Ultrasound of the urinary tract - Renal infections
-
Upload
samir-haffar -
Category
Health & Medicine
-
view
3.484 -
download
5
description
Transcript of Ultrasound of the urinary tract - Renal infections
Ultrasound of the urinary tract
Renal infections
Samir Haffar M.D.
Renal infections
Acute pyelonephritis Acute focal & multifocal pyelonephritis Renal abscess Pyonephrosis Emphysematous pyelonephritis Xanthogranulomatous pyelonephritis Renal malakoplakia Hydatid disease of kidney Renal tuberculosis HIV-associated nephropathy
Acute pyelonephritis
Acute pyelonephritis
• Symptoms Flank pain, costovertebral angle tenderness Fever, chills, nausea, & vomiting Lower symptoms: dysuria, frequency, urgency
• Laboratory Neutrophilic leukocytosis, elevated ESR & C-RP Elevation of serum creatinine in severe infection
• Urinalysis Numerous leukocytes & bacteria Presence of leukocyte esterase & nitrites Sterile urine (obstruction of infected kidney)
• Causes Bacterial: EC in 80% Fungal: Candida albicans & tropicalis – Fungal
balls
US of acute pyelonephritis
US abnormalities (20 %)
Renal enlargement (> 15 cm – affected kidney > 1.5 cm longer ) Hypoechoic renal parenchyma Loss of corticomedullary differentiation
Loss of renal sinus fat Dilatation of collecting system without obstructive cause Abscess formation
Rumack CM et al. Diagnostic Ultrasound. Elsevier-Mosby, St. Louis, USA, 3rd edition, 2005.
Majority of cases (80 %)
Normal-appearing kidney – Routine Imaging not required
Acute pyelonephritis
Diffuse renal enlargementDecreased echogenicity
Loss of corticomedullary differentiation
Longitudinal US of left kidney Longitudinal US of right kidney
Normal right kidney
Kao HW et al. J Med Ultrasound 2008 ; 16 : 113 – 122.
Severe acute bacterial pyelonephritis
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Slightly enlarged right kidney that is otherwise unremarkable
despite advanced disease
US image of right kidney Abdominal CT scan
Enlarged kidneySmall low-attenuation foci (abscess)
Findings prompted nephrectomy
US is limited in visualization of small micro-abscesses
Fungal ball
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Longitudinal US of right kidneyImmunocompromised patient
Echogenic mass within dilated calyxConfirmed to be a fungus ball
CT (before, immediately after, & at delayed intervals from contrast material injection)
is the preferred modality for evaluatingacute bacterial pyelonephritis
Acute focal & multifocal pyelonephritis
Acute focal & multifocal pyelonephritis
• Focal PN Infection confined to single lobe Multifocal PN Infection confined to multiple lobes
• Risk factors DM – immunosuppression
• Clinical features More severe symptoms than APL Commonly progresses to sepsis
• Treatment Similar to other cases of APL 7 days of parenteral antibiotics Then 7day of oral antibiotics
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
US of acute multifocal pyelonephritis
Identical to focal disease but seen in more than one lobe
US of acute focal pyelonephritis
Sonolucent mass Poorly marginatedExtending from medulla to capsuleAbsence of distinct wall (abscess) Occasional low amplitude echoes
Echogenic mass Commonly seen
CT scan more sensitive than US to detect focal disease
Acute focal pyelonephritis
Infection confined to single lobe
Rubens DJ et al. Ultrasound Clin 2007 ; 2 : 391 – 413.
Decreased attenuation area
Typical of focal pyelonephritis
3-cm echogenic mass in lower pole of right kidney
CT scan more sensitive than US to detect focal pyelonephritis
Acute multifocal pyelonephritis
Infection confined to multiple lobes
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Absence of color flow
Color Doppler
2 wedge-shaped areas of decreased echogenicity in renal cortex
Transverse US of right kidney
Acute bacterial pyelonephritis
Wedge-shaped hyperechoic focusin upper pole of right kidney
US scan of right kidney Color flow US image
Diminished flow throughinvolved area
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Renal abscess
Renal abscess
• Symptoms Fever, chills, & pain in back & abdomenSymptoms of urinary tract infection
• Hig risk DM, hemodialysis, IV drug abusers
• Causes Renal carbuncles before antibiotics: SA
Ascending infection: EC, Klebsiella, Proteus
• Management < 3 cm Parenteral antibiotics 3 – 5 cm Percutaneous drainage > 5 cm Surgical drainage
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
US of renal abscess
• Hypoechoic mass with thick irregular walls or capsule
• Indistinct margins acutely & distinct wall thereafter
• Increased through-transmission
• Occasional development of fluid debris level
• Gas in hypoechoic/cystic mass strongly suggests abscess
Serial US examinations are essential in followingthe evolution of an abscess
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Early and mature abscess cavities
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Cavity better definedWell defined border
Through transmission
Mature abscess
Hypoechoic focus from abscessin upper pole of right kidney
Early abscess
Renal abscess
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Well-defined hypoechoic lesion Posterior through transmission
Increased peripheral vascularity
Gas-forming renal abscesses
Kao HW et al. J Med Ultrasound 2008 ; 16 : 113 – 122.
Large hypoechoic massGas causing reverberation artifact
Longitudinal US of right kidney
Gas-forming renal abscess
Axial CECT
It will be difficult to distinguish abscess from renal tumor
Radiologic-guided drainage can be helpful
Pyohydronephrosis
Pyohydronephrosis Infection of obstructed collecting system
• Obstruction Stone, tumor, sloughed papilla, stricture• Complications Decline in renal function, septic shock• Symptoms UT obstruction with flank pain & fever
Subtle symptoms: weight loss, dull painNo symptoms at all (15% of cases)
• Ultrasound Echogenic debris in collecting system Fluid-fluid levels within collecting systemGas in collecting system (dirty shadows)
Early diagnosis & treatment is crucial
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Pyohydronephrosis
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Longitudinal US of right kidneyEnlarged hydronephrotic kidney
Fluid–fluid level in dilated calyces secondary to pus
Pyohydronephrosis
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Dilated collecting systemthat is nearly completely filled with echogenic debris
Emphysematous pyelonephritis
Classification & management of EPN
Retrospective review of 48 cases based on CT only
Clinical risk factors: thrombocytopenia, ARF, mental status changes, shockHuang JJ et al. Arch Intern Med 2000 ; 160 : 797 – 805.
Radiologic class
Finding on CT
Management
Class 1 Gas in collecting system only IV antibiotics PCD Decompression of UT obstruction
Class 2 Gas in renal parenchyma No extension to perirenal space
IV antibiotics PCD Decompression of UT obstruction
Class 3A Extension of gas or abscess to perirenal space
IV antibiotics Immediate nephrectomy if risk factors
Class 3B Extension of gas or abscess to pararenal space
IV antibiotics Immediate nephrectomy if risk factors
Class 4 Bilateral EPN or solitary functioning kidney with EPN
IV antibiotics & PCD Nephrectomy if failed
US in emphysematous pyelonephritis
• Enlarged kidney
• High amplitude echoes within renal parenchyma
• Low-level posterior dirty acoustic shadowing
• Depth of parenchymal involvement underestimated by US
Isolated presence of gas within collecting system seen after many interventional procedures
CT always warranted & considered ideal study to visualize extent & amount of gas
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Emphysematous pyelonephritis
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Longitudinal gray-scale sonogram of left kidneyAir within renal parenchyma with reverberation artifact
Compartments of the retroperitoneum
Emphysematous pyelonephritis
Tajima K et al. N Engl J Med 2007 ; 356 ; 526 – 527.
Gas throughout right kidney
Abdominal radiograph CT scan of abdomen
Extensive destruction of renal parenchyma with associated gas
Gas in retroperitoneal tissues
Gas in renal parenchymaDifferential diagnosis
• Emphysematous pyelonephritis (EPN)
• Focal renal abscess
• Enterorenal fistula
• Trauma to kidney or bladder SurgeryBiopsyBladder catheterizationNephrostomy placement
Akhtar AL et al. AJR 2010 ; 194 : WS31 – WS33.
Xanthogranulomatous pyelonephritis
Xanthogranulomatous pyelonephritis (XGPN)
Chronic destructive granulomatous process from atypical
immune response to subacute bacterial infection
Xanthogranulomatous Pyelonephritis (XGPN) Rare inflammatory condition
• Long-term & recurrent obstruction from stone with infection
• Replacement of parenchyma by lipid-laden macrophages
• Most common organism: Proteus mirabilis or E. Coli
• Adults in fifth to seventh decade – Women in 70%
• Nonspecific symptoms: malaise, flank pain, low-grade fever
• Nephrectomy is the standard approach for diagnostic & tt
• Excellent prognosis
Kao HW et al. J Med Ultrasound 2008 ; 16 : 113 – 122.
US of Xanthogranulomatous PyelonephritisDefinitive preoperative diagnosis extremely difficult
• Focal formMass-like lesion – Mistaken for renal cell carcinoma
• Diffuse form (more common)Diffuse renal enlargementHypoechoic masses: Abscesses (↑ sound transmission) Granulomatous (↓ sound transmission)Echogenic foci (stones) – Acoustic shadow not always presentCommon extension to perirenal spaces with abscess & fistula
CT evaluation more informative than US in XGPN
Xanthogranulomatous pyelonephritis (XGPN)
Craig WD et al. RadioGraphics 2008 ; 28 : 255 – 276.
Bilateral staghorn calculiDilated right collecting system
CECT scanUS image of right kidney
Staghorn calculus with ASDilated collecting system
US of Xanthogranulomatous pyelonephritis
Diffuse renal enlargementwith echogenic foci
Kao HW et al. J Med Ultrasound 2008 ; 16 : 113 – 122.
Right kidney hydronephrosiswith stones in lower pole
Coronal CECTLongitudinal US of right kidney
Renal malakoplakia
Renal malakoplakia Rare inflammatory disorder
• Chronic gram-negative urinary tract infection (E. coli)
• Deposition of soft, yellow plaques in bladder & urinary tract
• Abnormal macrophage function causing incomplete intracellular bacterial lysis.
• Deposition of histiocytes (von Hansemann cells) filled withthese bacteria & bacterial fragments
• Bacteria form nidus for calcium phosphate crystals formingsmall basophilic bodies called Michaelis-Gutmann bodies
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Renal malakoplakia
• Usually occurs in women
• Most patients older than 50 years
• Underlying condition compromising immune system:Diabetes, immunosuppression, chronic debilitating disease
• Symptoms of urinary tract infectionFever, irritative voiding symptoms, flank pain
• Symptoms of bladder irritability & hematuria may be seen
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
• Nonspecific
• Often mimic other pathology such as renal tumors
• Most common US features:Diffuse enlargement of affected kidneyIncreased echogenicity of renal parenchymaHypoechoic lesions &distortion of parenchymal echoes
US of Renal malakoplakia
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Renal malakoplakia
Dharmadhikari R & Crisp A. J Ultrasound Med 2006 ; 25 : 1219 – 1222.
Enlarged right kidneyWell-defined hypoechoic mass occupying lower two thirdsDecreased corticomedullary differentiation at upper pole
Hydatid disease of kidney
WHO classification of cystic echinococcosis (CE)International consensus classification
5 types on the basis of US appearances
CE I
Unilocular simple cysts
CE 3
CE 2
CE 4
CE 5
WHO Informal Working Group. Acta Trop 2003 ; 85 : 253 – 261.
Floating membrane (water lily sign)
Multivesicular multiseptated cyst
Heterogeneous degenerative contents
Thick calcified wall
Active
Transitional
Active
Inactive
Inactive
Hydatid disease of kidney (very rare)Imaging findings depend on stage of cyst growth
Volders WK et al. RadioGraphics 2001 ; 21 : S255 – S260.
Multicystic hypoechoic masswith septations
Thick-walled cystic mass in left kidneyFluid in central part hyperattenuating
Posterior coarse peripheral calcifications
Hydatid disease of the kidneyImaging findings depend on stage of cyst growth
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Well-defined cystic lesionMultiple internal septae
suggestive of daughter cysts
Floating membranes of hydatid cyst
following rupture of cystWater lily signCE 2 CE 3
Renal tuberculosis
Renal tuberculosis
• Considered in patients with history of tuberculosis
• Often asymptomatically even in advanced disease
• ¼ of patients present with unilateral poorly functioning kidney• Other suspicious findings
Chronic cystitis or epididymitis recalcitrant to treatmentFirm seminal vesicles on digital rectal examinationChronic fistula tract that forms at surgical sites
• Dg: urine culture demonstrating growth of M tuberculosis.
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
US of renal tuberculosis
Traditionally described as limited
• Mass lesions in renal parenchyma of mixed echogenicitywith or without necrotic areas & calcifications
• Mucosal thickening & stenosis of calyces
• Mucosal thickening of renal pelvis & ureter
• Ureteral stricture & hydronephrosis
• Bladder changes: mucosal thickening & reduced capacity
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Role of high-resolution ultrasonography
US of renal tuberculosis
Known case of tuberculosisHypoechoic areas in renal cortex suggestive of lobar caseation
Longitudinal US of right kidney
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Renal tuberculosis
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Hypoechoic areas of caseous necrosis Dense peripheral calcification with posterior acoustic shadowing
Renal tuberculosis
Kao HW et al. J Med Ultrasound 2008 ; 16 : 113 – 122.
Multiple chunky calcificationsin left upper abdomen
Abdominal radiography Longitudinal US of left kidney
Extensive AS caused by calcificationsMorphologic detail of kidney obscured
HIV-associated nephropathy
HIV-associated nephropathy (HIVAN)
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Major sonographic findings Enlarged kidney
Increased cortical echogenicity
Loss of corticomedullary differentiation
Obliteration of sinus fat
In increased cortical echogenicity in a young patient withouthistory of medical renal disease, HIVAN must be considered
HIV-associated nephropathy (HIVAN)
Vourganti S et al. Ultrasound Clin 2006 ; 1 : 1 – 13.
Transverse US of right kidneyLongitudinal US of right kidney
Enlarged, markedly echogenic kidneyLoss of corticomedullary differentiation
Obliteration of sinus fat
Thank You