176 CHAPTER 5 Infections and inflammatory conditions

Tuberculosis

Tuberculosis (TB) of the genitourinary (GU) tract is caused by Mycobacterium tuberculosis. TB predominantly affects Asian populations, with a higher incidence in males than females.

Pathogenesis

Primary TB

The primary granulomatous lesion forms in the mid to upper zone of the lung. It consists of a central area of caseation surrounded by epithelioid and Langhans giant cells, accompanied by caseous lesions in the regional lymph nodes.

There is early spread of bacilli via the bloodstream to the GU tract; however, immunity rapidly develops, and the infection remains quiescent. Acute diffuse systemic dissemination of tubercle bacilli can result in symptomatic military TB.

Post-primary TB

Reactivation of infection is triggered by immune compromise (including HIV). It is at this point that patients develop clinical manifestations.

Kidney

Hematogenous spread causes granuloma formation in the renal cortex, associated with caseous necrosis of the renal papillae and deformity of the calyces, leading to release of bacilli into the urine. This is followed by healing fibrosis and calcification, which causes destruction of renal architecture and autonephrectomy.

Ureters

Spread is directly from the kidney and can result in stricture formation (vesicoureteric junction, pelviureteric junction, and mid-ureteric) and ureteritis cystica.

Bladder

Infection is usually secondary to renal infection, although iatrogenic TB can be caused by intravesical BCG treatment for carcinoma in situ. The bladder wall becomes edematous, red, and inflamed, with ulceration and tubercles (yellow lesions with a red halo).

Disease progression causes fibrosis and contraction (resulting in a small capacity ‘thimble’ bladder), obstruction, and calcification.

Prostate and seminal vesicles

Hematogenous spread causes cavitation and calcification, with palpable, hard-feeling structures. Fistulae may form to the rectum or perineum.

Epididymis

Hematogenous spread results in a “beaded” cord. Infection may spread to the testis.

Presentation

Early symptoms include fever, lethargy, weight loss, night sweats, and UTI not responding to treatment. Later manifestations include LUTS, hematuria, and flank pain.

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Investigations

•Urine: At least 3 early morning urines (EMUs) are required, but often many more EMU specimens will be needed before a positive culture for TB is obtained. A typical finding is sterile pyuria (leukocytes, but no growth). Ziehl–Neelsen staining will identify these acidand alcoholfast bacilli (cultured on Lowenstein–Jensen medium).

•CXR and sputum

•Tuberculin skin test

•IVP or CT urogram: Findings include renal calcification (nephrocalcinosis), irregular calyces (“moth-eaten kidney”), infundibular stenosis, cavitation, pelviureteric and vesicoureteric obstruction, and a contracted, calcified bladder.

•Cystoscopy and biopsy

Treatment

Treatment is with 6 months of isoniazid, rifampicin, and pyrazinamide. Regular follow-up imaging with IVP is recommended to monitor for ureteric strictures, which may need stenting, nephrostomies, or ureteric reimplantation.

Severe bladder disease may require surgical augmentation, reconstruction, or urinary diversion.

178 CHAPTER 5 Infections and inflammatory conditions

Parasitic infections

Schistosomiasis (bilharziasis)

Urinary schistosomiasis is caused by the trematode (or fluke) Schistoma haematobium. It is endemic in Africa, Egypt, and the Middle East. Fresh water snails release the infective form of the parasite (cercariae), which can penetrate skin, and migrate to the liver (as schistosomules), where they mature. Adult flukes couple, migrate to vesical veins, and lay eggs (containing miracidia larvae), which leave the body by penetrating the bladder and entering the urine.

The disease has two stages: active (when adult worms are actively laying eggs) and inactive (when the adult has died, and there is a reaction to the remaining eggs). The development of squamous cell carcinoma of the bladder is result of the chronic inflammation.

Presentation

The first clinical sign is “swimmer’s itch”—a local inflammatory response. Other early manifestations include Katayama fever, a generalized allergic reaction, which includes fever, urticaria, lymphadenopathy, hepatosplenomegaly, and eosinophilia. Active inflammation results in hematuria, frequency, and terminal dysuria.

Investigation

•Midday urine specimen; bladder and rectal biopsies may contain eggs (distinguished by having a terminal spine).

•Serology tests (ELISA).

•Cystoscopy identifies eggs in the trigone (“sandy patches”).

•IVP or CT urogram may show a calcified, contracted bladder, and obstructive uropathy.

Treatment

Give praziquantel 40 mg/kg in 2 divided doses 4–6 hours apart. Alternative medications include metrifonate or niridazole.

Complications

Chronic infection can lead to obstructive uropathy, ureteric stenosis, renal failure, and bladder contraction, or ulceration. The most significant and concerning complication is the development of squamous cell carcinoma of the bladder that often presents at an advanced stage.

Hydatid disease

Infection occurs after ingestion of the dog parasite Echinococcus granulosus (tapeworm). Sheep are the intermediate hosts. Cases occur in the Middle East, Australia, and Argentina, with 3% affecting the kidneys. Large cysts form, which can be asymptomatic or present with flank pain. A peripheral eosinophilia is seen with a positive hydatid complement-fixation test. X-rays and CT scans show a thick-walled, fluid-filled spherical cyst with a calcified wall.

Medical treatment is with albendazole. Where surgical excision is indicated, cysts can be first sterilized with formalin or alcohol. Praziquantel is also recommended preoperatively or if cyst contents are spilt (which can provoke systemic anaphylaxis).

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Genital filariasis

Lymphatic filariasis is caused by Wuchereria bancrofti nematode infection and is common in the tropics. Manifestations include funiculoepididymitis, orchitis, hydrocele, scrotal and penile elephantiasis, and lymph scrotum (edema).

Diagnosis is made on capillary finger-prick, or venous blood is used for thick blood microscopic thick film and serology.

Medical treatments include diethylcarbamazine, ivermectin, and albendazole.