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Prostate Abscess


Prostate Abscess

Article Author:
Anil Kumar Reddy Reddivari
Article Editor:
Parth Mehta
Updated:
6/22/2020 2:38:08 PM
For CME on this topic:
Prostate Abscess CME
PubMed Link:
Prostate Abscess

Introduction

An abscess usually forms following an inflammatory reaction to an infectious process. It is a collection of purulent material, including cell debris, liquified tissue from infective agents, and enzymes. A prostate abscess is a localized collection of purulent fluid within the prostate, often as a complication of acute bacterial prostatitis (ABP). It is difficult to distinguish acute bacterial prostatitis from a prostate abscess based on the presenting symptoms and physical examination.[1] A prostatic abscess can result in fatal consequences if appropriate measures are not taken, possibly resulting in severe urosepsis and septic shock.[2] In the current day practice of medicine, the number of prostatic abscess patients has considerably declined due to the judicious use of antibiotics. However, a prostate abscess is relatively common in developing countries and also in high-risk patients with diabetes, end-stage renal disease (ESRD) patients on hemodialysis, liver cirrhosis, and immunodeficiency. Due to the lack of clear diagnostic and treatment guidelines, a prostate abscess could be a challenge in the real world and could lead to significant morbidity.[3]

Etiology

A prostatic abscess is manifested as a complication from prostatitis. Generally, they occur in patients with poorly controlled diabetes or patients with a compromised immune system. Though rare in the current antibiotic era, patients who are not treated appropriately or adequately for acute prostatitis are at high risk of developing an abscess. Men at risk for prostate abscess include those having chronic foley or suprapubic catheters, diabetes, cirrhosis, ESRD, immunosuppression patients including HIV. Patients who do intermittent self-catheterizations or having bladder outlet obstruction are more prone to prostate abscess formation. Besides, patients with underlying voiding dysfunction either from neurological diseases or due to severe benign prostatic hypertrophy (BPH) are also at high risk. In recent trends, prostate abscess occurring as a complication after a prostate biopsy is more observed in literature which could also occur after some forms of pelvic injury. [4][5][6] 

In old literature of the pre-antibiotic era, sexually transmitted organisms like Neisseria gonorrhoeae and Chlamydia were common pathogens, but most recent data suggests causative etiology be gram-negative bacteria. In a meta-analysis study, Escherichia coli has been attributed to more than 70 percent of the cases followed by Klebsiella, Pseudomonas, Proteus, Enterobacter and Enterococcus species.[2] Staphylococcus aureus causing prostate abscess is also well documented, possibly through hematogenous infection. Fungal causative organisms like Blastomyces, Cryptococcus, and Nocardia have been listed as causes of prostatic abscess. In a case series of melioidosis, Burkholderia pseudomallei is a common pathogen causing a prostatic abscess.[7]

Epidemiology

Overall, the incidence of prostatic abscess can be as high as 0.5% of all urologic diseases, and the mortality rate is between 1 to 16 percent. Approximately 6 percent of acute bacterial prostatitis patients develop a prostate abscess.[8] Generally, older age group patients are more affected due to underlying risk factors, but prostate abscess due to sexually transmitted organisms may occur in younger males.

Pathophysiology

Typically the pathogenesis of prostate abscess is due to suboptimally treated acute bacterial prostatitis. Infection of prostate tissue occurs as a result of the reflux of infected urinary contents into prostatic ducts. Risk factors, as mentioned in the etiology section above, lead to this reflux of infective organisms and aggravated by the underlying systemic disease. Other diseases predisposing to a prostate abscess are chronic prostatitis, epididymitis, gonorrhea, pyelonephritis.[9] Hematogenous dissemination from a distant primary infected focus such as liver abscess, perirenal abscess, appendicitis, diverticulitis, or skin and subcutaneous infections causing bacteremia, primarily due to Staphylococcus aureus could also lead to an abscess in prostatic tissue.[2]

History and Physical

A comprehensive history of all underlying medical illnesses and any immunocompromised state should be promptly obtained in all cases of acute bacterial prostatitis, which helps to suspect and access risks of developing a prostate abscess. Persistence of symptoms in ABP or chronic bacterial prostatitis, especially in patients with risk factors or inadequate antibiotics, should alert providers for the evaluation of an abscess. As this pathology commonly from an ascending urinary tract infection, patients present with a range of urinary symptoms like increased urinary frequency, dysuria, hematuria, and burning urination. More specifically, perineal discomfort should point towards prostate etiology, and in some cases, patients could present with acute urinary retention.[10] Other systemic manifestations of an infectious etiology are evident by fever, chills, myalgia, and low back pain. Physical examination findings that may present in the presence of prostate abscess are purulent urethral discharge, painful rectal examination, and possible fluctuant area in the prostate.

Evaluation

Diagnosis of prostatic abscess based on history and physical findings is difficult because the symptoms are nonspecific and overlap with other lower urinary tract pathology. High clinical suspicion in nonresponding acute prostatitis patients is necessary for timely diagnosis and management. Due to its rare incidence and non-evident clinical features, the diagnosis of a prostatic abscess is sometimes delayed. Necessary investigations, complete blood count with differential, urine analysis, blood culture, and urine culture are ordered to evaluate underlying infectious disease and source of infection. After suspicion of a prostate abscess based on history and physical findings plus basic labs, imaging studies should be obtained to confirm the diagnosis.

Transrectal ultrasound (TRUS) is usually the initial diagnostic test for prostate abscess. Findings of hypoechoic areas with well-defined walls are present.[10] Being partially invasive procedure, TURP is associated with pain and discomfort for the patient. It can also overlook small abscesses.[11] Computed tomography (CT scan) of the abdomen and pelvis can better delineate the spread of infection to adjacent organs, especially used in more severe and sicker patients.[12] Rarely magnetic resonance imaging (MRI) is needed, which reveals an abscess as a hypodense area on T1, hyperdense on T2 image.[11] Imaging studies not only help in diagnosis but also guide in treatment by assisting in the drainage of the abscesses.[10][13]

Treatment / Management

Early diagnosis is favorable because prostatic abscesses require prolonged treatment protocols, sometimes need surgical drainage. Surgical procedures are not necessary in all cases of prostate abscesses. However, surgical drainage has shown to limit the duration of antibiotics and also enhance voiding function in patients with prostatic abscess.[2] Even though currently, there are no strict guidelines or algorithms for the management of prostatic abscess, expert consensus, as discussed below, is the guiding standard. After clinical suspicion of a prostate abscess, a diagnostic evaluation takes place with TRUS, based on the size and number of abscesses, conservative management could opt for less than 1 cm size abscess or additional surgical drainage is needed with ultrasound guidance in abscess size more than 1 cm.

Closely monitoring the response, conservatively treated patients may need drainage if no significant improvement. Patients not responding to initial ultrasound-guided drainage, should have additional imaging like CT scan or MRI to rule out extraprostatic spread of the abscess in which case open drainage may be warranted.[3] According to available literature, smaller abscesses (less than 1 cm) responded well to medical management, whereas larger abscesses (more than 1 cm) responded better with either single or continuous drainage.[14]

Conservative management includes broad-spectrum intravenous antibiotics necessitating inpatient hospital admission. Empiric antibiotic therapy should be targeted mainly towards gram-negative organisms. Antibiotic adjustment could be through urine grams stain results showing evidence to suspect other etiology like gram-positive bacteria or rare causes due to fungal organisms. Commonly used first-line antibiotics are levofloxacin (renal adjusted dose), intravenous carbapenem, broad-spectrum beta-lactam penicillin, or a cephalosporin. The addition of an aminoglycoside (tobramycin 5mg/kg daily) in the initial treatment regimen could be considerations, depending on the severity of the disease. A two-week course of antibiotics is a requirement for complete resolution.[15]

Different approaches have been described for ultrasound-guided drainage of the abscess, namely transrectal drainage (TRUS), transurethral aspiration, and perineal access of the abscess. Each approach has its advantages and disadvantages. In the past, transurethral drainage was the common choice for therapy due to reduced length of hospital stay, but due to possible voiding dysfunction complications, it is out of favor by many experts. Currently, transrectal drainage with transrectal ultrasound guidance is the first choice of approach because of its low risk of complications and is done under local anesthesia and is repeatable if needed.[16] The transcutaneous perineal route of aspiration is also an option at times. Open surgical drainage is necessary if the abscess has spread to deeper tissue, such as the levator ani muscle.

Differential Diagnosis

The common conditions which could present with similar presentations are urethritis, urinary tract infection, and acute or chronic bacterial prostatitis. A prostate abscess should be strongly suspected if there is a palpable fluctuant mass. Other differential diagnoses while evaluating for a prostate abscess are benign prostatic hyperplasia and perineal abscess, which could mimic by being painful local swelling conditions.

Prognosis

Prognosis of prostate abscess mainly depends on the timely diagnosis and treatment. Early recognition of this complication with appropriate treatment modalities could dramatically improve prognosis. Conservatively treated patients would need a longer duration of antibiotics. Typically, regardless of interventions, the treatment period with antibiotics is longer in cases of prostate abscess compared to ABP patients without abscess.[2] Prognosis also depends on underlying medical conditions contributing to abscess development. Elderly males above 65 years of age, presenting temperature higher than 100.4 F, history of retention of urine or benign prostatic hypertrophy, and history of chronic catheterization are all considered poor prognostic factors.

Complications

Delay in diagnosis and treatment of prostatic abscess can lead to severe complications with significant morbidity and mortality. The infection could be spread locally to adjacent perineal areas which could necessitate more invasive intervention, and also could result in more longterm complications involving the genitourinary functions. Bacteremia and sepsis subsequently causing septic shock and multi-organ failure can potentially occur in severe cases, increasing mortality. Emphysematous prostatitis manifests as having air, and reports exist of purulent material in the prostate gland with cases of Klebsiella organisms.[17]

Deterrence and Patient Education

With the evolution of medicine, a prostate abscess is not just a consequence of untreated prostatitis; men with prostate abscess have multiple medical problems and are debilitated or immunologically compromised. In the younger population, a prostatic abscess can be the initial presentation of immune compromising conditions. In older men, it is becoming more common as a complication of benign prostatic hyperplasia or a prostate biopsy.[18] Due to the challenges in differentiating prostate abscess in patients of ABP, and the importance of long-term adherence to the antibiotics treatments, it is crucial for patients to be aware of this pathology to obtain a prompt diagnosis and timely treatment. Male patients with lower urinary tract infections and prostate infections should be educated to monitor for warning signs and symptoms of abscess formation. As this condition often manifests in diabetic and immunosuppressed patients, real-life scenarios could present more challenges in the management of these patients more than just prostate abscess management. 

Enhancing Healthcare Team Outcomes

Prostatic abscesses are often underdiagnosed because symptoms can overlap with several other diseases of the urinary tract. Due to the need for subspeciality evaluation and management, primary care providers and hospitalists should coordinate with surgical services and the urology team to improve outcomes. Interprofessional team communication and care coordination between endocrinologists for underlying diabetes management, infectious diseases, and ancillary services like the wound care team play a significant role in prognosis and complications. The treating clinician can also enlist the assistance of a board-certified infectious disease pharmacist, who can collaborate on agent selection and provide the latest antibiogram data, as well as verifying dosing and performing medication reconciliation. The pharmacist should educate the patient on antibiotic compliance. Also, it is vital that the primary clinicians adequately control the blood glucose, counsel the patient on safe sex practices, and when to seek treatment. These educational processes can benefit from nursing staff who will not only provide training and answer questions but can perform followup monitoring and evaluate treatment effectiveness and inform the clinician of any concerns.

Open communication between the team is vital if one wants to prevent morbidity and mortality.  Patients with prostate abscess must be watched closely, as they may experience a high mortality rate if adequate and timely treatment does not occur.[13] This is why interprofessional teamwork is necessary to achieve optimal outcomes for the patient. [Level 5]


References

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