Pituitary DO Flashcards
HPA Axis hormones functions
- respond to stress
- thyroid stim, growth, reproduction
Which pituitary gland is the producer? which is the storer?
Anterior - Producer
Posterior - Storer
Anterior and Posterior Pituitary glands secrete which hormones?
Growth hormone excess is referred to as _____
Growth hormone deficiency is referred to as _____
what stim and inhibits Growth hormone secretion?
GHRH stim
Somatostatin inhibits
High levels of growth hormone are usually caused by ____
a GH-secreting tumor
what increases growth hormone secretion?
think big picture
What decreases growth hormone secretion?
Giantism vs Acromegaly
Which occurs during childhood?
Giantism = during childhood (b4 growth plates close)
Acromegaly = Adulthood
genetic causes of Giantism
- familial isolated pituitary adenoma
multiple endocrine neoplasia type 1 (MEN1) - McCune-Albright syndrome (MAS)
- Carney complex with onset during
- prepubescence
Giantism SS
- Longitudinal acceleration of linear growth secondary to insulinlike growth factor I (IGF-I) excess
- Tumor mass may cause headaches, visual changes due to optic nerve compression, and hypopituitarism
- Hyperprolactinemia is a common finding; it results from pituitary growth hormone (GH) excess,
Acromegaly WU
- Two baseline GH levels are obtained prior to ingestion of 75 or 100 g of oral glucose, and additional GH measurements are made at 30, 60, 90, and 120 minutes following the oral glucose load. A rise, or no suppression is diagnostic.
- Measure serum GH 1 hour after oral administration of 100 g of glucose. Clearly elevated GH levels (>10 ng/mL) after oral glucose, combined with the clinical picture, secure the diagnosis of acromegaly, while a normal GH level (< 5 ng/mL) after oral glucose essentially excludes the diagnosis.
GnRH can be measured
IGF-I can be measured
Prolactin is often also measured since it can be co-secreted in 20% of tumors
Imaging: MRI of brain
CT scans of abdomen/pelvis or chest if brain is negative
Acromegaly Complications
Acromegaly Trmnt
- # 1 Trnassphenoidal Sx
- Radiation
- Octreotide -
- Bromocriptine -
- Pegvisomant (Somavert) -
MC pituitary hormone deficiency in children
Growth Hormone Deficiency
2 main ways you get pituitary dwarfism
- Isolated LOW growth hormone
- Generalized - ALL pituitary hormones are LOW
Pituitary Dwarfism WU
- IGF-1 levels
- XR of LT Hand to determine bone age
- MRI to r/o calcifications, tumors, structural anomalies
- ACTH, 8 am serum cortisol level, LH, FSH, Prolactin levels
Dx Criteria for Pituitary Dwarfism
Dwarfism Trmnt
- recombinant Growth Hormone
- +/- other pituitary hormone replacement
Which HPA hormones should be eval for deficiencies?
ALL
Cortisol
Thyroid
ADH
Sex hormone around time of puberty
Why do new moms need to try breastfeeding ASAP
Stim Prolactin -> breastfeeding
What stim prolactin secretion
- sleep
- stress
- pregnancy
- chest wall stimulation or trauma
- TRH, dopamine receptor antagonists, primary hypothyroidism
- prolactinomas (tumor)
Approximately 75% of patients presenting with galactorrhea and amenorrhea have _____.
hyperprolactinemia
Drugs that can cause Hyperprolactinemia
Dopamine-receptor antagonists (phenothiazines, butyrophenones, thioxanthenes, metoclopramide, sulpiride, pimozide)
Conventional and atypical antipsychotics (Haloperidol, risperidone{70-100%}, olanzapine, quetiapine, amisulpride)
Dopamine-depleting agents (methyldopa, reserpine)
Others (isoniazid, danazol, tricyclic antidepressants, monoamine antihypertensives, verapamil, estrogens, antiandrogens, cyproheptadine, opiates, H2-blockers [cimetidine], cocaine)
Prolactin levels >_______ req brain imaging
100-250ng/mL
Med induced will be high but under 100 usually
why may you need a DEXA scan if you have Hyperprolactinemia?
persistent low estrogen/testosterone can lead to osteoporosis
Initial drug of choice if hyperprolactinemia ET is pituitary in orgin
Bromocriptine (Dopamone AGONIST)
Prolactin Deficiency is MC assosiated with post-partum _____ Syndrome
Sheehan
postpartum pituitary necrosis
necrosis of cells of the anterior pituitary gland following significant post-partum bleeding, hypovolemia, and shock.
Mom lost a lot of blood during birth and is having trouble starting breastfeeding. Concern for?
Sheehan syndrome (postpartum pituitary necrosis)
Prolactin deficiency
Lose blood flow to anterior pituitary -> ischemia
WU for prolactin deficiency
Prolactin Deficiency trmnt
Lifelong replacement of pituitary hormones:
Hypothyroidism can be treated with levothyroxine
Cortisol deficiency can be treated with prednisone or hydrocortisone.
Gonadotropin deficiency should be treated with estrogen if the uterus has been removed with a combination of estrogen and progesterone if a uterus is present.
The growth hormone is probably the most common hormone that needs replacing, and the dosage must be individualized to the patient’s need.
For patients who develop diabetes insipidus, desmopressin (DDAVP)
Excess ADH is ____
SIADH
ADH deficiency is ____
Diabetes insipidus
what does ADH do?
dont pee
save water at collecting duct
Vasoconstricts at high levels
What incr and decr ADH secretion?
Central Diabetes Insipidus (ADH Deficiency)
Primary vs Secondary Central Diabetes Inspidus
Non-central Diabetes Insipidus
- Nephrogenic Diabetes Insipidus - tubule receptors dont respond correctly to ADH
- Psychogenic Polydipsia - drinking too much water -> kidney becomes insensitive to ADH (>6L)
Water Deprivation Test
Pt does water deprivation test. No urine concentration increase is seen. What may this be?
Diabetes insipidus
Are those with psychogenic polydipsia able to concentrate their urine during water deprivation test?
YEs
Tx for water deprivation test?
restrict fluid intake to ≤ 2 L/day
Norm concentrating ability will return within several weeks
Central Diabetes Insipidus (ADH Deficiency) Trmnt
Desmopressin (DDA VP)
mimics endogenous vasopressin
3 non-hormonal drugs that reduce polyuria?
- Diuretics, primarily thiazides
- Vasopressin-releasing drugs (eg, chlorpropamide, carbamazepine, clofibrate)
- Prostaglandin inhibitors(NSAIDs)
Chlorpropamide, carbamazepine, and clofibrate stimulates increased renal tubular water reabsorption (pee less). This is effective on which type(s) of diabetes Insipidus?
ONLY central diabetes insipidus. May even eliminate need for vasopressin!
WONT work for nephrogenic diabetes insipidus bc their receptors are shot
Nephrogenic Diabetes Insipidus Trmnt
Indomethacin (NSAIDs make you pee less)
Na+ intake restriction
Thiazide Diuretic
ADH excess is referred to as ____
SIADH
Syndrome of Innapropriate AntiDiuretic Hormone Secretion
SIADH definition
Dilute serum (hyposmolarity)
concentrated urine
NO other physiological cause of vasopressin secretion
Normally, low plasma osmolality inhibits vasopressin secretion, allowing the kidneys to produce dilute urine.
Euvolemic vs Hypervolemic vs Hypovolemic Hyponatremia
- Euvolemic - norm water gain and loss (equalized free water)
- Hypervolemic - water retention is greater (CHF, Cirrhosis)
- Hypovolemic - Na+ loss is greater (MCC by renal diuretic like thiazide or extra renal causes)
Which type of hyponatremia is SIADH?
Euvolemic Hyponatremia
SIADH etiology
SIADH WU
SIADH Trmnt
Treatment of cause
Fluid restriction
Sometimes a vasopressin receptor antagonist Sometimes NS
SIADH Fluid Restriction
only drink ____ L a day
250-500L
Also give loop diuretic combo with IV 0.9% saline to slowly correct severe Na+ deficits without inducing vol overload
If pt with SIADH cannot tolerate water restriction, giving ____ will unconcentrate the urine. However, it can cause acute kidney injury (AKI)
Demeclocycline
