Ann. Pak. Inst. Med. Sci. 2010; 6(1): 44-49

Objective: To determine the relative frequency of occurrence of hypocalcemia in various disorders.
Study Design: It is across-sectional/ descriptive study.
Settings and Duration:The study was carried out at Armed Forces Institute of Pathology, Rawalpindi from April 1999 – April 2000.
Materials and Methods: In this study one hundred patients with hypocalcemia (Serum Total Calcium < 2.10 mmol/L) were selected irrespective of the age and sex. The history and physical examination was carried out for each patient.
The blood specimen was analyzed for serum calcium, phosphate, albumin, alkaline phosphate, magnesium, urea, creatinine, electrolytes, PTH, and blood bicarbonate according to the requirement to find the etiology.
Results: The chronic renal failure was found in 49%, rickets in 21%, hypopara-thyroidism in 8%, infections in 7%, acid-base disorders 3%, maliganancies 4%, miscellaneous diseases 5%, unknown in 3%.
Conclusion: Chronic renal failure and rickets are most frequently associated with hypocalcemia in our clinical setup. Hypocalcemia is also associated with other disorders like infectious diseases, acid-base disorders, maliganancies, and miscellaneous diseases which include acute pancreatitis, magnesium deficiency, aplastic anaemia, diabetes mellitus and hypertension. The lowest calcium levels were found in hypo-parathyroidism and there was significant difference in means of the calcium levels in various disorders causing hypocalcemia i.e 0.001, as analysed by the application of statistical test ANOVA.
Keywords: Hypocalcaemia, Chronic renal failure, Rickets.

Introduction


Hypocalcemia is a common condition in our country because of low socio-economic status, nutritional insufficiency, malabsorption, multiple pregnancies and vitamin D deficiency.¹ It has been found that the prevalence of hypocalcemia is about 18% in all patients in a hospital and 82%in intensive care units.² A wide range of disorders leads to hypoclcemia in addition to those mentioned above. These include chronic renal failure, hypo-protenemia, panceatitis, nephrotic syndrome. Hormonal imbalance like diabetes mellitus³, hypoparathyroidism4 hyper and hypothyroidism, Cushings disease, Addisons disease, deficiency of growth hormone,⁵ androgens, and also of oestrogen in post menpausal women. Drugs like bisphosphonates6, alcohol may lead to hypocalcemia. In addition to these increased demands as in lactation⁷ may also cause hypocalcemia. Calcium level is also influenced by concentrations of minerals specially phosphate and magnesium.⁸
The blood calcium is maintained by the action of parathyroid hormone and vitamin D on the kidneys, bones and gastrointestinal tract. Parathyroid hormone stimulates calcium resorption in the kidney and calcium release from bone. It also stimulates renal production of 1, 25-dihydroxyvitamin D (calcitriol) from 25-hydroxyvitamin D. 1, 25-Dihydroxyvitamin D is the most active form of vitamin D, and it acts on the gastrointestinal tract to increase calcium absorption. Vitamin D is obtained mainly through synthesis in the skin, with a small contribution from the diet. Skin synthesis requires exposure to ultraviolet light and is reduced by skin pigmentation.

Calcium is essential for wide range of metabolic processes, however most of it about 99% reside in skeleton which serves as it’s dynamic reservoir whereas remaining 1% exist in the extra cellular tissue. In plasma it is found in free form about 50%, bound to plasma proteins 40% and complexed form 10%. It is important for the coagulation, neuromuscular transmission, hormone secretion, cell division such as coagulation, neuromuscular transmission, hormone secretion and cell division. Recently it has been found to be critical for apoptosis, chemotaxis, gene expression, water and mineral balance etc.⁹ So hypocalcemia may lead to serious complications such as seizure, tetany, ventricular arrhythmias¹⁰, laryngospasm . Frequent clinical findings of hypocalcaemia include muscle cramps, parenthesia, tingling sensations in hands and feet, chronic diarrhoea abdominal pain ,bone pain ,fractures, dry skin, patchy hair ,transverse ridging of the nails and enamel, weight loss and alopecia.²

The frequency of occurrence of hypocalcemia in different disorders varies in different parts of the world. Only a few studies have been found regarding the frequency of various causes of hypocalcaemia in general population¹⁰ Therefore, a study was designed to determine the frequency of various diseases causing hypocalcemia.