Nursing Care Plan for Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Pathophysiology

SIADH is diagnosed as a collection of symptoms that take place with otherwise normal function. This syndrome is characterized by hyponatremia, concentration of urine and dilution of blood. The patient has an adequate amount of blood, but it is more dilute than normal. SIADH causes the body to retain fluid resulting in decreased electrolyte balance.

Etiology

SIADH is caused as an effect of other disorders, often nervous system disorders such as epilepsy, Guillain-Barre syndrome or head trauma, or cancers of the pulmonary, brain, GI and genitourinary systems. It is caused when the hypothalamus is stimulated to produce excess amounts of AVP (arginine vasopressin) which is an antidiuretic hormone (ADH) that triggers the kidneys to retain fluid in the tubules and excrete sodium. As the amount of fluid builds up in the cells and tissues, it creates an imbalance of electrolytes, specifically sodium, causing hyponatremia.  The excess fluid dilutes the blood instead of being excreted causing the urine to become concentrated.

Desired Outcome

Patient will maintain normal electrolyte and fluid balance

Syndrome of Inappropriate Antidiuretic Hormone (SIADH) Nursing Care Plan

Nursing Interventions and Rationales

• Monitor I & O, daily weights

• Continuous ECG monitoring

• Assess and monitor vital signs every 1-2 hours

• Assess and monitor respiratory status; note changes in respiration, auscultate lungs

• Administer medication and electrolyte supplements appropriately
  • Electrolyte supplements (potassium)
  • Demeclocycline or lithium  – stops the kidneys from responding to extra ADH

• Monitor lab / diagnostic values
  • Serum potassium
  • Serum sodium
  • Serum chloride
  • Serum osmolality (concentration)
  • Urine specific gravity

References

• https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/syndrome-of-inappropriate-secretion-of-antidiuretic-hormone#v28394815
• https://emedicine.medscape.com/article/246650-overview#a3
• http://www.chop.edu/conditions-diseases/syndrome-inappropriate-antidiuretic-hormone-secretion-siadh
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3474650/