Final Exam - Endocrine problems part 2 (Unit 12): Disorders of the Posterior Pituitary Gland Flashcards
What does SIADH stand for ?
Syndrome of Inappropriate Antidiuretic Hormone
What does ADH stand for ?
Antidiuretic Hormone
_____ plays a major role in the regulation of water balance and osmolarity ?
ADH (Antidiuretic Hormone)
SIADH occurs when ?
When ADH is released despite normal or low plasma osmolarity
What is another name for SIADH ?
“Fluid retainers” !
fluid overload
What is the most common cause of SIADH ?
Malignancy , esp. small cell lung cancer
What is SIADH characterized by ?
- Fluid retention
- Weight gain
- Concentrated urine
- Serum hypoosmolality
- dilution hyponatremia
- Low urine output
In SIADH, low plasma osmolality and serum sodium can cause what ?
Cerebral edema
=
- lethargy
- confusion
- HA
- seizure
- comaWhat labs are used to determine if SIADH Is present/the cause ?
- Serum Sodium < 134 mEq/L (dilution hyponatremia)
- Serum osmolarity < 280 most/kg (blood serum is very dilute)
- Urine specific gravity greater than 1.025 (urine is very concentrated)
Dangerously low sodium increases the risk for what ?
Seizures
What is the Tx for SIADH ?
- Daily weights
- I &O’s
- Diuretics (monitor for K+ loss)
- Prevent injury r/t low Na+ (seizure risk)
If a pt with SIADH has mild symptoms and their sodium is greater than 125mEq/L, what is the Tx ?
Tx may me daily fluid restriction to 800 to 1000mL
If a pt with SIADH has a sodium level less than 120mEq/L, what will their Tx be ?
IV hypertonic saline solution (3% to 5%)
Diabetes Insipidus is the complete opposite of what ?
SIADH
What is Diabetes Insipidus ?
Decreased secretion of ADH, or decreased renal response to ADH
People with Diabetes Insipidus are constantly doing what ?
Urinating
What are Clinical Manifestations of Diabetes Insipidus ?
- Polydipsia
- Polyuria (5 to 20 L/day)
- Elevated serum osmolarity (blood serum is very concentrated)
How does the urine present in pt’s with Diabetes Insipidus ?
- Low urine specific gravity
- Low urine osmolarity
** Urine is very diluted (clear) **
In pt’s with Diabetes Insipidus, all they want to do is what ?
Drink water !
Elevated serum osmolarity is a clinical manifestation of DI, how do most people compensate for this ?
by drinking lots and lots of water ! so serum osmolarity may be normal
In pt’s with DI, if oral fluid intake can not keep up with urinary losses, what can occur ?
Severe dehydration can occur
What is the Tx for Diabetes Insipidus ?
- Daily weights
- I & O’s
- Check urine S.G.
- Give oral or IV fluids in amounts equal to urine output (want to keep them hydrated)
What is the hormone replacement of choice for central DI ?
Desmopression acetate (DDAVP), an analog of ADH
ADH is released by what ?
The posterior pituitary gland
ADH is released in response to any of the 3 what ?
- low blood volume in the body
- low BP
- Hypernatremia (increased serum (blood) osmolarity)
When ADH is released from the posterior pituitary gland, what does it do to the kidneys ?
Causes the kidneys to reabsorb more water!
Thus,
- increasing blood volume
- increasing BP
- helps to dilute the blood, to bing the osmolarity back to a normal level
What is the main symptom of DI ?
Excreting LARGE amounts of dilute urine
the kidneys are not reabsorbing the water as we should be
SIADH is caused by what ?
Excess ADH is released from the posterior pituitary gland
- Even though the blood is very dilute, the posterior pituitary gland still releases ADH, even though it should not !
How does SIADH result in fluid overload ?
- the posterior pituitary gland releases ADH even though the blood is very dilute or normal
- B/c the posterior pituitary gland is releasing all this extra ADH inappropriately, its causing the kidneys to reabsorb more water RESULTING IN: fluid overload
