The normal level of calcium is 9-11mg/dl. It is necessary for bone strength, nerve conduction, muscle contraction, maintenance of heart rate and rhythm and blood clotting. Hypocalcemia refers to the condition where calcium levels fall below 9 mg/dl. Hypocalcemia can vary from just a biochemical abnormality producing no symptoms to severe, life-threatening situations. The symptoms depend on the levels of calcium, duration of Hypocalcemia, and speed with which it developed.
Hypocalcemia can be caused by increased loss of calcium from the body and decreased entry of calcium into the circulation.
1. Increased loss of calcium
a. increased phosphate levels: when phosphate is expelled from the body, calcium travel with it in conditions such as :
i. renal failure
ii. muscle destruction
iii. tumor lysis
iv. phosphate administration
b. acute pancreatitis
c. wide-spread bone metastasis in prostate and breast cancer
2. Decreased entry of calcium into the circulation
b. Magnesium deficiency
c. Severe hypermagnesemia
d. Vitamin D deficiency
3. Other causes
Hypoparathyroidism is the most common cause. Acute pancreatitis causes calcium to deposit in the abdomen as soap.
Signs and Symptoms
Chronic and moderate Hypocalcemia can be asymptomatic. Acute severe Hypocalcemia can affect multiple systems such as:
· CNS effects:
o parasthesias or numbness of the fingertips
o twitching of the muscles of the face and eyes
o muscle cramps
o severe prolonged contraction of the respiratory muscles, causing stridor and even cyanosis
o memory loss, confusion, depression and dementia
o extra pyramidal signs
· Cardiovascular system
o Ekg changes
o Low blood pressure
o Congestive heart failure
· Autonomic nervous system
o Smooth muscle spasm leading to biliary colic and bronchospasm
o Dry skin
o Hyper pigmentation
o Steatorrhea or frothy stools
- History: including that of surgery, renal insufficiency, and acute pancreatitis
- Physical examination
- Serum calcium levels- less than 8.2 mEq/L
- 25 OH Vitamin D levels
Acute symptoms are seen when the level is below 7 mEq/L and IV calcium is recommended in a hospital setting. One hundred to 200 mg of elemental calcium is recommended in 10-20 minutes. Faster administration can cause cardiac problems, including cardiac arrest. Co-existing hypomagnesemia should also be corrected. Two milligrams of magnesium sulfate in 10-15 minutes is recommended. Acute hypophosphatemia may also have to be addressed.
Chronic Hypocalcemia can be corrected by oral calcium and vitamin D supplements.
Calcium carbonate 650mg
Calcium gluconate 1000mg
Calcium citrate 950mg
Calcium lactate 300mg
Normal daily dietary requirements of calcium is 1500mg. Sources rich in calcium are milk, milk products- such as cheese and yogurt, sardines, salmon, spinach, tofu, turnip, kale and Chinese cabbage.