Prostatitis

Introduction

Prostatitis describes inflammation of the prostate gland, but the term covers a spectrum of conditions with very different causes, presentations and treatments. It is common - affecting perhaps 10-15% of men at some point - and is a frequent cause of chronic pelvic pain in men under 50.¹

The single most important conceptual point is that the great majority of symptomatic prostatitis is not bacterial. Over 90% of cases fall into the chronic pelvic pain syndrome category, in which no organism is identified and repeated courses of antibiotics achieve nothing except adverse effects and resistance.

Aetiology and risk factors

Bacterial prostatitis (categories I and II)

Infection usually reaches the prostate by reflux of infected urine into the prostatic ducts, or by ascending urethral infection. The organisms mirror those of urinary tract infection:

• Escherichia coli - the commonest by a clear margin
• Klebsiella, Proteus, Enterococcus and Pseudomonas
• Chlamydia trachomatis and Neisseria gonorrhoeae - consider particularly in men under 35 or with sexual risk factors, and take a sexual history
• Staphylococcus aureus - occasionally, usually haematogenous
• Mycobacterium tuberculosis - rare, in endemic areas or the immunosuppressed

Risk factors

• Recent urinary tract infection or urethritis
• Urinary catheterisation or instrumentation - including transrectal prostate biopsy, a recognised and important cause of acute prostatitis and sepsis (part of why transperineal biopsy is now preferred)
• Bladder outlet obstruction and incomplete emptying - benign prostatic hyperplasia, stricture
• Urinary retention
• Unprotected anal intercourse and other sexual risk factors
• Diabetes mellitus and immunosuppression
• Phimosis
• Previous prostatitis - recurrence is common

Chronic pelvic pain syndrome (category III)

The cause is poorly understood and probably multifactorial. Proposed contributors include pelvic floor muscle dysfunction and spasm, neuropathic pain sensitisation, intraprostatic urinary reflux causing chemical inflammation, autoimmune mechanisms, and psychological factors including anxiety, depression and a history of adverse experiences. It behaves much more like a chronic pain syndrome than an infection, and should be managed as one.

Clinical features

Acute bacterial prostatitis (category I)

• Fever, rigors, malaise and myalgia - the patient is systemically unwell, and may be frankly septic
• Perineal, suprapubic, rectal, penile or lower back pain
• Urinary symptoms - dysuria, frequency, urgency, poor stream, and sometimes acute urinary retention from prostatic swelling
• Pain on ejaculation and haematospermia
• Digital rectal examination: the prostate is exquisitely tender, warm, swollen and 'boggy'
• Tachycardia, hypotension and confusion indicate sepsis

Chronic bacterial prostatitis (category II)

• Recurrent urinary tract infections with the same organism - the hallmark
• Relapsing pelvic or perineal discomfort between episodes, often milder
• Lower urinary tract symptoms
• Usually afebrile and systemically well between acute flares

Chronic pelvic pain syndrome (category III)

• Pelvic, perineal, suprapubic, testicular, penile or low back pain for at least 3 of the previous 6 months - the defining feature
• Pain on ejaculation, and sexual dysfunction including erectile difficulties and reduced libido
• Lower urinary tract symptoms - frequency, urgency, hesitancy, sensation of incomplete emptying
• Systemically well, afebrile, with negative cultures
• Substantial impact on quality of life and mood - anxiety and depression are common and should be asked about directly
• Examination is often unremarkable, though there may be pelvic floor tenderness on DRE

Differential diagnosis

Investigations

• Urine dipstick and midstream urine for culture - the key investigation; frequently positive in acute bacterial prostatitis and identifies the organism to guide therapy
• Blood cultures - if febrile or systemically unwell
• FBC, CRP and U&Es - inflammatory response and renal function
• Sexual health screen (NAAT for chlamydia and gonorrhoea) - especially in men under 35 or with risk factors; a first-void urine sample is used
• Post-void residual bladder scan - to detect retention, which is common in acute prostatitis
• Blood glucose / HbA1c - diabetes as a predisposing factor
• PSA - do not measure during acute prostatitis, as it will be markedly and misleadingly raised. If needed, defer for at least 6 weeks after the infection has resolved. Prostatitis is one of the commonest benign causes of a raised PSA
• Transrectal or transperineal ultrasound, or CT/MRI of the pelvis - if a prostatic abscess is suspected because of failure to improve
• Meares-Stamey four-glass test or the simpler two-glass (pre- and post-massage) test - localises infection to the prostate in chronic disease by comparing urine and expressed prostatic secretions. Rarely performed in routine UK practice but classically described
• NIH-CPSI questionnaire - the Chronic Prostatitis Symptom Index quantifies pain, urinary symptoms and quality of life in category III, and is useful for tracking response
• Urodynamics and cystoscopy - in selected chronic cases to exclude other pathology

Management

Acute bacterial prostatitis (category I)

• Antibiotics that penetrate prostatic tissue - a fluoroquinolone (ciprofloxacin 500 mg twice daily or ofloxacin) is first line, with trimethoprim as an alternative. Nitrofurantoin must not be used: it concentrates in urine but does not achieve therapeutic levels within the prostate
• Duration: at least 14 days, and commonly 28 days, because antibiotic penetration into prostatic tissue is poor and relapse is common with shorter courses
• Intravenous antibiotics and admission if systemically unwell, septic, vomiting, in retention, or immunosuppressed - typically a broad-spectrum agent with or without gentamicin
• Analgesia (paracetamol and NSAIDs) and stool softeners, since defaecation is often painful
• Manage urinary retention - if catheterisation is needed, a suprapubic catheter is generally preferred to avoid traumatising the inflamed prostatic urethra; discuss with urology
• Review at 48-72 hours - failure to improve suggests prostatic abscess or a resistant organism, and warrants imaging
• Follow-up culture after treatment to confirm clearance

Chronic bacterial prostatitis (category II)

• A prolonged course of a quinolone or trimethoprim for 4 to 6 weeks, guided by culture
• Alpha-blockers (e.g. tamsulosin) to relieve voiding symptoms
• Analgesia and management of any underlying obstruction or stones
• Low-dose suppressive antibiotics occasionally used in frequent relapse
• Consider prostatic calculi as a persistent nidus for infection where relapse is repeated

Chronic pelvic pain syndrome (category III)

This requires a multimodal, chronic-pain approach, and the most important message is that repeated courses of antibiotics are not appropriate once infection has been reasonably excluded.

• Explanation and reassurance - explaining that this is a genuine pain syndrome and not an untreated infection or cancer is therapeutic in itself
• Alpha-blockers (tamsulosin) - most useful where voiding symptoms predominate, particularly in men not previously treated
• Analgesia - simple analgesics and NSAIDs, escalating to neuropathic agents such as amitriptyline, gabapentin or pregabalin where pain has neuropathic features
• Pelvic floor physiotherapy - specialist physiotherapy with myofascial release and relaxation techniques is genuinely effective where there is pelvic floor spasm
• Psychological support - CBT and pain management programmes; screen for and treat anxiety and depression
• A single trial of antibiotics (4-6 weeks) is sometimes given at first presentation where infection cannot be confidently excluded, but should not be repeated if ineffective
• Lifestyle measures - avoiding prolonged sitting and cycling, heat therapy, and reducing caffeine and alcohol
• Referral to a specialist urology or chronic pain service where symptoms persist

Complications

• Sepsis and septic shock - the principal danger of acute bacterial prostatitis, and a recognised complication of transrectal prostate biopsy
• Prostatic abscess - suspect when fever persists beyond 48-72 hours of appropriate antibiotics; requires imaging and drainage (transurethral or transrectal)
• Acute urinary retention - from prostatic oedema
• Progression to chronic bacterial prostatitis - occurs in a proportion of acute cases, particularly if treated with too short a course
• Recurrent urinary tract infection, with the prostate acting as a bacterial reservoir
• Epididymo-orchitis
• Infertility and sexual dysfunction - impaired semen quality, painful ejaculation, erectile dysfunction
• Chronic pelvic pain and its considerable effect on quality of life
• Anxiety and depression - common in category III and frequently under-treated
• Fournier's gangrene - a rare but life-threatening necrotising fasciitis of the perineum, particularly in diabetics
• Diagnostic confusion with prostate cancer through PSA elevation, leading to unnecessary biopsy

Red flags

Prognosis

Acute bacterial prostatitis responds well to adequate treatment, with fever and pain typically settling within 2 to 6 days of starting an appropriate antibiotic. The critical determinant of a durable cure is the duration of therapy: courses shorter than two weeks are associated with relapse and progression to chronic bacterial prostatitis, which is why 14 to 28 days is standard. A minority develop a prostatic abscess or sepsis, and these carry significant morbidity.

Chronic bacterial prostatitis is more difficult, largely because antibiotics penetrate prostatic tissue poorly and bacteria may be protected within calculi or biofilm. Cure rates with a 4 to 6 week quinolone course are in the region of 60-80%, but relapse is common and some men require repeated or suppressive therapy.

Chronic pelvic pain syndrome has the least satisfying outlook, and expectations should be set honestly. Symptoms typically fluctuate over years, with periods of remission and relapse rather than a clean cure. That said, most men improve substantially with a multimodal approach combining alpha-blockers, appropriate analgesia, pelvic floor physiotherapy and psychological support - and outcomes are considerably better when the condition is framed correctly from the outset as a chronic pain syndrome rather than as a persistent infection. Repeated fruitless antibiotic courses, by contrast, delay effective treatment, cause harm, and reinforce an unhelpful illness model.