eMedicine Specialties > Infectious Diseases > Genitourinary Tract Infections

Urinary Tract Infection, Males

Author: Burke A Cunha, MD, Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital
Contributor Information and Disclosures

Updated: Oct 19, 2009

Introduction

Background

This article addresses prostatitis, epididymitis, orchitis, and, as they apply to adult males, pyelonephritis, cystitis, and urethritis. Nosocomial urinary tract infections (UTIs) and their main risk factor, indwelling urethral catheters, are also discussed, with attention directed to unique aspects of the male urinary system. Special hosts (eg, patients with spinal injury, diabetes, or transplants) and special conditions (eg, candiduria, perirenal abscess) are discussed in more detail in Urinary Tract Infection, Females. For issues relating to multidrug-resistant organisms (eg, Acinetobacter) or particular organism infections (eg, gonorrhea, schistosomiasis), consult those particular articles.

The normal male urinary tract has many natural defenses to infection. Transitional epithelium conducts urine from the kidneys to an elastic bladder, which can store large volumes at low pressures. The male urethra is separated from the rectum by several centimeters of keratinized squamous epithelium; the long urethra provides an additional barrier between the bladder and the perineum. Because of these many defenses, many experts consider UTIs in males, by definition, to be complicated. Complicated infections are those more likely to be associated with anatomic abnormalities, requiring surgical intervention to prevent sequelae. The diagnosis and treatment of UTIs in males should proceed with this concept in mind.

UTIs can be divided anatomically into upper- and lower-tract infections. In the male, lower-tract disease includes prostatitis, epididymitis, cystitis, and urethritis. Upper-tract disease (pyelonephritis) is similar in males and females. The phrase "significant bacteriuria" is sometimes used to emphasize that the number exceeds that which might be caused by contamination during the collection of the specimen. Bacteriuria can be symptomatic or asymptomatic.

Prostatitis

In the 1800s, prostatitis was thought to be secondary to excessive alcohol consumption or physical or sexual activity. It was often associated with gonorrhea and could be fatal or lead to abscess formation. By the 1920s, most cases were attributed to microorganisms, and antibiotics combined with prostate massage were standard therapy after World War II. Although the role of bacteria was questioned in the 1950s, it was reemphasized in 1968 when Meares and Stamey described their "4-glass test."¹

Epididymitis

Epididymitis is a clinical syndrome caused by infection or inflammation of the epididymis. It is the most common cause of acute scrotum in adult male populations. Long-term complications include abscesses, infarction, recurrence, chronic pain, and infertility.

Orchitis

Orchitis was first described in approximately 400 BC by Hippocrates. Because of the widespread use of mumps vaccination, it is no longer a common infection in the United States. Orchitis is one of the few genitourinary infections resulting from a viral pathogen.

Pyelonephritis

Pyelonephritis is an infection of the renal parenchyma. Infection usually occurs in a retrograde ascending fashion from the bladder, but it may occur hematogenously. The ureteral orifice becomes edematous, and it loses its one-way valve function during infection. Retrograde flow of bacteria into the upper tracts and into renal parenchyma results in clinical symptoms.

Bacterial cystitis

Bacterial cystitis without concomitant infection in other portions of the genitourinary tract is believed to be a rare event in males. The abrupt onset of irritative voiding symptoms (eg, frequency, urgency, nocturia, dysuria) and suprapubic pain are clinically diagnostic.

Urethritis

Urethritis has been described for thousands of years. The term gonorrhea (gonus meaning seed, rhoia meaning flow) was coined by Galen. Gonococcal urethritis remains the most commonly reported communicable bacterial disease in the United States.

Urinary catheters

Up to 25% of hospitalized patients have urinary catheters inserted; of these, 10-27% develop UTIs. UTI accounts for approximately 40% of all nosocomial infections; 15% of these infections occur in clusters and often involve highly resistant organisms. The single most important risk factor for nosocomial bacteriuria and UTI is the presence of an indwelling urethral catheter; 80% of nosocomial UTIs are associated with the use of urethral catheters. Once the urethral catheter is in place, the daily incidence of bacteriuria is 3-10%. Because most become bacteriuric by 30 days, that is a convenient dividing line between short- and long-term catheterization.

Pathophysiology

Entry of microorganisms into the prostate gland almost always occurs via the urethra; with intraprostatic reflux of urine, bacteria migrate from the urethra or bladder through the prostatic ducts. Other possibilities include entry via the hematogenous route, via the lymphatics from the rectum, and during prostatic surgery; many patients have no known precipitating event. Prostatic fluid contains various antibacterial substances, including zinc and antibodies, which are lacking in some patients with chronic bacterial prostatitis. Interestingly, acute prostatitis usually does not result in chronic prostatitis, and chronic bacterial prostatitis is usually not antedated by acute prostatitis. Of men referred for prostatitis, less than 10% have either acute or chronic bacterial prostatitis.

Acute prostatitis

This is an acute infection of the entire prostate gland, resulting in fever and localized pain. Microscopically, neutrophilic infiltrates, diffuse edema, and microabscesses may be seen, which may coalesce into larger collections.

Chronic prostatitis

This may be caused by inflammatory or noninflammatory diseases. It has been subdivided by the National Institutes of Health (NIH) into category II (chronic bacterial prostatitis), category III (chronic abacterial prostatitis; category IIIA is chronic inflammatory abacterial prostatitis and category IIIB is chronic noninflammatory abacterial prostatitis, also known as chronic pelvic pain or prostatodynia), and category IV (asymptomatic inflammatory prostatitis). Chronic prostatitis may arise via dysfunctional voiding, intraprostatic reflux, chronic exposure to microorganisms (see Causes), autoimmune mechanisms, irritative urinary metabolites, and as a variant of neuropathic pain. Chronic bacterial prostatitis often produces few or no symptoms related to the prostate, but it probably is the most common cause of relapsing UTI in men.

Epididymitis

The pathophysiology of epididymitis is divided; Chlamydia trachomatis and Neisseria gonorrhoeae are the most common pathogens in patients younger than 35 years, whereas Enterobacteriaceae and gram-positive cocci are frequent pathogens in older patients. In either case, infection results from retrograde ascent of infected urine from the prostatic urethra, into the vas deferens, and, finally, into the epididymis.

Orchitis

Orchitis is one of the few genitourinary infections resulting from a viral pathogen. Mumps orchitis occurs in 18% of postpubertal boys infected with the mumps virus. Other viruses that can cause the disease include coxsackie B, mononucleosis, and varicella. Unlike the majority of genitourinary infections, viral particles are spread to the testicle by the hematogenous route. Granulomatous orchitis is rare and results from hematogenous dissemination of tuberculosis, fungi, and actinomycosis.

Pyelonephritis

This results from hematogenous or ascending infection. Bacteremia, particularly with virulent organisms such as Staphylococcus aureus, can result in pyelonephritis with focal renal abscesses. Bacterial adherence allows for mucosal colonization and subsequent infection by an ascending route. Whereas type 1 pili are produced by most uropathogenic strains of Escherichia coli, P-pili, which bind to the uroepithelial glycosaminoglycan layer, are found in most strains of E coli that cause pyelonephritis. Genotypic factors may affect uroepithelial susceptibility to these adherence molecules. Endotoxin from gram-negative organisms can retard ureteral peristalsis. E coli is responsible for approximately 25% of cases in males, with Proteus and Providencia causing many remaining infections; Klebsiella, Pseudomonas, Serratia, and enterococci are less frequent.

Bacterial cystitis

Most cases of cystitis occur by an ascending mechanism. Patients may have poor bladder emptying from prostatic obstruction or dysfunctional voiding. Elevated postvoid residuals allow bacteria to multiply to critical levels. High voiding pressures and poor bladder compliance diminish the natural uroepithelial resistance to infection.

Urethritis

The urethral nonsquamous epithelium can be penetrated by N gonorrhoeae, resulting in periurethral microabscesses. Necrotic debris is sloughed into the urethra lumen, producing a milky penile discharge.

Frequency

United States

The prevalence of UTI in males varies according to age. Young men rarely develop a UTI, and the prevalence of bacteruria is 0.1% or less. In marked contrast, adult women are 30 times more likely than men to develop a UTI. The rate of infection increases with age in both sexes, with the increase especially notable in men older than 50 years. In men aged 65 years or older, 10% have been found to have bacteriuria, as compared with 20% of women in this age group.

• In contrast to UTI, prostatitis affects men of all ages and, from 1990-1994, accounted for almost 2 million office visits per year in the United States. Prostatitis syndromes account for 25% of male office visits for genitourinary complaints, 8% of visits to urologists, and 1% of visits to primary care physicians. Of these men, 5% have bacterial prostatitis, 64% have nonbacterial prostatitis, and 31% have prostatodynia.
• Epididymitis has a bimodal distribution, corresponding to different age groups and pathogens. Most cases in men younger than 35 years are due to sexually transmitted pathogens. Older patients are more likely to have obstructive prostatism or a history of instrumentation or catheterization.
• Mumps orchitis occurs in 18% of postpubertal boys infected with the mumps virus.

Mortality/Morbidity

The natural history of UTIs varies based on the site of the infection, the host, and the pathogen. Asymptomatic bacteruria appears to be a benign finding in men; it does not contribute to mortality in elderly patients, it does not impair renal function, and it does not cause hypertension.

• Risk factors for serious morbidity or renal impairment from UTIs have been well characterized. They include urinary obstruction, infection with urea-splitting bacteria, congenital urinary tract anomalies, renal papillary necrosis, catheter drainage, diabetes, spinal cord injury with high-pressure bladders, and acute bacterial prostatitis.
• Other complications that can result from UTI include recurrent infection, perinephric and intrarenal abscess formation, hydronephrosis, pyonephrosis, emphysematous pyelonephritis, bacteremia, and gram-negative sepsis.
  • Pyonephrosis refers to infected hydronephrosis associated with suppurative destruction of the kidney parenchyma, which results in nearly total loss of renal function.
  • Emphysematous pyelonephritis is an acute necrotizing parenchymal and perirenal infection caused by gas-forming bacteria. Women are affected more often than men, and nearly all cases occur in patients with diabetes. The overall mortality rate is 43%.
  • Bacteremia occurs in approximately 20% of men with acute pyelonephritis or acute bacterial prostatitis. The current literature does not mention any patients dying from prostatitis or after a vigorous prostatic massage, but this was often reported in the preantibiotic era.
• Patients with nosocomial UTIs have their hospital stay extended by an average of 3 days, and these patients are 3 times more likely to die during hospitalization. Approximately 2-4% of patients with nosocomial UTIs develop bacteremia, which is associated with a 13% mortality rate. The urinary tract is the second most common source of nosocomial bacteremia (17%).

Race

Gonococcal urethritis is more common in ethnic minorities, lower socioeconomic groups, and those living in urban centers. Some of these associations may be limited by confounding.

Age

UTI is rare in young men, with 8 infections per 10,000 men occurring in the 21- to 50-year age group; urethritis of venereal origin is a much more common cause of dysuria in this age group.

• The incidence of UTI in men begins to increase with age, particularly after age 50 years. The prevalence may reach as high as 20-50% in patients who are debilitated and live in nursing homes. Also, the spectrum of causative agents is somewhat broader in these elderly men.
• The peak age for urethritis is 20-24 years. It is more common in ethnic minorities, lower socioeconomic groups, and those living in urban centers. The risk to a male having intercourse with an infected female is 17%.
• Most cases of epididymitis in men younger than 35 years are due to sexually transmitted pathogens. Older patients are more likely to have obstructive prostatism or a history of instrumentation or catheterization.

Clinical

History

In men, complaints of dysuria, urinary frequency, and urgency are approximately 75% predictive for urinary tract infection (UTI), whereas the acute onset of hesitancy, urinary dribbling, and slow stream are only approximately 33% predictive for UTI. Clinical symptoms may be inconsistent with laboratory test results. Absence of bacteruria despite symptoms of frequency, urgency, or dysuria suggests urethritis. On the other hand, bacteruria may be symptomatic or asymptomatic. In elderly patients, the typical manifestations of UTI may be absent or replaced by vague findings of failure to thrive or worsening mental status.

• Prostatitis syndromes
  • These syndromes tend to occur in young and middle-aged men. Symptoms may include pain (in the perineum, lower abdomen, testicles, or penis or with ejaculation), bladder irritation, and sometimes blood in the semen.
  • Acute prostatitis typically presents with spiking fever, chills, malaise, myalgia, dysuria, pelvic or perineal pain, and cloudy urine. Obstructive symptoms can result from swelling of the acutely inflamed prostate, and these range from dribbling and hesitancy to anuria. A less common presentation is with a vague flulike illness.
  • Patients with chronic prostatitis, by definition, have had symptoms for at least 3 months. Chronic bacterial prostatitis and nonbacterial prostatitis have similar presentations, including dysuria, frequency, urgency, perineal discomfort, and a low-grade temperature. The only way to differentiate between these 2 entities is through culture of prostatic secretions. Although not life-threatening, the patient's quality of life has been compared to someone with unstable angina or active Crohn disease. Prostatodynia, a noninflammatory disorder, has a symptom complex similar to that of chronic prostatitis, except that the patient does not give a history of recurrent UTIs. Interestingly, many men with chronic bacterial prostatitis are asymptomatic.
• Orchitis
  • The most common presentation of orchitis is in a patient in the later stages of epididymitis. In this situation, inflammation has spread to the adjacent testicle and results in a tender, warm, and swollen hemiscrotal mass. Patients have the characteristic history and urine findings of epididymitis.
  • Of patients with orchitis resulting from tuberculosis, 70% have other genitourinary or pulmonary symptoms of this disease.
  • Viral orchitis is notable for the symptoms of the viral syndrome. Orchitis occurs in approximately 18% of postpubertal boys infected with the mumps virus. Orchitis symptoms usually begin within 1 week of parotitis. Up to 30% of cases are bilateral, and sterility develops in up to 10% of cases.
• Pyelonephritis
  • This is suggested by fever, chills, and flank pain combined with pyuria and bacteriuria. Although fever is very suggestive of pyelonephritis, it has been demonstrated in some males with simple cystitis.
  • The differential diagnoses include appendicitis, diverticulitis, pancreatitis, and lower-lobe pneumonia.
  • Occasionally, the urinalysis and urine culture findings are negative, such as when an obstruction of the upper urinary tract is present due to stone disease.
• Cystitis
  • Symptoms cannot reproducibly differentiate cystitis (lower UTI) from pyelonephritis (upper UTI).
  • Dysuria, frequency, urgency, and suprapubic pain usually are present in patients with cystitis. Fever and flank pain usually are not present; however, they might be present.
• Urethritis
  • The incubation period of gonococcal urethritis is 2-6 days. Occasionally, 2 weeks may elapse before symptoms occur. Dysuria, thick milky discharge, and pruritus are the presenting symptoms.
  • The incubation period of nongonococcal urethritis (NGU) is 2-6 weeks. Symptoms are less severe, and discharge may be clearer than with gonococcal urethritis. Patients are likely to have a higher level of education (ie, 90% of urethritis cases in college health services is NGU) and fewer sexual contacts.
• Catheterized and hospitalized patients
  • Clinical and microbiologic criteria for the diagnosis of UTI are not well established in catheterized hospitalized patients.
  • Symptoms may be atypical or may be attributed to other disease processes, and no reliable colony count cutoff defines significant bacteriuria. Low-level (100-1000 colony-forming units [CFU] per mL) colonization can progress to high-level (>100,000 CFU/mL) bacteriuria within 3 days in 96% of catheterized patients who are cultured on subsequent days (and not treated with antimicrobials). Thus, most experts agree that growth of more than 100 CFU/mL of a predominant pathogen represents catheter-related UTI.
  • Polymicrobial bladder infections are not uncommon in catheterized patients, and nonpathogenic organisms can be significant in catheterized patients.

Physical

Males who present with genitourinary complaints warrant a thorough general physical examination, with particular attention to the vital signs, kidneys, bladder, prostate, and external genitalia. Auscultation over the upper abdominal quadrants and the costovertebral angles may reveal the bruits of renal artery stenosis, an aneurysm, or an arteriovenous malformation. The costovertebral angles should also be percussed for tenderness. Palpation of the suprapubic area should be performed; a bladder that contains 500 mL or more of fluid is often palpable as a suprapubic mass.

The external genitalia should be examined carefully. The penis should be examined for the presence of ulcers or lesions, and special attention should be paid to the urethral meatus for the presence of erythema or discharge. The testes and epididymis must be examined and palpated for tenderness and swelling. A rectal examination is mandatory, with a 360° sweep of the interior of the rectum followed by careful palpation of the prostate. In patients with suspected acute bacterial prostatitis, palpation should be very gentle so as not to cause bacteremia.

• Acute bacterial prostatitis
  • Careful examination of the prostate is not contraindicated, but prostatic massage is contraindicated. Upon examination, it is warm, swollen, soft ("boggy"), and extremely tender.
  • The patient may have a fever and appear acutely uncomfortable; hypotension may be noted.
• Chronic bacterial prostatitis
  • The physical findings are variable in chronic bacterial prostatitis. A low-grade fever may be present, and the rectal examination may be unremarkable or may reveal severe anal sphincter spasm. The prostate may be mildly or extremely tender.
  • Examination of urine voided after prostate massage is more helpful diagnostically than quantitating the amount of pain experienced during the digital examination.
• Epididymitis
  • In early epididymitis, the epididymis is tender and indurated, but the testis itself is nontender and soft.
  • In hours to days, inflammation progresses to the adjacent testicle and a reactive hydrocele occurs. Identifying the lateral sulcus between the testicle and epididymis then becomes increasingly difficult, and discerning testis from epididymis may be impossible.
• Orchitis
  • The most common presentation of orchitis is in a patient with late signs of epididymitis.
  • In this situation, the inflammation has spread to the adjacent testicle and results in a tender, warm, swollen, hemiscrotal mass.
• Pyelonephritis
  • Patients with pyelonephritis have fever, chills, and flank pain.
  • They will appear ill, and they may have hypotension.
• Urethritis
  • Patients with urethritis have a thick milky discharge; the underpants may be impressively stained.
  • Typically, those with gonorrhea have a thicker, more copious discharge, but significant overlap with chlamydial urethritis is not uncommon.
  • Gram stain is the key to an immediate diagnosis, although patients frequently have co-infections.

Causes

Obstruction from any cause is a major risk factor for the development of UTI. Prostatic hypertrophy with partial obstruction is the main contributor to the increase in UTI in males older than 50 years. Instrumentation of the urinary tract, catheterization, and urological surgery are other important risk factors. Risk factors for acute cystitis in young men include homosexual behavior with anal intercourse, intercourse with a female infected or colonized with a uropathogen, lack of circumcision, and HIV infection with CD4 counts of 200/μL or less. Other risk factors observed more commonly in elderly or institutionalized males include cognitive impairment, fecal or urinary incontinence, and use of catheters.

• Pathogens of the prostate
  • Acknowledged pathogens of the prostate are gram-negative uropathogens (eg, Enterobacteriaceae such as E coli, Klebsiella, and Pseudomonas).
  • Probable pathogens include Enterococcus and S aureus.
  • Possible pathogens include coagulase-negative Staphylococcus, Chlamydia, Ureaplasma, anaerobes, Candida, and Trichomonas.
  • Acknowledged nonpathogens of the prostate include diphtheroids, lactobacilli, and Corynebacterium.
  • Viruses and cell wall–deficient bacteria have a controversial association with prostatitis. Rare cases have been reported from Clostridia and Burkholderia (formerly Pseudomonas) pseudomallei (the causative agent of melioidosis).
  • Unusual pathogens reported in patients with AIDS include cytomegalovirus and some fungi (Aspergillus, Histoplasma, and Cryptococcus). The prostate is a known reservoir for Cryptococcus neoformans.
• Chronic bacterial prostatitis
  • Most commonly, this is caused by E coli (80%), but other gram-negative bacteria and enterococci also may be observed.
  • Whether Staphylococcus epidermidis, S aureus, and diphtheroids are pathogenically significant is doubtful.
  • Rare cases may be caused by yeasts (eg, Candida, Blastomyces, Histoplasma, Cryptococcus) and mycobacteria.
• Nonbacterial prostatitis
  • Bacterial pathogens cannot be demonstrated in cases of nonbacterial prostatitis.
  • The evidence supporting a causative role for Chlamydia and Ureaplasma is not convincing.
• Epididymitis
  • C trachomatis and N gonorrhoeae are the most common causes of epididymitis in patients younger than 35 years.
  • Enterobacteriaceae and Enterococcus are frequent pathogens in older patients.
• Orchitis
  • Primary orchitis is one of the few genitourinary infections resulting from viral pathogens; mumps, coxsackie B, Epstein-Barr, and varicella reach the testis via the hematogenous route. Colorado tick fever has been associated with epididymoorchitis.
  • Rarely, granulomatous orchitis results from the hematogenous spread of tuberculosis, fungi, and actinomycetes. Brucella has been associated with orchitis; clinically, these patients resemble patients with tuberculosis.
  • Secondary orchitis is more common and is a late complication of untreated epididymitis (see above).
• Pyelonephritis and cystitis: Bacteria responsible for pyelonephritis and cystitis in males include E coli, Klebsiella, Enterobacter, Proteus, Pseudomonas, Serratia, Enterococcus, and Staphylococcus species.
• Urethritis
  • Most often, this is caused by N gonorrhoeae.
  • Causes of NGU include C trachomatis (in up to 50% of cases), Ureaplasma urealyticum, Trichomonas vaginalis, and herpes simplex virus.
  • Mycoplasma plays a controversial role in urethritis.
• Catheter-associated bacteriuria
  • Risk factors for catheter-associated bacteriuria include female sex, significant comorbid conditions (especially diabetes mellitus), age older than 50 years, lack of systemic antibiotic, and a serum creatinine level greater than 2 mg/dL.
  • Catheter-associated bacteriuria usually resolves after the catheter is removed; however, one third may have symptoms, and bacteremia is the most serious complication.
  • Risk factors for bacteremia secondary to catheter-associated UTI are male sex, UTI caused by Serratia marcescens, older age, underlying urologic disease, and an indwelling catheter.
  • Short-term catheters are placed for a mean duration of 2-4 days. The usual indications are for acute illnesses, output measurement, perioperative routine, and acute retention. Approximately 15% of patients develop bacteriuria, usually with a single organism (E coli). Approximately 10-30% develop a fever, and the risk of postoperative wound infection associated with bacteriuria is increased.
  • Long-term catheters are placed for chronic medical or neurologic problems, including chronic urinary retention and incontinence. Essentially all patients develop bacteriuria, which is polymicrobial in up to 95% of cases. New pathogens often emerge, while many persist because of adherence properties (fimbrial adhesion in Providencia and E coli) or their effect on the local environment (Proteus and Morganella). Catheter obstruction may occur via an interaction between bacteria, the glycocalyx, protein, and crystals; Proteus mirabilis is a potent producer of urease, which alkalinizes the urine, precipitating struvite and apatite.

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