It has been recognized for several years that the terminal stages of nephritis are accompanied by an increase in the inorganic phosphorus of the blood serum and some decrease in the calcium.
In 1915 Greenwald1 reported observations on the acid-soluble (largely inorganic) and lipoid phosphorus of human blood serum. He observed that normally the acid-soluble phosphorus as P varied between 2 and 6 mg. per hundred cubic centimeters, but that in severe nephritis it might be considerably increased. A year later Marriott and Howland2 confirmed these observations and pointed out that the retention of (acid) phosphate would seem to be sufficient to account for the degree of acidosis observed. They found further in most of their cases a marked reduction in the calcium of the serum. They state:
What influence this low calcium content may have on the production of such symptoms as convulsions and hemorrhages can only be suggested.
SCHMITZ HW, ROHDENBURG EL, MYERS VC. THE INORGANIC PHOSPHORUS AND CALCIUM OF THE BLOOD IN NEPHRITIS. Arch Intern Med (Chic). 1926;37(2):233-243. doi:10.1001/archinte.1926.00120200083006