na concentration disorders Flashcards
What are the three types of hypo/hyper natremia?
hypovolemic: volume deficit
hypervolemic: volume overload
euvolemic: nearly normal fluid status
What are the main causes of hypovolemia [renal and extra-renal)?
Renal loss of water: diuretic use OR Addison’s disease
Extra-renal loss of water: sweating, vomiting, diarrhea
What conditions are associated with euvolemic hypernatremia?
- diabetes insipidus due to absence or non-responsiveness of kidneys to ADH
- leads to decreased water reabsorption and dilute urine; decreased thirst and water intake
Two types:
- central diabetes insipidus (low ADH): tumor or trauma
- nephrogenic diabetes insipidus (high ADH but kidney insensitive): congenital
AND nursing home syndrome
How can we differentiate between renal and extra-renal losses of water for hyponatremia?
We can use the Urine [Na] to help us determine
- renal: normal urine [na] ~20 meq/L
- extra-renal: low urine [na]
THINK: if body is losing Na in the sweat, there will be less excreted in the kidney = low urine [na]
What conditions are associated with euvolemic hyponatremia?
- SIADH: excess ADH leads to concentrated urine and excess fluid; caused by tumor, pulm disease
- hypothyroidism
- beer drinkers potomania
- psychogenic polydipsia
What are the treatments for hypernatremia?
hypo: hypotonic saline= water into cells to dilute
euv: give water or ADH (central diabetes ins)
hyper: diuretic + fluid
What are the treatments for hyponatremia?
*hypo: isontonic saline; then correction of [na]
- euv:
- mild: no treatment
- severe + asymptomatic: fluid restriction
- severe + CNS symptoms: hypertonic solution (maybe diuretics)
*hyper: diuretics
what symptoms are associated with hypovolemic hyponatremia?
- orthostatic htn
- flat neck veins
- decreased skin tonicity
what symptoms are associated with hypervolemic hyponatremia?
- CHF
- edema
- liver cirrhosis
- renal failure
