Electrolyte Abnormalities Flashcards
Normal Na value?
135-145 mEq/L
What are the 3 different types of hyponatremia?
1) Hypertonic
- sosmol > 295, Na < 135
2) Isotonic
- norm sosmol, Na < 135
3) Hypotonic (true hyponatremia)
- sosmol < 275, Na < 135
What lab values support a diagnosis of Hypertonic Hyponatremia?
sosmol > 295 and Na < 135
What lab values support a diagnosis of Hypotonic Hyponatremia?
sosmol < 275 and Na < 135
What lab values support a diagnosis of Isotonic Hyponatremia?
sosmol 275 - 295 and Na < 135
What is the normal serum osmolality value?
275-295 mOsm/kg
What is the normal serum sodium range?
135-145 mEq/L
Which type of hyponatremia is called the “true hyponatremia”?
Hypotonic Hyponatremia
What are the main causes of hyponatremia?
- high/excessive H2O intake
- H2O retention or decreased urine output
- increased ADH release from the anterior pituitary
Antidiuretic Hormone (ADH) is released from what organ?
Anterior Pituitary gland
What are the symptoms of hyponatremia?
SALTLOSS
- Stupor or coma
- Anorexia
- Lethargy
- decreased Tendon reflexes
- Limp muscles / weakness
- Orthostatic hypotension
- Seizures
- Stomach cramping
What is the acronym used to remember the symptoms of hyponatremia?
SALTLOSS
What are the diagnostic tests used to diagnose hyponatremia?
- serum sodium level < 135
- serum osmolality
- urine osmolality
- urine sodium level
What is the cause of hypertonic hyponatremia?
there is an increase in another solute which causes increased Na loss from kidneys
- ex: hyperglycemia
What is the first step when assessing a patient with hypotonic hyponatremia?
- Na < 135 and mOsm/L < 275
- determine if the patient is fluid overloaded or deficient
What is the treatment for a patient with hypotonic hyponatremia and is fluid overloaded?
- restrict H2O intake
- diurese
- replace Na PRN
what is normal urine Na levels?
10-20 mEq/L
In a patient that with hypotonic (mOsm < 275) hyponatremia (Na < 135) and is volume depleted, how can you tell if a patient is loosing fluids through the GI tract or diaphoresis vs renally?
check Urine Na levels (normal is 10-20 mEq/L)
- < 10 = GI / diaphoresis
- > 20 = renal (most common cause is overuse of diuretics)
What is the treatment a hyponatremic patient is overcorrected?
start D5W and ddAVP (desmopresin) which is a synthetic anti diuretic hormone
How much does 10 mEq of KCL raise the serum postassium?
approximately 0.1 mEq/L
