Lecture Summary: SIADH vs. Diabetes Insipidus

Key Hormone: Antidiuretic Hormone (ADH)

• Also called vasopressin.
• Function:
  • Regulates water in the body and constricts blood vessels.
  • Works with the kidneys to retain or release water.

Brain Involvement

• Hypothalamus: Produces ADH.
• Posterior Pituitary Gland: Stores and secretes ADH.

Conditions Overview

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

• Characteristics: Increased ADH.
• Causes:
  • Damage to hypothalamus or posterior pituitary gland.
  • Lung cancer (e.g., small cell lung cancer).
  • Infections (pneumonia, meningitis).
  • Medications like chlorpropamide (used for diabetes insipidus).
• Symptoms:
  • Fluid overload, edema, weight gain, high blood pressure.
  • Tachycardia, hyponatremia, confusion, seizures.
  • Low urine output with high specific gravity.
• Nursing Interventions:
  • Fluid restriction.
  • Monitor weights, intake/output, safety.

Diabetes Insipidus (DI)

• Characteristics: Decreased ADH.
• Causes:
  • Kidney problems, medications, pregnancy.
  • Brain trauma affecting hypothalamus or pituitary gland.
  • Drugs like demeclocycline.
• Symptoms:
  • Excessive urination (up to 24 liters/day), intense thirst.
  • Dehydration, dry mucous membranes, hypotension.
  • Low urine specific gravity, hypernatremia.
• Nursing Interventions:
  • Avoid diuretic foods and drinks (e.g., caffeine).
  • Monitor hydration status, skin turgor, mucus membranes.

Treatment and Management

SIADH Treatments

• Loop Diuretics (e.g., Lasix): Promote fluid loss.
  • Monitor for hypokalemia.
• Hypertonic IV Solutions (e.g., 3% saline): Reduce cell swelling.
  • Monitor for fluid overload and respiratory distress.
• Demeclocycline: Inhibits ADH.
  • Avoid calcium-rich foods.

Diabetes Insipidus Treatments

• Chlorpropamide (Diabinese): Increases ADH but monitor for hypoglycemia and photosensitivity.
• Desmopressin (DDAVP): ADH replacement therapy.
  • Monitor for hyponatremia and fluid retention.

Conclusion

• Understanding ADH function helps differentiate and manage SIADH and DI.
• Visit RegisteredNurseRN.com for quizzes and further practice.