) or craniopharyngiomas, but not pituitary adenomas.
Anti-diuretic Hormone (ADH)
