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Hyponatremia in Cirrhosis

Kinsley Ojukwu

Background

  • Hyponatremia in cirrhosis is often defined as serum Na < 135 mmol/L

  • Very common problem; prevalence: ~50% of individuals have serum < 135 mmol/L, ~22% < 130 mmol/L

  • Degree of hyponatremia is associated with progression of cirrhosis; patients with hypona have greater incidence of HE, SBP, and HRS, increased complications & mortality pre/post-tx.

  • Patients most commonly have hypervolemic (dilutional) hypona.

  • Pathophysiology

    • Hypovolemic hyponatremia: 2/2 excessive diuretic use
    • Hypervolemic hyponatremia: Advanced cirrhosis -> chronic inflammation and fibrosis in liver -> increased resistance to portal flow -> portal hypertension -> release of vasoactive compounds (primarily nitric oxide) -> splanchnic arterial vasodilation -> reduced effective

Evaluation

  • Uosm, Sosm, UNa to rule out competing processes (e.g. beer potomania)

Management

  • Do not correct Na faster than 6-8mEq/L in 24 hours

  • Discontinue anti-hypertensives (including beta blockers) in patients with ascites and hypona.

  • Hold diuretics when Na <125

  • Fluid restriction is recommended only in patients with Na <125. Restriction is generally effective at 1-1.5L and must be less than daily UOP to increase free water excretion

  • Replete K to 4.0

  • 25% albumin infusion (1g/kg split into BID dosing), has been shown to increase serum Na and have higher rates of hypona resolution at 30 days

  • Treatment considerations include vasopressors, urea tabs

  • Vaptans are generally not used in clinical practice given recent RCTs showing harm with use

  • Salt tabs should not be used to raise serum Na due to worsening hypervolemia

  • Nephrology should be consulted if not improved after 48 hours