[citation needed] In 90% of cases, neonatal Bartter syndrome is seen between 24 and 30 weeks of gestation with excess amniotic fluid (polyhydramnios).

Diagnostic pointers include high urinary potassium and chloride despite low serum values, increased plasma renin, hyperplasia of the juxtaglomerular apparatus on kidney biopsy, and careful exclusion of diuretic abuse.

Loss of reabsorption of sodium here also has the undesired effect of abolishing the hypertonicity of the renal medulla, severely impairing the ability to reabsorb water later in the distal nephron and collecting duct system, leading to significant diuresis and the potential for volume depletion.

Finally, increased sodium load to the distal nephron elicits compensatory reabsorption mechanisms, albeit at the expense of potassium by excretion by principal cells and resulting hypokalemia.

This increased potassium excretion is partially compensated by α-intercalated cells at the expense of hydrogen ions, leading to metabolic alkalosis.

[9] The clinical findings characteristic of Bartter syndrome is hypokalemia, metabolic alkalosis, and normal to low blood pressure.

In severe cases where supplementation alone cannot maintain biochemical homeostasis, nonsteroidal anti-inflammatory drugs (NSAIDs) can be used to reduce glomerular filtration and can be very useful, although may cause gastric irritation and should be administered alongside stomach acid suppression therapies.

In young babies and children, a low threshold to check serum electrolytes during periods of illness compromising fluid intake is necessary.

[16] Surveillance renal ultrasound should be employed to monitor for the development of nephrocalcinosis, a common complication which further augments urinary concentrating difficulty.

[17] The limited prognostic information available suggests that early diagnosis and appropriate treatment of infants and young children with classic Bartter Syndrome may improve growth and perhaps intellectual development.