Prostatitis

01Pathophysiology

Prostatitis refers to inflammation of the prostate gland, which can be infectious or non-infectious in origin. Understanding the anatomy is the foundation: the prostate surrounds the prostatic urethra just below the bladder neck. This anatomic position explains why prostatic inflammation produces both irritative voiding symptoms (dysuria, frequency, urgency) and obstructive symptoms (hesitancy, weak stream, incomplete emptying).

In acute bacterial prostatitis, the most common mechanism is ascending urethral infection by gram-negative enteric organisms, with E. coli accounting for roughly 80% of cases. Bacteria colonize the prostatic ducts, triggering an intense neutrophilic inflammatory response. The resulting edema and glandular swelling produce the characteristic boggy, tender prostate on digital rectal exam. The intense inflammation also explains the systemic signs: high fever, chills, and leukocytosis. Because the inflamed prostate compresses the urethra, patients may develop acute urinary retention, which is a commonly tested complication.

In chronic bacterial prostatitis, the same organisms persist within the prostate despite prior antibiotic courses. The prostate gland contains prostatic calculi and biofilm-forming niches that shield bacteria from both antibiotics and host immune defenses. This is why patients experience recurrent UTIs with the same organism separated by asymptomatic intervals. The prostate essentially serves as a reservoir for reinfection of the urinary tract.

Chronic pelvic pain syndrome (CPPS), which is the most common form of prostatitis encountered clinically, has a poorly understood pathophysiology. Proposed mechanisms include neuromuscular dysfunction of the pelvic floor, autoimmune inflammation, and neuropathic pain sensitization. The hallmark is chronic pelvic/perineal pain lasting more than 3 months with no identifiable bacterial pathogen on culture. This distinction from chronic bacterial prostatitis is a frequent testing point.

02Classification and Clinical Manifestation

NIH Classification System

Clinical features by System

03Diagnostic Workup

For Acute Bacterial Prostatitis (Category I)

The diagnosis is primarily clinical. A young to middle-aged male presenting with fever, dysuria, perineal pain, and a boggy/tender prostate on DRE has acute bacterial prostatitis until proven otherwise. The best initial test is a urinalysis with urine culture obtained by midstream clean-catch (not catheterization if avoidable, as catheter passage through an inflamed prostate is painful and risks bacteremia). Expect pyuria, bacteriuria, and a positive culture growing a gram-negative rod.

Order blood cultures and a CBC if the patient appears septic or systemically toxic. Blood cultures are positive in approximately 30% of acute cases.

A critical rule: Do NOT perform prostatic massage in acute bacterial prostatitis. Vigorous manipulation of an acutely infected, inflamed gland risks bacteremia and sepsis. This is one of the most tested facts on this topic.

PSA will often be elevated during acute prostatitis, but this is a reactive elevation and must not be interpreted as evidence of prostate cancer. PSA should be rechecked after resolution of infection (typically 6 to 8 weeks later) to obtain a meaningful baseline.

If a patient with acute bacterial prostatitis does not improve after 48 to 72 hours of appropriate IV antibiotics, suspect a prostatic abscess and obtain imaging, typically transrectal ultrasound or CT pelvis with contrast.

For Chronic Bacterial Prostatitis (Category II) and CPPS (Category III)

The gold standard for distinguishing chronic bacterial prostatitis from CPPS is the Meares-Stamey 4-glass test. This involves sequential collection of:

1. VB1 (voided bladder 1): First 10 mL of urine (urethral specimen)

2. VB2 (voided bladder 2): Midstream urine (bladder specimen)

3. EPS (expressed prostatic secretions): Obtained by prostatic massage

4. VB3 (voided bladder 3): First 10 mL after massage (prostatic specimen)

If the bacterial count in EPS or VB3 is at least 10-fold higher than in VB1 and VB2, the infection is localized to the prostate, confirming Category II (chronic bacterial prostatitis). If WBCs are present in EPS/VB3 but cultures are negative, the diagnosis is Category IIIa (inflammatory CPPS). If neither WBCs nor bacteria are found, the diagnosis is Category IIIb (non-inflammatory CPPS).

A simplified 2-glass pre- and post-massage test (PPMT) compares a pre-massage midstream urine to a post-massage urine and is considered an acceptable alternative in clinical practice.

04Management and Treatment

Acute Bacterial Prostatitis

The cornerstone of treatment is prolonged antibiotic therapy. Fluoroquinolones are preferred because they achieve excellent penetration into prostatic tissue, unlike many beta-lactams that penetrate poorly. The standard outpatient regimen is ciprofloxacin 500 mg PO twice daily or levofloxacin 500 mg PO once daily for a total of 4 to 6 weeks. The extended duration is necessary because the prostate's ductal anatomy creates sanctuaries where bacteria can survive shorter courses, and undertreating risks conversion to chronic bacterial prostatitis (Category II).

For the patient who is systemically ill, septic, or unable to tolerate oral medications, start with intravenous antibiotics. A common empiric IV regimen includes ampicillin plus gentamicin for enterococcal coverage, or a third-generation cephalosporin (ceftriaxone) with or without an aminoglycoside. Transition to oral fluoroquinolone once the patient is afebrile for 24 to 48 hours and clinically improving, then complete 4 to 6 weeks total.

If the patient develops acute urinary retention, manage with suprapubic catheterization rather than transurethral catheterization. Passing a Foley catheter through an acutely inflamed prostate is painful, technically difficult, and risks worsening infection or causing bacteremia.

Chronic Bacterial Prostatitis

The same fluoroquinolone regimens are used for the same duration (4 to 6 weeks minimum). Some patients with refractory or relapsing disease may require up to 12 weeks of therapy. Alpha-blockers (tamsulosin) can be added as adjunctive therapy to relieve obstructive symptoms.

For patients with recurrent episodes despite adequate antibiotic courses, consider low-dose suppressive antibiotic therapy (e.g., TMP-SMX or nitrofurantoin at bedtime) to prevent symptomatic UTI recurrences. In rare refractory cases with documented prostatic calculi serving as a nidus, transurethral resection of the prostate (TURP) has been used, although this is not a first-line approach.

CPPS (Category III)

Management is multimodal and empiric because no single therapy is consistently effective. The initial approach combines:

• Alpha-blocker (tamsulosin 0.4 mg daily) for a minimum 6-week trial to relax prostatic smooth muscle and bladder neck

• NSAIDs for anti-inflammatory and analgesic effect

• A 4 to 6 week empiric trial of antibiotics (doxycycline or a fluoroquinolone) is reasonable in treatment-naive patients, as some patients with CPPS may harbor fastidious organisms not detected on standard culture

If initial therapy fails, consider pelvic floor physical therapy (increasingly recognized as beneficial), tricyclic antidepressants (amitriptyline) for neuropathic pain modulation, or referral to a pain specialist.

05Differential Diagnosis and Distractors

06Traps and High-Yield Pearls

The single most tested trap on prostatitis is the contraindication to prostatic massage in acute bacterial prostatitis. A vignette will describe an acutely febrile young man with a tender prostate and then ask for the "next best step." Students who select "obtain expressed prostatic secretions" or "perform the 4-glass test" will get this wrong. The Meares-Stamey test is reserved for chronic prostatitis classification, never for an acute presentation where massage risks bacteremia and sepsis.

The second common trap involves PSA interpretation. A vignette may present a patient recovering from acute prostatitis whose PSA is found to be elevated. The question tests whether you know to defer PSA-based cancer screening until 6 to 8 weeks after the infection resolves, because inflammation falsely elevates PSA. Ordering a prostate biopsy during or immediately after prostatitis is the wrong answer.

A third testing angle is the prolonged antibiotic duration. Students accustomed to treating simple UTIs for 3 to 7 days will undertreat prostatitis. The prostate's poor antibiotic penetration (relative to the bladder mucosa) demands 4 to 6 weeks of therapy. Vignettes that present a patient whose prostatitis symptoms recur after a short antibiotic course are testing whether you recognize inadequate treatment duration as the cause of relapse.

Finally, know the management of urinary retention complicating acute prostatitis. The answer is suprapubic catheterization, not a transurethral Foley. This comes up reliably because it is counterintuitive to students who default to Foley catheterization for retention in other settings.

The core competency being tested across all prostatitis questions is the ability to classify the type of prostatitis based on the clinical presentation, then match the correct diagnostic approach and treatment duration to that category, while avoiding procedural complications (massage in acute disease, Foley in retention, premature biopsy after elevated PSA).