Sicker patients need IV antibiotics. For women, urologic referral is necessary only for UTI relapsing with the same organism. For men, refer after one recurrence even with a different organism. These two may also coexist. Suprapubic tenderness may be present in cystitis.
Pelvic exam is indicated if vaginitis or urethritis suspected.
Presence of vaginitis doesn't rule out cystitis-both are common and they may coexist. Leukocyte esterase is OK as a prescreen. Given its low false-positive rate, one may treat empirically with antibiotics based on a positive result. The disadvantage of using leukocyte esterase alone is that you don't see the urine sediment. Presence of hematuria with pyuria virtually rules out urethritis.