Magnesium Metabolism Studies in Children with Chronic Inflammatory Disease of the Bowel

Abstract

Magnesium metabolism was studied in seven patients with severe chronic inflammatory disease of the bowel (CIDB), and in 20 children without intestinal pathology. Four of the CIDB patients had ulcerative colitis and three had granulomatous disease of the bowel. All had diarrhea as well as other gastrointestinal complaints for 1 to 6 years prior to the study. All were being treated with sulfasalazine and were also receiving corticosteroids intermittently. All but one had had intestinal surgery. Basal plasma and urine were obtained in all patients and, if surgery was performed, a piece of muscle was excised. The CIDB patients received an intravenous magnesium infusion of 2 mEq/kg/day for 4 days, 2 days postsurgery. Electrocardiograms were recorded throughout the study. The mean basal plasma magnesium levels were reduced in CIDB patients as compared with controls. Mild hypomagnesemia was observed in six of seven CIDB patients. The mean basal urine excretion of magnesium was also reduced in CIDB patients, but the muscle concentrations of this element were similar to controls. Basal hypomagnesuria was present in only two of the three patients with granulomatous disease and in one patient with ulcerative colitis. The three patients with granulomatous disease excreted minimal amounts of magnesium in the urine during intravenous administration of this ion. A positive magnesium balance persisted throughout the 4‐day period of infusion. In contrast, only two of the four patients with ulcerative colitis had magnesium retention during the first day of intravenous administration, and all four had negative magnesium balances thereafter. The data suggest that hypomagnesemia in CIDB patients may occur with or without magnesium deficiency. However, the excretion of magnesium in urine after a parenteral magnesium load was the best index of magnesium deficiency. In three CIDB patients, with involvement of small bowel, magnesium depletion was found.