Prostatitis is the most common urologic diagnosis in men under 50 and the third most common in men over 50 (after BPH and prostate cancer), with a prevalence of ≈7% in men over 18 and 6–8% of male urology outpatient visits. Most of the clinical challenge lies in category III chronic pelvic pain syndrome (CPPS), where pain — not infection — dominates.
Epidemiology and Histopathology
Histologically, prostatitis is an increased number of inflammatory cells within the prostatic parenchyma — most commonly a lymphocytic infiltrate in the stroma immediately adjacent to the acini. This finding may or may not accompany clinical prostatitis, BPH, or prostate cancer, and is seen at autopsy in up to 44% of prostate samples from men without definitive prostate disease.
NIH Classification
| Category | Name | Defining feature |
|---|---|---|
| I | Acute bacterial prostatitis | Acute infection |
| II | Chronic bacterial prostatitis | Recurrent UTIs from a prostatic focus |
| IIIA | Inflammatory CP/CPPS | Pain, no bacteria, excess leukocytes in EPS / post-massage urine / semen |
| IIIB | Non-inflammatory CP/CPPS | Pain, no bacteria, no significant leukocytes |
| IV | Asymptomatic inflammatory prostatitis | Leukocytes ± bacteria, no pain (incidental) |
There is no validated WBC/HPF cut-off separating inflammatory from non-inflammatory CPPS; consensus favours 5–10 WBCs/HPF in EPS as the upper limit of normal, which fluctuates over time and with ejaculation frequency.
Microbiology and Pathogenesis
- Gram-negative organisms predominate — Enterobacteriaceae from GI flora (E. coli, Serratia, Klebsiella, Proteus, Pseudomonas), with E. coli the most common (65–80%).
- Gram-positive — enterococci account for 5–10%; the role of other gram-positive urethral commensals is controversial.
Risk factors for bacterial colonisation/infection of the prostate: intraprostatic ductal reflux, phimosis, specific blood groups, unprotected anal intercourse, UTI, acute epididymitis, indwelling urethral or condom-catheter drainage, and transurethral surgery (especially with untreated infected urine).
Nonbacterial prostatitis/CPPS reflects an interrelated cascade of inflammatory, immunologic, endocrine, muscular, neuropathic, and psychological mechanisms triggered in a susceptible man:
- Intraprostatic ductal reflux — reflux of urine ± bacteria into the prostatic ducts. Prostatic calculi are made of substances found only in urine (not prostatic secretions), evidence that reflux occurs; bacteria can hide in biofilms within these calculi, causing recalcitrant infection and recurrent UTIs despite seemingly adequate antibiotics.
- Chemically induced inflammation from noxious refluxed urinary substances.
- Dysfunctional voiding — high-pressure dysfunctional flow from anatomic or neurophysiologic obstruction.
- Pelvic-floor muscle abnormality / neural sensitisation — neural dysregulation with extraprostatic tenderness, and altered autonomic responses driving pain.
- Immunologic — possibly autoimmune; CPPS can persist via immune mechanisms long after bacteria are eradicated.
- Psychosocial factors contribute to development and exacerbation.
Clinical Presentation
- Category I (acute bacterial) — acute pain with storage and voiding LUTS and signs of sepsis (fever, chills, malaise, nausea/vomiting, even hypotensive septicaemia); pain is perineal/suprapubic ± external genitalia. About 5% progress to chronic bacterial prostatitis.
- Category II (chronic bacterial) — documented recurrent UTIs from a focal prostatic reservoir of uropathogens.
- Category III (CPPS) — the predominant symptom is pain (perineum, suprapubic, penis; also testes, groin, low back); pain during or after ejaculation is among the most bothersome features, often with storage/voiding symptoms. IIIA and IIIB are clinically indistinguishable. By definition it is chronic after 3 months; symptoms wax and wane, and ≈1/3 improve over a year (those with shorter duration and fewer symptoms). Quality of life is greatly diminished.
- Category IV (asymptomatic) — incidental (e.g. on prostate biopsy).
Diagnosis and Evaluation
- Mandatory: history and exam including DRE; urinalysis/culture; pelvic-floor assessment.
- Recommended: two-glass lower-tract test; the NIH Chronic Prostatitis Symptom Index (NIH-CPSI); sexual-function questionnaire; flow rate; post-void residual; urine cytology.
- Not recommended routinely: four-glass test, semen analysis/culture, STI/urethral cultures, urodynamics or video-urodynamics, TRUS, pelvic imaging, PSA, cystoscopy, and prostate biopsy. Note that chronic LUTS in young men may be misdiagnosed as non-bacterial prostatitis when they actually have undiagnosed voiding dysfunction; PSA can rise markedly in acute bacterial prostatitis and normalises over 6 weeks to months; cystoscopy is justified only in refractory cases; and seminal vesiculitis (with abscess) can complicate bacterial prostatitis.
Phenotyping — UPOINT classifies CPPS into one or more of six domains and directs individualised therapy: Urinary, Psychosocial, Organ-specific, Infection, Neurologic/systemic, Tenderness (muscle).
Exam findings: in category I the prostate is hot, boggy, and exquisitely tender — expressing prostatic fluid is unnecessary and potentially harmful. Categories II and III are usually unremarkable apart from pain, and the degree of palpation pain does not differentiate the syndromes.
NIH-CPSI has 9 questions across three domains: pain, urinary function, and quality of life.
Lower urinary tract localisation:
- Category I — a urine culture is the only test required.
- Category II/III — the 4-glass test: VB1 (first 10 mL = urethra), VB2 (midstream = bladder), EPS (expressed prostatic secretion collected during massage), and VB3 (first 10 mL after massage). All go for quantitative culture, and centrifuged sediment is examined for leukocytes, macrophages, oval fat bodies, erythrocytes, bacteria, and fungal hyphae.
- Category II — a 10× increase in bacteria in EPS or VB3 versus VB1/VB2.
- Category IIIA — no uropathogens but excess leukocytes (>5–10 WBCs/HPF) in EPS or VB3.
- Category IIIB — no uropathogens and no significant leukocytosis.
- 2-glass test — a simpler, cost-effective alternative (midstream pre-massage urine + first 10 mL post-massage urine) that categorises most patients.
Management
Acute Bacterial Prostatitis
- First-line (AUA): TMP-SMX or a fluoroquinolone (e.g. TMP-SMX 1 DS tab PO BID); second-line a 2nd-generation cephalosporin; third-line a 3rd-generation cephalosporin. (Australian Family Physician options: trimethoprim 300 mg daily, cephalexin 500 mg BID, or amoxicillin-clavulanate 500/125 mg BID — each ×14 days.)
- Duration ≈2 weeks, starting with parenteral therapy (depending on severity) then oral broad-spectrum cover.
- For ESBL or suspected-ESBL organisms (often after transrectal prostate biopsy), use a carbapenem (ertapenem, imipenem, meropenem), amikacin, or colistin for ≥10–14 days.
Chronic Pelvic Pain Syndrome
No therapy shows marked benefit in sham-controlled trials. Moderate benefit (selected trials): α-blockers and pregabalin. Modest benefit: anti-inflammatories, phytotherapies, ESWT, TUMT, and selected neurostimulation.
- Recommended — α-blocker as part of multimodal therapy in newly diagnosed, α-blocker-naive men with voiding symptoms; an antibiotic trial in selected antibiotic-naive, recently diagnosed patients; selected phytotherapies (Cernilton, Quercetin); directed physiotherapy; and multimodal therapy directed at the individual UPOINT phenotype.
- Not recommended — α-blocker monotherapy (especially if previously treated), anti-inflammatory monotherapy, antibiotics as primary therapy (especially after prior failure), 5α-reductase-inhibitor monotherapy (consider only with coexisting BPH), most minimally invasive procedures (TUNA, laser), and invasive surgery (TURP, radical prostatectomy).
Modality specifics:
- Antibiotics — bacteria are cultured in only 5–10% of cases, but antibiotics may help via three mechanisms: a strong placebo effect, eradication/suppression of non-cultured organisms, and an anti-inflammatory effect. For CP caused by E. coli, give a month of fluoroquinolone, continuing only 4–6 weeks if pre-treatment cultures were positive and/or the patient improved. Fluoroquinolones work best against E. coli/Enterobacteriaceae (less so P. aeruginosa or enterococci); TMP-SMX is less effective; macrolides are superior for proven chlamydial infection. Up to 20% of initial failures respond to a second cycle of a different agent. Do not prescribe to previously treated men with long-standing CP/CPPS.
- α-blockers — target the poor bladder-neck relaxation underlying the LUTS, but trials do not support them in recently diagnosed α-blocker-naive men.
- Anti-inflammatories/immune modulators — high-dose, long-duration COX-2 monotherapy is not recommended; an RCT of pentosan polysulfate 900 mg/day (3× the usual dose) showed modest benefit for some men (alopecia is an associated effect); these are adjuncts, not monotherapy.
- Hormonal — finasteride/dutasteride are not recommended as monotherapy except with coexisting BPH. Allopurinol showed no advantage over placebo.
- Prostatic massage / pelvic-floor physiotherapy — massage evidence is "soft" but may be a multimodal adjunct (frequent ejaculation may do the same); pelvic-floor physiotherapy (perineal massage, myofascial trigger-point release) helps selected patients with demonstrable pelvic-floor pathology refractory to other therapy. Acupuncture is reasonable in selected men.
- Lifestyle/conservative — the foundation of care: education (sometimes sufficient alone), avoiding exacerbating foods/drinks/activities, low-impact exercise, local heat, and coping skills.
- Surgery has no role unless a specific indication is found — a prostate abscess that fails rapid antibiotic response is drained (percutaneous is more effective and less morbid than transurethral), and seminal-vesicle abscesses are managed by antibiotics, transrectal aspiration, or excision.
Self-Test
1. Describe the NIH classification of prostatitis. Category I — acute bacterial; II — chronic bacterial (recurrent UTIs from a prostatic focus); III — CPPS (pain without culturable bacteria), split into IIIA (inflammatory, excess leukocytes in EPS/post-massage urine/semen) and IIIB (non-inflammatory, no significant leukocytes); IV — asymptomatic inflammatory prostatitis (leukocytes ± bacteria, no pain, found incidentally).
2. Approximately what percentage of patients with acute bacterial prostatitis develop chronic bacterial prostatitis? About 5%.