Endo

Diabetes Insipidus

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Diabetes Insipidus

  • Pathophysiology
  1. Excessive constant water diuresis due to:
    1. Central Anti-Diuretic Hormone deficiency (ADH) or
    2. Lack of renal response to Anti-Diuretic Hormone
  • Symptoms
  1. Polyuria
  2. Polydipsia
    1. Unquenchable thirst
  • Differential Diagnosis
  1. Psychogenic polydipsia
  • 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