15- HYPOCALCEMIA

• Hypocalcemia

  • Serum calcium concentration < 2.2
  • Severe if <1.9 or symptomatic
• Causes of hypocalcemia

  • Hypoparathyroidism (surgical, irradiation, autoimmune, infiltration, hypomagnesemia)
  • Drugs: antiepileptics, calcitonin, bisphosphonates
  • Acute pancreatitis, acute rhabdomyolysis
  • Pseudohypoparathyroidism
  • Malabsorption, post-surgery
  • Liver/renal impairment (cirrhosis, nephrotic syndrome, CKD)
  • 2° hyperparathyroidism
  • Osteoblastic metastasis (prostate cancer)
• Presentation of hypocalcemia

  • Convulsions/seizures
  • Arrythmias
  • Tetany
  • Stridor & spasms
  • Paresthesia, fatigue, anxiety, hoarseness (due to laryngospasm), wheezing and dyspnea (due to bronchospasm), muscle cramps
• Chvostek sign


  • Facial twitching, especially around the mouth, is induced by gently tapping the ipsilateral facial nerve as it courses just anterior to the ear
• Trousseau sign


  • Carpal spasm is induced by inflating a blood pressure cuff around the arm to a pressure 20 mm Hg above obliteration of the radial pulse for 3-5 minutes
• Investigations for hypocalcemia

  • RFT, calcium (total and ionized calcium), serum albumin, Ph, & Mg
  • Urinary calcium excretion, urinary cAMP
  • 25-hydroxyvitamin D levels and serum PTH levels
  • ECG: long Qt interval
• Treatment for hypocalcemia

  1. IV calcium gluconate 10 ml 10% diluted in 100 mL of 5% dextrose in water (D5W) given over 10 minutes à can be repeated until calcium corrected

  2. Can be given as infusion over 6 hours after 1st dose until Ca reaches a safe level ex: 2.1. Recheck calcium levels every 2 hours

  3. Chronic treatment according to underlying cause (vit D supplements, vit D analogues, Ca supplements, Mg supplements)