What are the signs and treatment of hypocalcemia (low calcium levels in the blood)?

Signs and Treatment of Hypocalcemia

Hypocalcemia can manifest with various symptoms ranging from mild paresthesia to life-threatening tetany and seizures, requiring prompt identification and treatment with calcium supplementation and vitamin D therapy. 1

Clinical Manifestations of Hypocalcemia

Neuromuscular Signs and Symptoms

• Paresthesia (tingling sensation around mouth, hands, and feet)
• Neuromuscular irritability
• Tetany (severe muscle spasms affecting hands and feet)
• Muscle cramps
• Abnormal involuntary movements
• Chvostek's sign (facial muscle spasm when tapping facial nerve)
• Trousseau's sign (carpal spasm when blood pressure cuff inflated)

Severe Manifestations

• Seizures
• Laryngospasm
• Bronchospasm
• Stridor
• Tetany

Cardiovascular Signs

• Prolongation of QT interval on ECG
• Cardiac arrhythmias
• Cardiomyopathy (rare)
• Hypotension
• Bradycardia

Other Symptoms

• Fatigue
• Irritability
• Lower bone mineral density (long-term)
• Risk for osteopenia/osteoporosis (long-term)

Treatment Algorithm for Hypocalcemia

Acute Symptomatic Hypocalcemia (Emergency)

1. Intravenous calcium administration:

   • Calcium chloride 10% injection for severe, symptomatic hypocalcemia requiring prompt increase in plasma calcium 2
   • Calcium gluconate IV for less urgent situations
   • Typical dose: 100-200 mg of elemental calcium 3

2. Monitor ECG during administration, especially in patients on cardiac glycosides 4

Chronic Hypocalcemia Management

1. Oral calcium supplementation:

   • Calcium salts such as calcium carbonate 1
   • Total elemental calcium intake should not exceed 2,000 mg/day 1

2. Vitamin D therapy:

   • Daily vitamin D supplementation for all patients 1
   • For more severe/refractory cases, hormonally active vitamin D metabolites (calcitriol) with endocrinologist consultation 1

3. Regular monitoring:

   • Calcium, parathyroid hormone, magnesium, thyroid-stimulating hormone, and creatinine concentrations 1
   • Targeted calcium monitoring during vulnerable periods (peri-operative, perinatally, pregnancy, acute illness) 1

4. Special considerations:

   • For patients with renal impairment, start at lowest dose and monitor serum calcium levels every 4 hours 4
   • Caution with overcorrection which can result in hypercalcemia, renal calculi, and renal failure 1

Important Caveats and Pitfalls

1. Underlying causes: Identify and address the underlying cause of hypocalcemia (hypoparathyroidism, vitamin D deficiency, chronic kidney disease, etc.)

2. Associated conditions: Check for hypomagnesemia and hypothyroidism, which may be contributory conditions 1

3. Exacerbating factors: Hypocalcemia may be worsened by:

   • Alcohol or soda drinks, especially colas 1
   • Biological stress (surgery, fracture, injury, childbirth, infection) 1

4. Drug interactions:

   • Avoid simultaneous administration with cardiac glycosides as synergistic arrhythmias may occur 4
   • Calcium may reduce response to calcium channel blockers 4

5. Special populations:

   • In pregnancy, maternal hypocalcemia can result in increased spontaneous abortion, premature labor, and preeclampsia 4
   • In pediatric patients, carefully monitor for signs of hypocalcemia or hypercalcemia 4

By promptly recognizing the signs of hypocalcemia and implementing appropriate treatment, serious complications can be prevented and patient outcomes improved.