Hypocalcemia is defined as reduction in the level of the ionized calcium in the blood to less than 0.95 mmole/ litre.

In some cases it is associated with symptoms such as neuromuscular impairment in the form of convulsions ,carpopedal spasm,parathesia ,laryngiospasm ,stridor……etc .Calcium circulates in blood stream in three fractions :protein bound to calcium,primarly to albumen(40%) and in 50% of the cases calcium is present in the ionized state which is physiologically active (Dias ,c et a l, 2013) . Symptomatizing hypocalcemia may occur in cases of vitamin D deficiency rickets (nutritional deficiency in infants less than two years ) .It may also occur in vitamin D resistant rickets e.g renal rickets because of failure of the kidney to synthesize 1-OH cholecalciferol of the 1-25 di-OH cholecalciferol (the active form of vitamin D).

Hypocalcemia is defined as reduction in the level of the ionized calcium in the blood to less than 0.95 mmole/ litre.

In some cases it is associated with symptoms such as neuromuscular impairment in the form of convulsions ,carpopedal spasm,parathesia ,laryngiospasm ,stridor……etc .Calcium circulates in blood stream in three fractions :protein bound to calcium,primarly to albumen(40%) and in 50% of the cases calcium is present in the ionized state which is physiologically active (Dias ,c et a l, 2013) . Symptomatizing hypocalcemia may occur in cases of vitamin D deficiency rickets (nutritional deficiency in infants less than two years ) .It may also occur in vitamin D resistant rickets e.g renal rickets because of failure of the kidney to synthesize 1-OH cholecalciferol of the 1-25 di-OH cholecalciferol (the active form of vitamin D). In some cases the liver fails to synthesize the 25-OH group of the active 1-25 di hydroxy cholecalciferol . In cases of malabsorption hypocalcemia may occur because of lack of absorption of both calcium and vitamin D from the gastrointestinal tract.

Symptomatizing Ionized hypocalcemia has been reported as an early event associated with organ dysfunction in children admitted to intensive care unit. This suggests that hypocalcemia may occur in association with other causes than those mentioned above. It has been reported in cases with sepsis, shock and in association with the use of anticonvulsants. It may occur in cardiac arrythmia and tetany (Khadilkar,V & Khadilkar,V,2017).

Regulation of calcium haemostasis is done by two principle hormones: vitamin D and parathyroid hormone.

These hormones act on three target organs: the intestine, the kidney and bones. In cases of advanced vitamin D deficiency rickets and in cases of vitamin D resistant rickets compensatory hyperparathyroidism may occur.( Basatemur & Sutcliffe,2015) Research question: to find out the causes and differential diagnosis of syptomatizing hypocalcemia in infants and children admitted to Assiut University Children Hospital using the available datafrom the literature.

The current strategy for dealing with this problem will be described using an algorithm covering the various clinical presentations and investigations to reach the final diagnosis guided by( Fukomoto,S et al,2008 , Pacaud,D & Dawrant ,J,2007 as well as Kelly,A & Levine,M,2013)

Inclusion Criteria:

• All symptomatizing hypocalcemic cases presenting acutely to the Assiut University Children Hospital with convulsions, carpopedal spasm, stridor, renal symptoms or malabsorption symptoms aged > 1 month to the age of 17 years.

Exclusion Criteria:

• All neonatal hypocalcemic cases.

: All data will be collected in a sheet form for all cases of acutely symptomatizing hypocalcemia admitted during period from 1st November 2018 to End of November 2019.