List 6 diagnoses on the differential for hypocalcemia.
Hypocalcemia with low PTH (hypoparathyroidism):
- Surgical/Autoimmune destruction of the parathyroid glands
- Abnormal parathyroid gland development
- Altered regulation of PTH
Hypocalcemia with high PTH:
- PTH resistance (impaired PTH action)
- Vitamin D deficiency/resistance
- Extravascular deposition
- Hyperphosphatemia
- Osteoblastic metastases
- Acute pancreatitis
- Sepsis or severe illness
Disorders of magnesium metabolism:
- Drugs:
- Calcium chelators
- Bisphosphonates
- Cinacalcet
- Chemotherapy
- Foscarnet
- Fluoride poisoning
What are two clinical findings in the patient with hypocalcemia?
- Trousseau’s sign
- Chvostek’s sign: twitching facial muscles when the facial nerve is tapped on
How do you treat severe hypocalcemia (corrected calcium <1.85, or calcium between 1.85-2 mmol/L with symptoms/signs)?
- 1 vial calcium gluconate (1 g of calcium/10 mL vial) in 50 mL of D5W over 5 minutes iv
- then give 1 mg/kg/ml iv for 5-10 hours, checking serum calcium levels in 6 hours
- eventually switch to oral calcium carbonate 1250 mg bid (=500 mg of elemental calcium) tid +/- rocaltriol 0.25 mcg od-bid
