ADH disorders (405) Flashcards
what are the two ADH disorders
1) SIADH (too much)
2) DI (too little)
if hypernatremic, cells will
shrink
if hyponatremic, cells will
swell
hypo and hyper natremic both lead to what patient presentation
patient will be confused
increased ADH secretion leads to
decreased water excretion which increased fluid volume
SIADH
overproduction of ADH
-results in excess water reabsorption & decreased serum sodium levels
-cells swell
most common cause of SIADH
ectopic hormone (ADH) production from lung cancer cells (paraneoplastic disease)
DI
underproduction of ADH
-can be caused by neurogenic origins (head trauma) or nephrogenic (kidney doesn’t respond to ADH)
what is the most common cause of drug induced nephrogenic DI
lithium
SIADH pathophys map
inc ADH -> inc water reabsorption in renal tubules -> inc intravascular fluid volume -> dilutional hypoNa & dec serum osmolality
SIADH clinical manifestations
based on severity & rate of onset of hypoNa
-muscle cramping
-dyspnea
-fatigue
-dulled sensorium, confusion, lethargy
-impaired taste & anorexia
severe SIADH sx are associated w/ a Na+ level of
<100-115
SIADH are at risk for what
altered mental status
SIADH nursing interventions
-assess for FVO
-monitor I&O
-monitor metal status
-restrict fluids w/ an order
-IVF per order
-support
-drugs (not first line)
immediate goal for SIADH
restore normal fluid volume & osmolality
if SIADH mild (Na <125)
fluid restriction only (1000 ml/d)
if SIADH severe (Na <120)
- 3-5% NS given slowly over days
- 500 ml/d fluid restriction
when to use drug therapy w/ SIADH
only in chronic
-diuretics
-demeclocycline (blocks ADH)
DI pathophys map
dec ADH -> dec water reabsorption in renal tubules -> dec intravascular fluid volume -> inc serum Na & excess urine output
DI: neurogenic
-usually abrupt onset
-most severe S/s but usually self limiting
need to treat the symptoms
DI: nephrogenic
-less abrupt onset
-less severe symptoms
DI clinical manifestations
-polyuria & polydipsia
-urine: very low specific gravity & osmolality
-serum: high omsolality
-fatigue & weakness
DI does not have which classic DM symptom
polyphagia
high serum osmolality increases what
thirst
DI goal
maintain fluid & electrolyte balance
DI interventions
-IVF
-I&Os
-daily wts
-monitor labs (urine & serum)
-pharm
when to notify the provider for a pt w/ DI
inc urine volume w/ dec specific gravity
may need to inc DDAVP
neurogenic DI pharm therapy
DDAVP
DDAVP
“vasopressin”
-used for neurogenetic DI
-MOA: synthetic ADH
-give small doses
