A sexually active woman with dysuria and fever; flank pain suggests what diagnosis and initial management?

• A. Acute cystitis; nitrofurantoin
• B. Ureteral stone
• C. Acute pyelonephritis; treat with antibiotics such as ciprofloxacin or TMP-SMX; hospitalization if severe
• D. Pyelonephritis treated with only fluids

Answer: (C)

When fever with flank pain accompanies dysuria, think of an upper urinary tract infection—acute pyelonephritis—rather than just a bladder infection. The kidney involvement explains the fever and flank tenderness, which aren’t typical of cystitis alone.

The best approach is to start antibiotics that cover common gram-negative uropathogens, especially E. coli. Oral ciprofloxacin or trimethoprim-sulfamethoxazole are appropriate outpatient options in many cases, provided local resistance rates are acceptable and the patient can tolerate oral medications. The course is typically around 7–14 days, and obtaining a urine culture before starting therapy helps tailor treatment.

Hospitalization is reserved for more severe illness or instability: high fever with rigors, significant dehydration or vomiting, inability to keep fluids down, or signs of sepsis; in those scenarios, IV antibiotics and close monitoring are indicated. Pregnancy also shifts management toward inpatient IV therapy due to higher risks.

So, this presentation is best managed as acute pyelonephritis with antibiotics such as ciprofloxacin or TMP-SMX, with admission if the patient has severe illness.