Fluids, Electrolytes & Nutrition: Phosphate (PO4)

Hyperphosphatemia

Causes

  • Renal Failure – Most Common
  • Tumor Lysis Syndrome
  • Rhabdomyolysis
  • Hypoparathyroidism
  • Bisphosphonates
  • Lactic Acidosis with Acute Extracellular Shift of Phosphate
  • Exogenous Administration

Presentation

  • Most are Asymptomatic
  • Tetany
  • Soft-Tissue Calcifications

Treatment

  • Primary Treatment: Low Phosphate Diet & Phosphate Binders
    • Phosphate Binders: Calcium Carbonate or Sevelamer (Renagel)
  • If Acute & Severe: Normal Saline Infusion
    • May Require Hemodialysis

Hypophosphatemia

Causes

  • Refeeding Syndrome
  • Liver Resection (Depletion for Hepatocyte Regeneration)
  • Hyperparathyroidism
  • Acute Respiratory Alkalosis & Hyperventilation
  • Malnutrition with Poor Oral Intake
  • Medications (Antacids)
  • Chronic Diarrhea
  • Urinary Phosphate-Wasting Syndromes (Fanconi Syndrome, etc.)
  • Renal Replacement Therapy

Presentation

  • Impaired Renal Reabsorption of Calcium & Magnesium (Can Be Dramatic but with an Unknown Mechanism)
  • Decreased Intracellular ATP Levels Causing Failure of Energy-Dependent Functions
    • Metabolic Encephalopathy
    • Myocardial Contractility Impairment
    • Diaphragm Weakness – May Cause Failure to Wean from Ventilator
    • Myopathy
    • Ileus

Treatment