A number of reports of magnesium (Mg) disturbances in newly born and older infants have appeared in the last decade. The most dramatic instances have been infants who were both hypomagnesemic and hypocalcemic and whose symptoms and biochemical disturbances responded only to the administration of Mg salts. The advent of atomic absorption spectrophotometry1 as a direct, relatively simple, accurate method of measuring Mg with very small specimens has reinforced interest in neonatal Mg physiology and pathology. In the present review, data drawn from many sources have been collected to synthesize and classify this growing body of information.
Physiology of Magnesium
Distribution and Importance.—Magnesium is the second most common intracellular cation. About one half of body Mg is in bone, one quarter in muscle, and the remainder is in other soft tissues. Normal serum Mg levels in newly born infants2-4 are similar to those in children2,5 and