This is acute pyelonephritis. Most urinary tract infections are ascending infections, but hematogenous spread can also occur. Urinary tract stasis from obstruction is a common antecedent.
Women are more prone to infections because of a shorter urethra.
With acute inflammation of the lower urinary tract, increased numbers of white cells would be present. White cell casts would indicate acute pyelonephritis of the kidney. Budding cells with pseudohyphae characteristic of Candida infection are present.