Nephrogenic diabetes insipidus due to hypokalemia and hypomagnesemia in T1D: Case Study

Nephrogenic diabetes insipidus (NDI) is rarely considered against more common differentials such as diabetes mellitus in patients presenting with polydipsia and polyuria. Hypokalemia and hypercalcemia are known to induce nephrogenic diabetes insipidus (NDI), but not much is known about hypomagnesemia.

Sangey E et. al conducted a case study on a 27-year-old male patient who acquired nephrogenic diabetes insipidus (NDI) due to hypokalemia and hypomagnesemia.

The patient was a previously healthy male who was diagnosed with appendicitis later on admission to the referral facility, he was diagnosed with a new presentation of type 1 diabetes mellitus. Postappendectomy, he was referred to the Emergency & ICU Department, Shree Hindu Mandal Hospital, Dar es Salaam Tanzania, for further management.

After 24 hours of admission, the patient had a urinary output of 9 L of dilute urine with a negative fluid balance of 3 L. His serum potassium was persistently low despite receiving a continuous KCl infusion for over 24 hours. His serum potassium level was 1.94 mmol/L so his serum magnesium levels were ordered to rule out the probable cause of refractory hypokalemia, which revealed hypomagnesemia of 0.50 mmol/L (0.66 −1.25 mmol/L). Also, his ECG showed diffuse U‐wave morphology correlating with hypokalemia and/or hypomagnesemia.

Based on these findings, a diagnosis of nephrogenic diabetes insipidus (NDI) was made secondary to hypomagnesemia induced severe hypokalemia.

Following a modified treatment plan, 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 yielded normal electrolyte results.

The researchers concluded that this was a rare clinical occurrence that they had observed and treated in their practice. They were not sure if similar occurrences took place in their setting in the past, hence from now on they would always maintain a high level of suspicion in similar clinical presentations to ensure NDI does not ever go unrecognized.

Reference:

The combined effect of hypomagnesemia and hypokalemia inducing nephrogenic diabetes insipidus in a patient with type 1 diabetes mellitus by Sangey E et. al published in the Clinical Case Reports

DOI: 10.1002/ccr3.4564