Multidetector CT in Renal Tuberculosis

Abstract

Tuberculosis (TB) is one of the commonest infectious diseases in the developing countries with rising incidence seen due to HIV and AIDS. Pulmonary tuberculosis is the commonest form seen. Renal Tuberculosis is the most common extrapulmonary form. There are no specific clinical symptoms associated with renal tuberculosis. The constitutional symptoms like low grade fever, weight loss, anorexia commonly seen with pulmonary TB are not usually seen with renal TB. Renal TB is also cause of interstitial nephritis which leads to end-stage renal failure. Hence the role of radiologist assumes importance in supporting the timely diagnosis although cultures or histologic analysis is required for definitive diagnosis. The individual imaging finding may not be diagnostic as it can be seen with other renal pathologies too, however, presence of multiple imaging findings in a single case is pointer to this disease. Renal TB involves both cortex and collecting system. This article gives review of pathophysiology and computed tomography features of Renal TB.

Multidetector computed tomography has replaced conventional intravenous excretory urography in imaging of the kidneys: A scoping review of multidetector computed tomography findings in renal tuberculosis

“…Tuberculosis is usually caused by infection with Mycobacterium tuberculosis ; however, there are other described mycobacteria. 4,5,6,7,8,9,10,11 TB can affect any system in the body and pulmonary TB is the most common form. 2,5,12,13 Extrapulmonary TB is uncommon; however, co-infection with HIV or other immunocompromised states increases susceptibility.…”

“…4,8,21 The spread of infection to the kidney is almost always haematogenous from a pulmonary source with inoculation of mycobacteria in the renal cortex forming granulomas. 7,16–21 These are invisible on imaging and, in the immunocompetent state, may remain indolent for 5–25 years; however, reactivation may occur during the immunocompromised state, resulting in enlargement and coalescence of the granulomas which then rupture into the renal tubular system. 7,16,22–26 Some literature report a latent period of up to 40 years.…”

“…7,16–21 These are invisible on imaging and, in the immunocompetent state, may remain indolent for 5–25 years; however, reactivation may occur during the immunocompromised state, resulting in enlargement and coalescence of the granulomas which then rupture into the renal tubular system. 7,16,22–26 Some literature report a latent period of up to 40 years. 10,11,16 Renal TB is particularly rare in children because of the long latent period and it is even rarer in children below 5 years of age.…”

“…2,7,10,11,12,29 Urinary bladder involvement causes interstitial cystitis and granulomas may form in the bladder wall mimicking tumour; the end result is that of fibrosis of the bladder wall and reduced bladder capacity. 6,7,13,16,26 The end result of chronic infection of the kidney is renal tissue destruction, which is subsequently replaced by dystrophic calcifications and autonephrectomy, also known as ‘putty kidney’. 4,12,16,26,30 Calcifications in the wall of the ureter and in the bladder wall may also be seen.…”

“…6,16,17,30 Renal TB infection may also spread beyond the renal capsule and form masses, also known as ‘pseudotumour’, which can be confused with renal malignancy. 2,7,12,17,27,29 Rarely, renal TB may present with single or multiple parenchymal nodules without involvement of the renal collecting system, known as the pseudotumour type. 7,12,29 Perinephric abscesses which may further complicate with formation of renal sinuses and fistulae are very rare.…”