Disorders of Sodium and Potassium Metabolism

Disorders of Sodium and Potassium Metabolism

Outline
* Review of sodium and potassium metabolism
* Paradigm for analyzing pathophysiology
* Abnormalities of potassium balance
* Abnormalities of sodium and water balance
* Example cases

Major Mediators of Sodium and Water Balance
* Angiotensin II
* Aldosterone
* Antidiuretic hormone (ADH)

Renin-Angiotensin-Aldosterone Axis

Angiotensin II
Aldosterone
Role of ADH (antidiuretic hormone)
Overview of Biochemical Homeostasis
Overview of Potassium Balance
Etiologies of Hyperkalemia
Excessive Dietary Intake
Decreased Urinary Excretion
Internal Redistribution
Etiologies of Hypokalemia
Poor Intake
Increased Urinary Excretion
Increased GI Losses
Diarrhea
Laxative abuse
Vomiting / NG drainage

Increased Transcutaneous Losses
Transmembrane Shift
Overview of Sodium Balance
Etiologies of Hyponatremia
Poor Intake of Sodium
Increased Urinary Loss of Sodium
Increased GI Loss of Sodium (Fluid loss must be followed by repletion with free water).
Increased Transcutaneous Loss of Sodium (Fluid loss must be followed by repletion with free water).
Excessive Intake of Water (1° polydipsia)
Decreased Urinary Excretion of Water
Transmembrane Shift of Water
Primary Sodium Loss
Primary Water Excess
Etiologies of Hypernatremia
Primary Sodium Excess
Excess Intake of Sodium
Decreased Urinary Excretion of Sodium
Primary Water Loss
Poor Intake of Water
Increased Urinary Loss of Water
Increased GI Loss of Water
Increased Transcutaneous Loss of Water
Transmembrane Shift of Water (most often due to rapid production of intracellular lactate)

4 Case studies

Disorders of Sodium and Potassium Metabolism.ppt