Acute Cystitis
System: Genitourinary Infections · Parent MOC: MOC - Diseases by System
One-Sentence Definition
Acute infection of the bladder mucosa, usually ascending from periurethral flora, presenting with dysuria, frequency, and urgency without systemic upper-tract signs.
Clinical Presentation
- Dysuria, frequency, urgency, suprapubic discomfort; ± hematuria
- Not cystitis alone if fever/flank pain → Acute Pyelonephritis
- Complicated if male sex, pregnancy, stones, obstruction, immunocompromise, catheter
Pathogens
| Context | Organism | Notes |
|---|---|---|
| Uncomplicated community | Escherichia coli | ~75%+ |
| Other Enterobacterales | Klebsiella pneumoniae, Proteus (TBD) | |
| Complicated / healthcare | Enterococcus, Pseudomonas aeruginosa | |
| Culture-negative dysuria | Consider STI, noninfectious |
Pathogenesis
- Ascending colonization → adhesion (UPEC fimbriae) → inflammation
- Overlap with Normal Microbiota of gut/perineum
Diagnosis
| Step | Test | Note |
|---|---|---|
| Clinical | History | Often sufficient if classic uncomplicated ♀ |
| UA | Dipstick nitrite/LE | Supportive |
| Culture | Midstream / cath | Indicated if complicated, recurrent, failure, pregnancy |
Treatment Principles
- Short-course agents for uncomplicated cystitis per local resistance (nitrofurantoin, TMP-SMX, fosfomycin — region-specific)
- Avoid treating asymptomatic bacteriuria (except pregnancy / selected procedures)
- Complicated → culture-guided, longer courses
Prevention
- Hydration, post-coital voiding (behavioral); prophylaxis only selected recurrent cases
- Catheter avoidance (Device-Associated Infections)
Differential / Pitfalls
- Vaginitis, urethritis (STI), interstitial cystitis, pyelonephritis
- ESBL E. coli rising → MOC - Antimicrobial Resistance (AMR)
Learning Aids
Clinical Example
Example
Case: Healthy 28F, dysuria/frequency × 2 days, no fever/flank pain.
Question: Likely organism and do you need blood cultures?
Answer: Escherichia coli cystitis. No blood cultures; treat as uncomplicated per guidelines; culture if atypical/fails.
Related
- Acute Pyelonephritis · Genitourinary Infections
- Escherichia coli · Antimicrobial Susceptibility Testing
Active Recall
- Features that upgrade cystitis → pyelo?
- Dominant pathogen in uncomplicated cystitis?
- When is asymptomatic bacteriuria treated?