Short Explanatory Video
Calcium has a very important role in our body, from contractions of the heart and muscles to providing support and strength to our skeleton, it is vital for our body to function. Thus, we should be aware of the symptoms of low calcium.
Symptoms of low calcium can involve benign abnormalities and strange sensations within the body systems, as well as more serious symptoms that may be indicative of life-threatening diseases.
What is hypocalcemia?
Hypocalcemia, also commonly referred to as calcium deficiency, low serum calcium, or low blood calcium, is an electrolyte abnormality characterised by below-normal calcium levels in the blood.
This condition can be attributed to kidney disease, vitamin D deficiency, low dietary calcium intake, pancreatitis, and a special condition known as hypoparathyroidism.1
What causes hypocalcemia?
- Kidney Disease
One of the kidney's functions is converting vitamin D into an active form that the body needs for intestinal absorption of dietary calcium. In kidney disease, the kidney cannot perform this function properly, resulting in poor absorption of dietary calcium and hypocalcemia.2, 3
- Vitamin D Deficiency
Similarly, low dietary intake of vitamin D or reduced exposure to sunshine results in low vitamin D levels that can lead to reduced calcium absorption from the gut and cause calcium deficiency.2
- Low Dietary Calcium Intake
Low dietary intake of calcium-rich products, such as milk, also leads to calcium deficiency and low serum calcium levels.2
In hypoparathyroidism, the body has low levels of a hormone known as the parathyroid hormone or parathormone. This hormone mediates vitamin D-dependent calcium absorption within the intestines and decreases the urinary removal of calcium from the body to help keep blood calcium levels in a normal range. With hypoparathyroidism, the body loses a lot of calcium and cannot maintain normal calcium levels, thus resulting in calcium deficiency.
Hypoparathyroidism results from congenital abnormalities, injuries to the parathyroid gland, and dysfunction of the parathyroid gland that produces the parathyroid hormone.1, 2
In pancreatitis, the inflamed pancreas draws calcium from general blood circulation. This leads to low blood calcium.3
Risk factors for hypocalcemia
Risk factors for damage to the parathyroid gland, and by extension hypoparathyroidism, include surgeries or radiation therapy around the neck region where the parathyroid glands are located, and personal or family history of autoimmune diseases.3
A risk factor for parathyroid gland dysfunction is hypomagnesemia (and rarely, hypermagnesemia). The imbalance of blood magnesium levels interferes with the ability of the parathyroid gland to produce the parathyroid hormone. Hypomagnesemia is common in individuals who suffer from chronic alcoholism and malnourishment.4
Heavy alcohol use, obesity, cigarette smoking, diabetes, and a family history of pancreatitis are the risk factors for pancreatitis and hypocalcemia resulting from pancreatitis.5 Individuals with high blood pressure, diabetes, or are obese are also at risk of kidney disease and hypocalcemia.3
Symptoms of hypocalcemia
Calcium is important for the formation of strong and healthy bones. Ionised calcium is also vital for nerve conduction and muscle contraction. Symptoms of hypocalcemia include:
- Muscle cramps or aches
- Muscle spasms
- Numbness around the mouth
- Fragile bones
Calcium deficiency can also cause more life-threatening conditions, such as seizures, irregular heartbeats, cardiac arrests, heart failure, coma, and airway obstruction.1, 3
Diagnosis of hypocalcemia
Calcium deficiency can be diagnosed with blood tests that measure blood calcium and other serum electrolyte levels, such as magnesium.
According to Medscape, serum calcium levels below 8.5 mg/dL or ionised calcium lower than 1.0 mmol/L can be considered hypocalcemia. Doctors may also request an electrocardiogram and perform physical examinations to elicit signs of calcium deficiency. The doctor may gently tap your cheeks to check for facial twitching, a symptom that typically occurs in people with low calcium levels. This facial twitching in response to the gentle tap of the cheeks is known as the Chvostek sign.6
Another physical examination involves inflating a blood pressure cuff around the arm to observe for an involuntary contraction of the muscles of the hands and wrist. When this involuntary contraction of hand and wrist muscles occur, it is known as the Trousseau sign of latent tetany.7
Other investigations will be required to uncover the cause of the hypocalcemia. These investigations include serum parathyroid hormone levels, antibody tests, serum Vitamin D levels, kidney function tests, pancreatic enzyme levels, and imaging scans of organs of interest such as the kidneys, pancreas, and parathyroid glands.1
The treatment of hypocalcemia
Treatment of calcium deficiency involves calcium replacement using calcium supplements. In patients with life-threatening or acute hypocalcemia, IV calcium gluconate is administered.1Patients with Vitamin D deficiency will also benefit from vitamin D supplementation, either in the form of ergocalciferol (Vit D2) or cholecalciferol (Vit D3).1
Hypothyroidism, secondary to hypomagnesemia, is treated with magnesium supplements, such as magnesium sulphate, magnesium carbonate, or magnesium oxide. Most cases of hypoparathyroidism due to structural damage are usually life-long and such patients will need therapy throughout their lives to prevent the signs, symptoms, and complications associated with the condition.
Patients suffering from permanent hypoparathyroidism may benefit from a new once-daily injection parathormone replacement drug called Natpara.8 Hypoparathyroidism with high urinary excretion of calcium may also be managed using a thiazide diuretic to reduce urinary calcium losses.
Managing hypocalcemia from pancreatitis will involve treating the underlying cause of pancreatitis. In cases due to chronic alcoholism, attempts to treat alcohol dependence will be made.
Calcium deficiency can be prevented in most people in the following ways:
- Consuming adequate amounts of vitamin-D fortified foods
- Consuming foods rich in calcium (e.g. yoghurt, sardines, almonds, cheese, salmon, and milk)
- Daily sun exposure to help keep vitamin D levels adequate and prevents vitamin D deficiency-related hypocalcemia
- Reduce alcohol intake
- Avoid cigarette smoking
- Adopting health habits to reduce risk of obesity
Calcium has vital functions in the human body, especially within the neuromuscular and skeletal systems. Hypocalcemia means the body lacks enough calcium to carry out its roles, resulting in symptoms, such as muscle cramps and spasms.
Adequate consumption of calcium-rich and vitamin-D fortified foods, good nutrition and exercise to prevent obesity, and avoidance of alcohol and cigarette smoking can prevent hypocalcemia in most people.
- Fong J, Khan A. Hypocalcemia. Can Fam Physician. 2012 Feb;58(2):158–62.
- Parva NR, Tadepalli S, Singh P, Qian A, Joshi R, Kandala H, et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus. 10(6):e2741.
- Rao MN, Shoback DM. Hypocalcemia. In: Feingold KR, Anawalt B, Boyce A, Chrousos G, de Herder WW, Dhatariya K, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000 [cited 2022 Mar 10]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK344077/
- Hypoparathyroidism [Internet]. NORD (National Organization for Rare Disorders). [cited 2022 Mar 14]. Available from: https://nord1dev.wpengine.com/rare-diseases/hypoparathyroidism/
- Hart PA, Conwell DL. Chronic Pancreatitis: Managing a Difficult Disease. Am J Gastroenterol. 2020 Jan;115(1):49–55.
- Omerovic S, M Das J. Chvostek Sign. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2022 Mar 10]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK542326/
- Patel M, Hu EW. Trousseau Sign. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 [cited 2022 Mar 10]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK557832/
- Kim ES, Keating GM. Recombinant Human Parathyroid Hormone (1-84): A Review in Hypoparathyroidism. Drugs. 2015 Jul;75(11):1293–303.