diabetes insipidus and syndrome of inappropriate antidiuretic hormone

diabetes insipidis patho

• posterior pituitary disorder

• water loss is caused by either

  • anti-diuretic hormone deficiency

  • inability of kidneys to respond to ADH

• results in excretion of large volumes of dilute urine

  • polyuria

  • dehydration

  • fluid and electrolyte imbalance

    • increased plasma osmolarity

    • increased serum sodium—hypernatremia

      • increased thirst sensation

DI neruogenic

• primary

  • caused by defect in hypothalamus or pituitary gland

  • resulting in lack of ADH production or release

• secondary

  • result fo tumors in or near hypthalamus or pituitary gland, head trauma, infectious processes, or brain injury

DI nephrogenic

• problems with kidney response to ADH

• renal tubules do not respond to ADH

DI drug related

• most often caused by lithium carbonate and demeclocycline

  • interere with response to kindeys

DI history

• ask about recent surgery, head trauma, drug use

DI physical assessment

• hypotension, tachycardia, weak peripheral pulses, hemoconentration

• increased urine output (polyuria) greater than 4L ingested, dilute and low specific gravity

• poor turgor, dry mucous membranes

• constipation

• decreased cognition, irritability, fatigue

• increased thirst

• ataxia

DI urine testing

• as urine volume increases, urine osmolarity decreases

  • decreased urine specific gravity (less than 1.005)

  • decreased urine osmolarity (less than 200mOsm/L)

  • decreased urine pH, sodium, and potassium

DI blood testing: think concentrated

• as blood volume decreases, blood osmolarity increases

  • increased blood osmolality greater than 300 mOsm/L

  • increased serum sodium and potassium

DI drug therapy with desmopressin (DDAVP)

• synthetic form of vasopressin (ADH)

• replaces ADH and decreases urination

  • increased water absoption from kidneys

• induces water retention

• routes of administration

• mild: oral, sublingual, intranasal via metered dose spray

• severe: IV, IM

• neruogenic: chlorpropamide and thiazide diuretics facilitate vasopressin action

• nephrogenic: prostaglasulin inhibitors, thiazide diuretics, and mild salt depletion are prescribed

DI drug alert

• the parenteral form of desmopressin is 10x stronger than the oral form, and the dosage must be reduced

• dose is adjusted based on urine output

• give cautiously to those with coronary artery disease due to vasoconstriction

• monitor for signs of water toxicity

DI nursing management

• early detection of dehydration and maintaining adequate hydration

  • accurately measure I&O

  • check urine specific gravity

  • record daily withg

  • urge to drink fluids in amount equal to output

  • ensure patency of IV

nerogenic DI nuring management

• lifelong drug therapy

• chech ability

  • assess symptoms

  • adjust soages as prescribed for changes in condition and urine output

• teach

  • polyuria and polydipsia indicate need for dose of DDAVP

  • monitor for indication of dehydration

  • weigh daily and observe to sins of lfuds overload due to medication

    • monitor for signs of water toxicity and report immediately to ED

      • headache, confusion, nausea, vomiting

    • wear medical bracelet to identify disorder

syndrome of inappropriate anti diuretic hormone patho

• ADH (vasopressin) is secreted even when plasma osmolarity is low or normal

  • ADH is released when it is not needed

  • excess ADH leads to renal reabsortion of water

    • result in water retention and fluid overload

    • water retention causes dilutional hyponatremia

• also known as Scwarts-Bartter syndrome

malignancies cause SIADH

• small cell lung cancer

• pancreatic, duodenal, and GU carcinomas

• thymoma

• hydgkin lymphoma

• non-hodgkin lymphoma

pulmonary disorders causes SIADH

• viral and bacterial pneumonia

• lung abcesse

• activity tuberculosis

• pneumothorax

• chronic lung disease

• myocoses

• positive pressure ventilation

CNS disorders cause SIADH

• trauma

• infection

• tumors

• strokes

• prophyreia

• systemic lupus erthematouse

drugs causeing SIADH

• exogenous ADH

• chlorprpamide

• vincristine

• cyclophophamide

• carbamazepine

• opioid

• tryicylic antidepressents

• general anesthetics

• fluoroquinolone antibiotics

SIADH assessment

• early symptoms: related to water retention causing dilutional hyponatremia, GI disturbances may occur first (loss of appetite, nausea, vomiting)

• Dependent edema is not present due to free water being retaining, not salt

• letharhy, headaches, hostility, disorentation, change in LOC

• can progress to decreased responsiveness, seizures, and coma

• decreased deep tendon reflexed

• full, bounding pulse

• hyponatremia

SIADH urine testing: think concentrated

• as urine volume decreases, urine osmolatiy increases

• increased urine specific gravity to greater than 1,030

• increased urine osmolatity

• increased urine sodium

SIDAH blood testing: think dilute

• as blood volume increases, blood osmolatily decreases.

• decreased blood dodium (dilutinal hyponatremia)

• decreased blood osmolatily (less than 270)

• decreased in BUN, Hgb, creatinine clearance

SIADH drug therapy

• tolvaptan (oral), conivaptan (IV)

• vaopressin receptor antagonist (vaptans)

• promote water excretion without causing sodium loss

• only administered in hospital settings

  • serum sodium monitoring for hypernatremia complications

• Diuretics are used on limited basis when dosium levels are near normal and heart failure is present

• hypertonic saline, 3% NaCl

  • used when sodium levels is very low

  • give cautiously due to risk of fluid overflow and promotion of heart failure

SIADH focus interventions

• restricting fluid intake

• romoting excretion of water

• Replacing lost sodium

• interfere with action of ADH

SIADH interventions

• Monitor response to therapy and prevent complication

• fluid overload and pulmoary edema

• monitor neruogic status due to fluid shifts in the brain

• teach about fluid restrictions and drug therapy

• prevent injury

• needed when serum sodium falls below 120

  • risk for neurologic changes and seizures

• prevent overstimulation