TREATMENT

All potentially modifiable causes of NDI should be reversed. Lithium, for example, should be discontinued, and hypokalemia or hypercalcemia should be corrected. These measures may lead to complete recovery of renal function, although lithium-associated NDI may be irreversible in some cases.

It is important for all patients to maintain adequate hydration. If young children cannot obtain their own water, it must regularly be offered to them. A low-salt diet should be instituted to promote solute and water reabsorption in the proximal tubule.

In addition, a diuretic can be offered because it can paradoxically reduce urine output by causing a slight volume depletion, which up-regulates salt and water reabsorption in the proximal tubule. Thiazide diuretics are preferred over loop diuretics because the latter impair creation of the solute gradient in the medulla, which interferes with urine concentration. In addition, amiloride has been proposed as a potentially preventative measure in patients taking lithium, because this agent appears to limit lithium influx into principal cells. Its efficacy, however, remains unknown.