Renal Labs Part 2 (Exam 4) Flashcards
What is the primary circulating cation? (extracellular cation)
Na
What is the normal range for sodium?
136-145 mEq/L
How does sodium indicate free body water?
When free water is increased, Na is diluted and Na levels decrease.
When free water is decreased, Na is concentrated and levels increase.
What ion is a major contributor to plasma osmolality?
Na
What is a normal serum osmolality?
280-295mOsm/kg H2O
What hormone regulates body water and osmolality?
Antidiuretic hormone
What stimulates ADH?
Increased osmolality
Hypovolemia
Thirst
By what mechanism does ADH cause the body to hold onto water?
Increases the permeability in the collecting tubule allowing more water to be reabsorbed
Name a few conditions that would cause increased serum osmolality.
Hypernatremia Hyperglycemia Ketosis Dehydration Diabetes insipidus
Name 2 conditions that would cause decreased serum osmolality.
Overhydration
SIADH
Common cause of SIADH?
Iatrogenic causes
Diabetes insipidus is caused by?
Inadequate amount of ADH present
Symptoms of diabetes insipidus
Increased thirst, polyuria, dilute urine
What test evaluates the ability of the kidney to concentrate urine?
Urine osmolality
Name 2 conditions that would increase urine osmolality?
SIADH
CHF
Name 2 causes of decreased urine osmolality?
Diabetes insipidus
Excess fluid intake
What is more worrisome, hyponatremia or hypernatremia?
Hyponatremia
Serum sodium below ____ is hyponatremia?
136
What are the two types of hyponatremia?
Sodium depletion
Dilutional