Pathophysiology
 Deficiency of ADH or the kidneys inability to
respond to ADH.
 Key remembering
o Diabetes insipidus
o Decreased ADH
o Diuresis
Types of Diabetes Insipidus
 Nephrogenic
o The posterior pituitary gland is doing its
job and releasing ADH, there’s a problem
with the kidneys, and it is not
responding appropriately to the signal
and reabsorbing more water.
o The Kidneys do not respond to ADH
o Which results in inability to conserve
(reabsorb) water.
 Primary
o There’s a defect in the hypothalamus or
posterior pituitary
o Resulting in lack of ADH
 Secondary
o Results from tumors or tumor near the
hypothalamus or pituitary
o Head tumor or Metastatic tumors
o Infection
o Surgery
 Drug Related
o Drugs such as: Lithium and
Demeclocycline interferes with the
kidney response to ADH
Signs and Symptoms
 Large amount of Diluted Urine
 Polydipsia (excessive thirst)
 Severe Dehydration
 Pt at risk for Hypovolemic Shock
 Hypernatremia (increase sodium)
Risk Factors
 Hypernatremia
 Severe dehydration
 Putting pt on fluid restriction to decrease
urine output can cause worsening
dehydration and hypernatremia
Diagnostic
 24 hours urine Test
o Less than 2 Liters I n24 hours without
hypernatremia rules out Diabetes
Insipidus (DI)
 Vasopressin Challenge Test (DDAVP)
o Osmolality measures the concentration
o Normal Value: 700-1400
 The higher the value, the more
concentrated the urine
 Primary or Secondary: the
osmolality will increase with admin
of DDAVP (urine will be more
concentrated
 Fluid Deprivation Test
o Withholding fluids for 8-12 hours util 35% of body wt is lost
o Contraindication if pt is hypernatremia
o Inability to increase specific gravity and
osmolality of urine is characteristic of
Diabetes Insipidus
Labs
 Serum Osmolality
o Will be increased in DI (concentration)
o Normal Value: 288-291
o Critical Value: >295
 Urine Specific Gravity
o Will be decreased in DI (diluted)
o Normal Value: 1.015-1.03
o Critical Value: 1.001 to 1.005
 Serum Sodium
o Normal value: 135-145
o Critical Value: > 145
Assessment- Recognize Cues
 Most of the manifestations are related to
dehydration and extreme thirst
 Make sure Nasal passage is clear for meds
 Monitor VS, labs, and maintain Fluid Volume
 Daily wts
 Ask about
o Recent surgery
o Head trauma
o Drug used (Lithium)
 Extremely large amounts of diluted urine
output
o Greater than 4L/day and up to 30L/day
 S/S of fluid volume deficit
o Weight loss, Poor skin turgor, Dry
mucous membranes, Tachycardia, and
Hypotension
Management
 Desmopressin (DDAVP)
o Synthetic Vasopressin
o Used to control fluid balance
o Do Not have the same impact as the
natural ADH
o Used with caution in pt existing CV due
to vasoconstrictive properties
o Administer: intranasally or sublingual
 10 mcg/spray
 Dose is 1-6 sprays a day depending
on severity
o Given IM
 If unable to give Intranasally
 Thiazide Diuretics
o For Nephrogenic Diabetes Insipidus
o It decreases polyuria and increase
osmolality
 Mild Sodium Restriction
o To help maximize the effectiveness of
Thiazide Diuretics
 NSAID
 Sulfonylureas
o
Diabinese