SIADH Vs DI Flashcards
SIADH Causes/Etiology
Release of antidiuretic hormone occurs independent of osmolality or volume dependent stimulation Inappropriate water retention Tumor production of ADH Skull fractures or head trauma Central nervous system disorder Chronic lung disease
DI Causes/Etiology
Excessive urination and extreme thirst from an inadequate output of the pituitary hormone ADH or the lack of no the normal response by the kidney to ADH
Central, nephrogenic, psychogenic
SIADH Signs/Symptoms
Neurological changes HA, Sz, Coma Decreased DTRs Hypothermia Weight gain/edema Nausea, Vomiting Cold intolerance
DI Signs/Symptoms
Thirst/Cravings for water Polyuria Weight loss Changed in LOC Dizziness Elevated Tempp Tachycardia Hypotension Poor turgor
SIADH Lab/Diagnostics
Hyponatremia Decreased serum osmolality Increased urine osmolality Urine sodium > 20 Renal,, cardiac, thyroid function normal
DI Lab/Diagnostics
Hypernatremia
Elevated BUN/Cr
Serum Osmolarity >290
Urine SG <1.005
If central DI suspected - desmopressin challenge test
If no apparent cause MRI should be ordered
SIADH Management
Treat underlying cause
Na >120 restrict total fluids to 1L
NA 110-120 without neuro symptoms restrict to 500ml
Na <110 or neuro symptoms, replace with isotonic or hypertonic saline and LASIK’s 1-2 mEq/h. Monitor Na K losses hourly and replace
DI Management
NA > 150 give D5W to replace 1/2 the volume deficit in 12-24 hours
NOTE rapid lowering of social can cause cerebral edema
NA <150 1/2NS or NS
DDAVP 1-4ug every 12-24 hours for acute situations
Maintenance dose of DDAVP is 10ug every 12-24 hours intranasally
Central DI
Related to pituitary or hypothalamus damage resulting in ADH deficiency Idiopathic Damage to hypothalamus or pituitary Surgical damage Accidental trauma Infections Metastatic carcinoma
Nephrogenic DI
Due to a defect in the renal tubules resulting in renal insensitivity to ADH
Familial X-Linked trait
Acquired due to pyelonephritis, potassium depletion, sickle cell anemia, chronic hypercalcemia, medication (lithium, methicilin)
DI Management
Na >150 give D5W IV to replace 1/2 volume deficit in.12-24 hours; more rapid lowering of Na can cause cerebral edema
When Na <150 substitute for 1/2 NS or NS
DDVAP 1-4 IV or Sq every 12-24 hours for acute situations
***Maintenance dose DDAVP is 10 ug every 12-24 hours intranasally
