KEY FACTS
Terminology
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Urinary tract infection by mycobacterium tuberculosis via hematogenous spread from primary focus, usually lungs
Imaging
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Depends on stage of disease; may range from caliectasis, abscess, cavities, calcifications, and strictures in urinary tract
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Early stage: Normal kidney or small focal cortical lesions with poorly defined border ± calcification
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Progressive stage: Papillary destruction with echogenic masses near calyces
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Mural thickening ± ureteric and bladder involvement, associated stricture → hydronephrosis
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Small, fibrotic, thick-walled bladder
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Small, shrunken kidney, “paper-thin” cortex, and dystrophic calcification in collecting system
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CECT with CT urogram (CTU) is useful in diagnosing and assessing severity
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Heavily calcified caseous mass surrounded by thin parenchymal shell → “putty kidney”
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Hydrocalyces or “phantom calyx” (nonopacification of calyx due to infiltration and obliteration) proximal to infundibular stricture
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Late stages: Small, poor-functioning, scarred kidneys with dystrophic calcification
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CT (CTU) has replaced IVP for diagnosis and to rule out complications (strictures, abscess) and extrarenal manifestation
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Ultrasound useful in assessing complications (renal abscess, hydronephrosis)
Top Differential Diagnoses
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Papillary necrosis
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Pyonephrosis
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Xanthogranulomatous pyelonephritis
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Cystitis
