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PROSTATITIS

General Goal: To know the major cause(s) of this disease, how this disease is acquired, and the major manifestations this disease.

Specific Educational Objectives: The student should be able to:

1. recite the common means by which this disease is acquired and identify the major disease manifestations.

2. identify the various types of prostatitis based on clinical presentation and testing.

3. describe which forms of prostatitis are most amenable to treatment. Know which patients with prostatitis that you should NOT obtain prostatic secretions and why.

Reading: Mosby's Color Atlas and Text of Infectious Diseases by Christopher P. Conlon and David R. Snydman. pp.132-136.

Lecture: Dr. Neal R. Chamberlain

References: JAMES J. STEVERMER, M.D., M.S.P.H., and SUSAN K. EASLEY, M.D. Treating Prostatitis. Am Fam Physician 2000;61:3015-22,3025-6.

Overview

Prostatitis is an inflammation of the prostate gland. The term prostatitis describes a wide spectrum of disorders ranging from acute bacterial infection to chronic pain syndromes. Prostatitis describes a wide number of maladies with variable etiologies, prognoses and treatments. Unfortunately, these conditions have not been well studied, and most recommendations for treatment are based primarily on case series and anecdotal experience. Prostatitis can be a challenging condition to treat.

Etiology depends on the classification of the prostatitis. However, most of the cases of prostatitis due to an infection are the result of gram negative bacteria.

60% of the cases of acute bacterial prostatitis (ABP) are due to Escherichia coli (most common cause).

Frequently the following cause ABP:
Klebsiella sp.
Proteus sp.
Pseudomonas aeruginosa
Enterococcus spp.

Occasionally Chlamydia spp., Staphylcocccus aureus, or anaerobes such as Bacteriodes spp. cause ABP.

The overwhelming majority of infections are due to Gram-negative rod shaped bacteria. Twenty percent of patients may have two or more different kinds of Gram-negative bacilli present in the prostate.

Epidemiology

Prostatitis is a common condition. In a survey of National Guard members (20 to 49 years of age) using a self-reported diagnosis of prostatitis, a 5 percent lifetime prevalence was noted. A population-based study of men (40 to 79 years of age) in Minn., suggests a lifetime prevalence of close to 9 percent. Patients with a previous episode of prostatitis were much more likely to experience subsequent episodes. In a nationwide review of data from outpatient physician visits, it was noted that 15 percent of men who saw a physician for genitourinary complaints were diagnosed with prostatitis. Every year, approximately 2 million physician visits include the diagnosis of prostatitis. Despite its widespread prevalence, prostatitis remains a poorly studied and little understood condition.

Pathogenesis

How prostatitis occurs is still largely unknown. However, two main mechanisms for Acute Bacterial Prostatitis have been proposed.

Reflux of infected urine into the glandular prostatic tissue via the ejaculatory and prostatic ducts.
Ascension of a urethral infection from the meatus, particularly during sexual intercourse.

These mechanisms may also cause the other types of prostatitis.

Pathology

Acute prostatitis: Inflammation of the prostate. Numerous PMN's in and around the acini, associated with intraductal desquamation, cellular debris and tissue invasion by lymphocytes, plasma cells, and macrophages. Microabscesses may occur and develop into large abscesses.

Chronic forms of prostatitis: Less inflammation of the prostate. Infiltration by plasma cells and macrophages in and around the acini.

MANIFESTATIONS

Acute Bacterial Prostatitis (ABP): Because acute infection of the prostate is often associated with infection in other parts of the urinary tract patients may also have symptoms consistent with cystitis or pyelonephritis. Fever, shaking chills, perineal pain, low back pain, dysuria, urinary frequency and urgency, decreased libido or impotence, painful ejaculation, and varying degrees of bladder outflow obstruction. Physical exam reveals a warm, very tender, diffusely enlarged, irregular, and indurated prostate. It is best to avoid a vigorous digital examination of the prostate because it can induce bacteremia or make their bacteremia worse.

Chronic Bacterial Prostatitis (CBP): CBP is a common cause of recurrent urinary tract infections in men. Symptoms are quite variable and include irritative voiding symptoms, pain in the back, testes, epididymis or penis, low-grade fever, arthralgias and myalgias. Many patients are aysmptomatic between episodes of cystitis. Signs may include urethral discharge, hemospermia and evidence of secondary epididymo-orchitis. Usually the prostate is normal on digital rectal examination. Refer to table below for more help in diagnosis.

Chronic Nonbacterial Prostatitis/Chronic Pelvic Pain Syndrome- Inflammatory and noninflammatory (CNP/CPPS): In men going to urologic referral centers more than 90 percent meet the criteria for CNP/CPPS. Painful ejaculation, pain in the penis, testicles, or scrotum, low back pain, rectal or perineal pain, or even pain along the inner aspects of the thighs. They oftentimes have irritative or obstructive urinary symptoms and decreased libido or impotence. They usually do not have recurrent urinary tract infections. Usually the physical exam is unremarkable however they may have a tender prostate.

Asymptomatic Prostatitis: This new category was added because of the widespread use of the prostate-specific antigen (PSA) test. Symptomatic prostatitis can elevate the PSA test to abnormal levels. Patients being evaluated for other prostatic disease may be found to have prostatitis on biopsy. It appears that a 14 day course of antibiotics in men with asymptomatic prostatitis can return PSA levels to normal. Treatment is only recommended in patients with chronic asymptomatic prostatitis known to elevate PSA.

DIAGNOSIS

Prostatitis is not easily diagnosed or classified. Patients often present with varied and nonspecific symptoms. The physical examination is frequently not useful. If the history and physical suggest prostatitis consider using the four-glass test (Stamey-Meares four glass localization method) or the pre- and postmassage test (PPMT). Even though the Stamey-Meares method is the gold standard it has not been assessed for its usefulness in the diagnosis or treatment of prostatitis. The expression of prostatic secretions can be difficult and uncomfortable. The test is cumbersome and expensive which may explain why many primary care physicians and urologists infrequently use it. In most cases, empiric antibiotic therapy is reasonable whether or not the diagnostic test proves a bacterial cause.

Interpretation of Two Diagnostic Tests for Prostatitis

Diagnostic test	Test components
Pre- and postmassage test (PPMT)	Midstream urine culture*		Expressed prostatic secretions‡
Stamey-Meares four-glass test	Premassage urine culture*	Premassage urine microscopy†	Postmassage urine culture‡	Postmassage urine microscopy†
.
Type of prostatitis	Test findings
Acute bacterial prostatitis	+	+	Avoid massage in ABP	Avoid massage in ABP
Chronic bacterial prostatitis	-	±	+	+
Chronic nonbacterial prostatitis/ CPPSinflammatory	-	±	-	+
Chronic nonbacterial prostatitis/ CPPSnoninflammatory	-	-	-	-
Asymptomatic prostatitis	±	±	+	+

+ = Positive; - = negative; ABP = acute bacterial prostatitis; CPPS = chronic pelvic pain syndrome.
*--Negative result is no bacterial growth. Positive result is growth of a single bacterial species (>100,000 colony forming units per mL).
†--Negative result is <10 white blood cells per high-power field. Positive result is >10 to 20 white blood cells per high-power field.
‡--Positive result is significant bacteriuria in the postmassage specimen (any bacteria if the premassage urine is sterile or colony count per mL is at least 10 times greater than premassage count).

Two different classification systems are currently in use in the management of prostatitis. The comparison of the two different systems can be seen below.

Classifications of Prostatitis

Classic system*	NIH proposal†
Acute prostatitis	I	Acute prostatitis
Chronic bacterial prostatitis	II	Chronic bacterial prostatitis
Chronic nonbacterial prostatitis	IIIa	Chronic nonbacterial prostatitis/chronic pelvic pain syndromeinflammatory
Prostadynia	IIIb	Chronic nonbacterial prostatitis/chronic pelvic pain syndromenoninflammatory
--	IV	Asymptomatic prostatitis

*--Information from Stamey TA. Pathogenesis and treatment of urinary tract infections. Baltimore: Williams & Wilkins, 1980.
†--Proposed at the Chronic Prostatitis Workshop, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Md., December 7-8, 1995 and retrieved on April 20, 2000, from http://www.niddk.nih.gov/health/urolog/pubs/cpwork/cpwork.htm.

Classic system:
Acute prostatitis; rapid onset of symptoms with greater than 100,000 CPU's per ml in midstream urine culture premassage of the prostate as well as greater than 10 to 20 white blood cells per high powered field. Equivalent to Class I Acute Prostatitis in the new system. Please note massage of the prostate is not recommended as it could cause bacteremia.

Chronic bacterial prostatitis; onset of symptoms takes longer; weeks to months. Negative results for premassage midstream urine culture, positive or negative results for white blood cells premassage, positive postmassage urine culture, positive postmassage for white blood cells per high powered field. Equivalent to Class II Chronic bacterial prostatitis.

Chronic nonbacterial prostatitis; onset of symptoms takes longer; weeks to months. Negative premassage urine culture, white blood cell count, and postmassage urine culture. Positive postmassage white blood cell count. Equivalent to Class IIIa chronic nonbacterial prostatitis/chronic pelvic pain syndrome-inflammatory.

Prostadynia; onset of symptoms takes longer; weeks to months. All cultures and white blood cell counts are negative. Equivalent to Class IIIb chronic nonbacterial prostatitis/chronic pelvic pain syndrome- noninflammatory.

???; Asymptomatic prostatitis: not in the older classification system; may be positive for presmassage samples. Positive urine culture and white blood cell counts postmassage.

Chronic nonbacterial prostatitis/CPPS (includes classes IIIa and IIIb) is the most common symptomatic type of prostatitis, and it may be the most prevalent of all prostate diseases, including benign prostatic hyperplasia.

PROGNOSIS

Acute Bacterial Prostatitis (ABP): Usually responds very well to therapy. However, many physician treatments are only for 2 weeks and many treatment failures occur. Treatments for 3-4 weeks or longer result in few recurrences. Prostatic abscesses may develop requiring transurethral drainage or resection.

Chronic Bacterial Prostatitis (CBP): Efficacy of antibiotic treatment is limited by the lack of inflammation in the prostate. Many treatment failures occur and it is most likely due to lack of penetration of the antibiotic into the prostate. With treatment failures come recurrent urinary tract infections. Long course antibiotics oftentimes are needed. In extreme cases prostatectomy may provide a definitive cure. Unfortunately, complications following this surgery really limit this approach.

Chronic Nonbacterial Prostatitis/Chronic Pelvic Pain Syndrome- Inflammatory and noninflammatory (CNP/CPPS): A large number of possible etiologies and disorders are most likely lumped into this category of prostatitis. This condition can last for long periods of time. Certain drugs can be given to lessen the severity of symptoms. This condition will not result in prostate cancer.

Asymptomatic Prostatitis: Only problematic when testing for PSA or if the prostatitis becomes symptomatic.

THERAPY

Acute Bacterial Prostatitis (ABP): Patients respond well to most antibiotics primarily because the prostate is inflamed. Antibiotics that are usually used include: tetracycline, trimethoprim-sulfamethoxazole, or a quinolone. Men that are likely to get sexually transmitted diseases should be treated with an antibiotic that also covers Chlamydia spp.. The duration of the therapy is not very well studied however, most experts recommend 3-4 weeks of treatment. Longer courses of therapy may be needed. If the patient is extremely ill (septic) they should be hopitalized and receive parenteral antibiotics. Treatment is similar to treatments for sepsis. Unfortunately, most (65 percent of primary care physicians and 40 percent of urologists) only treat for 2 weeks and as a result see more treatment failures.

Severe obstructions may require suprapubic catherters. Supportive measures include antipyretics, analgesics, hydration, and stool softeners.

Chronic Bacterial Prostatitis (CBP): The cure rate with antibiotics ranges from 33 to 71 percent depending of the study and the antibiotics used. Initially treatment with trimethoprim-sulfamethoxazole should be considered for at least 3-4 weeks. Treatment failures can be treated with norfloxacin for 28 days with a cure rate in one study of 64 percent. Rarely, transurethral prostatectomy may be curative. Prostatectomy may be necessary but surgical complications are frequent.

Chronic Nonbacterial Prostatitis/Chronic Pelvic Pain Syndrome- Inflammatory and noninflammatory (CNP/CPPS): Treatment is challenging and very difficult. Failures are commonplace. Initially an antibiotic trial is attempted as indicated above. Hot sitz baths, nonsteroidal anti-inflammatory drugs (NSAIDs), avoiding intake of alcohol or spicy foods. Irritatve symdromed may be helped with anticholinergic drugs or alpha-blocking agents. Reassurance that their condition is neither infectious nor contagious and it is not known to cause prostatic cancer or other serious disorders. Counseling to manage the chronic pain may be helpful.

Asymptomatic Prostatitis: It appears that a 14 day course of antibiotics can return PSA levels to normal. Treatment is only recommended in patients with chronic asymptomatic prostatitis known to elevate PSA. In these patients it is wise to treat with antibiotics before drawing anymore PSA samples.