Phase 3- Dexamethasone Administration in 1st Episode of Febrile Urinary Tract Infection Episode as Renal Damage Prevention Strategy. DEXCAR

The urinary tract infection (UTI) is one of the most common bacterial infections in children. These infections can be grouped clinically as asymptomatic bacteriuria , cystitis (lower urinary tract infection ) and acute pyelonephritis (APN ) when the infection reaches the upper urinary tract. This classification is of great clinical relevance because while cystitis is usually a benign condition without further complications , the APN is associated with an increased risk of kidney damage, acquired through renal scarring . Renal scarring is a consequence of the inflammatory and immune response that is triggered to eradicate the bacteria involved in the UTI. Parenchymal infection can be solved , but there are a number of poorly understood factors that may perpetuate inflammation and this would promote the formation of scar nephritis. One of the most relevant factors involved in the renal scarring development are the production of inflammatory mediators (complement proteins, bactericidal peptides, cytokines such as IL6 and IL8, chemokines, and adhesion molecules defensins). Thus, it is obvious to think that the use of anti-inflammatory drugs may prevent the release of these mediators and the development of permanent kidney damage.

Intervention: the two parallel groups will receive the conventional therapy plus:

1. dexamethasone: 0'30 mg per kg every 12 hours during 3 days.
2. placebo (physiological saline)at the same dosing regimen.

Centralized lecture of the late DMSA after 6 months of the pyelonephritis episode will be performed. Renal scarring presence and grade will be reported.