Kidney is Being Attacked: MDCT Findings, Pathology, Clinical Correlation and Algorithmic Approach of Renal Infection.

Transcription

1 Kidney is Being Attacked: MDCT Findings, Pathology, Clinical Correlation and Algorithmic Approach of Renal Infection. Poster No.: C-0986 Congress: ECR 2014 Type: Educational Exhibit Authors: H. M. Shebel, M. Dighe, H. Abou El Atta, T. A. El-Diasty ; Mansoura/EG, Seattle, WA/US Keywords: Kidney, CT, Computer Applications-Detection, diagnosis, Infection DOI: /ecr2014/C-0986 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 32

2 Learning objectives 1.Understand different types of renal infections. 2.Review the pathogenesis of renal infective diseases. 3.Design and establish an anatomically based algorithm for classification and diagnosis of various renal infections. 4.Discuss MDCT characteristic findings of different types of renal infection. Page 2 of 32

3 Background Introduction: Most cases of renal infection are diagnosed by clinical and laboratory investigations however, in many cases imaging is essential for diagnosis of specific type of infection, to detect complications and to specify therapy or interventions. Computed tomography (CT) is the modality of choice in diagnosis, management and intervention in these cases. In this exhibit will discuss the pathogenesis, imaging findings, and anatomical based classification of renal infection. Pathogenesis Bladder is the usual source of ascending infection producing ascending pyelonephritis.from the bladder organisms migrate up through the ureter to the collecting system. In minority of cases the source of infection is hematogenous. In normal urinary system there is a natural protective mechanism aganist this route of ascending infection.continous urine stream from the kidney down to the bladder act as a washing system. this stream is maintained by normal perstalsis of the urter. A potent endotoxins produced from the organism can block the adrenergic nerves within smooth muscle of the ureter producing functional obstruction and stasis of the urine stream resulting in inhibition of the protective mechanism and easy migration of the organism to the collecting system. Dilated system as in case of obstruction or advanced reflux there is already stasis of urine stream makes the system more vulnerable to invasion by the organism. Fig.1 Page 3 of 32

4 Fig. 1: Diagram illustrating the pathogenesis of renal infection. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Bacteria enter the kidney through renal tubules at the papillary tip producing an inflammatory reactio that extends to the renal interstitium. Page 4 of 32

5 Images for this section: Fig. 1: Diagram illustrating the pathogenesis of renal infection. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 5 of 32

6 Findings and procedure details Classification of Renal Infection In this educational exhibit we intorduce an anatomically based approach for classification of different types of renal infection. Renal infection could be classified into 3 categories: -Parenchymal Infection, collecting system infection, combined parenchymal and collecting system infection.fig 2. Fig. 2: Diagram represents anatomical based classification of different types of renal infection. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Page 6 of 32

7 I- Parenchymal infection: Emphysematous Pyelonephritis ( Type 1): - Usually affecting the immunocompromised patients or in chronic disease as in diabetic patients. - Gas forming organisms are usually contributed to this type of infection such as E coli, Klebsiella pneumonia, and Proteus mirabilis. - The producing gas is usually involves the kidney or its surroundings. - Type1 (33%) is aggresive characterized by renal parenchymal gas destruction. - MDCT findings are parenchymal enlargement, tissue necrosis and destruction. Gas appears as streaky or mottled areas within the renal parenchyma. No Intra- or extrarenal fluid collection. Fig 3 Fig. 3: A, axial NCCT, B, Sagittal reformatted NCCT C, negative window image show air is replacing the parenchyma of the right kidney. D, U.T.P shows the air is occupying the renal region. References: Dept of Radiology, University of Washington UWMC.Seattle Human Immunodeficiency Virus HIV: Page 7 of 32

8 - HIV associated renal disease may be a secondary to renal parenchymal infection by HIV, opportunistic renal infection, or a side effect of antiviral drug therapy. - Male predominance espcially African american was reported and usual age affected between 20 and 64 years. -Clinical picture include proteinuria, hematuria, and sometimes pyuria and may progress to chronic kidney disease. - In unenhanced MDCT images, there is globular enlargrmrnt of both kidneys with medullary hyperattenuation. After administration of a contrast agent, striations can be seen on the nephrographic phase of MDCT.Fig 4 Fig. 4: Axial contrast enhanced CT shows mild globular enlargement of the kidneys with contrast locules concentrated in the medula. References: Dept of Radiology, University of Washington UWMC.Seattle Malacoplakia: Page 8 of 32

9 - Malacoplakia is a rare, inflammatory process induced in response to chronic infection. - The disease could affects both adults and children groups sepcially if they affected with HIV infection. - Urinary bladder is usually the affected organ however, whole urinary tract could be involved. Involvement of the bladder by a mass could produce hydronephrosis on the ipsilateral side. - The classic MDCT findings of renal involvement is enlargment of the affected kidney associated with multiple small masses of low enhancement pattern. These masses may coalesce to form one large mass may reach to 8cm. Both kidneys could be affected in 50 % of cases. Fig 5 Fig. 5: A and B : Axial enahnced CT shows multiple bilateral low attenuated masses [arrows] enhancing less than renal parenchyma. C, Coronal reformated CT images of the same patient shows the relation of the renal masses pathologically proved to be Malackplekia. Page 9 of 32

10 References: Dept of Radiology, University of Washington UWMC.Seattle Fig 6 Algorithm describes main features of parenchymal infection Fig. 6: Algorithm describes main features of parenchymal infection References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG II- Collecting system infection: Emphysematous pyelitis: - Emphysematous pyelitis is diagnosed when gas is localized to the renal collecting system.it has a less mortality rate less than that of emphysematous pyelonephritis. - MDCT findings are a dilated collecting system, gas bubbles or gas-fluid levels within the renal caliceal system or renal sinus, and lack of parenchymal gas. Fig 7 Page 10 of 32

11 Fig. 7: Axial contrast CT of at the level of the kidney and ureter shows air density occupying both renal sinuses as well as along the course of the iliac ureter [ arrow heads ] References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Pyonephrosis: - Pyonephrosis is an infection of obstructive urinary system may lead to septic shock. - CT findings include dilated obstructed collecting system. - High attenuation fluid in the collecting system with layering of the contrast on excretory phase. - Thickened and enhancing renal pelvis more than 2mm. - Renal or perirenal inflammatory reaction.fig 8 Fig. 8: Ultrasound image [ on the left ] shows marked hydronephrosis with abundant low levels internal echoes [arrow]. Both axial CT images [on the right] show dilated pelvis and collecting system with high denisty attenuation. Page 11 of 32

12 References: 2 Dept of Radiology, University of Washington UWMC.Seattle Pyeloureteritis Cystica - Pyeloureteritis cystica, mainly caused by Schistosomiasis infection. CT findings are characterized by mural air bubble-like filling defects in the renal pelvis and ureter usually seen at CT urography.fig 9 Fig. 9: Coronal reformatted CTU image show multiple small mural defects were recognized[arrows] Patient had history of Schistosomiasis infection. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Page 12 of 32

13 Algorithm describes main features of collecting system infection Fig 10 Fig. 10 References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG III- Parenchmal and collecting syetem infection: Emphysematous Pyelonephritis ( Type II): - The same risk factors and organisms as in type I could be contributed in case of Emphysematous Pyelonephritis Type II. - Type II is less aggresive than type I and represent 66%. - The characterisitic MDCT findings include renal or perirenal fluid collections associated with gas locules within the collection or the collecting system.fig 11 Page 13 of 32

14 Fig. 11: Emphysematous pyelonephritis typeii: A: non contrast CT revealed gas locules in the parenchyma and collecting system [arrows] with hypodense fluid collection [asterisks].b: post contrast CT revealed same areas of gas locules with marginal enhancement of the collection impressive of inflammatory condition. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Xanthogranulomatous pyelonephritis (XGP): - Xanthogranulomatous pyelonephritis is a chronic destructive granulomatous process induced by recurrent urinary tract infection in which renal parenchyma is replaced by lipid laden macrophages. - Female patients are more frequently affected than male patients in a ratio of 2:1. Both children and the dults may be afflicted.it is unilateral more than bilateral. - MDCT Imaging findings: include enlarged kidney, with decreased or absent function, central stone, peripheral cystic dilatation, enhancing walls of the abscess cavities, perinephric extension, a large central laminated or branching stones.fig 12 Page 14 of 32

15 Fig. 12: XGP A: non contrast CT with obstructive stone at the renal pelvis and increased attenuation of the hydronephrotic kidney. B and C: the left kidney shows multiple abscess locules and parenchymal enhancement as well as perirenal inflammatory reaction. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Acute pyelonephritis: - Acute pyelonephritis is a combined infection of the renal parenchyma and renal pelvis involving the tubules and interstitium sparing glomerului. - Commonest organism are gram-negative organism such as Escherichia coli (>80%), Proteus, Klebsiella, or Enterobacter. - Acute pyelonephritis has multiple pattern in MDCT. - Characteristic MDCT findings include: - Kidneys may appear normal in non contrast CT. - In enhanced CT a characteristic wedge-shaped areas or linear zones of less enhancement that involve the renal parenchyma espcially the cortex in the nephrographic phase. In delayed phase, the pattern of enhancement is reversed. This pattern is likely due to the affected parts of the renal parenchyma has a delay concentration of the contrast than that of non affected parts. Fig 13 Fig. 13: A: Non contrast CT shows subtle areas of parenchymal hypodenisty due to oedema (arrow). B: Post contrast parenchymal phase shows linear zones of lesser Page 15 of 32

16 parenchymal enhancement (arrows). C:The streaky areas become more enhance in delayed phase. (arrow) References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG - Focal bacterial nephritis is another form or phase of acute pyelonephritis in which an inflammatory mass like lesion affects renal parenchyma. This mass could be confusing with renal cell carcinoma espcially in abscence of appropriate clinical settings. Some authors reported that the inflammatory like masses didnot exihbit rapid venous washout in the triphasic CT Shebel et al., follow up CT or even tissue core biopsy may indicated in such situation. Fig 14. Fig. 14: Focal bacterial nephritis A: Non contrast CT show normal appearance of the kidney. B:Corticomedullary phase shows focal soft tissue lesion like mass. C: parenchymal phase show the focal lesion take enhancement less than parenchyma. Delayed phases show same pattern of C. biopsy revealed focal bacterial nephritis. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG - In a late stage if liquefaction occurs, the characteristic abscess findings are established in the renal or perirenal region. CT findings include low attenuation like cystic mass shows marginal enhancement after contrast administration. Fig 15 Fig. 15: Perirenal abscess A: non contrast show perirenal hypodense lesion (arrow). B & C: parenchymal and delayed phases show cystic like lesion surround the upper Page 16 of 32

17 pole of the left kidney with faint marginal enhancement (arrows). Diagnostic aspiration revealed abscess. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Chronic pyelonephritis: - Chronic pyelonephritis is a late condition that asociated with many kidney disorder. such as, vesicoureteral reflux in young children, prolonged urinary tract obstruction, renal calculi or ischemic changes due to pathology of the renal artery. - The disease may be focal, segmental, or diffuse and unilateral or bilateral. -The imaging findings are characterized by renal scarring, atrophy and cortical thinning, hypertrophy of residual normal tissue, thickening and dilatation of the caliceal system, and overall renal asymmetry with gradual loss of renal function. Fig 16 Fig. 16: Non contrast axial CT shows small size right kidney with multiple scarring and residual of renal stones.gross picture image of the nephrectomized kideny. References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Tuberculosis (TB): - Tuberculosis (TB) of the kidney is usually caused by Mycobacterium tuberculosis from the lung infection. Page 17 of 32

18 - Renal affection usually starts at the level of the renal papillae producing papillary necrosis and sloughed papillae leading to clayceal obstruction and dilatation or caliectasis due to infundibular stricture. - As the disease progress parenchymal affection occurs with its thining and finally producing parenchymal atrophy and gradual loss of renal function. - Finally renal calcifications developed which is a common manifestation, seen in up to 45% of patients. - Unenhanced CT is highly sensitive for detection of renal calcification. - Contrast-enhanced CT shows a focal area of hypoperfusion, calyceal dilatation, cortical thinning, parenchymal scarring, and fibrotic strictures of the infundibula, renal pelvis, and ureters.fig 17 Fig. 17: Post contrast CT early (A) and delayed (B) show marked caliectasis of the left kidney with thin parenchyma associated with perirenal inflammatory reaction (Arrow) in B. C: Coronal reformatted image shows the same finding as in A. Page 18 of 32

19 References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Algorithm of the main CT features of the parenchymal and collecting system infection Fig 18 Fig. 18 References: Radiology, Urology and Nephrology Center, Urology and Nephrology Center - Mansoura/EG Page 19 of 32

20 Images for this section: Fig. 2: Diagram represents anatomical based classification of different types of renal infection. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 20 of 32

21 Fig. 3: A, axial NCCT, B, Sagittal reformatted NCCT C, negative window image show air is replacing the parenchyma of the right kidney. D, U.T.P shows the air is occupying the renal region. Dept of Radiology, University of Washington UWMC.Seattle Page 21 of 32

22 Fig. 4: Axial contrast enhanced CT shows mild globular enlargement of the kidneys with contrast locules concentrated in the medula. Dept of Radiology, University of Washington UWMC.Seattle Fig. 5: A and B : Axial enahnced CT shows multiple bilateral low attenuated masses [arrows] enhancing less than renal parenchyma. C, Coronal reformated CT images of the same patient shows the relation of the renal masses pathologically proved to be Malackplekia. Dept of Radiology, University of Washington UWMC.Seattle Page 22 of 32

23 Fig. 6: Algorithm describes main features of parenchymal infection Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 7: Axial contrast CT of at the level of the kidney and ureter shows air density occupying both renal sinuses as well as along the course of the iliac ureter [ arrow heads ] Page 23 of 32

24 Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 8: Ultrasound image [ on the left ] shows marked hydronephrosis with abundant low levels internal echoes [arrow]. Both axial CT images [on the right] show dilated pelvis and collecting system with high denisty attenuation. 2 Dept of Radiology, University of Washington UWMC.Seattle Page 24 of 32

25 Fig. 9: Coronal reformatted CTU image show multiple small mural defects were recognized[arrows] Patient had history of Schistosomiasis infection. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 25 of 32

26 Fig. 10 Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 26 of 32

27 Fig. 11: Emphysematous pyelonephritis typeii: A: non contrast CT revealed gas locules in the parenchyma and collecting system [arrows] with hypodense fluid collection [asterisks].b: post contrast CT revealed same areas of gas locules with marginal enhancement of the collection impressive of inflammatory condition. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 12: XGP A: non contrast CT with obstructive stone at the renal pelvis and increased attenuation of the hydronephrotic kidney. B and C: the left kidney shows multiple abscess locules and parenchymal enhancement as well as perirenal inflammatory reaction. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 13: A: Non contrast CT shows subtle areas of parenchymal hypodenisty due to oedema (arrow). B: Post contrast parenchymal phase shows linear zones of lesser parenchymal enhancement (arrows). C:The streaky areas become more enhance in delayed phase. (arrow) Page 27 of 32

28 Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 14: Focal bacterial nephritis A: Non contrast CT show normal appearance of the kidney. B:Corticomedullary phase shows focal soft tissue lesion like mass. C: parenchymal phase show the focal lesion take enhancement less than parenchyma. Delayed phases show same pattern of C. biopsy revealed focal bacterial nephritis. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 15: Perirenal abscess A: non contrast show perirenal hypodense lesion (arrow). B & C: parenchymal and delayed phases show cystic like lesion surround the upper pole of the left kidney with faint marginal enhancement (arrows). Diagnostic aspiration revealed abscess. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 28 of 32

29 Fig. 16: Non contrast axial CT shows small size right kidney with multiple scarring and residual of renal stones.gross picture image of the nephrectomized kideny. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 29 of 32

30 Fig. 17: Post contrast CT early (A) and delayed (B) show marked caliectasis of the left kidney with thin parenchyma associated with perirenal inflammatory reaction (Arrow) in B. C: Coronal reformatted image shows the same finding as in A. Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Fig. 18 Radiology, Urology and Nephrology Center, Urology and Nephrology Center Mansoura/EG Page 30 of 32

31 Conclusion Renal infection is a common clinical problem and in many situations need good imaging modality for proper diagnosis and intervention. MDCT can depict different signs of renal infection and its complication. Using an anatomical based approach for classification of different types of renal infection makes their diagnosis more easy and accurate for radiologist reflecting on patient management. Page 31 of 32

32 References -Baumgarten DA, Baumgartner BR. Imaging and radiologic management of upper urinary tract infections.urol Clin North Am 1997;24: Craig WD, CDR, MC, USN Wagner Bj, MD,Travis MD, LCDR, MC, USN: From the Archives of the AFIP Pyelonephritis: Radiologic-Pathologic Review RadioGraphics 2008; 28: Goldman SM, Fishman EK. Upper urinary tract infection: the current role of CT, ultrasound, and MRI. Semin Ultrasound CT MR 1991;12: Kawashima A, Sandler CM, Goldman SM. Imaging in acute renal infection. BJU Int 2000;86(suppl 1): Tsugaya M, Hirao N, Sakagami H, et al. Computerized tomography in acute pyelonephritis: the clinical correlations. J Urol 1990;144: Shebel HM, Elsayes KM, Sheir KZ, Abou El Atta HM, El-Sherbiny AF, Ellis JH, ElDiasty TA.Quantitative enhancement washout analysis of solid cortical renal masses using multidetector computed tomography.j Comput Assist Tomogr MayJun;35(3): doi: /RCT.0b013e318219f92b. -Shebel HM, Elsayes KM, Abou El Atta HM, Elguindy YM, El-Diasty TA.Genitourinary schistosomiasis: life cycle and radiologic-pathologic findings.radiographics JulAug;32(4): doi: /rg Page 32 of 32