overview-sodium and water homeostasis

General (NEJM 2015;372:55 & 373:1350)

• Disorders of serum sodium are generally due
  • to Δs in total body water, not sodium
• Hyper- or hypo-osmolality
  • → rapid water shifts →
  • Δs in brain cell volume →
  • Δ MS, seizures

Key hormones

• Antidiuretic hormone (ADH)
• Aldosterone