Genitourinary System

Dysuria, urinary frequency, and urgency with suprapubic discomfort, WITHOUT fever, flank pain, or CVA tenderness (those suggest upper-tract/pyelonephritis). Hematuria may occur. Lower-tract irritative symptoms without systemic signs define simple cystitis.

Nitrofurantoin 5 days, TMP-SMX 3 days (where E. coli resistance <20%), or fosfomycin single dose. Fluoroquinolones are reserved (not first-line) because of adverse effects and resistance. Beta-lactams are alternatives if first-line agents cannot be used.

Nitrofurantoin concentrates in the urine but does NOT achieve adequate renal parenchymal/tissue or serum levels, so it cannot treat pyelonephritis. It is also avoided at term (38-42 wk) and in neonates due to risk of hemolytic anemia (G6PD-related). It is contraindicated when CrCl is low (poor urinary concentration).

UTI in the setting of a functional or structural urinary abnormality, immunocompromise, or comorbidity that raises failure risk: male sex, pregnancy, indwelling catheter, obstruction/stone, urinary instrumentation, diabetes, immunosuppression, recent antibiotics, or hospital-acquired infection. These require broader/longer therapy and often urine culture.

Only in pregnant women and before urologic procedures expected to cause mucosal bleeding. It should NOT be treated in nonpregnant women, the elderly, diabetics, or catheterized patients (overtreatment drives resistance and C. difficile). Screen and treat in pregnancy because of pyelonephritis and preterm-birth risk.

Escherichia coli, responsible for ~75-95% of uncomplicated cases. Other Enterobacteriaceae (Klebsiella, Proteus), Staphylococcus saprophyticus (young sexually active women), and Enterococcus account for most of the rest. Proteus is associated with struvite stones and alkaline urine.