Relation of magnesium to calcium in human blood serum

Mg deficiency in chronic inflammatory bowel disease and requirements during intravenous nutrition

Assessment of magnesium (Mg) status by serum and 24-hr urine estimations has been used to study a group of 17 patients with severe Crohn's disease, 10 of whom have required intravenous (IV) nutrition. Mg depletion was present in 15 (88%) and severe enough to cause symptoms in two. Urine levels were low in most patients and would appear to be a more sensitive indication of Mg depletion than serum levels alone. Serum Mg levels were significantly lower in the Crohn's group than in a group of hospital controls; 5-10 mmol of IV Mg were required daily to prevent Mg depletion during IV nutrition and some patients required higher intakes. Three patients with particularly severe malabsorption required oral Mg supplements in the long-term. The rationale for using our method of assessing Mg status, and the importance of recognizing and treating chronic Mg deficiency are presented.

Lithium therapy and alkaline earth metal metabolism: a biochemical screening study

A study is described of 90 patients receiving lithium prophylactically for recurrent affective disorder. A total of 90 biochemical variables was analysed by correlation matrices. No abnormality in calcium or magnesium metabolism was detected though this may merely be a reflection of the insensitivity of the screening technique used.

Plasma magnesium concentration in primary hyperparathyroidism

The plasma magnesium concentration has been determined in 73 patients with primary hyperparathyroidism. In most patients it lay within the normal range (1.7-2.3 mg./100 ml.), but in five it was less than 1.6 mg./100 ml. These patients had relatively high urinary magnesium outputs, and one of them, studied in greater detail, failed to retain parenterally administered magnesium. Hence hypomagnesaemia in hyperparathyroidism may be associated with a defect in renal magnesium conservation, which may be reversible.