- 1 What is Hypocalcemia?
- 2 Hypocalcemia Pathophysiology
- 3 Hypocalcemia Causes
- 3.1 Decreased Level of Calcium in the Circulation
- 3.2 Elevated Loss of Circulating Calcium
- 3.3 Other Causes
- 4 Hypocalcemia Symptoms
- 5 Hypocalcemia Diagnosis
- 6 Hypocalcemia Treatment
- 7 Hypocalcemia Prevention
- 8 Points to Consider
What is Hypocalcemia?
Hypocalcemia is a condition of electrolyte imbalance wherein there is decreased level of serum calcium . In this state, the calcium in the blood falls below 8.5 mg/dl. The normal serum calcium is 8.5 to 10.5 mg/dl . Deficiency in calcium may lead to interference to the normal functioning of the body, particularly the muscle and nerve cells .
Calcium is considered to be one of the electrolytes with the most number in the body. Its levels are highly regulated by vitamin D and the parathyroid hormone .The extracellular calcium-sensitive receptors, also known as CaSRs, are known to play a vital role in the calcium homeostasis. These receptors allow the regulation of calcium by the parathyroid gland and other tissues . Also, calcium levels are influenced by hormones, such as calcitonin, and other electrolytes, such as phosphorus and magnesium .
It is a common knowledge that most calcium (almost 99%) is deposited in the bones and teeth. The remaining calcium (1%) is left circulating in the blood . About 40% of the calcium in the blood is attached to albumin, whereas the 15% is bound to phosphates, sulphates, citrate, and lactate. The remaining 45% circulates in the body in its biological active form or ionized form . When the level of this ionised calcium falls below its normal level, hypocalcemia occurs .
Calcium is responsible for various functions such as:
- Bone growth and strength
- Muscle contraction
- Cell function
- Stability of cell membranes
- Blood homeostasis [1, 5]
Decreased Level of Calcium in the Circulation
This ranks as number one in the leading cause of hypocalcemia. This is associated with the following conditions:
- Post-operative state: Hypocalcemia usually occurs in patients who have undergone total thyroidectomy as well as in radical resection in patients with neck and head cancers. Hypocalcemia also results from blood transfusion and fluid administration post-surgery.
- Autoimmune and Congenital Hypoparathyroidism: In this condition, patients’ antibodies act against the calcium-sensing receptoprs.
- Pseudoparathyroidism: A medical disorder wherein the receptors have resistance to parathyroid hormone leading to hypocalcemia.
2. Vitamin D Deficiency
- Poor vitamin D in the dietary intake
3. Related Electrolyte Imbalances
- Hypophosphatemia 
Elevated Loss of Circulating Calcium
This condition causes hypocalcemia when there is an increased level of phosphate intracellularly. This leads to the release of calcium deposited in the bone and extraskeletal tissues. It is common in:
- Tumor lysis syndrome
- Renal failure
- Phosphate administration
2. Acute pancreatitis
- Causes precipitation of calcium in the abdomen
3. Hungry bone syndrome
- This is a condition wherein the serum calcium is immediately deposited into the bones.
- Occurs after hyperparathyroidism surgery
4. Severe osteoblastic metastases
- Breast Cancer
- Prostate Cancer
Chelation leads to decrease in the level of ionized calcium which results in hypocalcemia. This is caused by medications such as:
- Citrate: administered in the blood transfused
- EDTA 
- Results to hypomagnesemia and hypocalcemia
- Leucovorin, cisplatin, 5-fluorouracil
- Hypocalcemia, associated to hypoalbuminemia, usually occurs in patients with sepsis.
3. Certain beverages
Some chemicals contained in several beverages can lead to pulling out of calcium deposited in the bones. The beverages which can cause hypocalcemia are:
- Chemicals found in softdrinks
- Alcoholic beverages
- Excessive caffeine in drinks [4, 6]
1. Neuromuscular symptoms
- Paresthesia: Tingling and numbness can be felt around the lips, or in the toes and fingers
- Muscle problems: cramps (lower and upper extremities), spasms, myalgias
- Wheezing due to bronchospasm
- Voice changes caused by laryngospasm
- Carpopedal spasm: This is characterized by flexion of the wrist with the fingers drawn together.
- Trousseau’s sign
- Chvostek’s sign [3, 6, 7]
2. Neurologic/Neuropsychiatric symptoms
- Emotional problems: depression, anxiety, irritability
- Impairment in intellectual thinking
- Personality changes
- Fatigue [6, 7]
3. Cardiovascular Symptoms
- Decreased blood pressure (hypotension)
- Prolonged QT interval
- Congestive Heart Failure 
4. Other symptoms
- Dermatologic problems: dry and coarse skin, eczema, hyperpigmentation
- Steatorrhea: Presence of excess lipid or fats in the stool 
1. Neuropsychiatric Symptoms
- Dementia in adult patients
- Mental retardation for children
- Parkinsonism (extrapyramidal symptoms)
- Presence of calcifications in the basal ganglia
- Papilledema [3, 6, 7]
2. Dermatologic problems
- Chronic pruritus
- Dry skin, brittle nails, and coarse hair
- Psoriasis 
3. Other chronic symptoms:
- Poor dental health 
This is done to determine the cause of hypocalcemia in patients. Certain questions may be asked by the doctor to know about the symptoms experienced. 
The assessment for the presence of possible symptoms is done, particularly with:
1. Chvostek’s sign
This is also known as Weiss’ sign, facialis phenomenon, and Schultze-Chvostek sign. It manifests as an effect of tetany in hypocalcemic patients. In anxious patients with normal calcium levels, this may also be present. To assess for its presence, the following are done:
- The medical examiner will tap the patient’s cheek, particularly the location of the facial nerve. In patients with hypocalcemia, muscular spasm is observed on the front of the ear, just below the zygomatic arch. This can be easily assessed in the form of twitching of the nose, mouth, or face. 
2. Trousseau’s sign
This occurs as a result of increased excitability of the neuromuscular system of the body. This can be examined by:
- Using a blood pressure cuff, it is wrapped around the patient’s arm, and inflated. The inflation of the BP cuff will be above the systolic level of the patient. Then, this is maintained for several minutes.
- As a result of this test, patients with hypocalcemia will experience carpopedal spasm. This is observed as the flexion of the wrist and coming together (adduction) of the fingers.
- In some patients, paresthesia may be also felt at the fingers. 
Picture 2: A. Chvostek’s Sign B. Trousseau’s Sign
1. Checking for serum electrolyte levels
2. Hormone levels
- Serum parathyroid hormone
3. Evaluation of Vitamin D levels
- The metabolism of Vitamin D will be checked as well to see if there is a deficiency.
- This is performed to detect dysrrhythmias (prolongation of QT interval) 
Picture 3: ECG of a patient with hypocalcemia shows prolonged QT interval
1. Calcium Supplementation
- Intravenous supplementation of calcium: Calcium Gluconate 10% given through slow IV push
- Oral calcium supplementation 
2. Treatment of underlying cause
- If caused by hypomagnesemia, normalize the level of magnesium to resolve the presence of hypocalcemia.
- If vitamin D deficiency is the culprit, giving of vitamin D supplements orally is advised. 
3. Continuous monitoring and treatment of symptoms
- Assessment and treatment of symptoms such as tetany and seizures are necessary to prevent high-risk complications.
- Frequent checking of the serum calcium level throughout the duration of treatment. 
Physical Therapy Management
- Detection and assessment for the presence of hypocalcemia signs and symptoms.
- Management of the present manifestations.
- Doing appropriate referral of these conditions as needed. 
1. Diet modification
Diet high in calcium is advised to replace the deficient level of serum calcium in the body.Foods rich in calcium are:
- Green leafy vegetables such as spinach
- Dairy products
- Dried herbs: rosemary, poppy seed, oregano
- Herrings [4, 7]
- Incorporate in the diet adequate foods rich in calcium
- Calcium supplements may be taken as well
- To prevent hypocalcemia in patients scheduled for parathyroidectomy, they may be given calcium supplements several days prior to their surgery.
- In patients who are undergoing total parenteral nutrition, checking of calcium and magnesium serum levels are a must. 
Points to Consider
Hypocalcemia is a very preventable disorder. There are various ways to prevent the serious effects and possible complications of this electrolyte imbalance. The easiest way is to ensure adequate calcium in the daily dietary intake. Also, to enhance calcium absorption in the body, vitamin D supplements are also advised to be taken.