Urinary tract obstruction

Transcription

1 Urinary tract obstruction

2 Common causes : stone, blood clot Radiographic findings depend on I. Level of obstruction II. Severity of obstruction : partial or complete III. Timing of obstruction

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4 Pathophysiology Acute obstruction (<1 wk) Dilatation of renal pelvocalyceal system proximal to point of obstruction, clubbed shape calyx Atrophy of distal nephron Intermediate obstruction (>2 wks) Atrophy of proximal nephron

5 Pathophysiology Chronic obstruction (>3 wks) Irreversible Atrophy of renal papilla Progressive clubbed shape calices Parenchymal reduction Elongation and tortuousity of ureter

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7 Radiographic investigation 1. Confirm obstruction 2. Localization 3. Cause of obstruction 4. Evaluation severity & treatment planning

8 Plain KUB detect stone KUB will detect: Calcium stones Cystine stones 90% KUB will miss: Uric acid stones 10% Pure struvite Xanthine stone Small stones Stones obscured by bones

9 Ultrasound confirm obstruction Dilated collecting duct, anechoic (urine) Compressed renal fat, hyperechoic Thinning renal parenchyma Hydroureter

10 IVP 1. Localized obstruction

11 IVP 2. Identify cause Mechanical Non-mechanical Intraluminal Intramural Extraluminal stone, tumor, blood clot stricture retroperitoneal tumor, BPH

12 IVP 3. Renal function 1) Scout film 2) 3 min: Nephrogram 3) 5, 10min: Pelvocalyeal system and ureter 4) 30 min, full bladder 5) Post void Decreased renal function: Delayed nephrogram because of prolonged contrast infiltration by the glomerular units

13 IVP 1) Scout film 2) 3 min: Nephrogram 3) 5, 10min: Pelvocalyeal system and ureter 4) 30 min, full bladder 5) Post void Renal function Obstruction: Delay dense nephrogram Delay excretion of contrast media

14 IVP 1) Scout film 2) 3 min: Nephrogram 3) 5, 10min: Pelvocalyeal system and ureter 4) 30 min, full bladder 5) Post void Anatomical change: - Hydronephrosis - Hydroureter - Tortuous of ureter - Cortical thinning

15 1. Dense nephrogram 2. Delayed excretion 3. Hydronephrosis, hydroureter 4. Generalized renal enlargement 10 mins 5 mins Full bladder Scout 30 mins

16 CT scan(for further investigation) 1. Renal function Delayed parenchymal enhancement Delayed contrast excretion 2. Anatomical change: Proximal dilatation Cortical thinning in chronic obstruction 3. Etiology Stone, mass, external compression

17 Mechanical obstruction (98%) Urolithiasis (stone) most common cause*** Tumor urothelial carcinoma Blood clot Prostate enlargement Pelvic tumor gynecological malignancy, rectosigmoid carcinoma, lymph nodes Stricture post-infection, prior trauma, post-operation, history of irradiation Non-mechanical obstruction Vesicouretral reflux (VUR) Neurogenic bladder

18 Mechanical obstruction (98%) Urolithiasis (stone) most common cause*** Tumor urothelial carcinoma Blood clot Prostate enlargement Pelvic tumor gynecological malignancy, rectosigmoid carcinoma, lymph nodes Stricture post-infection, prior trauma, post-operation, history of irradiation Non-mechanical obstruction Vesicouretral reflux (VUR) Neurogenic bladder

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20 Plain KUB 1. Soft tissue shadow 2. Abnormal calcification 3. Free air or free fluid 4. Bony structure - stone - granuloma - tumor - atherosclerosis 1. Number 2. Location 3. Density 4. Size & Shape 5. Axis 6. Mobility 7. Compare with old film

21 ?? Left proximal ureteric stone Left renal stone

22 Stone or Phlebolith?? 1 2

23 Landmark for UVJ

24 Suggested of phlebolith

25 Distal UC or UVJ stone Phlebolith Density Homogeneous Central lucency Shape Oval Round Number 1 >1 Location Not lower than ischial spine ม กอย ในตำแหน งท ต ำ กว ำ distal ureter และ UVJ

26 1. Number 2. Location 3. Density 4. Size & Shape 5. Axis 6. Mobility 7. Compare with old film

27 IVP Normal nephrogram Delayed dense nephrogram Delayed excretion 10 min IVP

28 IVP Hydronephrosis Hydrureter

29 Left UPJ stone

30 Ultrasound Hyperechoic lesion with Posterior acoustic shadow Hydronephrosis stone

31 CT scan Non-contrast CT = CT renal stone protocol

32 Indication: Patient with suspected ureteric stone (presented with acute frank or colicky pain) Technique: Thin slice (2-3 mm), non-contrast CT scan of KUB system for renal stone detection

33 Mechanical obstruction Tumor urothelial carcinoma Blood clot Stricture post-infection, prior trauma, post-operation, history of irradiation Prostate enlargement Pelvic tumor gynecological malignancy, rectosigmoid carcinoma, lymph nodes

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36 Urethral stricture Post surgical stricture

37 Malignant retroperitoneal lymph node

38 Obstruction at bladder outflow tract Bilateral hydronephrosis and hydroureter Bladder trabeculation, thickened bladder wall, bladder diverticulum Due to chronic increased bladder pressure

39 Causes of BOO Adult Prostate gland hypertrophy: most common Bladder: tumor, vesical stone, ureterocele Pelvic tumors (cervix, uterus, rectum) Urethral stricture Children Posterior urethral valve Ectopic ureterocele

40 Prostate gland: most common Bladder diverticulum Smooth filling defect at base of bladder Hooking ureters

41 Bladder tumor Irregular filling defect

42 A 56-year-old man who presented with gross painless hematuria.

43 Vesical stone

44 Urethral stricture: trauma, infection, post-op Urethral stone

45 Posterior urethral valve (PUV) A congenital obstruction caused by a malformation of the posterior urethra

46 1. Distended bladder with incomplete emptying 2. Increased bladder pressure: bladder trabeculation & diverticulum 3. BPH: smooth filling defect at base of bladder 4. Bladder tumor: irregular filling defect

47 1. Distended bladder with incomplete emptying 2. Increased bladder pressure: bladder trabeculation & diverticulum 3. BPH: smooth filling defect at base of bladder 4. Bladder tumor: irregular filling defect

48 Non-mechanical obstruction Congenital UPJ obstruction Vesicoureteric reflux (VUR) Neurogenic bladder

49 Functional obstruction Abnormal peristalsis Prenatal US Early excretion IVP Late excretion IVP Cause: intrinsic narrowing from patent but aperistaltic segment at UPJ Preferred exam: ultrasound Finding: Hydronephrosis

50 1. Primary or congenital VUR 2. Secondary VUR : chronic cystitis, duplication of ureter, neurogenic bladder, infravesical obstruction

51 Preferred exam: VCUG Findings: Hydronephrosis and/or hydroureter (5 grades)

52 Causes = cerebral or spinal disease Vertebral fracture, disc herniation Meningomyelocele Vascular disease (infarction, AVM) Tumor T12 level Demyelinating disease (multiple sclerosis) Spastic type Flaccid type

53 Central neural lesion: bladder hyperreflexia Frequency Urgency Urge incontinence

54 Peripheral lesion (detrusor muscle: S2-S4) Overdistended bladder Unable to void

55 Cystic and solid renal mass

56 Cystic renal lesion Simple renal cyst Complicated renal cyst Solid renal mass Benign: AML, oncocytoma, adenoma Malignant: RCC, lymphoma, metastasis, Wilms tumor

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59 Simple cyst Common, increased with aging Most are asymptomatic

60 Simple cyst cyst

61 Simple cyst : 0-20 HU.

62 Complicated cyst

63 Complicated cyst

64 Complex cyst need - Close follow up with US - Further CT scan / MRI - Biopsy / surgery

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66 Benign : Angiomyolipoma (AML)

67 Malignant : Renal cell carcinoma (RCC) IVP : not for diagnosis US

68 Malignant : Renal cell carcinoma (RCC) - CT: enhancement, calcification, necrosis

69 RCC with perinephric spreading

70 Malignant : Renal metastasis Primary: lung, breast, GI, lymphoma Route of spread: hematogenous, lymphatic, direct extension Finding: Multiple > solitary Bilateral > unilateral Metastasis from bronchogenic carcinoma

71 Malignant : Lymphoma Non-Hodgkin > Hodgkin s Secondary > primary Findings: 1) Multiple bilateral renal masses (m/c) 2) Infiltrative lesion 3) Direct invasion from perirenal/hilar

72 Malignant : Wilm s tumor Age 1-8 year (mean age 3.5 years) M/C presentation: abdominal mass Findings: Solid mass, necrosis, hemorrhage Metastasis to lymph node, lung

73 Suspected renal mass US Hydronephrosis Cystic renal lesion Solid renal mass Simple cyst Do nothing Complicated cyst Follow up US CT scan Biopsy CT scan or MRI -characterization -location -staging -evaluate contralat.- kidney

74 Urinary tract infection

75 Lower UTI Upper UTI Complication Role of imaging: Medical conditions Surgical conditions (pyonephrosis, renal abscess, perinephric abscess) Prefered exam: ultrasound

76 Role : to find out the underlying pathology Indication Suspected of KUB stone Uncommon infection: TB, fungus Poor respond to antibiotics Recurrent infection Suspected of neurogenic bladder Suspected of complicated UTI Due to immunocompromised host or underlying DM

77 IVP May be normal Enlarged kidney Displaced calyces Delayed nephrogram

78 US Enlarged kidney Decreased parenchymal echogenicity

79 CT Scan Enlarged affected kidney Patchy decreased density on pre-contrast Perinephric fat stranding Decreased enhancement Urothelial thickening Striated nephrogram

80 Preferred exam: US or CT

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82 Preferred exam: US or CT

83 Pus produces fluid layers (dependent echogenic debris) within the dilated collecting system

84 Severe necrotizing infection E. coli is frequent associated causative organism. Characterized by gas within renal parenchyma and occasionally within perirenal tissues. More than 90% of cases occur in diabetic patients Female predominance

85 Plain film Air in renal parenchyma ± entend into perirenal or retroperitoneum space

86 US Acoustic shadow from air ring down or reverberation artifact

87 CT scan Renal enlargement, impaired renal function, thickening perirenal fascia

88 A form of chronic pyelonephritis Chronic obstruction plays a part in development. Proteus mirabilis is frequent associated causative organism. DM is an associated condition in 10% of cases Characterized by destruction and replacement of renal parenchyma by lipid-laden macrophages. Gross pathologic Massive renal enlargement, lithiasis, hydronephrosis Perinephric fibrosis and lobulated yellow masses replacing renal parenchyma. Diffuse > focal

89 Plain KUB Renal enlargement Staghorn calculus Extrarenal extension is suggested by indistinct outlines of the kidney and psoas muscle IVP Decreased or absent excretion in 85% of cases

90 CT scans Staghorn calculus with contracted renal pelvis Enlarged kidney and multiple dilated calyces Characteristic low-attenuation (10-15 HU), peripherally enhancing rounded masses bear s paw sign Extrarenal extension of inflammation thickening of Gerota fascia

91 Preferred exam: US -Decreased renal size -Parenchymal scar -Focal dilatation of the calyx opposing the scar

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93 IVP

94 25% associated with pulmonary TB 1. Renal parenchyma infection 2. Ureter and collecting system

95 TB kidney Irregular calyx Infundibular stenosis Calyceal dilatation Fibrosis / scarring Amputated calyx Calcification moth-eaten calyx Infundibular stenosis Amputation of bilateral upper pole calices

96 TB ureter Irregular fibrosis: segmental dilatation and stenosis of ureter

97 TB bladder Contracted bladder = small bladder capacity Calcifed bladder wall

98 Urinary tract trauma

99 I. Renal trauma II. Ureteric trauma III. Bladder trauma IV. Urethral injury

100 Renal trauma Blunt renal trauma : 90% Penetrating renal injury : 10%

101 Look for 1) Fracture of the lower ribs 2) Fracture transverse process at T12-L3 level 3) Abnormal soft tissue shadow obscuration of kidney or psoas shadow 4) Localized bowel ileus 5) Scoliosis of the lumbar spine to contralateral side 6) Pleural effusion or hemothorax

102 CT scan with IV contrast injection Corticomedullary phase Nephrographic phase Excretory phase* (delayed 5-10 minutes) If clinical unstable Single shot IVP Bolus 100 ml contrast medium injection Film KUB at 15 minutes

103 CT scan Gold standard Contrast enhancement Intravenous contrast injection Oral contrast administration if possible Accurately identifies Vascular injury Parenchyma laceration Urinary extravasation Perirenal hematoma Other intra-abdominal injuries

104 CT scan Nephrogenic phase Detect active arterial extravasation Parenchymal injury Excretory phase 5 10 minutes after contrast injection Urinary extravasation

105 Parenchymal and capsule injury - Renal contusion - Renal laceration: depth - Subcapsular hematoma - Perinephric hematoma

106 Parenchymal and capsule injury - Renal contusion - Renal laceration - Subcapsular hematoma - Perinephric hematoma

107 Subcapsular hematoma Perinephric hematoma - Intact renal capsule - Torn renal capsule - Hematoma under renal capsule - Hematoma extend into perirenal space - Pressured effect to underneath renal parenchyma - No or minimal pressured effect

108 Multiple lacerations = Shattered kidney

109 Collecting system injury - Urinary extravasation - UPJ injury

110 Vascular injury - Renal artery avulsion - Renal artery thrombosis

111 Blunt abdominal trauma 1. Gross hematuria 2. Microscopic hematuria with shock ( SBP < 90 mmhg) 3. Adjacent organ injury, flank pain/contusion/ palpable mass 4. Deceleration injury 5. Pediatric + UA: RBC > 50 cell/hpf

112 Penetrating injury 1. Any degree of hematuria 2. Deep cut wound 3. Hemodynamically unstable

113 Stable patient US Suspected renal injury Unstable patient Hematoma No hematoma CT scan IVP Single shot IVP at OR Angiogram

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115 Ureteric trauma Penetrating > blunt injury Findings: contrast extravasation or obstruction

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117 Most from blunt trauma Clinical presentation Suprapubic pain Hematuria Urinary ascites Plain film Fracture and dislocation of pelvic bone (60%) Soft tissue mass in pelvis (hematoma) Air in urinary bladder (penetrating injury) Investigation: Cystogram or CT cystogram

118 1. Bladder contusion Incomplete tear of submucosal layer Normal or teardrop shape

119 2. Intraperitoneal bladder rupture - Rupture bladder dome Sudden increase intravesicular pressure in a full bladder - Surgical treatment

120 3. Interstitial bladder injury: rare 4. Extraperitoneal bladder rupture - Most common type - Associated with anterior pelvic ring fracture - Ruptured bladder base - Conservative

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122 1. Posterior urethral injury : asso. with pelvic Fx 2. Anterior urethral injury : straddle injury Bleeding per urethral meatus R/O urethral injury first! Retrograde urethrography

123 Normal urethrogram

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