Hyperphosphataemia

• Consequences:

  • Cardiovascular disease (secondary to vascular calcification)
  • Decreased bone mineral density
  • Associated with increased mortality in those with CKD
• Normal range:

  0.8-1.5 mmol/L
• Symptoms:

  • Most patients will be asymptomatic
  • Severe:
  • Altered mental status
  • Muscle weakness
  • Muscle pain
  • Seizures
• Causes:

  • Renal impairment - CKD is most common cause
  • Acute phosphate load - rhabdomyolysis, tumour lysis syndrome, exogenous phosphate containing laxatives
  • Excessive phosphate resorption: hypoparathyroidism, drugs i.e. bisphosphonates
• Management:

  • Acute hyperphosphatemia will usually self resolve is renal function is normal
  • IV saline can be used to accelerate phosphate excretion
  • Severe cases often associated with significant hypocalcaemia - may need urgent renal replacement therapy
• In chronic hyperphosphatemia (e.g. due to CKD), treatment is focused on decreasing phosphate intake (dietary modification) and absorption (phosphate-binding medications).