text_1: 40-year-old woman came to the emergency room with tetany and sensory changes in her back for 3 days and she had hypomagnesemia.  She also had low potassium and low calcium and the emergency room doctor thought the low magnesium could be due to the low calcium, but I didn't think that was right.  I decided to review the causes of low magnesium and the treatment and associated findings.
text_2: What would cause low magnesium?