ADH Flashcards
antidiuretic hormone disorders
SIADH
diabetes insipidus
where does primary, secondary, and tertiary refer to?
primary: w/ gland itself
secondary: pituitary
tertiary: hypothalamus
SIADH
syndrome of inappropriate antidiuretic hormone
abnormal production or sustained secretion of ADH
characterized by:
fluid retention, hypoosmolality, hyponatremia, and concentrated urine
causes of SIADH
malignant tumors (small cell carcinoma of lung)
CNS disorders (head trauma, stroke, brain tumor)
drug therapy (morphine, SSRI’s, some chemo drugs)
other (hypothyroidism, infection)
patho of SIADH
increased diuretic hormone –> increased water reabsorption in renal tubules –> increased intravascular fluid volume –> dilutional hyponatremia and decreased serum osmolality
osmolality of SIADH
serum osmolality: low
urine osmolality + specific gravity: high
serum sodium: low
urine output: low
*weight gain (pt is retaining PURE water WITHOUT salt)
s/s of SIADH
depend on severity and rate of onset of hyponatremia
SOB, fatigue
neurologic (dulled senses, confusion, lethargy, muscle twitching, convulsions)
GI (impaired taste, anorexia, vomit, cramps)
SEVERE: Na<100-115
~irreversible neurologic damage
water intoxication - can you die?
YES
cerebral cells swell (hypotonic)
treatment of SIADH
meds NOT 1st line –> instead at underlying cause
chronic SIADH: demeclocycline
mild: fluid restriction
severe: hypertonic saline sol’n
*loop diuretics help promote diuresis (watch Na levels!)
demeclocycline
tetracycline broad-spectrum antibiotic – antibiotic therapy, tx of chronic SIADH
MOA: interferes with renal response to ADH
SE: photosensitivity (AVOID sun), teeth staining, nephrotoxic
diabetes insipidus
a deficiency of ADH or decreased renal response to ADH
excessive loss of water in urine
2 forms:
neurogenic (most common form)
nephrogenic
neurogenic DI
neuro origin (central)
cause: hypothalamus or pituitary gland damage
associated disorders: stroke, TBI, brain surgery, cerebral infections
sudden onset
usually permanent
nephrogenic DI
renal origin
cause: loss of kidney fxn, often drug-related (ex: lithium)
associated disorders: CKD
slow onset
progressive course of disease
diabetes insipidus: patho
decreased antidiuretic hormone –> decreased water reabsorption in renal tubules –> decreased intravascular fluid –> increased serum osmolality (hypernatremia) & excessive urine output
DI: osmolality
serum osmolality: high
urine osmolality and specific gravity: LOW
serum sodium: high
urine output: high
*weight loss
