Conditions Effecting the Endocrine System and PharmacotherapyPart Three: Hypothalamus & Pituitary Flashcards
Exam 3
Hypothalamus: Where is it located?
Located at the base of the brain
Hypothalamus: what is it connected to and how?
Connected to the pituitary gland by pituitary stalk
Connected to anterior pituitary through blood vessel network
Connected to posterior pit. via a nerve tract
Hypothalamus: What does it produce?
Produces releasing and inhibiting hormones that work on the anterior pituitary
Hypothalamus: What does it produce (having to do with water)?
It produces antidiuretic hormone (ADH), which is stored in the posterior pituitary until it is needed.
Regulation by Hypothalamus:
What type of hormones does it release?
Growth hormone–releasing hormone
Thyrotropin-releasing hormone
Gonadotropin-releasing hormone
Corticotropin-releasing hormone
Regulation by Hypothalamus:
Negative feedback loop having to do with hypothalamus?
Hypothalamus: Releasing factor X –> pituitary: hormone A –>
Target organ get stimulated, causing release of hormone B –> Produces biologic effect
Hormone B –> hypothalamus & pituitary to suppress further release of factor X & hormone A, suppressing further release of hormone B
Hypopituitarism
Insufficient amounts/absence of anterior pituitary hormones
Panhypopituitarism
Is a rare condition that involves a lack of all the hormones your pituitary gland makes.
Hypopituitarism:
What is the most common cause of this?
Pituitary infarction or space-occupying lesions (most common)
Hypopituitarism:
Causes are: Pituitary infarction or space-occupying lesions (most common) what are examples?
Pit tumors, adenomas, aneurysms, significant blood loss
Hypopituitarism:
Causes include:
Pit infarction or space-occupying lesions (most common)
Congenital defects
Cerebral or pituitary trauma
Autoimmune conditions
Infections of brain & supporting tissues
Traumatic brain injury
Hypopituitarism:
Caused by: Congenital defects like what?
Pituitary hypoplasia, or aplasia
Hypopituitarism:
Caused by: Cerebral or pituitary trauma
such as?
Surgery,
infections,
stroke,
radiation,
injury
Hypopituitarism:
Cause by: Autoimmune conditions like?
Hypophysitis (inflamed pituitary)
Hypopituitarism:
Patho: How is the pituitary?
Pituitary highly vascular
Hypopituitarism:
Patho: What does the pituitary heavily rely on?
Relies heavily on blood from the hypothalamus
Hypopituitarism:
Patho: What does this make you vulnerable to? What does that lead to?
Vulnerable to ischemia & infarction –> tissue necrosis, edema, fibrosis –> sx of hypopituitarism
Hypopituitarism:
Patho: What may compress pituitary cells? What does that lead to?
Adenomas & aneurysms may compress pit cells –> compromised hormonal output
Hypopituitarism: Clinical Presentation/Tx - What does it depend on?
Depends on which hormones affected
Hypopituitarism: Clinical Presentation/Tx
Depends on which hormones affected
What are examples?
E.g. ACTH, TSH, FSH, LH, Growth hormone deficiency
Hypopituitarism: Clinical Presentation/Tx
What is evaluation and treatment?
Levels of pituitary hormones
Imaging – MRI, CT
Replacement of target hormones
Hyperpituitarism: Patho
What is it?
Hypersecretion of ant pit hormones
Hyperpituitarism:
Patho
What is caused by?
Commonly caused by a benign, slow-growing pituitary adenoma
Hyperpituitarism:
Patho
What does it do to nerves? What does that lead to?
Impingement on nerves: Visual & cranial nerve disturbances
Hyperpituitarism:
Patho: Because it is an extension to hypothalamus, what else is effected?
Extension to hypothalamus disturbs controls of wakefulness, thirst, appetite, & temp
Hyperpituitarism: Patho- Can be caused by what else?
Hypersecretion from tumor
Hyperpituitarism: Patho-Hypersecretion from tumor
Why does this occur?
Adenomatous tissue secretes hormones of the cell type from which it arose
Hyperpituitarism: Patho
How may HYPOpituitarism occur from this?
Hypopituitarism may occur from pressure exerted by tumor
Hyperpituitarism: Clinical Manifestations
What occurs?
Increased section of growth hormone from tumor
Hyperpituitarism: Clinical Manifestations
If tumor exerts enough pressure on surrounding pituitary cells what occurs?
Hypothyroid
Adrenal hypofunction
Hyperpituitarism: Clinical Manifestations
If tumor exerts enough pressure on surrounding pituitary cells hypothyroid occurs-why?
Hypothyroid-Because of lack of TSH
Hyperpituitarism: Clinical Manifestations
If tumor exerts enough pressure on surrounding pituitary cells adrenal hypofunction occurs-why?
Adrenal hypofunction
Low ACTH –> hypocortisolism
Hyperpituitarism: Clinical Manifestations
What are they related to?
Related to tumor growth & hyper or hyposecretion
Hyperpituitarism: Clinical Manifestations
What manifestations occur?
Visual changes, impairment –> blindness
Increased tumor size
Cranial nerves –> neuromuscular function
Hyperpituitarism: Clinical Manifestations
Increased tumor size leads to?
Increased tumor size –> headache, fatigue, neck pain, seizures
Acromegaly- what is it?
Is an increase in growth hormone which leads to grow huge bones
Patho of acromegaly:
How does production of too much growth hormone occur?
Cells produce too much growth hormone that is released into the bloodstream
Patho of acromegaly:
Cells produce too much growth hormone that is released into the bloodstream- What does this do to the liver?
Caused the liver to release a hormone called insulin growth factor-1 (IGF-1)
Patho of acromegaly:
Cells produce too much growth hormone that is released into the bloodstream- What does this do to the bones and soft tissue?
Causes the bones and soft tissue to grow
Patho of acromegaly
When is it diagnosed?
Usually dx’d adults aged 40-59
Patho of acromegaly
What occurs in children?
Peds – gigantism
Patho of acromegaly
Peds – gigantism
How does it occur?
Children & adolescents
Growth plates have not yet closed
Excessive skeletal growth ≈ 8-9ft
Patho of acromegaly
What are results of this?
overgrowth of bones and soft tissue (especially in the face, hand, and feet),
joints become enlarged, thicker, wider and arthritic
Patho of acromegaly:
Results:
What kind of issues occur?
cardiac disease,
arthritis,
carpal tunnel syndrome,
cardiomegaly,
sleep apnea, diabetes,
and hypertension,
hyperglycemia
Patho of acromegaly:
What are signs and symptoms?
Thicker eyelids,
widened nose,
protruding mandible and brow,
thicker lips,
widening of space btwn teeth
Secondary diabetes mellitus
Patho of acromegaly:
Signs and symptoms: Why does Secondary diabetes mellitus occur?
GH antagonizes insulin
Acromegaly Management:
What diagnostic tests are done?
PMH
PE
Serum hormone levels
Brain CT
Pituitary MRI
Vision testing
X-rays
Acromegaly Management:
Diagnostic tests done: How do serum hormone levels appear for acromegaly?
Acromegaly - ↑’d IGF-1 & GH
Acromegaly Management:
Treatment strategies: How to treat?
Underlying etiology & hormone affected
Somatostatin analogues (Octreotide)
GH receptor antagonists
Acromegaly Management:
Treatment strategies: How to treat tumors?
Tumors, often reoccurring:
SX
Radiation
Chemo
Acromegaly Management: What do Somatostatin analogues (Octreotide) do?
Inhibit GH production
Antidiuretic Hormone:
What is it known as?
ADH (also known as vasopressin)
Antidiuretic Hormone:
What does it promote?
Promotes renal conservation of water
Antidiuretic Hormone: What does it work on?
Works on the collecting ducts of the kidney to increase their permeability to water
Antidiuretic Hormone: Where does the water come from?
H2O withdrawn from the tubular urine back into extracellular space
Antidiuretic Hormone:
What does water reabsorption lead to?
Reabsorption (conservation) of H2O leads to very concentrated urine by the time it leaves the body
Antidiuretic Hormone:
What factors promoting/stimulating ~
controlled via hypothalamus
Antidiuretic Hormone:
Factors promoting/stimulating ~ controlled via hypothalamus
High blood osmolality sensed by hypothalamus –> ADH gets released from posterior pituitary to reabsorb water to dilute body fluids
Hypotension
Decrease in plasma volume
Diabetes Insipidus- What is it?
Deficiency of ADH
Diabetes Insipidus- What is it?
Excessive fluid excretion
DI= “Dry Inside”
Diabetes Insipidus- What do the kidneys do?
Kidneys unable to conserve water
What is DI deficit in?
While both have excess urine output, DI is from a deficit of antidiuretic hormone.
Diabetes Insipidus: What is it?
Partial or complete deficiency of ADH
Diabetes Insipidus:
What is it a diagnosis of?
DX of inability to produce concentrated urine
Diabetes Insipidus:
What area is diseased?
Disease of posterior pituitary
Diabetes Insipidus:
Patho: What does insufficient ADH lead to?
Insufficient ADH –> Large volumes of dilute urine, increased plasma osmolality
Diabetes Insipidus: What are the two types?
Central (neurogenic) DI (hypothalamus/pituitary is the cause)
Nephrogenic DI (kidneys are at fault)
Diabetes Insipidus:
What are examples of Central (neurogenic) DI (hypothalamus/pituitary is the cause)?
Examples:
Brain tumor,
head injury,
brain surgery,
CNS infections,
TBI,
thrombosis,
infections
Diabetes Insipidus:
Central (neurogenic) DI (hypothalamus/pituitary is the cause): How does it?
Pressure to the posterior pituitary from inflammation in the brain or a growth
Diabetes Insipidus:
Central (neurogenic) DI (hypothalamus/pituitary is the cause): How is the onset?
Abrupt onset
Diabetes Insipidus:
Nephrogenic DI (kidneys are at fault):
What occurs?
Adequate amount of vasopressin secreted by the posterior pituitary, but kidneys fail to respond because of other abnormalities
Diabetes Insipidus:
Nephrogenic DI (kidneys are at fault):
Why does it occur?
Genetic mutation
Diabetes Insipidus:
Nephrogenic DI (kidneys are at fault):
How is onset?
Gradual onset
Diabetes Insipidus: Nephrogenic DI (kidneys are at fault)
What are examples?
Examples: renal damage,
meds (eg loop diuretics, colchicine, lithium),
pyelonephritis,
uropathy,
polycystic kidney disease
Diabetes Insipidus: How is ADH secretion in Central (neurogenic) DI?
Decreased antidiuretic hormone
Diabetes Insipidus: Central (neurogenic) DI leads to decreased ADH. What does that cause?
Decreased water reabsorption in renal tubules
Diabetes Insipidus: Nephrogenic DI -how does it effect ADH?
Adequate ADH released
Diabetes Insipidus: Nephrogenic DI -causes adequate ADH released what does that lead to?
Decreased response of collecting ducts to ADH
Diabetes Insipidus: What does Central (nephrogenic) DI and Nephrogenic DI both lead to?
Increases excessive urine loss (polyuria)
Diabetes Insipidus: Central (nephrogenic) DI and Nephrogenic DI both lead to Increases excessive urine loss (polyuria): What does this cause?
Decreases intravascular fluid volume
Clinical Manifestations of Diabetes Insipidus include:
Polyuria
Polydipsia
Nocturia
Clinical Manifestations of Diabetes Insipidus: Why does polyuria occur?
kidneys excrete excessive dilute urine
Clinical Manifestations of Diabetes Insipidus: How much urine is lost with polyuria?
Can lose up to 8 to 12L/day (normal output 1-2L/day)
Clinical Manifestations of Diabetes Insipidus: Polyuria- What is the quality of the urine?
Low urine osmolality
Clinical Manifestations of Diabetes Insipidus:
Polydipsia- Why is this common?
Excessive thirst common due to quickly excreted water causing dehydration
Clinical Manifestations of Diabetes Insipidus:
What is thirst a compensation for?
Thirst is a compensation reaction for the loss of hydration
Clinical Manifestations of Diabetes Insipidus:
Complications
Hypernatremia
Severe dehydration
Clinical Manifestations of Diabetes Insipidus:
Hypernatremia: Why does this occur?
Hypernatremia - ADH primarily affects water reabsorption, not electrolytes; thus, sodium is retained in the body
Clinical Manifestations of Diabetes Insipidus:
Why does severe dehydration occur?
Severe dehydration - Excessive fluid loss through urine leads to intravascular fluid loss
Diabetes Insipidus: What is the treatment?
Fluid replacement – oral or IV
Eliminate causes
ADH replacement
Diabetes Insipidus Treatment:
What does ADH replacement consist of?
Vasopressin
DesmopressinDDAVP
Diabetes Insipidus Treatment:
ADH replacement - Vasopressin:
What is Vasopressin identical to?
Identical to naturally occurring ADH
Diabetes Insipidus Treatment:
ADH replacement - Vasopressin:
What kind of actions does it have?
Has powerful vasoconstrictive actions
Diabetes Insipidus Treatment:
Vasopressin:
Has powerful vasoconstrictive actions: What does it cause?
Can cause CV events, ischemia
Diabetes Insipidus Treatment:
Desmopressin DDAVP : What is it?
Structural analogue
Diabetes Insipidus Treatment:
DesmopressinDDAVP: How fast is response?
Response is rapid
Diabetes Insipidus Treatment:
DesmopressinDDAVP: How is urine levels?
Urine volume quickly drops to normal
Diabetes Insipidus Treatment:
DesmopressinDDAVP: How long is treatment?
Tx may be lifelong
Diabetes Insipidus Treatment:
DesmopressinDDAVP: How is the medication administered?
Adm PO, Sq, IV or nasal spray
Diabetes Insipidus Treatment:
What are adverse effects?
Water Intoxication
Diabetes Insipidus Treatment:
How does water intoxication occur?
Occurs from excessive water retention
Diabetes Insipidus Treatment:
Adverse Effects:
How does water intoxication present?
Preceding drowsiness, listlessness, HA
Severe –> convulsions, terminal coma
Diabetes Insipidus Treatment:
Adverse Effects: Water intoxification
What is treatment?
Tx: diuretic tx/fluid restriction
Diabetes Insipidus Treatment:
Adverse Effects: Water intoxification
How to prevent water intoxication?
Prevent with reduction of fluid intake @ TX start
Diabetes Insipidus Treatment:
Adverse Effects: Water intoxication
What does water intoxication cause an increased risk for?
↑ risk with renal impairment
Syndrome of Inappropriate ADH (SIADH): In basic terms, what is it
Excessive ADH
Syndrome of Inappropriate ADH (SIADH): What happens to renal water retention?
Increased renal water retention Siadh = “Soaked Inside”
SIADH: How is ADH?
Too much ADH is secreted from the pituitary or kidney’s response to it is excessive
SIADH:
What does ADH cause the body to do in general (not related to disease)?
ADH causes the kidney to reabsorb H2O so urine production decrease
SIADH: When does excessive ADH occur?
Increases after spinal surgery, with traumatic brain injuries, and certain drugs
SIADH: Who is it common in?
More common in older adults and hospitalized patients
SIADH: How is urine concentration?
Urine inappropriately concentrated because H2O reabsorbed that normally would be excreted.
SIADH: Patho
What effect does SIADH have on salt levels of the body?
Patho:Dilutional hyponatremia (hypoosmolality)
SIADH: What are causes of this?
Meds
Cancers
Pulmonary disorders
GI fluid losses
Fluid loss replaced only with D5W
CNS disorders
Self-induced water intoxication
Adrenal insufficiency (lack of aldosterone)
Post op
SIADH: Causes of SIADH
What meds could cause SIADH?
Meds:
Thiazides diuretics,
Chemo,
antidepressants,
antipsychotics,
narcs,
anesthetics,
NSAIDs,
thiazides
SIADH: Causes of SIADH
How could cancers cause SIADH?
*Cancers: ectopic production of ADH by solid tumors
SIADH: Causes of SIADH
What pulmonary disorders can cause SIADH?
Pulmonary disorders:
pneumonia,
TB,
CF,
resp failure
SIADH: Causes of SIADH
What *CNS disorders can cause SIADH?
brain tumors,
head injury,
meningitis,
intracranial hemorrhages,
stroke
SIADH:
Why would SIADH occur post op?
Postop: ADH released in response to stress of surgery, anesthesia, pain, nausea
Patho of SIADH:
What are the steps to SIADH?
(4 steps)
- ADH is released despite normal or low plasma osmolarity
- Increases water reabsorption in renal tubules
- Decreases urine production (oliguria)
- Increases intravascular fluid volume
Clinical Manifestations of SIADH include:
Fluid Retention and Weight Gain
Oliguria, Hyponatremia, Muscle Cramping, Weakness, GI sx
Mental Confusion, Lethargy, Muscle twitches, Irritability, Seizures, Coma