Focal nephronia in babies. Here?

My son who is 14 weeks old(wt: 6.3 kg) now is suffering from recurrent high grade fever since 3 weeks. This fever lasts for 2 to 3 days and reoccur every week along with severe diarrhoea and vomittings. Complete blood test showed increase in platelet count 586000/cumm and crp at 24 mg/L. Dengue test is negative and resulted in a normal bilirubin serum test. Urine culture showed absence of bacterial growth and urine routine is clean. Ultrasound shows mild hydro uretro nephrosis renal pelvis measuring 7mm (apsiameter) in right kidney and its ureter seen mildly dilated in its entire course till vesico ureteric junction. Radio isotope dmsa scan showed preserved cortical function with focal nephronia in the upper 1/3 of right kidney. Preserved inhomogenous cortical tracer concentration and irregular cortical outline.   Can focal nephronia itself cause high fever while urine routine and urine culture is clean. PLEASE HELP !!! Are we missing out anything here?