What follow-up investigations are necessary for a patient recovering from hypomagnesemia?

For a patient recovering from hypomagnesemia, follow-up investigations should include regular monitoring of serum magnesium levels to ensure stability and correction of deficiency. Initially, magnesium should be checked daily if there is a risk of refeeding syndrome, then three times a week until stable, and subsequently weekly once stable. This monitoring helps detect ongoing depletion or recurrence of hypomagnesemia. Additionally, assessment of related electrolytes such as calcium and potassium is important, as hypocalcaemia may be secondary to magnesium deficiency and potassium levels can also be affected. Renal function tests (urea, creatinine, and electrolytes) should be monitored at baseline and then regularly to assess fluid and electrolyte balance and kidney function. Clinical monitoring should include assessment of fluid status and symptoms related to electrolyte imbalance. If the patient is receiving intravenous fluids or nutrition support, more frequent monitoring may be necessary until stable. Urinary sodium may be helpful in complex cases with gastrointestinal fluid loss. Overall, the frequency of investigations should be tailored to the patient's clinical status and risk factors, with a trend towards less frequent monitoring as stability is achieved.