Resident Report 12/9 – Nephrogenic DI

Teaching Points:

  • Clinical Manifestations:
    • Nocturia (usually first sign), polydipsia, polyuria
  • At baseline, [Na] resides in the high normal range as long as patient is able to replete free water.
    • Patients become hypernatremic when they are in an altered stated and unable to replete their free water needs.
    • Ex: Pts are strapped down, kept NPO during acute stresses
  • Sodium level becomes impaired during the following conditions:
    • When thirst is impaired or cannot be expressed
    • CNS lesions who have hypodipsia or adipsia.
    • Impaired adults who cannot independently access free water.
  • Nephrogenic DI is the most common side effect of lithium.
  • Water Deprivation test should be used to distinguish etiologies of polyuria and polydipsia.
  • Lithium enters the principal cells via ENaC. Accumulation leads to interference of aquaporin production.
  • Chronic Lithium use can lead to irreversible nephrogenic DI.
  • Treatment of Li-induced Nephrogenic DI
    • Discontinuation of Lithium
    • If Lithium is to be used, treat with amiloride
      • Only shown to work with mild to moderate nephrogenic DI.
      • Need to check Lithium level as a result of fluid depletion.
    • Other treatment modalities:
      • NSAIDs
      • HCTz and low sodium diet
    • Can also potentially cause RTA and nephrotic syndrome.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s