DISCUSSION
Intravesical instillation of BCG remains the most adequate therapy for
superficial urothelial carcinoma of the bladder, ensuring cure rates of
up to 80%. It is thought that BCG produce a local immune response which
results in the production of proinflammatory cytokines and influx of
leucocytes, ultimately result to lysis of tumor cells. Its side effects
may include urinary frequency (71%), cystitis (67%), fever (25%) and
hematuria (23%), that in most cases resolve spontaneously within 48h
and can be managed symptomatically [4]. Other more
serious side effects may be granulomatous hepatitis and pneumonitis
occurring in 0.7% of the cases, sepsis in 0.4%, arthralgias in 0.5%
and cytopenias in 0.1%. Less than 1% of the patients evolved with
disseminated BCG infection [5]. The exact
pathogenesis underlying the systemic infection occurring after
instillation of intravesicular BCG is not fully understood. It is
thought that local inflammatory process results in disruption of the
uroepithelial bladder cells thereby allowing organisms to disseminate
hematogenously or via the lymphatic system. It has also been reported
that BCG can persist in the bladder and spread hours to months, and even
years, following the completion of the therapy[6]. Until the date, was not possible to
identified risk factors associated to disseminated BCG infection,
including the time from TUR, the number of BCG instillations or
associated immunosuppression [7]. Disseminated BCG
should be suspected in every patient with previous intravesical BCG
therapy that presents with fever and/or organ disfunction, with or
without symptoms in the genitourinary tract. However, establishing the
diagnosis is difficult: regardless of a history of BCG exposure, all
other causes of fever must be excluded, although, clinical improvement
after treatment initiation reinforces the diagnosis. Histologic
examination of biopsies of different possible involved organ usually
demonstrates granulomatous inflammation but only the microbiologic tests
confirm the diagnosis [7]. Disseminated BCG
infection should be treated with antituberculosis therapy. The most
common regimen consisted of isoniazid, rifampin and ethambutol.
Corticosteroid use is not consensual and is usually reserved for severe
cases that evolve with respiratory failure [7].