Urinary tract infection, from cystitis to sepsis
The most common bacterial infection there is — and a category that runs from a few days of antibiotics for a healthy woman to a drain at 3 a.m. for an obstructed kidney. The art is knowing who to treat, who to leave alone, and the one obstructed system that can't wait.
The one-liner
Treat symptomatic infection, not the urine dipstick. Uncomplicated cystitis gets short-course antibiotics; asymptomatic bacteriuria is treated ONLY in pregnancy or before urologic instrumentation. Never massage the prostate in acute bacterial prostatitis. And an obstructed, infected system is decompressed within hours — that's the one that kills.
Urinary tract infection is the most common bacterial infection in the world, and the word covers an enormous range — from a few days of dysuria in an otherwise healthy woman to a septic, obstructed kidney that needs draining tonight. The skill is not memorizing antibiotics; it is sorting which patient is in front of you, because the same lab result means completely different things in different bodies.
The first split: complicated or not
- Uncomplicated — a healthy, non-pregnant woman with a normal urinary tract.
- Complicated — everyone else: men, pregnancy, obstruction, stones, catheters, immunocompromise, diabetes, or any structural or functional abnormality. The threshold for imaging and for taking it seriously is lower.
E. coli is the dominant organism throughout, and local resistance patterns drive the antibiotic choice more than any textbook.
What everyone gets wrong
Treating the dipstick instead of the patient. Asymptomatic bacteriuria — bacteria in the urine without symptoms — is not treated in the vast majority of people, including the elderly and catheterized patients, where it is enormously common and antibiotics only breed resistance and cause harm. There are exactly two settings where you treat it:
- Pregnancy — untreated bacteriuria risks pyelonephritis and preterm labor.
- Before urologic instrumentation that breaches the mucosa (e.g. TURP, ureteroscopy).
A positive urine culture is not a diagnosis. Symptoms are. Outside pregnancy and pre-instrumentation, asymptomatic bacteriuria is left alone.
Cystitis: short and simple
Uncomplicated cystitis is a clinical diagnosis treated with short-course antibiotics — nitrofurantoin for a few days, or trimethoprim-sulfamethoxazole or fosfomycin, guided by local resistance. No imaging, no culture needed in the straightforward case.
Pyelonephritis: the kidney is involved
Fever, flank pain, and costovertebral angle tenderness mark ascent to the kidney. Mild cases can be managed orally as an outpatient; systemic illness, vomiting, pregnancy, or a complicated host earns IV antibiotics and admission. The crucial reflex: imaging (CT) to exclude obstruction or abscessin anyone who is severely ill or failing to improve — because a pyelonephritis that won’t settle may be an obstructed system in disguise.
The emergency hiding in the category
One scenario outranks all the others: an obstructed, infected collecting system — pus behind a stone or stricture. This does not get better with antibiotics alone; it needs decompression within hours by nephrostomy or ureteric stent. It is the single UTI presentation that quietly kills, and it is covered in full under the infected-obstructed kidney.
Two prostate detours
- Acute bacterial prostatitis — fever, perineal pain, a boggy tender prostate. Treat with a prolonged course of a fluoroquinolone or TMP-SMX. The rule that gets tested: do not perform vigorous prostatic massage in acute bacterial prostatitis — it risks precipitating bacteremia.
- Recurrent UTI in women — climb a ladder of behavioral measures, then vaginal estrogen in post-menopausal women, then prophylactic antibiotics (continuous or post-coital) as a last step, after imaging excludes a structural cause.
If you remember one thing
Treat symptoms, not cultures. Short-course antibiotics clear simple cystitis; asymptomatic bacteriuria is left alone except in pregnancy and before instrumentation; and the one UTI that cannot wait is the obstructed, infected kidney — that one gets a drain, tonight.