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Diabetes Insipidus

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Diabetes Insipidus

  • Subtypes
  1. Central Diabetes Insipidus
  2. Nephrogenic Diabetes Insipidus (most common)
  • Pathophysiology
  1. Excessive constant water diuresis due to:
    1. Central Anti-DiureticHormone deficiency (ADH) or
    2. Lack of renal response to Anti-DiureticHormone
  • Symptoms
  1. Polyuria
  2. Polydipsia
    1. Unquenchable thirst
  • Differential Diagnosis
  1. Psychogenic Polydipsia
  • Labs
  1. Serum Osmolality
    1. Increased in both Nephrogenic DI and Central DI
  2. Urinalysis
    1. Urine Specific Gravity under 1.008
  • Diagnosis
  1. Fluid Deprivation Test
    1. Water deprivation
      1. No response in Nephrogenic DI or Central DI
    2. Exogenous ADH administration
      1. Corrects Central DI
      2. Does not correct Nephrogenic DI
  2. Hare-Hickey Test
    1. Fluid restriction or Injection of Hypertonic Saline
    2. Measure ADH to Serum Osmolality ratio
      1. Decreased ratio in Central Diabetes Insipidus
      2. Increased ratio in Nephrogenic Diabetes Insipidus
  • Management
  1. Central Diabetes Insipidus
    1. See Central Diabetes Insipidus
  2. Nephrogenic Diabetes Insipidus
    1. Remove provocative factors