Garjae D. Lavien, MD
Michael J. Naslund, MD
BASICS
DESCRIPTION
• Prostate abscess is an infection of the prostate with focal accumulation of pus within the prostate gland
• Difficult to initially clinically distinguish from acute bacterial prostatitis
• Usually as a result of ineffective antibiotic therapy for acute prostatitis
– Rare in nonhospitalized patients
EPIDEMIOLOGY
Incidence
Decreasing with widespread use of antibiotics
Prevalence
Diagnosed in 0.2% of patients with urologic symptoms, 0.5–2.5% of patients hospitalized for prostatic symptoms (1)
RISK FACTORS
• Bladder outlet obstruction, history of bacterial prostatitis
• Chronic hemodialysis
• Compromised immune system (eg, HIV/AIDS, diabetes, etc.)
• Indwelling catheters
• Lower urinary tract instrumentation
• Sexually transmitted infections
Genetics
N/A
PATHOPHYSIOLOGY
• Usually an ascending infection in association with poor bladder emptying.
• Urethral infection combined with intraprostatic reflux of infected urine causes acute prostatitis.
• Acute prostatitis can, in patients with immunosuppression or other risk factors, progress to abscess.
• Hematogenous dissemination, especially with Staphylococcus sp. seen in immunocompromised patients/IV drug users.
• Most common etiologic agent is Escherichia coli (2)[B].
• With the advent of antibiotics, the incidence of Neisseria gonorrhea as causative agent has decreased significantly.
• Most common etiologic agent seen in emphysematous prostate abscess (EPA) is Klebsiella pneumoniae (3)[B].
• With severe immunocompromise, such as HIV; more unusual organisms such as TB, Cryptococcus, histoplasmosis, and Candida should be considered.
• Melioidosis is an infection (usually abscesses in many sites including the prostate).
– Caused by the gram-negative Burkholderia pseudomallei.
– Usually associated with diabetes.
– Very high prevalence in East Asia and Northern Australia.
ASSOCIATED CONDITIONS
• Any disease process that causes immunocompromise:
– Cancer
– Chronic renal failure, hemodialysis
– Cirrhosis
– Diabetes
– HIV/AIDS
GENERAL PREVENTION
• Aimed at preventing and treating sexually transmitted infections
• Relieving/improving signs/symptoms of bladder outlet obstruction
• Diabetic glycemic control
• Appropriate treatment of patients with acute prostatitis
DIAGNOSIS
HISTORY
• Fevers, chills
• Urinary symptoms with attention paid to voiding patterns prior to acute presentation
– Dysuria, urinary urgency and frequency are almost universal symptoms
– Suprapubic or subpubic pain,
– Severe perineal pain
– Rectal tenesmus
• Acute urinary retention
• Sexual history/social history (IV drug use, etc.)
• Associated medical comorbidities
ALERT
Where prostate abscess or acute prostatitis is suspected, rectal exam may be contraindicated.
PHYSICAL EXAM
• Perineal pain, tenderness
• Urethral discharge
• Digital rectal exam can reveal exquisitely tender and warm prostate with fluctuance or simply an enlarged prostate
• Signs of other medical comorbidities (ie, new cardiac murmur, ascites, cough, track marks, etc.)
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Complete blood count with differential
• Urinalysis, urine/blood cultures
• Gram stain/culture of prostatic fluid once drained
• AFB or mycobacterium-specific PCR if TB suspected
• Prostate-specific antigen should not be obtained in this setting as it will usually be elevated due to the inflammatory process
Imaging
• Transrectal ultrasound (TRUS)
– Will reveal hypoechoic zones with irregular internal echoes, septations, and indirect borders with the surrounding prostate;
– Must be performed cautiously.
– May guide drainage and aspiration
– The presence of gas suggests EPA
• Color Doppler sonography
– Will show an increase in vascularity around the abscess, due to hyperemia stemming from the surrounding inflammation
• Computed tomography (CT)
– Can determine penetration of the abscess into the periprostatic tissues and identify gas within the prostate
– CT findings include nonenhancing fluid-density collections that can be multiseptated or rim-enhancing lesions.
• MRI
– MRI may not be feasible in patients who are critically ill and require acute management
Diagnostic Procedures/Surgery
• TRUS with aspiration
• Transperineal ultrasound with aspiration
• Transurethral unroofing of prostate abscess
Pathologic Findings
• Purulent material will be expressed from prostate during surgical drainage procedure:
– Gram stain and culture of material will give causative agent, most commonly bacterial
DIFFERENTIAL DIAGNOSIS
• Clinically can be hard to distinguish from urinary tract infection (UTI), acute prostatitis, or any other lower UTI.
• Should have clinical suspicion, which can be confirmed with imaging.
TREATMENT
GENERAL MEASURES
• Initial treatment should focus on broad-spectrum antibiotics, IV hydration, and pain control.
• In the setting of acute urinary retention, a Foley catheter placement can be attempted.
– Occasionally the transurethral catheter may block drainage of an acutely inflamed prostate or cause bacteremia.
– In the setting of extreme discomfort or if the catheter is difficult to pass, a suprapubic punch cystostomy is preferred.
MEDICATION
First Line
• Broad-spectrum IV antibiotic therapy followed by directed therapy after causative organism determined by urine culture or Gram stain/culture of abscess fluid:
– 2nd-generation cephalosporins (cefoxitin, zinacef) or 3rd-generation cephalosporins (ceftriaxone, cefotaxime, ceftazidime)
– IV fluoroquinolones
– Clindamycin for additional anaerobic coverage is recommended initially
600–900 mg IV every 8 hr (q8h)
– After acute phase, continue oral antibiotic regimen based on cultures for up to 4 wk
Second Line
• Vancomycin for coverage of MRSA is suspected.
– Dose based on renal function
• Fungal infections may require 4–6 wk of systemic therapy in addition to drainage.
SURGERY/OTHER PROCEDURES
• Transurethral unroofing of prostate abscess
• Transperineal or transrectal needle aspiration with US guidance followed by urethral catheter drainage
– Can be performed using local anesthesia or sedation
– Higher risk of recurrence of abscess
• Open incision and drainage through a perineal approach
– Utilized in patients with penetration of the abscess through the capsule of the prostate or through the levator ani
– Allows placement of a drain
– Increased morbidity compared to open percutaneous or transurethral approaches
• Suprapubic cystotomy can be used as an adjunct for urinary diversion in patients with urinary retention
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
• Relates to predisposing conditions
• For patients with bladder outlet obstruction, therapy should be started to relieve obstruction, (ie, α-blockers or 5α-reductase inhibitors)
Complementary & Alternative Therapies
N/A
ONGOING CARE
PROGNOSIS
• Should recover fully once definitive therapy undertaken
• Although EPA is rare, a 25% mortality rate has been reported
COMPLICATIONS
• May progress to spontaneous fistulization into the urinary bladder, prostatic urethra, rectum, or perineum.
• Urosepsis, and possibly death if diagnosis not made in timely manner.
FOLLOW-UP
Patient Monitoring
• Supportive once definitive therapy performed
• Once acute events resolves, monitoring focuses on optimizing medical comorbidities and improving voiding symptoms.
• Author recommendation: CT or TRUS 4–6 wk after definitive therapy to confirm that no residual abscess remains
• Follow-up urine culture recommended
Patient Resources
N/A
REFERENCES
1. Granados EA, Riley G, Salvador J, et al. Prostatic abscess: Diagnosis and treatment. J Urol. 1992;148:80–82.
2. Ludwig M, Schroeder-Printzen I, Schiefer HG, et al. Diagnosis and therapeutic management of 18 patients with prostatic abscess. Urology. 1999;53(2):340–345.
3. Tai H. Emphysematous prostatic abscess: A case report and review of literature. J Infect. 2007;54:e51–e54.
ADDITIONAL READING
• Baker SD, Horger DC, Keane TE. Community-acquired methicillin-resistant Staphylococcus aureus prostatic abscess. Urology. 2004;64(4):808–810.
• Jang K, Lee DH, Lee SH, et al. Treatment of prostatic abscess: Case collection and comparison of treatment methods. Korean J Urol. 2012:53(12):860–864.
See Also (Topic, Algorithm, Media)
• Prostate, Abscess Image 
• Prostatitis, Acute, Bacterial (NIH I)
• Urinary Tract Infection (UTI), Adult Male
• Urosepsis
CODES
ICD9
• 596.0 Bladder neck obstruction
• 601.0 Acute prostatitis
• 601.2 Abscess of prostate
ICD10
• N32.0 Bladder-neck obstruction
• N41.0 Acute prostatitis
• N41.2 Abscess of prostate
CLINICAL/SURGICAL PEARLS
• Prostate abscess is uncommon and thus often overlooked in the differential diagnosis.
• Suspect prostatic abscess in patients presenting with fever and persistent lower urinary tract symptoms that do not respond to antibiotics.
• A pelvic CT scan is generally the best test to evaluate for the possibility of a prostate abscess.
• A delay of antimicrobial therapy in the management of acute bacterial prostatitis can increase the risk of prostatic abscess.