Hypocalcaemia

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What is Hypocalcemia?

Calcium is an essential element in our body. It plays many important roles including conduction of ions in the body. When calcium levels go down below the average levels in blood serum, it is known as Hypocalcemia. Thus, hypocalcemia is low calcium levels in the liquid part of the blood which is the fluid and solute composition of the blood. The normal range of calcium levels in a healthy individual is 2.1-2.6 mmol/L. Calcium levels below 2.1 are considered as Hypocalcemia. Mildly low levels are often harmless and asymptomatic and can be treated with medication.


Hypocalcemia primarily causes Tetany, which is spontaneous tonic muscle contractions that occur due to increased neuronal excitability taking place as a result of low extracellular fluid calcium concentration. This, in turn, reduces the threshold for excitation of the neural tissue. In brief, Hypocalcemia or hypomagnesemia (low levels of extracellular fluid magnesium) reduce the amount of depolarization necessary to induce an increase in sodium conductance and depolarize nerve cells.


Causes of Hypocalcemia

The main causes of Hypocalcemia are as follows:

  • It is mainly caused by a deficiency of vitamin D or as a result of hypoparathyroidism.

  • Due to failure of secretion of parathyroid hormones.

  • It occurs mostly due to vitamin D related disorders.

  • Mutations in the CASR gene, which is the primary cause of autosomal dominant hypocalcemia.

  • Due to dietary calcium deficiency or CMPI which is Cow’s milk protein intolerance causing an immune disorder. (CMPI is different from lactose intolerance).

  • Malabsorption of Calcium like coeliac diseases.

  • Short gut.

  • Tufting enteropathy.

  • Pancreatitis in which the pancreas is inflamed.

Symptoms of Hypocalcemia

Generally, mild low levels of Hypocalcemia are asymptomatic. But harmfully low calcium levels may show symptoms like:

  • Chvostek’s and Trousseau’s signs – latent Hypocalcemia.

  • Paresthesia around mouth, toes, and fingers.

  • Generalized tetany characterized by involuntary contraction of muscles or Carpopedal.

  • Hyperactive tendon reflexes.

  • Tingling sensation around mouth and lips and in the extremities of hands and feet.

  • Petechiae which is characterized by the appearance of red or purple small spots on the skin or conjunctiva of the eyes.

  • Neuromuscular excitability.

  • Laryngospasm, stridor, and apneas (neonates).

How to Treat Hypocalcemia

Because hypocalcemia is mostly asymptomatic, the main causes of hypocalcemia should be investigated and corrected when the symptoms gradually show up.  The decreased level of magnesium in blood should be altered by increasing the intake of magnesium-rich food. This will also prevent hypomagnesemia. Any increase in calcium will become transient without replenishing magnesium in the body.

  • Parathyroid hormone and vitamin D levels should ideally be checked before initiating treatment for hypocalcemia.

  • Emergency treatment usually is only needed in rare cases such as those with primary hypoparathyroidism, hypoparathyroidism secondary to hyperthyroid or hyper parathyroid corrective procedures and subsequent parathyroid damage, complications of pregnancy or nursing, or if phosphate-containing enema administration has taken place recently, citrate toxicity, and ethylene glycol toxicity.

  • Short-term or long-term treatment usually is needed only to treat primary hyperparathyroidism and complications of pregnancy or nursing (eclampsia).

  • Intravenous calcium gluconate can be administered.

  • In case of severe hypocalcemia, calcium chloride is given in place of calcium gluconate.

  • Maintenance doses of both calcium and vitamin-D are often suggested to prevent further decline.

FAQ (Frequently Asked Questions)

1. What is Hypocalcemia?

Ans: When calcium levels go down below the average levels in blood serum, it is known as Hypocalcemia. Thus, hypocalcemia is low calcium levels in the liquid part of the blood which is the fluid and solute composition of the blood. The normal range of calcium levels in a healthy individual is 2.1-2.6 mmol/L. Calcium levels below 2.1 are considered as Hypocalcemia. Mildly low levels are often harmless and asymptomatic and can be treated with medication.

2. How to Diagnose Hypocalcemia?

Ans: Hypocalcemia is a condition of low levels of ECF calcium. Therefore, the total serum calcium concentration of less than 2.2 mmol/L is an indication of the condition. However, low plasma protein can lower total calcium but it does not affect the ionized serum calcium. So, ionized calcium should be estimated based on albumin concentration to diagnose appropriately.

3. What are the Signs and Symptoms of Hypocalcemia?

Ans: Generally mild low levels of Hypocalcemia are asymptomatic. But harmfully low calcium levels may show symptoms like:

  • Chvostek’s and Trousseau’s signs – latent Hypocalcemia.

  • Paresthesia around mouth, toes, and fingers.

  • Generalized tetany characterized by involuntary contraction of muscles or Carpopedal.

  • Hyperactive tendon reflexes.

  • Tingling sensation around mouth and lips and in the extremities of hands and feet.

  • Petechiae which is characterized by the appearance of red or purple small spots on the skin or conjunctiva of the eyes.

  • Neuromuscular excitability.

  • Laryngospasm, stridor, and apneas (neonates).

4. What are the Risk Factors for Hypocalcemia?

Ans: Risk factors for Hypocalcemia include:

  • Chronic and acute renal failure.

  • Vitamin D deficiency.

  • Magnesium deficiency.

  • Acute pancreatitis.

  • Hypoparathyroidism and pseudohypoparathyroidism.

  • Infusion of phosphate, citrate, or calcium-free albumin.

Moreover, calcium deficiency is rarely seen in children or teens as compared to adults or people of old age.