Hypercalcemia

Definition
  • Hypercalcemia is excessive levels of blood calcium. Mild hypercalcemia is usually asymptomatic while severe hypercalcemia leads to a characteristic clinical syndrome.
Pathophysiology
  • Overview
    • The symptoms associated with the clinical syndrome of hypercalcemia are primarily due to defects in conduction of electrical signals or physical deposition of calcium.
  • Electrical Dysregulation
    • Recall that entry of calcium into neurons and myocytes occurs during conduction of action potentials. Therefore, any organ whose regulation is dependent on electrical conduction may become dysregulated (which includes the CNS , cardiac electrophysiology, and GI Motility).
  • Physical Deposition:
    • Increased concentration of calcium may result in precipitation of calcium salts. This usually manifests int he kidneys as nephrolithiasis
Clinical Syndrome
  • Mild Hypercalcemia: Usually asymptomatic and picked up during routine blood chemistries.
  • Severe Hypercalcemia:
    • CNS: Lethargy, stupor, and coma
    • Heart: bradycardia or arrhythmias
    • GI System: Constipation
    • Kidney:
      • Renal and Urinary Tract Stones: Especially calculi of the calcium subtype.
      • Nephrocalcinosis: Diffuse deposition of calcium in the renal parenchyma.
      • Polyuria: Elevated calcium levels reduce the Kidney's urine concentrating ability.
Common Etiologies