Campbell-Walsh Urology, 11th Edition

PART III

Infections and Inflammation

17

Tuberculosis and Parasitic Infections of the Genitourinary Tract

Alicia H. Chang; Brian G. Blackburn; Michael H. Hsieh

Questions

Tuberculosis

  1. Which of the following mycobacteria does NOT cause tuberculosis (TB)?
  2. Mycobacterium bovis
  3. Mycobacterium avium-intracellulare
  4. Mycobacterium africanum
  5. Mycobacterium microti
  6. Bacille Calmette-Guérin (BCG)
  7. Which of the following statements about the epidemiology of tuberculosis is FALSE?
  8. TB incidence and mortality have been decreasing worldwide since the year 2000.
  9. Tuberculosis incidence is higher in those who are foreign-born than in those born in the United States.
  10. Prevalence of multidrug-resistant (MDR) tuberculosis cases is now approaching 12% in the United States.
  11. The lifetime risk of reactivation of TB is 5% to 10% in most people.
  12. Worldwide, tuberculosis is the cause of death in 25% of persons who test positive for human immunodeficiency virus (HIV).
  13. Which of the following routes of infection is the most common in genitourinary tuberculosis?
  14. Hematogenous seeding
  15. Lymphatic spread
  16. Direct inoculation
  17. Sexual transmission
  18. Ascending or retrograde infection
  19. Which of the following is a not a late complication of genitourinary tuberculosis?
  20. Infertility
  21. Scrotal fistula
  22. Autonephrectomy
  23. Thimble bladder
  24. Papulonecrotic tuberculid
  25. Which of the following persons is LEAST likely to have tuberculosis infection?
  26. A patient with fibrosis on chest radiograph and a tuberculin skin test (TST) of 5 mm
  27. A patient with HIV infection and a TST of 3 mm
  28. A recent immigrant from Vietnam with a TST of 11 mm
  29. A BCG-vaccinated patient with a TST of 14 mm
  30. A healthy U.S.-born teacher with a TST of 11 mm
  31. Which of the following results most specifically diagnoses genitourinary tuberculosis?
  32. A positive interferon gamma release assay
  33. A positive urine polymerase chain reaction (PCR) for Mycobacterium tuberculosiscomplex
  34. A TST reaction of 25 mm
  35. A positive urine acid-fast bacilli (AFB) culture
  36. A renal biopsy showing AFB
  37. Which of the following first-line antituberculosis agents does not cause hepatic toxicity?
  38. Isoniazid
  39. Rifampin
  40. Pyrazinamide
  41. Ethambutol
  42. Streptomycin
  43. Which of the following drugs might have efficacy against extensively drug-resistant (XDR) tuberculosis?
  44. Isoniazid (INH)
  45. Rifampin
  46. Pyrazinamide
  47. Moxifloxacin
  48. Amikacin
  49. Which of the urological interventions is emergently indicated?
  50. Nephrectomy of nonfunctional kidney in medically resistant hypertension
  51. Bladder augmentation of a contracted bladder in a patient with severe dysuria
  52. Percutaneous nephrostomy of obstructive hydronephrosis in acute renal failure
  53. Balloon dilatation and ureteral stenting of a proximal ureteral stricture
  54. Boari flap for a lower ureteral stricture that requires excision
  55. Which of the following statements is FALSE about genitourinary (GU) TB patients?
  56. Magnetic resonance imaging (MRI) is often used to help diagnose patients with GU TB.
  57. Computed tomography (CT) is most useful in extensive TB disease when other organ systems might be involved.
  58. The most common finding of GU TB on plain film is calcification.
  59. Intravenous urography (IVU) is the best test to detect early renal changes due to TB.
  60. The most common finding on IVU is obstructive uropathy from scarring.

Schistosomiasis

  1. Of the following drugs, the most effective to treat schistosomiasis is:
  2. albendazole.
  3. praziquantel.
  4. mebendazole.
  5. diethylcarbamazine.
  6. ivermectin.
  7. The life cycle stage of Schistosoma haematobiumthat infects humans transdermally is:
  8. the worm.
  9. the schistosomule.
  10. the cercariae.
  11. the egg.
  12. the sporocyst.
  13. S. haematobiuminfections are estimated to affect the following number of people:
  14. 1.1 billion
  15. 1.1 million
  16. 900,000
  17. 112 million
  18. 11 million
  19. The life cycle stage of S. haematobiumthat induces the majority of human tissue pathology is:
  20. the worm.
  21. the schistosomule.
  22. the cercaria.
  23. the egg.
  24. the sporocyst.
  25. The eponym for acute schistosomiasis is:
  26. Katayama fever.
  27. Bilharz syndrome.
  28. Barlow fever.
  29. Toshiro syndrome.
  30. Tan's triad.
  31. The diagnostic, first-line gold standard for urogenital schistosomiasis is:
  32. polymerase chain reaction (PCR).
  33. serology.
  34. cystourethroscopy with bladder biopsy.
  35. rectal biopsy.
  36. urine egg counts.
  37. Without treatment, Schistosomaworms can live in human hosts for an average of:
  38. 3 months.
  39. 9 months.
  40. 3 to 5 years.
  41. 5 decades.
  42. 5 weeks.
  43. Surgical options for reconstruction of irreversible ureteral lesions caused by urogenital schistosomiasis include all of the following EXCEPT:
  44. renal autotransplantation.
  45. Boari flaps.
  46. ureteroureterostomies.
  47. ileal ureter.
  48. suprapubic intravesical ureterostomy.
  49. Intermediate snail hosts for S. haematobiumare members of the following genus:
  50. Biomphalaria.
  51. Oncomelania.
  52. Bulinus.
  53. Helix.
  54. Achatina.

Other Parasitic Infections

  1. The rickettsia-like organism that is an endosymbiont of the parasites which cause lymphatic filariasis (LF) and onchocerciasis is:
  2. Rickettsia rickettsii
  3. Wuchereria bancrofti
  4. Wolbachiaspp.
  5. Brugia malayi
  6. Brugia timori
  7. The chronic manifestations of LF are mostly seen in:
  8. short-term missionaries to endemic areas.
  9. short-term aid workers to endemic areas.
  10. long-term (current) residents of endemic areas.
  11. short-term tourists to endemic areas.
  12. short-term visiting friends and relatives travelers (VFRs) to endemic areas.
  13. Most patients infected with Onchocerca volvuluslive in:
  14. Latin America.
  15. Oceania.
  16. Asia.
  17. Sub-Saharan Africa.
  18. the Middle East.
  19. The majority of patients infected with Wuchereria bancroftihave:
  20. lymphedema.
  21. hydrocele.
  22. no clinical manifestations.
  23. acute adenolymphangitis (ADL).
  24. elephantiasis.
  25. Which drug should not be given to patients infected with O. volvulusor to those infected with high-grade Loa loa microfilaremia?
  26. Diethylcarbamazine (DEC)
  27. Albendazole
  28. Doxycycline
  29. Azithromycin
  30. Amoxicillin

Answers

Tuberculosis

  1. b. Mycobacterium avium-intracellulare.M. bovis, M. africanum, and M. microti are members of the M. tuberculosis complex (MTBC) and can cause TB disease. BCG is derived from M. bovis and can cause TB in certain individuals. Of the mycobacteria listed, M. avium-intracellulare is one of the many nontuberculous mycobacteria.
  2. c. Prevalence of multidrug-resistant tuberculosis cases is now approaching 12% in the United States.Although MDR TB is concerning because of the difficulty of treatment, in 2012, the proportion of TB cases caused by MDR TB was only 1.2% in the United States.
  3. a. Hematogenous seeding.Each of the answers is a known route of infection for the development of GU TB. However, hematogenous seeding is by far the most common one.
  4. e. Papulonecrotic tuberculid.Papulonecrotic tuberculid is the only manifestation listed that can present early in the course of TB disease. The tuberculids are hypersensitivity reactions to MTBC antigens that were disseminated to the skin from other infectious foci, and as such, they are culture negative and typically PCR negative.
  5. e. A healthy U.S.-born teacher with a TST of 11 mm.Refer to Table 17-1 for the Centers for Disease Control and Prevention guidelines on TST interpretation. Patients (a), (b), and (c) are likely TB infected. A BCG-vaccinated person is likely from a country with high enough incidence of TB to warrant vaccination; hence a cutoff of 10 mm is likely to apply for this person. Patient (e) has no clear risk factors for TB; hence a cutoff of 15 mm would apply for this person.

Table 17-1

Guidelines for Determining a Positive Tuberculin Skin Test Reaction

From American Thoracic Society and Centers for Disease Control and Prevention. Diagnostic standards and classification of tuberculosis in adults and children. Am J Respir Crit Care Med 2000;161(4 Pt. 1): 1376–95.

* For persons who are otherwise at low risk and are tested at entry into employment, a reaction of 15 mm induration is considered positive.

  1. d. A positive urine AFB culture.
  2. d. Ethambutol.Ethambutol is rarely hepatotoxic. Its main toxicity is ocular, such as decreased visual acuity or red-green color blindness. Streptomycin is not considered hepatotoxic either, but it is also not considered a first-line agent in the United States.
  3. c. Pyrazinamide.By definition, MDR TB is resistant to INH, rifampin, any quinolone, and at least an additional injectable aminoglycoside. Hence, of the choices, pyrazinamide is the most likely to have efficacy against XDR TB.
  4. c. Percutaneous nephrostomy of obstructive hydronephrosis in acute renal failure.All of the choices are appropriate indications for urological intervention. However, only (c) is emergently indicated. For the other interventions, waiting at least 4 to 6 weeks after initiation of medical therapy is preferred.
  5. a. Magnetic resonance imaging (MRI) is often used to help diagnose patients with GU TB.Although MRI has potential uses in the diagnosis of GU TB, it is not sufficiently superior to CT or IVU to warrant its frequent use.

Schistosomiasis

  1. b. Praziquantel.Although all of the drugs listed are antiparasitic agents, only praziquantel is used to treat schistosomiasis. In fact, praziquantel is the only drug approved for schistosomiasis by the World Health Organization (WHO).
  2. c. The cercaria.The worm and egg stages are found in chronically infected humans but are intravascular or deposited in tissues such as the bladder, respectively. Cercariae infect humans by burrowing through the skin, whereupon they transform into schistosomules.
  3. d. 112 million.Although an estimated 1 billion people are at risk of contracting schistosomiasis because they live in endemic areas, only 112 million are actively infected with S. haematobium.
  4. d. The egg.The majority of human tissue pathology caused by urogenital schistosomiasis is induced by the host immune response against S. haematobium eggs. In comparison to eggs, worms, schistosomules, and cercariae are much less immunogenic and are thought to correspondingly cause much less chronic tissue pathology.
  5. a. Katayama fever.The syndrome associated with acute schistosomiasis is named after the Katayama valley in Japan, a formerly endemic region for Schistosoma japonicum.
  6. e. Urine egg counts.Although PCR and serology are highly sensitive for detecting infection, they are not considered first-line diagnostic modalities. Cystourethroscopy with bladder biopsy and rectal biopsy are highly invasive and reserved for difficult-to-diagnose cases or suspected cancer. Microscopic enumeration of S. haematobium eggs shed in urine are the diagnostic, first-line gold standard (albeit slow and impractical in many field settings).
  7. c. 3 to 5 years.Although there have been reports that some schistosome worms can live for several decades, on average they are believed to only live for 3 to 5 years.
  8. a. Renal autotransplantation.Renal autotransplantation is reserved for reconstruction of the urinary tract in the setting of multiple and/or large renal tumors. There are much less morbid surgical options for reconstruction of schistosomiasis-associated ureteral lesions.
  9. c. Bulinus.Biomphalaria and Oncomelania are host snails for Schistosoma mansoni and S. japonicum, respectively, but not S. haematobium. Helix and Achatina snails are terrestrial and not considered hosts for human-specific schistosomes.

Other Parasitic Infections

  1. c. Wolbachiaspp. Wolbachia endosymbionts infect W. bancrofti, Brugia spp., and O. volvulus. They appear to be involved in embryogenesis and, when killed with antimicrobial therapy (e.g., doxycycline), result in decreased microfilaria release and suppressed larval molting.
  2. c. Long-term (current) residents of endemic areas.Because transmission is inefficient, long-term exposure to multiple infective bites appears to be necessary for transmission of LF and the development of chronic disease due to LF. Therefore, short-term visitors to endemic areas rarely develop LF, which is mostly seen in long-term residents of endemic areas.
  3. d. Sub-Saharan Africa.Although endemic to Latin America and the Middle East as well, 99% of persons who have onchocerciasis live in sub-Saharan Africa.
  4. c. No clinical manifestations.Although W. bancrofti infection can lead to all of these clinical manifestations, most infected persons remain asymptomatic.
  5. a. Diethylcarbamazine (DEC).DEC can cause blindness in patients with onchocerciasis (due to the inflammatory response to parasites in the anterior chamber of the eye) and encephalopathy in patients with high-grade L. loa microfilaremia.

Chapter review

  1. Hematogenous spread of tuberculosis occurs to the kidney, epididymis, and fallopian tubes.
  2. The likelihood of reactivation of dormant TB increases with diabetes and immunosuppression, such as with HIV infection and malignancies.
  3. Healing tubercles result in extensive fibrosis, which may cause infundibular stenosis and ureteral pelvic junction stricture.
  4. Tuberculosis usually affects the lower ureter. Tuberculosis of the bladder is secondary to infection from the kidney.
  5. Lower urinary tract symptoms are the commonest presentation of genitourinary tuberculosis; up to 25% of patients will present with sterile pyuria.
  6. When culturing for tuberculosis, the first morning void specimen is most appropriate.
  7. Pipestem ureter and bladder contracture may be sequelae of tuberculosis.
  8. The dome of the bladder is most often affected in tuberculosis; the ureteral orifice may have the appearance of a "golf hole."
  9. Surgical treatment is reserved for a nonfunctional kidney and to correct obstructive effects of fibrosis rather than to remove infected tissues.
  10. First-line drugs for treating tuberculosis are rifampicin, INH, pyrazinamide, and ethambutol.
  11. Pyridoxine must be given with INH to prevent a peripheral neuropathy.
  12. Patients must have a minimum of 3 to 6 weeks of medical treatment before surgical therapy is undertaken in those with active tuberculous infection.
  13. Strictures of the ureter usually occur in the distal third; however, they may occur throughout the ureter, resulting in a beaded corkscrew appearance when infected with TB.
  14. Rifampin resistance serves a s surrogate marker for multidrug-resistant TB.
  15. S. haematobiumhas a terminal spine and dwells principally in the perivesical venous plexuses.
  16. Schistosomiasis may cause inflammatory polyps of the bladder, sandy spots in the bladder (which represent submucosal egg deposition), calcification of the entire outline of the bladder, and strictures of the ureter (usually in the distal portion) with hydronephrosis. It may be associated with bladder cancer.
  17. Squamous cell carcinoma of the bladder is the most common histologic variant occurring as a result of schistosomiasis. These cancers are usually well differentiated or verrucous and therefore carry an overall good prognosis.
  18. W. bancroftiaccounts for 90% of human lymphatic filariasis.
  19. Obstructive lymphatic disease typically occurs in people who have multiple reinfections following the initial infection with filaria.
  20. W. bancroftiresults in chyluria and filarial hydrocele and occasional extensive scrotal and penile lymphedema.
  21. Echinococcosis may result in cysts in the kidney; cyst rupture or spillage during surgical removal can cause anaphylaxis.

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