Renal inflammatory diseases of the kidney Part 2

THORSANG CHAYOVAN

(Does not include pyelonephritis/pyonephrosis/pyelitis)

Xanthogranulomatous pyelonephritis

• Chronic destructive granulomatous disease

• Middle-aged women (age 40-60)

• Diabetes

• Symptoms: fever, flank pain, persistent bacteriuria, or history of recurrent infected nephrolithiasis

RadioGraphics 1991; 11:485-498 RadioGraphics 2000; 20:215-243

Pathophysiology of XGP

Long-standing partial obstruction

subacute bacterial infection

Incomplete immune response

Parenchymal destruction

Caliectasis (peripelvic fibrosis limits pelviectasis)

Deposition of lipid-laden macrophages (xanthoma cells)

Irreversible destruction of the renal parenchyma

Two forms of XGP

Diffuse/global (85%)

Localized/focal (15%)

Xanthogranulomatous pyelonephritis

Diffuse form of XGP

• Renal enlargement

• Calcifications filling the renal pelvis (often staghorn)

• Replacement of the renal parenchyma by dilated calyces and abscess (multiple wall-enhanced oval hypodensities)

• Cortical thinning

• Decreased contrast excretion

• Areas of fat attenuation = lipid-rich xanthomatous tissue

Radiol Clin N Am 50 (2012) 259–270

RadioGraphics 2008; 28:255–276

XanthogranulomatousPyelonephritis

• KUB• Exploded staghorn with large renal shadow

Infect Dis Clin North Am 2003 (Kawashima)

XanthogranulomatousPyelonephritis

• CT• “Bear Claw/paw”• Massive caliectasis

(without pelviectasis)• Parenchyma enhances• Stones

Infect Dis Clin North Am 2003 (Kawashima)

Focal form of XGP • DDx a renal tumor (RCC) “tumefactive/pseudotumoral”

RadioGraphics 2008; 28:255–276

Triad

• Nonfunctioning

• Renal enlargement • Caliectasis with less pelviectasis, parenchymal loss

• Stones (90%)• Staghorn

Complications of XGP

• Perinephric/psoas abscesses

• Fistulae (renocolic and renocutaneous)

Radiol Clin N Am 50 (2012) 259–270

Radiol Clin N Am 50 (2012) 259–270

RENAL TUBERCULOSIS

• The most common extrapulmonary site of TB

• Hematogenous spreading from lung

• 4% to 8% of pulmonary tuberculosis

• Ureteral and bladder involvement can occur via descending infection

Granulomas

immunocompetent host

(confined to the renal cortex)

Reactivationimmunocompromised host

(granulomas enlarge)

Capillary rupture

Medulla (along the loop of Henle and proximal tubules)

Proximal collecting system

Ureter

Bladder

Genital organs

Across retroperitoneal fascial planes

Tuberculous bacilli

periglomerular capillaries

Small abscesses

Radiol Clin N Am 50 (2012) 259–270

RENAL TUBERCULOSIS

• Insidious and asymptomatic• Renal involvement can be indolent for more than 20 years

• LUTS and/or back or flank pain

• Constitutional symptoms

• Diagnosis: • U/C

• Biopsy

Imaging of GU tuberculosis

• Depends on the stage of disease

• Progressive infection• Granuloma

• Caseous necrosis

• Cavitation

• Eventually destroy the kidney (autonephrectomy)

• The initial inoculation and granuloma formation• Not radiographically evident

RadioGraphics 2004; 24:251–256

TB: early in reactivation--acute inflammation

• Localized soft tissue edema and vasoconstriction focal hypoperfusion + striated nephrogram

• Papillary necrosis a moth-eaten calyx (on excretory urography or enhanced CT)

• Tuberculoma with central caseous necrosis

• Eventually rupture into the draining calyx renal pelvis

Striated nephrogram• acute obstruction

(ureteric/ tubular)• acute pyelonephritis• acute renal vein

thrombosis• acute renal contusion• acute post RT• acute tubular necrosis• hypotension

Radiol Clin N Am 50 (2012) 259–270

Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org, rID: 21350

Courtesy of Dr. Annie Agarwal

Radiographics 2004: 24;issue suppl_1

https://www.med-ed.virginia.edu/courses/rad/gu/kidneys/analgesic.html

https://www.med-ed.virginia.edu/courses/rad/gu/kidneys/analgesic.html

Courtesy of Dr. Annie Agarwal

Rev Chil Radiol 2010; 16(3): 128-133

Radiographics 2004: 24;issue suppl_1

Radiol Clin N Am 50 (2012) 259–270

Papillary necrosis

AD SPORT C

A: analgesic abuse (phenacetin, NSAID's, paracetamol)D: diabetes mellitusS: sickle cell diseaseP: pyelonephritis (especially in children)O: obstructionR: renal vein thrombosis

T: renal tuberculosis (not usually confined to papillae)

C: cirrhosis

http://radiopaedia.org/articles/renal-papillary-necrosis-mnemonic

excretory phase reveals a hypodense parenchymal mass in the upper pole of left kidney with perinephric extension. Biopsy of the lesion revealed tubercular abscessRadiol Clin N Am 50 (2012) 259–270

Late renal TB infection

• Fibrotic reaction causing stenosis and stricture • Uneven caliectasis

• Obstruction

• Progressive renal dysfunction

• Incomplete opacification of the calyx (phantom calyx)

• Calcium deposition • Putty kidney--dystrophic calcifications involving the entire kidney

• Parenchymal atrophy

• Progressive hydronephrosis

• Autonephrectomy

RadioGraphics 2004: 24;issue suppl_1

Courtesy of Dr. Annie Agarwal

Courtesy of Dr. Annie Agarwal

Courtesy of Dr. Annie Agarwal

Putty kidney• Diffuse or scattered renal

calcifications (25%)

• Often small kidney

Radiographics 2004: 24;issue suppl_1

RadioGraphics 2008; 28:255–276

http://radiopaedia.org/articles/putty-kidney

Radiol Clin N Am 50 (2012) 259–270

TB ureteral and bladder spreading

• Ureteral involvement • Initially, mucosal irregularity “sawtooth” ureter ± Ureteral dilatation • Stricturing and ureteral shortening • Multiple strictures a long segment of narrowing• Multiple nonconfluent strictures “corkscrew” ureter• Calcification

• CT can also demonstrate periureteral fibrosis and ureteral wall thickening

• Urinary bladder involvement• Reduced bladder capacity • ± Bladder wall thickening and calcification

Courtesy of Dr. Annie Agarwal

Courtesy of Dr. Annie Agarwal

Courtesy of Dr. Annie Agarwal

Radiol Clin N Am 50 (2012) 259–270

Tuberculosis• CT Urography/IVP

• Renal• Moth eaten, fuzzy calyx with papillary

necrosis• Infundibular, pelvic fibrosis (purse

string pelvis)• Calyceal/pelvic obstruction

(hydrocalyx, phantom calyx)• Renal nonfunction (autonephrectomy),

scarring calcification (putty kidney)• Note: renal changes mimic TCC

• Ureter• Ulcerations and irregularity; sawtooth

(early)• Multiple strictures; corkscrew (later)• Short, strait, aperistaltic (latest)• Calcifications (DDX: schistosomiasis)

• Bladder involvement is very late

AJR 2005; 184:143-150

RENAL CALCIFICATIONSA. Dystrophic calcification due to localised disease:

Usually one kidney or part of one kidney. Infections :

1. Tuberculosis

2. Hydatid disease

3. Xanthogranulomatous pyelonephritis

4. Abscess

Carcinoma

Aneurysm of renal artery

Renal CalcificationsB. Nephrocalcinosis

Medullary : 1. Hyperparathyroidism

2. RTA

3. Medullary Sponge Kidney

4. Renal papillary necrosis

5. Causes of hypercalcemia or hypercalciuria

6. Preterm infants

7. Primary hyperoxaluria

Cortical :1. Acute cortical necrosis

2. Chronic glomerulonephritis

3. Chronic transplant rejection

UPPER TRACT FUNGAL INFECTION

• Hematogenous seeding or ascending urinary tract infection• With hematogenous dissemination, fungi are filtered by the glomerulus and

become lodged in the distal tubules

• Candida aibicans or Aspergillus species

• Predisposing factors: immunosuppression, prolonged antibiotic or steroid therapy, diabetes mellitus, and urinary obstruction

• Acute pyelonephritis

• May eventually develop multiple renal abscesses

• May develop fungus balls (mycetomas/urobezoars)• A conglomeration of inflammatory cells, fungus, necrotic or mucoid debris,

and a calculous matrix

UPPER TRACT FUNGAL INFECTION

• A striated nephrogram

• Multiple abscesses (multiple, small, hypodense collections)

• Fungus balls or mycetomas• Urography: radiolucent filling defects in the collecting system• US: echogenic masses in the renal collecting system that do not demonstrate

acoustic shadowing and can mimic blood clots or pyogenic debris • CT: a nonspecific irregularly marginated mass of soft tissue attenuation in the

collecting system• DDx other causes of intraluminal filling defects

• Blood clots • Sloughed papillae

RadioGraphics 1997; 17:851-866

Radiol Clin N Am 50 (2012) 259–270

RENAL ASPERGILLOSIS

• Renal aspergillosis has been described to appear as a complex cystic lesion/abscess

Radiol Clin N Am 50 (2012) 259–270

UPPER TRACT FUNGAL INFECTION

• Antifungal therapy

• Unilateral: nephrectomy/percutaneous drainage

• Bilateral: local irrigation with amphotericin B

Post-radiation injury of the kidney

POST RADIATION

• Very radiosensitive organ• VS ureters--fairly resistant to radiation-induced changes (smoothly tapering)

• Radiation oncologists aim doses of 20 Gy+

• 28 Gy- to both kidneys in 5 weeks frequently leads to renal failure

• Low doses such as 10 Gy may be associated with a subsequent diffuse or focal parenchymal loss • 5% volume loss ↔ 20% renal function decline

POST RADIATION

• Acute radiation nephritis• Normal in size and shape

• Glomerular damage histologically

• Radiological changes appear months to years after treatment• Atrophic poorly functioning but non-obstructed kidneys with smooth outlines

• Compensatory hypertrophy of the non-irradiated contralateral kidney

• Portion affected according to portal

• DDx pyelonephritis, renal infarction, and, rarely, renal masses

RadioGraphics 2013; 33:599–619

RadioGraphics 2013; 33:599–619

Cancer Imaging. 2006; 6(Spec No A): S131–S139.

RENAL MALAKOPLAKIA

RENAL MALAKOPLAKIA

• A rare chronic inflammatory process

• Associated with E coli urinary tract collecting system infection (most commonly the urinary bladder)

• Isolated renal involvement is rare

• Middle-aged women with chronic urinary tract infections or in immunocompromised host• A peaks in the fifth decade of life, but occasionally occurs in children

• Symptoms of urinary tract infection/renal failure in advanced disease

Pathogenesis of malakoplakia

• Abnormal macrophage function

• These partially digested bacteria persist and form intracellular inclusion bodies (Michaelis-Gutmann bodies) in large eosinophilic macrophages (Hansemann histiocytes)

• Formation of tumorlike lesions with the macrophage

• Occasionally seen outside the genitourinary tract, including in the gastrointestinal tract and skin

RadioGraphics 2008; 28:255–276

RENAL MALAKOPLAKIA

• 75% multifocal diffusely enlarged kidney • Unilateral > bilateral• Imaging

• An enlarged kidney, a low-attenuation mass, or a diffuse infiltrative disease.• US: a diffusely enlarged kidney, poorly defined hypoechoic masses, and distortion of

the renal architecture• CT:

• Multiple hypoenhancing masses that can range in size and eventually coalesce to form larger masses

• A mass; DDx renal cell carcinoma• MR: multiple 1–2-cm nodules with low signal intensity on T1- and T2-weighted

images and delayed enhancement of intervening fibrous stroma

• Biopsy or surgery is required to make the diagnosis

RadioGraphics 2008; 28:255–276

• Findings:

• Bilateralor unilateral

• Focal, multifocal or diffuse

• infiltrating masses

• ± Renal pelvis involvement

• Uncommon calcifications

Radiographics. 2000;20:215-243

RENAL MALAKOPLAKIA

References

• http://www.ncbi.nlm.nih.gov/pubmed/22498442

• http://pubs.rsna.org/doi/full/10.1148/rg.241035071

• http://pubs.rsna.org/doi/pdf/10.1148/radiographics.20.1.g00ja08215

• http://pubs.rsna.org/doi/full/10.1148/rg.332125119

• http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1805064/

• Please see each pictures in the slides.

Pictorial resources