Week 3- Pituitary Flashcards
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS HORMONES HAVE ON ITS TARGET ORGANS/CELLS
Describe Oxytocin
Posterior/Anterior?
What does it do?
What stimulates its release?
Posterior Pituitary
Stimulated by positive feedback system
Helps during childbirth
- Stimulates uterine contraction
- Release of milk during lactation
- “Bonding hormone”
- Positive feedback system
Stimulated by:
- Stretching of cervix/utertus
- Nipple stimulation/breastfeeding
- Physical touch/bonding
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS HORMONES HAVE ON ITS TARGET ORGANS/CELLS
Vasopressin / Antidiuretic Hormone / ADH
Posterior/Anterior?
What does it do?
What stimulates its release? / What detects the change?
Posterior Pituitary
Function:
- Causes kidneys to reabsorb water
- Results in increased blood volume –> increase BP
- Causes vasoconstriction –> increased BP
Stimulated by:
- Increased osmolality (Blood/fluid is too thick, ADH is released to hold onto water) OR low blood pressure
- “Stimulated by blood changes, NOT hypothalmic hormoes. Blood osmolality is detected by hypothalamus & low BP is detected by heart + blood vessels”
Anterior Pituitary Gland
What does it do?
What is it stimulated by?
Produces 6 Hormones:
- Growth hormone
- Thyroid stimulating hormone
- Follicle stimulating hormone
- Luteinizing Hormone
- Prolactin
- Adrenocorticotropic Hormone
Hypothalamus sends hormones to APG, then APG sends tropic hormones out
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Growth Hormone
Anterior/Posterior?
What does it do?
What stimulates its release?
Produced by Anterior Pituitary Gland
Function:
- Stimulates bone growth
- Promotes protein synthesis
- Tissue repair
- Cell regeneration
Stimulated by:
- GHRH (Growth Hormone Releasing Hormone) from hypothalamus
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Thyroid Stimulating Hormone (TSH)
Anterior/Posterior?
What does it do?
What stimulates its release?
Tropic Hormone
Produced by Anterior Pituitary
Function:
- Stimulates thyroid gland to produce thyroid hormones
Stimulated by:
- TRH from hypothalamus
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Adrenocorticotropic Hormone (ACTH)
Anterior/Posterior?
What does it do?
What stimulates its release?
Produced by Anterior Pituitary
Function:
- Stimulates adrenal cortex to produce adrenal hormones–primarily cortisol
Stimulated by:
- Corticotropin Releasing Hormone (CRH) from hypothalamus
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Follicle Stimulating Hormone (FSH)
Anterior/Posterior?
What does it do?
What stimulates its release?
Tropic Hormones
Produced by Anterior Pituitary
Function:
- Stimulates development of sperm and eggs
Stimulated by:
- Gonadotropin-Releasing-Hormone (GnRH) from the hypothalamus
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Luteinizing Hormones (LH)
Anterior/Posterior?
What does it do?
What stimulates its release?
Tropic Hormone
Produced by anterior pituitary
Function:
- Secondary sexual development
- Stimulates production of testosterone and estrogen
- Stimulates production of empty follicle to become corpus luteu
Stimulated by Gonado-tropin Releasing hormone (GnRH) from hypothalamus
LECTURE OBJECTIVE - EXPLAIN THE EFFECTS THE HORMONES HAVE ON ITS TARGET ORGANS AND CELLS
Prolactin
Anterior/Posterior?
What does it do?
What stimulates its release?
Non-Tropic
Produced by Anterior Pituitary, stimulation from hypothalamus
Function:
- Milk production
- Suppresses GnRH which = decreased FSH & LH
- Anovulation (lack of ovulation) and amenorrhea (absence of menstruation)
(Oxytocin stimulates release of milk)
Stimulated by:
- Prolactin Releasing Hormone (PRH) from hypothalamus
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Diabetes Insipidus
What is it?
Causes? (2 types of pathways!)
Deficiency of ADH
Results in excretion of large amount of highly dilute urine and extreme thirst
-“No ADH, so the patient loses a lot of water in urine”
-“Think ‘dry inside’ i.e. no water”
Causes:
Neurogenic:
- Trauma
- Brain tumor
-Radiation
Nephrogenic:
- Inadequate response of renal tubules to ADH
- Renal disease
- Drug toxicity
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
What are the clinical manifestations of Diabetes insipidus?
- Extreme Polyuria (excess urination
- Extreme polydipsia (Thirst)
- Dehydration
- Hypotension –> hypovolemic shock
- Weight loss, Anorexia
- Urine output does NOT decrease by limiting fluid
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Diagnostic tests / Labs regarding Diabetes Insipidus
Concentrated blood, dilute urine
Fluid deprivation test
- Frequent monitoring of vitals, terminate test if unstable vitals
- “If we deprive fluid, urine output should decrease in healthy person”
Trial of Synthetic Vasopressin
- Differentiates neurogenic vs. nephrogenic
- “If the vasopressin works and urine output decreases, that means the condition is neurogenic DI. IF it was nephrogenic DI, the kidneys don’t respond properly to ADH, so the urine output should remain about the same.”
Labs
- Hypernatremia (>145 mEq/L; excess sodium in blood)
- Hyperosmolarity ( >295 mOsm/kg)
Urinalysis
- Dilute, pale urine; Low specific gravity 1.001 - 1.005
- Low urine osmolality (<200 mOsm/kg)
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
How to treat Diabetes Insipidus
Maintain fluid balance
Neurogenic DI:
- Pharmacologic therapy
- Desmopressin (Synthetic ADH)
Nephrogenic DI:
- Desmopressin will be ineffective
- Low salt diet
- Pharmacologic: Hydrochlorothiazide, indomethacin
Desmopressin (DDAVP)
What is it?
Indications?
Side effects?
Synthetic Vasopressin / ADH
- Mimics the actions of endogenous ADH
Indications:
- Diabetes insipidus (neurogenic); NOT nephrogenic, as kidneys won’t respond to it
- Nocturnal enuresis (bed-wetting)
Side effects
- Increased thirst (d/t too much fluid retention = dilutional hyponatremia which can trigger thirst)
- Xerostomia (dry mouth)
- Increased BP
- Oliguria (low urine output)
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Syndrome of Inappropriate ADH (SIADH)
What is it?
Causes?
Excessive amount of ADH
Excessive fluid retention
“SI = soaked inside”
Causes:
- Often non-endocrine causes
- Malignant cells synthesize ADH
- Direct stimulation of posterior pituitary (brain tumor, surgery, head injury)
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Manifestations of Syndrome of Inappropriate ADH (SIADH)
“Think fluid overload, but with oliguria”
Small amounts of concentrate urine
Fluid Volume Excess:
- Tachycardia, hypertension
- JVD, Anasarca (General Edema)
- Rales
Dilutional Hyponatremia:
- Lethargy, Weakness, muscle cramps
- If severe = seizure, coma
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Labs / Diagnostics for SIADH
Diagnostics:
- Serum sodium <120 mEq/dl
- Plasma Osmolality <275 mOsm/kg
- Serum ADH
- Urine tests (sodium, osmolality, specific gravity)
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Treatment for SIADH
Treat underlying cause
Correction of dilutional hyponatremia
Meds:
- Serum albumin replacement
- Sodium replacement
“SIAD = Serum ALbumin & soDium”
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Anterior Pituitary Disorders:
Neoplasias / Tumors
benign or malignant??
s/s
Usually benign
s/s:
Headache
Visual disturbances
Galactorrhea (abnormal secretion of breast milk)
Plus endocrine symptoms r/t excess hormone secretion
Think: “Blockage in the frontal area & pituitary tumor = hyperpituitarism”
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Pituitary tumors:
- Diagnostic tests
Detailed history and physical: “identifies symptoms r/t hormonal imbalances caused by tumor compression”
Visual acuity exam: “pituitary tumor may compress optic nerves”
CT or MRI: “Identify the tumor “
Serum hormone levels: “check hormones levels, confirm type of tumor”
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Treatment for Pituitary Tumor
Surgical Therapy
Hypophysectomy:
- Removal of entire pituitary gland
- Patient needs lifetime hormone replacement
- Incision via nose
Tran sphenoidal Microsurgery:
- Microsurgical approach
- Preserves normal pituitary tissue
Radiation Therapy
Post-Op Hypophysectomy Care
Maintain HOB >30 degrees
Avoid increase in intracranial pressure:
- Coughing, sneezing, vomiting
- Vigorous hair brushing, drinking with straw
- Bending at waist
Potential transient diabetes insipidus:
- Monitor urine output; notify PCP if urine output is >100mL/hr
- check urine specific gravity
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Hypopituitarism
What is it?
What causes it?
S/S?
Hyposecretion; usually r/t problem originating within pituitary gland
Causes:
- Congenital defects
- Infarction, tumors
- Removal
- Radiation
s/s:
- Extreme weight loss, emaciation
- Atrophy of adrenal glands
- Hair loss, impotence
- Hypometabolism
LECTURE OBJECTIVE - DESCRIBE THE PATHO, CLINICAL MANIFESTATIONS AND TREATMENT FOR CONDITIONS
Hypopituitarism
What is the treatment for Hypopituitarism?
Hormone replacement therapy
