FIGURE 12-6

a.percutaneous drainage.

b.nephrectomy.

c.partial nephrectomy.

d.open surgical drainage.

e.cystoscopy and retrograde urography.

Answers

1.a. Chills, fever, and flank pain. Acute pyelonephritis is a clinical syndrome of chills, fever, and flank pain that is accompanied by bacteriuria and pyuria, a combination that is reasonably specific for an acute bacterial infection of the kidney.

2.b. Colonization. Bacteriuria without pyuria is generally indicative of bacterial colonization without infection of the urinary tract.

3.a. Occur in patients who are hospitalized or institutionalized. Nosocomial or health care–associated UTIs occur in patients who are hospitalized or institutionalized and may be caused by Pseudomonas and other more

antimicrobial-resistant strains.

4.b. Reinfections. Of these recurrent infections, 71% to 73% are caused by reinfection with different organisms, rather than recurrence with the same organism.

5.d. Antimicrobial treatment. Whether a patient receives no treatment or short-term, long-term, or prophylactic antimicrobial treatment, the risk of recurrent bacteriuria remains the same; antimicrobial treatment appears to alter only the time until recurrence.

6.e. Minimal. The long-term effects of uncomplicated recurrent UTIs are not completely known, but, so far, no association between recurrent infections and renal scarring, hypertension, or progressive renal azotemia has been established.

7.e. Frequent voiding. This route is further enhanced in individuals with significant soilage of the perineum with feces, women using spermicidal agents, and patients with intermittent or indwelling catheters.

8.b. Staphylococcus saprophyticus. S. saprophyticus is now recognized as causing approximately 10% of symptomatic lower UTIs in young, sexually active females, whereas it rarely causes infection in males and elderly individuals.

9.c. Pili. Studies have demonstrated that interactions between FimH and receptors expressed on the luminal surface of the bladder epithelium are critical to the ability of many uropathogenic E. coli strains to colonize the bladder and cause disease.

.b. Affects bacterial virulence. This process is called phase variation and has obvious biologic and clinical implications. For example, the presence of type 1 pili may be advantageous to the bacteria for adhering to and colonizing the bladder mucosa but disadvantageous because the pili enhance phagocytosis

and killing by neutrophils.

.a. Increased adherence of bacteria to vaginal cells. These studies established increased adherence of pathogenic bacteria to vaginal epithelial cells as the first demonstrable biologic difference that could be shown in women susceptible to UTI.

.e. Bladder mucosa. These studies individually and collectively support the concept that there is an increased epithelial receptivity for E. coli on the introital, urethral, and buccal mucosa that is characteristic of women susceptible to recurrent UTIs and may be a genotypic trait. Thus the vaginal fluid appears to influence adherence to cells and presumably vaginal

mucosal colonization.

.c. Voiding. Bacteria presumably make their way into the bladder fairly often. Whether small inocula of bacteria persist, multiply, and infect the host depends in part on the ability of the bladder to empty.

.c. Obstruction. A patient who suffers from an acute ureteral obstruction caused by a sloughed papilla and who has a concomitant UTI should have the

condition treated as a urologic emergency.

. a. Spinal cord injuries. Of all patients with bacteriuria, no group compares in severity and morbidity with those who have spinal cord injury.

.d. Suprapubic aspiration. A single aspirated specimen reveals the bacteriologic status of the bladder urine without introducing urethral bacteria, which can start a new infection.

.a. Squamous epithelial cells. The validation of the midstream urine specimen can be questioned if numerous squamous epithelial cells (indicative of preputial, vaginal, or urethral contaminants) are present.

.a. Low-risk asymptomatic patients. The main role of rapid screening methods for UTIs is in screening asymptomatic patients.

.b. Ureteral catheterization. Ureteral catheterization allows not only separation of bacterial persistence into upper and lower urinary tracts but also separation of the infection between one kidney and the other.

.a. Women. Several reports of women patients with recurrent UTIs show that excretory urograms are unnecessary for routine evaluation in women. Those who have special risk factors are excluded.

.e. CT. CT and magnetic resonance imaging are more sensitive than excretory urography or ultrasonography in the diagnosis of acute focal bacterial nephritis, renal and perirenal abscesses, and radiolucent calculi.

.c. Urine level. Efficacy of the antimicrobial therapy is critically dependent on the antimicrobial levels in the urine and the length of time that this level remains above the minimum inhibitory concentration of the infecting organism. Thus resolution of infection is closely associated with the susceptibility of the bacteria to the concentration of the antimicrobial agent achieved in the urine.

.c. Nitrofurantoin. Over a 5-year period the prevalence of resistance to trimethoprim-sulfamethoxazole, ampicillin, and cephalothin increased

significantly, whereas resistance to nitrofurantoin and ciprofloxacin remained uncommon.

. c. Fluoroquinolones. The fluoroquinolones have a broad spectrum of activity

that makes them ideal for the empirical treatment of UTIs.

.d. Administration of an antimicrobial agent within 30 minutes of the initiation of a procedure and for a period of time that covers the duration of the procedure. Surgical antimicrobial prophylaxis entails treatment with

an antimicrobial agent before and for a limited time after a procedure to prevent local or systemic postprocedural infections.

.d. Sterile urine. Prolonged use of an indwelling urethral catheter is common in hospitalized patients and is associated with an increased risk of bacterial colonization, with a 3% to 10% incidence of bacteriuria per catheter day in one study and 100% incidence of bacteriuria with long-term catheterization (> 30 days). Prophylactic antimicrobial therapy during catheterization is not generally recommended because bacterial resistance can develop

rapidly. Chronically catheterized patients have bacteriuria and should be treated therapeutically, not with prophylaxis.

.a. A history of childhood heart murmurs. The American Heart Association's recommendations on the prevention of bacterial endocarditis are based on the patient's risk of developing endocarditis and the likelihood that a procedure will cause bacteremia with an organism that can cause endocarditis.

Prophylaxis is recommended for both high-and moderate-risk patients. High-risk patients include individuals with prosthetic heart valves, previous bacterial endocarditis, cyanotic congenital heart disease, and systemic-pulmonary shunts or conduits. Moderate-risk patients include other congenital malformations (excluding isolated secundum atrial septal defects, surgically repaired atrial septal defect, ventricular septal defects, or patent ductus arteriosus), acquired valvular dysfunction, hypertrophic cardiomyopathy, and mitral valve prolapse with valvular regurgitation and/or thickened leaflets. Antimicrobial prophylaxis is not

recommended for patients with congenital malformations including isolated secundum atrial septal defects, surgically repaired atrial septal defect, ventricular septal defects, or patent ductus arteriosus; previous coronary artery bypass graft surgery; benign heart murmurs; previous Kawasaki disease or rheumatic fever without valvular dysfunction; or implanted pacemakers or defibrillators.

.d. Indwelling orthopedic pins. Bacterial seeding of implanted orthopedic hardware is a rare but morbid event. A joint commission of the American Urological Association, the American Academy of Orthopaedic Surgeons, and infectious disease specialists convened in 2003 and released an advisory

statement on antibiotic prophylaxis for urologic patients with total joint replacement. In general, antimicrobial prophylaxis for urologic patients with total joint replacements, pins, plates, or screws is not indicated. Prophylaxis is advised for individuals at higher risk of seeding a prosthetic joint and include those with recently inserted implants (within 2 years).

.a. Young women. In women with recent onset of symptoms and signs suggesting acute cystitis and in whom factors associated with upper tract or complicated infection are absent, a urinalysis that is positive for pyuria, hematuria, or bacteriuria or a combination should provide sufficient

documentation of UTI and a urine culture may be omitted.

.a. TMP-SMX. TMP and TMP-SMX are recommended in areas where the prevalence of resistance to these drugs among E. coli strains causing cystitis is less than 20%.

.b. 3 days. Three-day therapy is the preferred regimen for uncomplicated cystitis in women.

.c. Pregnant. In populations other than those for whom treatment has been documented to be beneficial (e.g., pregnant women and patients undergoing urologic interventions), screening for or treatment of asymptomatic bacteriuria is not appropriate and should be discouraged.

.a. Pregnant women. In populations other than those for whom treatment has been documented to be beneficial (e.g., pregnant women and patients undergoing urologic interventions), screening for or treatment of asymptomatic bacteriuria is not appropriate and should be discouraged.

.e. Initial bacterial resistance. Most commonly, the bacteria are resistant to the antimicrobial agent selected to treat the infection.

.a. Urine. Nitrofurantoin, which does not alter the bowel flora, is present for brief periods at high concentrations in the urine and leads to repeated elimination of bacteria from the urine, presumably by interfering with bacterial initiation of infection.

.a. A fluoroquinolone. Fluoroquinolones are ideal for self-start therapy because they have a spectrum of activity broader than that of any of the other oral agents and are superior to many parenteral antimicrobial agents, including aminoglycosides.

.b. P-piliated bacteria. If vesicourethral reflux is absent, a patient bearing the P blood group phenotype may have special susceptibility to recurrent pyelonephritis caused by E. coli that have P pili and bind to the P blood group

antigen receptors.

.d. A fluoroquinolone. For patients who will be managed as outpatients, single-drug oral therapy with a fluoroquinolone is more effective than TMPSMX for patients with domiciliary infections.

.a. Observation. Even though the urine usually becomes sterile within a few hours of starting antimicrobial therapy, patients with acute uncomplicated pyelonephritis may continue to have fever, chills, and flank pain for several more days after initiation of successful antimicrobial therapy. They should be

observed.

.d. 40%. Emphysematous pyelonephritis should be considered a complication of severe pyelonephritis rather than a distinct entity. The overall mortality rate is 43%.

.b. Renal mass. In a more chronic abscess, the predominant urographic abnormalities are those of a renal mass lesion.

.c. Delay in diagnosis. Although 71% of all the patients had eventual surgical treatment of their perinephric abscesses, the diagnostic delay of those patients admitted to medical services postponed definitive treatment and consequently caused higher mortality.

.d. Percutaneous drainage. Although surgical drainage, or nephrectomy if the kidney is nonfunctioning or severely infected, is the classic treatment for perinephric abscesses, renal ultrasonography and CT make percutaneous aspiration and drainage of small perirenal collections possible.

.e. No symptoms. There are no symptoms of chronic pyelonephritis until it produces renal insufficiency, and then the symptoms are similar to those of any other form of chronic renal failure.

.d. Proteus mirabilis. Although review of the literature shows Proteus to be the most common organism involved with xanthogranulomatous

pyelonephritis, E. coli is also common.

.b. Bacterial fragments. It is hypothesized that bacteria or bacterial fragments form the nidus for the calcium phosphate crystals that laminate the MichaelisGutmann bodies.

.d. The United States. In the United States the disease is rare, but it is found in immigrants from Eastern Europe or other foreign endemic areas or as an indigenous infection among Native Americans in the Southwest United States

and in Eskimos.

.c. Hyperventilation. Even before temperature extremes and the onset of chills, bacteremic patients often begin to hyperventilate. Thus the earliest metabolic

change in septicemia is a resultant respiratory alkalosis.

.c. Acute pyelonephritis. Pyelonephritis develops in 1% to 4% of all pregnant women and in 20% to 40% of pregnant women with untreated bacteriuria.

.a. Maternal sepsis. Pregnant women with asymptomatic bacteriuria are at higher risk for developing a symptomatic UTI that results in adverse fetal sequelae, complications associated with bacteriuria during pregnancy,

and pyelonephritis and its possible sequelae, such as sepsis in the mother. Therefore all women with asymptomatic bacteriuria should be treated.

.d. Penicillin. The aminopenicillins and cephalosporins are considered safe and generally effective throughout pregnancy. In patients with penicillin

allergy, nitrofurantoin is a reasonable alternative.

.a. Asymptomatic. Most elderly patients with bacteriuria are asymptomatic; estimates among women living in nursing homes range from 17% to 55%, as compared with 15% to 31% for their male cohorts.

.e. Is unnecessary. Prospective randomized comparative trials of antimicrobial or no therapy in elderly male and female nursing home residents with asymptomatic bacteriuria consistently document no benefit of antimicrobial therapy. There was no decrease in symptomatic episodes and no improvement in survival. In fact, treatment with antimicrobial therapy increases the occurrence of adverse drug effects and reinfection with resistant organisms and increases the cost of treatment. Therefore asymptomatic bacteriuria in elderly residents of long-term care facilities should not be treated with antimicrobial agents.

.d. Catheterization. Catheter-associated bacteriuria is the most common hospital-acquired infection, accounting for up to 40% of such infections.

.a. Closed drainage. Careful aseptic insertion of the catheter and maintenance of a closed dependent drainage system are essential to minimize development

of bacteriuria.

.a. Clean intermittent catheterization. Although never rigorously compared with indwelling urethral catheterization, CIC has been shown to decrease lower urinary tract complications by maintaining low intravesical pressure and reducing the incidence of stones.

.b. Discharge. Early on, the involved area is swollen, erythematous, and tender as the infection begins to involve the deep subcutaneous tissue. Pain is prominent, and fever and systemic toxicity are marked. The swelling and crepitus of the scrotum quickly increase, and dark purple areas develop and progress to extensive gangrene.

Pathology

1.c. Is unnecessary. The figure shows numerous neutrophils within the interstitium and the renal tubules. The neutrophils in the tubules become white blood cell casts. The pathologic findings including an enlarged kidney may persist for several weeks despite appropriate treatment. There is no indication for a biopsy in this patient.

2.c. Left nephrectomy. The figure shows the foamy macrophages with neutrophils and cellular debris characteristic of xanthogranulomatous pyelonephritis. It may be associated with renal calculi and Proteus infection. E. coli is also a common organism found in this disease. Although partial nephrectomy has been performed for a small localized mass in a functioning kidney, a left nephrectomy in this situation is likely required and is necessary to rid the patient of the infection. An associated retroperitoneal inflammatory process with thickening is not uncommon.

3.d. Treat with a sulfonamide for several months. Figure 12-3A shows von Hansemann histiocytes, and Figure 12-3B demonstrates the MichaelisGutmann bodies, both of which are characteristic of malakoplakia. It is thought to be infectious in origin, and therefore the treatment is an extended course of an antibiotic that achieves a high intracellular concentration.

Imaging

1.d. Right perinephric abscess. The CT scan is obtained in the late arterial to nephrographic phase of the examination (the aorta is still opacified with contrast agent), before the excretion of the contrast agent. Thus option b is incorrect. There are multiple calculi in the right kidney, which is small and atrophic, indicating a chronic process (thus option a is incorrect). There is thickening of the perinephric fascia, and gas bubbles are seen in the posterior paranephric space, extending to the right flank. In addition, there are fluid collections in the posterior paranephric space and in the soft tissues of the right flank, making option d the most likely diagnosis. Xanthogranulomatous pyelonephritis is a chronic inflammatory condition associated with staghorn calculi. The affected kidney is usually enlarged rather than shrunken, as is the case here (making option e unlikely).

2.e. Acute pyelonephritis. The image demonstrates a pelvic kidney with wedge-shaped area of decreased enhancement, characteristic of acute

pyelonephritis. Renal infarcts cause areas of poor perfusion that are more sharply defined and more poorly enhancing than in the present case (making option a unlikely). The clinical history of fever also supports an infection. With renal artery occlusion (option b) the kidney would demonstrate no enhancement. Chronic pyelonephritis causes scarring in the kidney, and the nephrogram is usually normal. The renal contour in the present case is smooth, making option c unlikely. Acute urinary obstruction (option d) is ruled out because the visualized collecting system does not appear dilated.

3.a. Percutaneous drainage. The image demonstrates a low-attenuation area in the posterior interpolar region of the left kidney, with perinephric fascial thickening, consistent with a renal abscess. Intravenous antimicrobial therapy with percutaneous drainage of renal abscesses is highly effective and is the treatment of choice. Antimicrobial therapy alone is unlikely to be effective, given the size of the abscess. Nephrectomy, partial nephrectomy, and surgical drainage are rarely indicated in young patients with normally functioning kidneys. Cystoscopy is not warranted.

Chapter review

1.UTIs cause significant morbidity; they do not cause progressive renal failure unless significant comorbidities are present.

2.Increased receptors for uropathogenic E. coli on vaginal epithelial cells and buccal mucosal cells in women with recurrent UTIs imply a genetic etiology; moreover, hormonal changes may alter adherence of bacteria to the receptors in the vaginal epithelial cells, explaining the cyclic nature of UTIs in women.

3.If appropriate antimicrobial therapy fails to eradicate bacteria and there is a rapid recurrence, imaging is indicated to determine abnormalities that may cause persistence.

4.When a patient has a symptomatic UTI and gram-negative rods are seen on the urine analysis but the routine culture is negative, an anaerobic infection should be suspected.

5.102 cfu/mL in a symptomatic patient confirms a UTI.

6.Patients with indwelling catheters should be treated only when symptomatic.

7.Whether a patient receives no treatment or short-term, long-term, or prophylactic antimicrobial treatment, the risk of recurrent bacteriuria remains the same; antimicrobial treatment appears to alter only the time

until recurrence.

8.There is no association between recurrent infections and renal scarring, hypertension, or progressive renal azotemia

9.Staphylococcus saprophyticus is now recognized as causing approximately 10% of symptomatic lower UTIs in young, sexually active females, whereas it rarely causes infection in males and elderly individuals.

10.The validation of the midstream urine specimen can be questioned if numerous squamous epithelial cells (indicative of preputial, vaginal, or urethral contaminants) are present.

11.The fluoroquinolones have a broad spectrum of activity that makes them ideal for the empirical treatment of UTIs.

12.Prophylaxis is recommended for both high-and moderate-risk patients. High-risk patients include individuals with prosthetic heart valves, previous bacterial endocarditis, cyanotic congenital heart disease, and systemic-pulmonary shunts or conduits. Moderate-risk patients include other congenital malformations (excluding isolated secundum atrial septal defects, surgically repaired atrial septal defect, ventricular septal defects, or patent ductus arteriosus), acquired valvular dysfunction, hypertrophic cardiomyopathy, and mitral valve prolapse with valvular regurgitation and/or thickened leaflets. Antimicrobial prophylaxis is not recommended for patients with congenital malformations including isolated secundum atrial septal defects, surgically repaired atrial septal defect, ventricular septal defects, or patent ductus arteriosus; previous coronary artery bypass graft surgery; benign heart murmurs; previous Kawasaki disease or rheumatic fever without valvular dysfunction; or implanted pacemakers or defibrillators.

13.In general, antimicrobial prophylaxis for urologic patients with total joint replacements, pins, plates, or screws is not indicated. Prophylaxis is advised for individuals at higher risk of seeding a prosthetic joint and include those with recently inserted implants (within 2 years).

14.Three-day therapy is the preferred regimen for uncomplicated cystitis in women.

15.If vesicourethral reflux is absent, a patient bearing the P blood group phenotype may have special susceptibility to recurrent pyelonephritis caused by E. coli that have P pili and bind to the P blood group antigen receptors.

16.Emphysematous pyelonephritis should be considered a complication of severe pyelonephritis rather than a distinct entity. The overall mortality rate is 43%.

17.Although surgical drainage, or nephrectomy if the kidney is nonfunctioning or severely infected, is the classic treatment for perinephric abscesses, renal ultrasonography and CT make percutaneous aspiration and drainage of small perirenal collections possible.

18.Proteus is the most common organism involved with xanthogranulomatous pyelonephritis; E. coli is also common.

19.Even before temperature extremes and the onset of chills, bacteremic patients often begin to hyperventilate. Thus the earliest metabolic change in septicemia is a resultant respiratory alkalosis.

20.Pregnant women with asymptomatic bacteriuria are at higher risk for developing a symptomatic UTI that results in adverse fetal sequelae, complications associated with bacteriuria during pregnancy, and pyelonephritis and its possible sequelae, such as sepsis in the mother. Therefore all pregnant women with asymptomatic bacteriuria should be treated.

21.The aminopenicillins and cephalosporins are considered safe and generally effective throughout pregnancy.

22.In elderly male and female nursing home residents with asymptomatic bacteriuria there is no benefit to administering antimicrobial therapy.

23.In the early stages of Fournier gangrene, the involved area is swollen, erythematous, and tender as the infection begins to involve the deep subcutaneous tissue. Pain is prominent, and fever and systemic toxicity are marked. The swelling and crepitus of the scrotum quickly increase, and dark purple areas develop and progress to extensive gangrene.