Can sepsis cause hypocalcemia (low calcium levels)?

Sepsis and Hypocalcemia: A Common and Significant Relationship

Yes, sepsis commonly causes hypocalcemia, which is associated with increased mortality and should be monitored and treated promptly when ionized calcium levels fall below 0.9 mmol/L. 1, 2

Prevalence and Significance of Hypocalcemia in Sepsis

• Hypocalcemia is extremely common in critically ill patients, occurring in up to 70-88% of ICU patients 3, 4
• Sepsis specifically is strongly associated with hypocalcemia 4
• Mortality rates are significantly higher in hypocalcemic septic patients (50%) compared to normocalcemic septic patients (29%) 5
• Hypocalcemia severity correlates with disease severity as measured by APACHE II scores 3

Pathophysiology of Sepsis-Induced Hypocalcemia

Sepsis causes hypocalcemia through multiple mechanisms:

• Elevated calcitonin precursors that correlate with severity of infection 2
• Acquired parathyroid gland insufficiency 5
• Renal 1-alpha-hydroxylase insufficiency 5
• Vitamin D deficiency 5
• Acquired calcitriol resistance 5
• Hypoalbuminemia (affects total calcium but not ionized calcium) 4

Monitoring Recommendations

• Monitor ionized calcium levels in all septic patients as part of standard care 6
• Normal range for ionized calcium is 1.1-1.3 mmol/L 6
• Ionized calcium levels are pH-dependent (0.1 unit increase in pH decreases ionized calcium by approximately 0.05 mmol/L) 6
• Include calcium monitoring as part of routine blood gas analysis in septic patients 6

Treatment Recommendations

• Administer calcium chloride to correct hypocalcemia when ionized calcium levels fall below 0.9 mmol/L or when symptoms are present 6, 7
• Calcium chloride is preferred over calcium gluconate:
  • 10 mL of 10% calcium chloride contains 270 mg of elemental calcium
  • 10 mL of 10% calcium gluconate contains only 90 mg of elemental calcium 6, 7
• Calcium chloride is particularly preferable in patients with liver dysfunction (common in sepsis) due to impaired citrate metabolism 6
• Ionized calcium levels below 0.8 mmol/L are associated with cardiac dysrhythmias and require urgent correction 6

Important Clinical Considerations

• Low calcium concentrations impair:

  • Coagulation cascade (calcium is a cofactor for factors II, VII, IX, X, proteins C and S) 6
  • Platelet function (adhesion, activation, aggregation) 6
  • Cardiac contractility 6
  • Systemic vascular resistance 6

• Hypocalcemia within the first 24 hours of critical illness can predict mortality and need for multiple transfusions 6

Caution in Treatment

• Recent evidence suggests treating moderate or mild hypocalcemia in sepsis may potentially lead to higher mortality and organ dysfunction 1
• Focus treatment on severe hypocalcemia (ionized calcium <0.8 mmol/L) or symptomatic patients 7, 1
• Monitor for overcorrection to avoid iatrogenic hypercalcemia 7

Hypocalcemia in sepsis represents a significant metabolic derangement that correlates with disease severity and outcomes. Prompt recognition and appropriate treatment of clinically significant hypocalcemia are essential components of sepsis management.