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Renal Tuberculosis



General Considerations

  • GU tract second most common site of tuberculous infection after lungs
  • Males more commonly infected than females, most often < 50 years old
  • Spread is hematogenous and usually occurs with primary exposure
    • Although may not be clinically apparent at this time, remaining latent for decades
    • Active pulmonary TB seen only 4-8% of time
    • Only about 25% of patients with GU TB have a known history of pulmonary TB
  • Begins as small tubercle and extends to renal tubules and medulla as necrotizing lesions produce larger cavities which communicate with collecting system
  • Stricturing eventually results in a fibrotic and small kidney
  • Prostatic TB is from descending infection, unlike involvement of seminal vesicles

Clinical Findings

  • Hematuria, microscopic or macroscopic
  • Stone formation
  • Frequency, dysuria and urgency
  • Sterile pyuria

Imaging Findings

  • Plain films may show large globular, amorphous calcifications or smaller nondescript stones
  • Intravenous pyelography or, more recently, CT urograms can be diagnostic
    • Affected kidney may contrast-enhance on CT
    • Renal calcification is common (24-44%)
      • Stones, focal or extensive globular calcification, ring-like calcifications of papillary necrosis
    • Cortical scarring
    • "Smudged" papillae (moth-eaten) –irregular due to inflammation and  necrosis
    • Several cysts surrounding a calyx with cortical thinning
    • Infundibular strictures
    • Hydrocalyces without dilatation of renal pelvis, or
    • Hydronephrosis
    • "Putty kidney" – sacs of caseous, necrotic material
    • Autonephrectomy – small, shrunken kidney with dystrophic calcification
  • Bilateral, but frequently asymmetric
    • About 75% unilateral radiologically
  • When ureters are involved, usually the upper or lower third (more common)
    • Beading (sawtooth ureter), corkscrew, strictures
  • Bladder involvement rarely leads to calcification of wall (think schistosomiasis)
    • Reflux, thickening of bladder wall (thimble bladder), fistula formation
  • On US, findings can include hypoechoic masses with hydronephrosis

Differential Diagnosis

  • Chronic pyelonephritis
  • Papillary necrosis
  • Medullary sponge kidney
  • Xanthogranulomatous pyelonephritis

Treatment

  • Anti-tuberculous drugs
  • Nephrectomy

Complications

  • Untreated, end result is autonephrectomy
  • Infertility in females
  • Sinus and fistula tract formation

Prognosis

  • With anti-tuberculous drugs, mortality is low (2%)


Renal Tuberculosis. Coronal reformatted non-enhanced CT scan of the abdomen and pelvis demonstrates a small, left kidney containing globular calcifications (white circle) pathognomonic for renal tuberculosis.
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Genitourinary Tuberculosis. eMedicine. Khan, A; Chandramohan, M and MacDonald, S

Renal Tuberculosis. Gibson, M; Puckett, M and Shelly, M. January 2004 RadioGraphics, 24, 251-256.