TABLE 3.

Scoring criteria for histopathological analysis

Lesion	Description for score
	0	1	2	3
Cystitis	No scorable lesions	Very rare PMNsa in stroma or lumen or occasional perivascular lymphoid cuffs	Many PMNs and moderate edema	Many PMNs; widespread, marked edema, transmural inflammation
Pyelonephritis	No scorable lesions	Very occasional PMNs in lumen or peripelvic tissue	Rafts of PMNs in the pelvis and/or scattered focal aggregates of PMNs in peripelvic tissue	Many PMNs in all sections, or a single large focus of PMNs in one section

^aPMNs, polymorphonuclear leukocytes.