Cerebrospinal fluid and serum levels of magnesium, zinc, and calcium in man

DESPITE THE ADVENT in 1960 of more accurate methods of determining trace metal contents of biological fluids, relatively little information has accumulated concerning their concentrations and interrelationship in cerebrospinal fluid. In 1927 Cohen' first described the relationship between serum and cerebrospinal fluid magnesium and found the cerebrospinal fluid magnesium values were 25 to 35% higher than that of serum. He found, in addition, that the magnesium content of the cerebrospinal fluid was independent of the age or sex of the patient and independent of the cell or protein content of the fluid. During periods of observation up to six hours, fluctuations in the serum magnesium failed to affect the cerebrospinal fluid concentration. With meningitis, however, the gradient between serum and cerebrospinal fluid concentrations tended to disappear. Other workers2 confirmed these observations and noted constancy of cerebrospinal fluid magnesium in a variety of neurologic diseases other than meningitis. In 1960, Maclntyre and associates described a simplified method of measurement by flame spectrophotometry which also increased the accuracy of the determination. In 1965 Pallis and co-worker9 studied serum and cerebrospinal fluid magnesium content in various diseases. The previously noted observations were confirmed, and in two instances of infantile tetany, the cerebrospinal fluid magnesium was within normal limits, although the serum magnesium was quite low. Experi-