Magnesium deficiency after ileal resections for Crohn's disease.

The magnesium status of the body was studied in 87 patients with various lengths of small-bowel resections for Crohn's disease. The urinary magnesium excretion decreased with increasing resection length, and so did the concentration of magnesium in muscle. Muscular fatigue, an early symptom of magnesium deficiency, was positively correlated to a pathologically low concentration of muscle magnesium. It was concluded that clinically important magnesium deficiency, which was not detected by determination of serum magnesium, occurred in patients with ileal resections exceeding 75 cm.