Diabetes Insipidus

Question 1

Diabetes Insipidus

Answer 1

• Rare disorder when an abnormally large volume of urine is insipid- dilute & odorless
• [>250 mL/hr (Brunner)]

Question 2

DI vs DM

Answer 2

• DI and DM are unrelated although both conditions cause frequent urination and constant thirst.
• DM causes high BG resulting from body’s inability to use glucose for energy.
• DI have normal blood glucose levels however, their kidneys cannot balance fluid in body (insufficient output of ADH)

Question 3

Normal physiology

Answer 3

• ADH is released from posterior pituitary. When released, ADH helps kidneys reabsorb water
• But in Diabetes Insipidus
• Decreased ADH leads to excretion of water and electrolyte imbalances.
  — Usually seen in:
  — - head trauma
  — - pituitary tumors
  — - CNS infections

Question 4

Diabetes Insipidus 2

Answer 4

• Water loss problem
• ADH deficiency (decreased production of ADH) or inability of kidney to respond to ADH
  — ADH deficiency = vasopressin deficiency
  — ADH aka vasopression
• Leads to excessive fluid excretion and dehydration

Question 5

Diabetes Insipidus 3

Answer 5

• Results in large amounts of dilute urine
• Because distal kidney tubules & collecting ducts do not reabsorb water
• This leads to polyuria, dehydration and F&E imbalances (esp increased serum Na levels)

Question 6

DI risk factors

Answer 6

• Head trauma
• pituitary tumors
• cerebral edema
• radiation to brain
• infection of central nervous system
• kidney disease
• use of meds that can interfere with kidney function (ex. Lithium)

Question 7

Diabetes Insipidus S/S

Answer 7

• Increased excessive urination
• Chronic severe dehydration (hypotension, tachycardia, electrolyte depletion)
• Increased plasma osmolality
• Low urine osmolality (50-200 mOsm/kg)
• Excessive thirst
• Urine is dilute
• Low specific gravity (<1.001)
• Anorexia, weight loss, weakness, constipation

Question 8

Serum osmolality

Answer 8

• Serum osmolality- measure of hydration status
• Will measure concentration of blood
• Blood osmolality will increase with dehydration
• Nl value: 275-295/300 milliosmoles –
  — The lower the number, the less concentrated the blood
  — The higher the number, the more concentrated the blood will be (this indicates dehydration)

Question 9

Specific Gravity

Answer 9

• Indicator of urine concentration
• Nl value: 1.001- 1.005 (Brunner)
• The lower the number, the more dilute the urine will be.
• The higher the number, the more concentrated the urine will be.

Question 10

DI Diagnostics

Answer 10

• Fluid deprivation test
• Fluids are withheld for 8-12 hrs to verify if an ADH problem exists.
• Pt weighed frequently during test
• Urine & plasma osmolality tests done before and after
• Inability to increase specific gravity and urine osmolality are characteristic of DI

Question 11

DI Nursing Care basics

Answer 11

• Maintain pt safety!
  — Orthostatic hypotension precautions –
  — Fall risk
• Oral and skin care
  — Mouth rinses and hard candies will help to relieve some discomfort (from dry mouth/dry mucous membranes)
  — Skin moisturizers, frequent repositioning
• Administer desmopressin acetate (DDAVP)
  — Desmopressin is a synthetic form of vasopressin (ADH)

Question 12

DI Nursing Care

Answer 12

• Therapy directed at increasing ADH levels by administering med: desmopressin (DDAVP)
• Prevent further dehydration
• Promote F&E balance
• Watch out for complications
  — Dehydration, hypotension, seizures, coma
  — Hypernatremia
  — Hypokalemia

Question 13

DI Nursing Care 2

Answer 13

• Maintain adequate hydration
• Assess for s/s dehydration
• Assess I&Os, electrolyte levels
• Assess urine color, amount, specific gravity
• Daily weights
• Ask about thirst & urinary frequency
• Encourage pt to drink fluids in amount equal to urine output

Question 14

DI Nursing Care 3

Answer 14

• Controlling manifestations with drug therapy
• desmopressin (DDAVP)
  — med replaces antidiuretic hormone
  — Synthetic form of vasopressin
  — given orally or intranasal spray
  — Therapeutic effects:
  — - decreased urine output, BP stabilizes or improves, HR returns to more normal level
• Med will cause FLUID RETENTION
  — - Watch for fluid volume excess symptoms & HTN
• During severe dehydration, ADH may be given IV or IM
  — Parenteral form of desmopressin is 10x stronger than oral and intranasal, dose must be reduced

Question 15

DI Nursing Care 4
Education:

Answer 15

• Permanent DI, requires life long drug therapy
• Desmopressin (DDAVP)
  — Induces water retention and can cause fluid overload
  — May need to restrict fluids once med reaches steady state
• Daily weights at home
• Polyuria & Polydipsia are indications of a need for another dose.
  — Consult with HCP for drug regimen