Based on these findings, a diagnosis of nephrogenic diabetes insipidus (NDI) was made secondary to hypomagnesemia induced severe hypokalaemia. The treatment was modified by the addition of 4g of magnesium sulphate along with 40 mmol of KCl in 5% Dextrose water (500 ml bottle) which ran at a rate of 125 ml/h, along with the same insulin rate of 0.05 U/kg/h (2.5 U/h). This treatment plan continued for 48 hours until his electrolytes normalized. In addition, oral Bendroflumethiazide 5 mg twice a day, Indomethacin 50 mg thrice a day, Eplerenone 25 mg twice a day and Magnesium trisilicate 250 mg thrice a day were added to his treatment.
Improvement in potassium and magnesium levels were seen on the 3rd day post admission with significant ECG improvement with the disappearance of U waves (Fig.2). A decrease in the exaggerated amount of urine output was also observed with an improvement in the patient’s hydration status. On the 8th day in the ICU, the patient had significant clinical improvement with normal serum electrolytes and an adequate positive fluid balance (input of 3.5 L and output of 2.9 L in 24 h). Thereafter, he was transferred from the ICU to the general ward to continue with the management and follow-up. Further follow-up as an outpatient post discharge have yielded normal electrolyte results.