N352 Endocrine Pathophysiology
Exam Latest Update
Negative Feedback Loop - ANSWER Mechanisms that monitor the internal
environment and restore homeostasis when conditions shift out of the normal
range (opposite direction)
Positive Feedback Loop - ANSWER Mechanisms that perpetuate a chain of
events (same direction)
Acromegaly Pathophysiology - ANSWER Most often caused by pituitary tumor
(adenoma)
Results from excessive hormonal stimulation (pituitary GH, liver produces IGF-1)
Leads to excessive growth of bones, cartilage, soft tissues, organs
Occurs AFTER epiphyseal plate closure
Acromegaly Clinical Manifestations - ANSWER · Enlarged hands and feet
· Prominent jaw, brow, nasal bone
· Enlarged tongue
· Edema
· Overactive sebaceous glands
· Excessive sweating
· Pain
· Headache
· Insulin resistance/hyperinsulinemia
· Hypertension
· Left sided heart failure
Acromegaly Lab Values/Diagnostic Tests - ANSWER History/physical exam
High IGF-1/GH
MRI (to r/o adenoma)
Growth measurement
Acromegaly Treatment - ANSWER Pharmacologic: drugs to reduced growth
hormone secretion (ocreotide acetate, pegvisomant)
Nonpharmacologic: radiation therapy to promote death in growth hormone
hyper-secreting cells
Surgical: removal of tumor (adenoma) causing hypersecretion of growth
hormone
, Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Pathophysiology -
ANSWER Excessive ADH production and release (despite changes in serum
osmolality and blood volume)
Most often occurs from an ADH secreting tumor (can also occur as result of
trauma, temperature extremes, surgery, infection, medications)
SIADH Clinical Manifestations - ANSWER -Decreased urine output (water
retention, concentrated urine)
-Severity of symptoms depends on serum sodium levels (hypotonic
hyponatremia)
-Significant symptoms typically appear when serum sodium less than 115-120
mEq/L
-Initial symptoms: anorexia, nausea, vomiting, headache, irritability,
disorientation, cramps, weakness
-Severe symptoms (below 110 mEq/L): Psychosis, gait disturbances, seizures,
coma
SIADH Diagnostic Criteria - ANSWER -Hyponatremia (serum sodium <135
mEq/L).
-Hypotonicity (plasma osmolality <280 mOsm/kg).
-Decreased urine volume.
-Highly concentrated urine with a high sodium content.
-Absence of renal, adrenal, or thyroid abnormalities.
SIADH Treatment - ANSWER -Remove cause
-Water restriction w/ mild symptoms
-Isotonic or hypertonic IV fluid replacement w/ severe hyponatremia
Diabetes Insipidus (DI) Pathophysiology - ANSWER •Insufficient ADH
•Inability to concentrate or retain water, cannot appropriately balance fluid
levels
DI Causes - ANSWER -Insufficient ADH production (hypothalamus) or secretion
(posterior pituitary) - most common cause is damage to hypothalamic
osmoreceptors d/t trauma/surgery
-Inadequate kidney response to ADH (nephrogenic DI - chronic renal
insufficiency, medications [lithium])
-Excessive ingestion of large volumes of fluid (psychiatric disturbance)
DI Clinical Manifestations - ANSWER -Polyuria - large urine output, highly diluted
urine, low specific gravity
-Excessive thirst
-Dehydration - fluid loss leads to serum hyperosmolality
-Shock, death if untreated
DI Diagnostic Criteria, Lab Values - ANSWER -History and physical exam
Exam Latest Update
Negative Feedback Loop - ANSWER Mechanisms that monitor the internal
environment and restore homeostasis when conditions shift out of the normal
range (opposite direction)
Positive Feedback Loop - ANSWER Mechanisms that perpetuate a chain of
events (same direction)
Acromegaly Pathophysiology - ANSWER Most often caused by pituitary tumor
(adenoma)
Results from excessive hormonal stimulation (pituitary GH, liver produces IGF-1)
Leads to excessive growth of bones, cartilage, soft tissues, organs
Occurs AFTER epiphyseal plate closure
Acromegaly Clinical Manifestations - ANSWER · Enlarged hands and feet
· Prominent jaw, brow, nasal bone
· Enlarged tongue
· Edema
· Overactive sebaceous glands
· Excessive sweating
· Pain
· Headache
· Insulin resistance/hyperinsulinemia
· Hypertension
· Left sided heart failure
Acromegaly Lab Values/Diagnostic Tests - ANSWER History/physical exam
High IGF-1/GH
MRI (to r/o adenoma)
Growth measurement
Acromegaly Treatment - ANSWER Pharmacologic: drugs to reduced growth
hormone secretion (ocreotide acetate, pegvisomant)
Nonpharmacologic: radiation therapy to promote death in growth hormone
hyper-secreting cells
Surgical: removal of tumor (adenoma) causing hypersecretion of growth
hormone
, Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Pathophysiology -
ANSWER Excessive ADH production and release (despite changes in serum
osmolality and blood volume)
Most often occurs from an ADH secreting tumor (can also occur as result of
trauma, temperature extremes, surgery, infection, medications)
SIADH Clinical Manifestations - ANSWER -Decreased urine output (water
retention, concentrated urine)
-Severity of symptoms depends on serum sodium levels (hypotonic
hyponatremia)
-Significant symptoms typically appear when serum sodium less than 115-120
mEq/L
-Initial symptoms: anorexia, nausea, vomiting, headache, irritability,
disorientation, cramps, weakness
-Severe symptoms (below 110 mEq/L): Psychosis, gait disturbances, seizures,
coma
SIADH Diagnostic Criteria - ANSWER -Hyponatremia (serum sodium <135
mEq/L).
-Hypotonicity (plasma osmolality <280 mOsm/kg).
-Decreased urine volume.
-Highly concentrated urine with a high sodium content.
-Absence of renal, adrenal, or thyroid abnormalities.
SIADH Treatment - ANSWER -Remove cause
-Water restriction w/ mild symptoms
-Isotonic or hypertonic IV fluid replacement w/ severe hyponatremia
Diabetes Insipidus (DI) Pathophysiology - ANSWER •Insufficient ADH
•Inability to concentrate or retain water, cannot appropriately balance fluid
levels
DI Causes - ANSWER -Insufficient ADH production (hypothalamus) or secretion
(posterior pituitary) - most common cause is damage to hypothalamic
osmoreceptors d/t trauma/surgery
-Inadequate kidney response to ADH (nephrogenic DI - chronic renal
insufficiency, medications [lithium])
-Excessive ingestion of large volumes of fluid (psychiatric disturbance)
DI Clinical Manifestations - ANSWER -Polyuria - large urine output, highly diluted
urine, low specific gravity
-Excessive thirst
-Dehydration - fluid loss leads to serum hyperosmolality
-Shock, death if untreated
DI Diagnostic Criteria, Lab Values - ANSWER -History and physical exam
