TB and non tb infection OF Urinary tract

Briefly describing imaging findings in tubercular and non tubercular infection of urinary tract

1. TUBERCULAR AND NON TUBERCULAR INFECTIONS OF URINARY TRACT

2. Renal tuberculosis A subset of  genitourinary tuberculosis , accounts for 15-20% of extra-pulmonary tuberculosis. Tuberculosis can involve both the renal parenchyma and the collecting system (calyces, renal pelvis, ureter, bladder and urethra) and results in different clinical presentations and radiographic appearances.

3. Clinical presentation Clinical features are often non specific and include: Dysuria; Pyuria; Back , flank pain or abdominal pain Microscopic or macroscopic hematuria Constitutional symptoms

4. Pathology Renal infection results from Hematogenous Spread at the time of primary infection, with multiple micro-abscesses developing at the site of periglomerular capillary seeding. Normal Host Immunity is usually able to dampen the disease with the usual development of a small inactive granuloma.  Usually there is a long latency between primary infection and presentation which in most case occurs due to host immunity becoming compromised. These quiescent granulomas then can reactivate, grow and eventually communicate with the calyces, leading to Downstream Infection. 

5. Tuberculosis Of Urinary Tract

6. PATHOLOGICAL CHANGES OF RENAL TUBERCULOSIS

7. PATHOLOGICAL CHANGES OF RENAL TUBERCULOSIS

8. Radiographic features Both the renal parenchyma and the upper collecting system (calyces and renal pelvis) can be involved. Infection limited to the renal parenchyma has two morphological appearances : pyelonephritis   appearances are similar to pyelonephritis caused by other organisms hypoperfusion and swelling of all or part of the kidney pseudotumoural type single or multiple nodules  mimics  renal cell carcinoma

9. Usually the collecting system is involved (either in isolation or in combination with the parenchyma), and appearances vary according to the stage of disease .  early papillary necrosis (single or multiple) resulting in uneven Cali ectasis  progressive multifocal strictures and hydronephrosis mural thickening and enhancement (on cross-sectional imaging)  endstage progressive hydronephrosis and parenchymal thinning dystrophic calcification

10. PLAIN FILM Plain film findings focus on calcification, which is seen in 25-45%, at various stages of disease.  Triangular in  papillary necrosis Focal or amorphous:  putty kidney   ( endstage )

11. Calcifications of tuberculosis (a) Abdominal radiograph demonstrates extensive calcifications forming a cast of the kidney and ureter. (b) Photograph of the cut specimen shows complete replacement of the normal kidney by inflammatory debris

12. Plain radiograph revealing classic lobar pattern of calcification, which is pathognomonic of end-stage renal tuberculosis. Ureteral calcification is also noted

13. Fluoroscopy: IVP Traditional plain film IVP is quite sensitive to renal tuberculosis with only 10% of affected patients having normal imaging. Features include: parenchymal scars 50% moth eaten calyces : early finding         irregular Cali ectasis           hydronephrosis Lower urinary tract signs also recognized include: Kerr kink   sawtooth ureter pipe-stem ureter beaded or  corkscrew ureter thimble bladder

14. Tuberculosis :Retrograde pyelogram and IVP Collimated image from intravenous urography demonstrates multiple papillary cavities. Retrograde pyelogram shows that the upper pole calix is stenotic (arrow) with associated papillary necrosis. The adjacent calix is fibrotic and distorted as well.

15. intravenous urogram revealing the ‘classic’ lobar pattern of calcification in a non-functioning (R) kidney

16. (R) ureteric stricture (white arrow) with ureteric calcification (black arrowheads), pseudo-calculi (black arrow), and irregular calcification in the parenchyma (circled area)

17. (A) Intravenous urogram revealing a “hiked up” renal pelvis (arrow). Tuberculosis cavity (white arrowheads) communicating with the upper group of calyces. Black arrowheads represent medial border of a compound upper calyx, (B) Intravenous urogram revealing fluffy cavities (white arrowheads) communicating with a compound upper calyx (black arrowheads). Odd-shaped pockets of contrast communicating with a lower calyx (and with each other) [circled area], represent caseated necrotic cavities

18. Ultrasound early normal kidney or small focal cortical lesions with poorly defined border  +/- calcification. progressive papillary destruction with echogenic masses near calyces distorted renal parenchyma irregular hypoechoic masses connecting to collecting system; no renal pelvic dilatation mucosal thickening +/- ureteric and bladder involvement small, fibrotic thick-walled bladder echogenic foci or calcification (granulomas) in bladder wall near ureteric orifice localised or generalised   pyonephrosis end stage small, shrunken kidney, "paper-thin" cortex and dense dystrophic calcification in collecting system. may resemble chronic renal disease

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20. USG image revealing an xanthogranulomatous pyelonephritis-like appearance in an enlarged tuberculous kidney

21. CT CT is the most sensitive modality for visualizing renal calcifications and CT IVP is more sensitive at identifying all manifestations of renal tuberculosis .  early papillary necrosis (single or multiple) resulting in uneven caliectasis   progressive multifocal strictures can affect any part of the collecting system generalized or focal hydronephrosis mural thickening and enhancement poorly enhancing renal parenchyma, either due to direct involvement or due to hydronephrosis  end stage progressive hydronephrosis results in very thin parenchyma, mimicking multiple thin walled cysts amorphous dystrophic calcification eventually involves the entire kidney ( known as  putty kidney )

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23. Fat-saturated T2W FSE sequence MRI image showing multiple small hypointense granulomas (thin white arrows) in the (R) kidney. The (L) kidney shows caliectasis with heterogeneous intermediate signal within on T2W images, due to caseous internal debris (thick arrow) MRI

24. Angiography Renal angiography shows no specific vascular changes in renal TB. The vessels appear normal in the early case, while in the more advanced case, there may be zones of irregularity (especially of the interlobar and arcuate arteries) and even complete occlusion. In instances of TB pyonephrosis , angiography reveals the appearance of hydronephrosis. Angiography is of greater help in determining how much viable renal tissue remains and in the planning of partial nephrectomy than it is in the specific diagnosis of TB.

25. Treatment and prognosis Multi-drug treatment is essential, however despite treatment, stricturing can progress. The role of nephrectomy is controversial and depends on the degree of renal impairment, bilateral vs unilateral disease and the status of the lower urinary tract.  Nephrectomy, partial nephrectomy or cavernostomy can be performed both open and endoscopically 

26. Differential diagnosis General imaging differential considerations include: papillary necrosis medullary sponge kidney TCC  (transitional cell carcinoma) of renal tract SCC (squamous cell carcinoma) of renal tract xanthogranulomatous pyelonephritis (XGP)

27. INTRODUCTION Acute Chronic infections Acute renal infections Acute pyelonephritis and its various complications such as focal bacterial nephritis (FBN), Renal abscess, Emphysematous pyelonephritis, Papillary necrosis and Pyonephrosis NON TUBERCULAR INFECTIONS OF THE URINARY TRACT

28. Chronic renal infections C hronic pyelonephritis, R eflux nephropathy, X anthogranulomatous pyelonephritis, M alacoplakia, S quamous metaplasia and C holesteatoma.

29. Plain X-ray and intravenous urography (IVU) have a declining role whereas ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI) play a vital role in detection and delineation of the extent of renal infectious diseases. Plain X-ray - Abnormal gas collection in the renal or perirenal area in emphysematous pyelonephritis - Renal abscess or stag-horn calculus in a patient suspected to have pyonephrosis . IVU - Limited role - Can exclude congenital anomalies , - Papillary necrosis and early tuberculosis may be diagnosed

30. CT - Gold standard for diagnosis as well as for delineating the extent of renal infective diseases . MRI - Being increasingly used as an effective modality for both medical and surgical diseases of kidney especially in pregnant women, in patients with renal failure where iodinated contrast cannot be used and in diabetics. Radionuclide studies with cortical scintigraphy agents such as 99mTc DMSA and glucoheptonate have been shown to be the most sensitive techniques for the diagnosis of acute pyelonephritis and detection of the renal scars in reflux nephropathy

31. ACUTE INFECTIONS ACUTE PYELONEPHRITIS Inflammatory process affecting the collecting system and the renal interstitium Usually bacterial but may be fungal or viral Predisposing factors prolonged catheter drainage, reflux, obstruction, congenital anomalies, diabetes and pregnancy .

32. Ultrasound -- Less sensitive -- Focal or diffuse enlargement of the kidney with low level echoes . -- Loss of corticomedullary (CM) differentiation . -- abnormal echogenicity of the renal parenchyma  focal/segmental hypoechoic regions (in edema) or hyperechoic regions (in haemorrhage ) mass-like change

33. ACUTE PYELONEPHRITIS Diffusely hypoechoic and thickened cortex with compressed renal sinuses.

34. IVP less sensitive , Only 25 percent of cases of acute pyelonephritis will have positive IVU findings global or focal renal enlargement with decreased, delayed, and persistent nephrogram Pelvicalyceal system may show minimal dilatation or attenuation of the calyces

35. Non-contrast CT - often the kidneys appear normal affected parts of the kidney may appear edematous, i.e. swollen and of lower attenuation renal calculi or gas within the collecting system may be evident Postcontrast CT one or more focal wedge-like regions will appear swollen and demonstrate reduced enhancement compared with the normal portions of the kidney the periphery of the cortex is also affected, helpful in distinguishing acute pyelonephritis from a renal infarct (which tends to spare the periphery; the so-called ' rim sign ’)

36. ACUTE PYELONEPHRITIS

37. MRI T1   - affected region appear hypointense compared with the normal kidney parenchyma T2   - hyperintense compared to normal kidney parenchyma T1 C + -  reduced enhancement Nuclear medicine Technetium-99m dimercaptosuccinic acid (DMSA) demonstrates a similar reduction in renal perfusion and function, which appears as one or more patchy scintigraphy defects in the outline of the kidneys .

38. DMSA scan Scintiscan obtained with technetium 99m dimercaptosuccinic acid demonstrates a photopenic, peripheral defect (arrow) in the upper lateral margin of the right kidney that correlates with an area of acute bacterial pyelonephritis.

39. Imaging differential diagnosis - Renal infarction   CORTICAL RIM SIGN   useful in distinguishing  acute pyelonephritis   from a segmental  renal infarc t  and is seen on contrast enhanced CT or MRI. The wedges of reduced enhancement seen in the setting of  acutepyelonephritis  represent oedema and ischemia which involves the whole wedge or renal parenchyma, from medulla to the capsule.  In segmental infarcts, the blood supply to the outer aspect of the cortex is derived from perforating branches of the  renal capsular artery  which is an early branch of the  renal artery . As such, when a branch of the renal artery is occluded (by thromboembolism,  dissection , etc ) perfusion may be preserved to a thin rim (2-4 mm) of cortex which enhances normally.

40. ACUTE PYELONEPHRITIS Absent cortical rim sign - pyelonephritis Renal infarct  with subtle but present  cortical rim sign .

41. INTRODUCTION Acute Chronic infections Acute renal infections Acute pyelonephritis and its various complications such as focal bacterial nephritis (FBN), Renal abscess, Emphysematous pyelonephritis, Papillary necrosis and Pyonephrosis

42. ACUTE FOCAL BACTERIAL NEPHRITIS IVU focal renal mass which on follow-up IVU may reveal an area of focal scarring due to healing opposite a normal or clubbed calyx. ultrasound hypoechoic poorly defined mass with internal echoes CT low density area with patchy enhancement Lack of well defined wall and central low density differentiates it from the renal abscess.

43. ACUTE FOCAL BACTERIAL NEPHRITIS Longitudinal ultrasound scan of the kidney showing poorly defined hypoechoic lesion with low level internal echoes in the upper polar region (arrow) which was due to focal bacterial nephritis. (B) Contrast enhanced CT scan of another patient showing a focal low density area with patchy enhancement in the posterior aspect of upper pole of left kidney (arrow)

44. RENAL AND PERIRENAL ABSCESS Complication of focal bacterial pyelonephritis, but may result from haematogenous infection or superadded infection in a renal cyst or direct involvement of the perinephric space from pancreas, colon, and retroperitoneum Plain X-ray abdomen S hows renal enlargement, rotation, displacement, presence of mottled gas in the renal areas, and loss of psoas outline. IVU shows poorly or nonfunctioning kidney with calyceal attenuation and compression due to mass affect. Ultrasound well-defined complex mass with good sound transmission Bright echoes with dirty distal shadowing are seen in the presence of air.

45. CT Gold standard to assess the renal as well as extrarenal extent of the renal abscess. changes in the renal contour, parenchymal density, enhancement pattern and perinephric abnormalities such as thickening of the Gerota’s fascia, psoas muscle involvement are best seen on CT Presence of non- enhancing poorly marginated area of decreased attenuation may be seen during the earlier course of renal abscess Later in the course of the disease, renal abscess appears as a sharply marginated area of low attenuation due to necrosis surrounded by a peripheral enhancing rim indicating a mature abscess

46. MRI hypointense lesion on T1WI hyperintense lesion on T2WI Gadolinium administration the lesion shows peripheral enhancement Differential diagnosis : Segmental renal infarct, Metastasis, Lymphoma, Trauma, and Renal vein thrombosis

47. EMPHYSEMATOUS PYELONEPHRITIS Indicates severe renal infection with gas forming organisms characterized by presence of gas in the collecting system or renal parenchyma. Two types: Type I - less common (33%), parenchyma destruction and shows streaky/mottled gas in interstitium of renal parenchyma radiating from medulla to cortex, crescent of subcapsular/perinephric gas with no fluid collection. Type II - more common (66%) shows bubbly/loculated intrarenal gas, renal/perirenal fluid collections and gas within the pelvicalyceal system.

48. Plain X-ray Air specks in renal area. frequently misinterpreted as bowel gas . US Dense echoes with dirty shadowing in intrarenal infection. If the gas enters the perinephric space, there will be non visualization of kidney (gassed out kidney) CT detects the presence of air, its precise location within the kidney as well as its extension into the perirenal or pararenal compartments of the retroperitoneal space. MRI limited as gas appears as an area of signal loss which cannot be differentiated from calculi, renal calcification

49. PYONEPHROSIS Infection in an obstructed collecting system with suppurative destruction of the renal parenchyma. US - the modality of choice to detect dilated collecting system which contains dependent echoes and shifting debris. CT -ideal to show intrarenal changes and the perirenal extension. High-density of urine in the dilated system should suggest infection

50. Thickening of the renal pelvic wall may be detected both on US or CT. Ultrasound guided aspiration may be performed to confirm the diagnosis as well as obtain specimen for culture and sensitivity. Percutaneous nephrostomy may also be performed under US guidance to provide immediate decompression of the collecting system as an adjunct prior to definitive surgery.

51. (A) Longitudinal ultrasound scan of right kidney showing dilated collecting system filled with echogenic material and thickened echogenic uroepithelium (arrow) suggestive of pyonephrosis. (B) Contrastenhanced CT scan shows hydronephrosis of left kidney with presence of high density urine and perinephric and periureteric stranding (arrow). (C) Caudal axial section in the same patient shows a left lower ureteric calculus

52. Chronic renal infections C hronic pyelonephritis, R eflux nephropathy, X anthogranulomatous pyelonephritis, M alacoplakia, S quamous metaplasia and C holesteatoma.

53. C hronic pyelonephritis Chronic inflammation of the kidney characterized by cortical scarring overlying the involved calyx (usually polar). Entire collecting system may be involved resulting in small kidney with clubbed calyces. Differential diagnosis Fetal lobulation,Ischemia,Hypoplastic kidney

54. REFLUX NEPHROPATHY Results from combined effects of the vesicoureteric reflux and bacterial infection. Begins in infancy and childhood, and is more common in females. Incompetent papillary duct orifices. Intrarenal reflux of infected urine which leads to destruction of the tubules and subsequent scarring. Fluoroscopic voiding cystourethrogram US - best screening tool to detect obstructive uropathy. Renal cortical scintigraphy - best technique to detect renal scarring.

55. XANTHOGRANULOMATOUS PYELONEPHRITIS Chronic granulomatous inflammation of the kidney usually seen in patients who have stones and obstruction. Replacement of the renal parenchyma with lipidladen macrophages which are paraaminosalicylic acid (PAS)-positive (xanthoma cells). common in women plain X-ray Presence of staghorn calculus and/or also small calcifications. IVU Focal mass ( tumefactive type), or diffusely enlarged nonfunctioning kidney. CT Presence of lucent areas on X-ray and nonenhancing cystic areas on CT corresponding to the xanthoma cell collection is characteristic.

56. RENAL PAPILLARY NECROSIS Most common cause of renal papillary necrosis is analgesic abuse and diabetes. Other causes: urinary tract infection (UTI), renal vein thrombosis, obstruction, dehydration, and sickle cell disease.

57. IVU Best technique for demonstrating the changes of papillary necrosis. Presence of extra calyceal contrast, ill-defined calyx, contrast outlining sloughed papillae (ring sign), and filling defect in the calyx Classical features may appear as  ball on tee forniceal excavation lobster claw signet ring sloughed papilla with clubbed calyx​ RENAL PAPILLARY NECROSIS

58. MALACOPLAKIA Granulomatous inflammatory disease seen almost exclusively in women who present with repeated attacks of UTI. Bladder and ureter are most frequently affected. Radiological features Enlarged poorly functioning kidney Filling defect in the bladder and the ureter. Strictures may also form, thus tuberculosis is an important differential diagnosis.

59. SQUAMOUS METAPLASIA Replacement of normal transitional cell epithelium by squamous epithelium as a result of infection. Presence of multiple linear radiolucencies in the ureter due to mucosal thickening resulting in so called “tree barking” or “Corduroy appearance” in IVU or RGU. The term, cholesteatoma is used when there is a filling defect in the collecting system due to sloughed keratinized material. PARASITIC INFECTION Schistosomes usually affects the bladder causing calcification. Intrarenal hydatids are rare - focal cystic masses which are usually thick walled and irregular, and may show calcification of crushed eggshell pattern.

60. Excretory urogram showing a mass at the lower pole of right kidney with displacement and dilatation of the collecting system and medial deviation of the ureter. (B and C) Ultrasound and contrast-enhanced CT scan of the same patient showing characteristic multiloculated appearance due to daughter cysts of hydatid later confirmed at surgery

61. REFERENCES GRAINGER & ALLISON’S DIAGNOSTIC RADIOLOGY. DIAGNOSTIC ULTRASOUND- M.RUMACK. RADIOPEDIA.

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