What are the symptoms and treatment of hypocalcemia?

Symptoms and Treatment of Hypocalcemia

Hypocalcemia requires prompt recognition and treatment as it can lead to serious complications including seizures, cardiac arrhythmias, and rarely cardiomyopathy. 1

Clinical Manifestations

Neuromuscular Symptoms

• Perioral numbness and paresthesias of hands and feet 1, 2
• Carpopedal spasms and muscle cramps 1, 2
• Neuromuscular irritability and tetany 3
• Seizures and convulsions (may be resistant to anticonvulsants) 1, 4
• Laryngospasm (can be life-threatening) 2

Cardiovascular Manifestations

• Prolonged QT interval on ECG 1, 5
• Decreased cardiac contractility (when ionized calcium <1.0 mmol/L) 1
• Reduced systemic vascular resistance 1
• Cardiac arrhythmias 1, 5

Other Symptoms

• Fatigue and irritability 5
• Abnormal involuntary movements 5
• Cognitive symptoms (confusion, memory impairment) 1

Diagnosis

Laboratory Tests

• Ionized calcium (more accurate than total calcium) 1
• Albumin-corrected total calcium 1
• Parathyroid hormone (PTH) level (essential for determining cause) 1
• Magnesium level (hypomagnesemia can cause or worsen hypocalcemia) 1
• Phosphorus level 1
• 25-hydroxyvitamin D 1
• Renal function tests 1

Treatment

Acute Symptomatic Hypocalcemia

1. Intravenous calcium gluconate is the treatment of choice for acute, symptomatic hypocalcemia 1, 2

   • Administer 100-200 mg of elemental calcium 2
   • Infusion rate should not exceed 200 mg/minute in adults 1
   • Monitor ECG during administration, especially in patients on cardiac glycosides 6

2. Magnesium replacement

   • If hypomagnesemia is present, correct magnesium first as calcium replacement may be ineffective otherwise 1, 2

Chronic Hypocalcemia Management

1. Oral calcium supplementation

   • Elemental calcium 1-2 g/day divided into multiple doses 1
   • Common formulations: calcium carbonate and calcium citrate 1

2. Vitamin D supplementation

   • Daily vitamin D supplementation recommended for all patients 5
   • Hormonally active vitamin D metabolites (e.g., calcitriol) for more severe/refractory cases 5, 7

3. Target calcium levels

   • Maintain calcium within 8.4-9.5 mg/dL, preferably toward the lower end 1
   • Avoid overcorrection which can lead to hypercalcemia, renal calculi, and renal failure 5

4. Special considerations

   • For patients with renal impairment: start at lowest dose range and monitor calcium levels every 4 hours 6
   • For patients with hypoparathyroidism: recombinant human PTH(1-84) may be considered for those who cannot maintain stable calcium levels with conventional therapy 7

Monitoring and Follow-up

• Regular monitoring of calcium, parathyroid hormone, magnesium, and renal function 5, 1
• Increased monitoring during periods of biological stress (surgery, fracture, infection, childbirth) 5
• Monitor for signs of overcorrection (hypercalcemia) 5

Special Considerations

• Avoid calcium administration with ceftriaxone in neonates due to risk of fatal calcium-ceftriaxone precipitates 6
• Caution when administering calcium to patients on cardiac glycosides due to risk of arrhythmias 6
• Calcium may reduce response to calcium channel blockers 6
• Hypocalcemia may be worsened by alcohol or cola drinks 5
• Long-term hypocalcemia increases risk of osteopenia/osteoporosis 5

Pitfalls to Avoid

• Failing to check magnesium levels (hypomagnesemia can cause refractory hypocalcemia)
• Treating seizures due to hypocalcemia with anticonvulsants alone (may be ineffective and can worsen hypocalcemia) 4
• Overcorrection leading to iatrogenic hypercalcemia 5
• Missing hypocalcemia during biological stress periods when risk increases 5