Acute infectuion of the upper urinary tract

• Acute pyelonephritis is usually due to bacterial infection from organism that enter the urinary system via the urethra .

• Predisposing factors • Anatomical abnormalities such as,stones, duplex

systems complicated by obst or reflux .• Obstructive lesions &.• Diabetes mellitus all are predispose to infection. and in the adults only selected cases require

imaging.IVU changes . .

Infection • Most patients with acute infection do not need urgent imaging investigation .• In patients presenting with sign of infection associated with pain particularly

if this not respond to treatment so US & Plain film may diagnose the underlying stones, obstruction, or abscess formation .

• In acute pyelonephritis the US is either normal or demonstrate diffused or focal swelling iwith decreased echoginicity. In some cases if the pain is sever ,an IVU may be done to demonstrate or role out acute ureteric colic . .

• Imaging of the urinary tract after resolution of the acute episode is indicated in all women with repeated UTI & in men with confirmed single UTI infection .

• US of the kidneys may demonstrate underlying obst or stones ,• Bladder is imaged while full ,to role out a bladder stones then following

micturition for residual urine which account for recurrent infection .• An IVU may be performed in suspected duplex system complicated by

obstruction or reflux. .• Investigation of the renal tract is indicated in all children with confirmed UTI

Infection

• US to look for size , stone, scaring, hydronephrosis or hydroureter .

• Bladder to assess post - micturition residual urine .

• Many hospitals do DMSA radionuclide scan to demonstrate scarring .

• Micturating cystography in male & ( some time in some female ),for the VU reflux & urethral valve

Renal & perinephric abscesses

• US is initial imaging .• CT is used to further characterize the abscess in

selected cases .• The radological appearance is same like acute

pyelonphritis with mass .• Intra renal abscess : -• US ( complex mass ) .• CT with IV contrast( thick wall cyst with

inhancement of the wall ), some time simple cyst may be infected .

Infection

• Perinephric abscess • CT & US show both solid & cystic elements ,

most perinephric abscess are secondary to an infective focus within the kidney or underlying renal abnormality .

• Pyonephrosis : only occurs in collecting systems that are obstructed & US is the most usefull imaging modality for pyonephrosis , in addition show dilated PCS with multiple echoes in from infected debris .

• Cystitis

Tuberculosis

• It is blood born diseases, from focus lungs & bones.• Pyuria . • TB affect the cortex & may cause tiny cortical

granulomas which rapture through the capillaries in to the renal tubules & involve other portion of the urinary & genital system ( calcification of epididymis ) .

• Bilateral disease .• In early stages the US & IVU may be normal .• US may demonstrate calcification & dilated PCS but this

is not specific . .

TB

• IVU changes :• Calcification irregular foci later autonephrectomy .( calci

implies healing but it does not mean the disease inactive) in plain film .

• Initial changes Irregularity of the calyx then later cavity filled with contrast .

• Stricture of any portion of PCS or ureter , multiplicity of strictures is an important diagnostic feature.

• Bladder wall irregular due to edema & in advanced case thick wall small volume .

• CT is sensitively demonstrate early calcifications , small cavities & extra-renal spread.

• IVU is sensitive to demonstrate early papillary changes.

Chronic pyelonephritis ( reflux nephropathy )

Refare to the late appearances of focal or diffused scaring of the kidne, due to reflux of the infected urine from the bladder in to the kidneys leading to destruction & scaring of the renal substances , most damage accurse in the first year of life. The severity of the reflux diminished as the child gets older & it is ceased by the time when the diagnosis of reflux nephropathy is made , the condition is often bilateral but asymmetrical .

Signs of reflux nephropathy:-1-scar formation , local reduction in renal parenchyma (1- 2 mm ), the

upper & lower calices are more affected ( IVU , US , DMSA ).2 –dilatation of the calices in the scared areas ( atrophied of the

pyramids ).3 –overall reduction in renal size ( loss of renal substances & the

scared area not grow ) .4 –dilatation of the affected collecting system may be seen( reflux ) .5 –vasico – ureteric reflux ( micturating cystography ) .

Papillary necrosis

• Part or all the renal papilla sloughs & may fall lnto the PCS ,• IVU .• Papillary necrosis causes :• Urinary outflow obstruction .• High analgesic intake .• Diabetes mellitus .• sickle cell disease , Thalassaemia .• Alcoholism .• Very sever infection or lnfection with obstruction.

Papillary necrosis

• IVU is comenly the best method for demonstration.

• IVU changes , if partially slouphed the contrast seen tracking around or in the papilla .

• If totally slouphed so the calix appear spherical filled with contrast with a filling defect seen .

• Obstruction of the ureter ( passed out ).• The necrotic papilla can calcify prior to the

slouphed & calcified papilla within the collecting system resemble urinery calculus .

Renal trauma

• The kidney & the spleen are the most internal abdominal organs to be injured , ( blunt & penetrating ) 3/4 of the patients with blunt injury & the remaining with penetrated injury . CT is the best Investigation .

• Demonstrated the presence or absence of perfusion to the injured kidney .

• Insure that the opposite kidney is normal .• Show the extend of the renal parenchyma damage .• Demonstrate injuries to other organs .• The appearance depend on the extend of the injury .

Renal trauma

• Minor injury ( contusion, small capsular haematomas ) produce swelling of the parenchyma which compresses the calices .

• If the kidney substance is torn ,renal out line is irregular & the calices are separated

• Large subcapsular or extracapsular blood collection may be seen & extravasation of the contrast may be seen.

Renal trauma

• Retroperitoneal hemorrhages may displace the kidney .

• Fragmentation of the kidney .

• If thrombosis or rapture of the renal artery occur there will be no nephrogram .

• Renal infarction is a very serous condition demanding argent restoration of blood flow or nephrectomy .