NORMAL ANATOMY OF THE KIDNEY

Cortex - hypo or isoechic to N liver or spleen, 80% of blood flow
US is best for measurement, CT gold standard for eval
If enlarged & smooth bilat Bx required for Dx
if unilat think acute infarct or venous infarct
Echogenic w preserved cortio-medullary jxn - depositon in cortex
glomerulonephritis, lupus nephritis, rejection, HTN nephrosclerosis
amyloidsis, diabetic nephrosclerosis
Prox Convoluted Tubules - resorb 80% of filtered fluid
Active transport resorbtion of Na+, phos, glu & amino acids
Dist Convoluted Tubules - final modulation of net K+ & H+ excretion

Renal Medullary Pyramids - Hypo relative to cortex, esp in neonate
fuse into solid structure at 26wks, upper & lower more fused
Vasa Recta - cap loops which extend down w Henle loops, 2% of blood
Loop of Henle - responsible for interstitial osmolality gradient
actively pumps Na+ to create osmotic gradient exerted on collecting tubes
Collecting Tubules - site of action for ADH

Vessels - easily dopplered at sinus, more difficult prox
R renal vein - short, angle slightly cephalad to IVC
L renal vein - long, crosses aorta to IVC, R artery behind IVC
tributaries are L adrenal, gonadal, ureteral & lumbar veins
easily compressed, L varicocele not concerning (R side is)
Veins lie ant & slightly inf to the arteries
Vein Hypoplasia - assoc w dysplasia, aplasia & agenesis of assoc kidney


THE NEPHROGRAM
all contrast filtered at glom, min tubular effect
Urinary vol of contrast = GFR X Plasma level of contrast
plasma level peaks best w bolus, creates best nephrogram
Vicarious excretion thru biliary & GI
if seen in colon or GB 24hrs later consider renal fail

Angiographic Nephrogram - first seconds w contrast in vasc
remain in microvasc and have not yet reached tubules

Urographic Nephrogram - peak at 1min w contrast in prox tub
Independent of state of hydration
most intense when plasma level is highest
Rim Nephrogram - chronic dil causing thin rim of cortex
can also be due to lg ventral or dorsal infarct

Striated Nephrogram - contrast in pyramidal rays
Acute obs, pyelonephritis or infantile polycstic kid Dz
Renal V Thrombosis, hypotension, contusion
Tubular obs with Tamm-Horsfall protein

Persistent Nephrogram - Renal V thrombosis, ATN, Hypotension
Renal Artery stenosis, obstruction (NOT seen w reflux)

Patchy Nephrogram - microvasc abn, polyarteritis, scleroderma


NORMAL VARIANTS

1. Dromedary Hump - 1.5cm left lateral cortical thickening

2. Junctional Cortical Defect - persistent fat in jxn or reniculi
extends from renal sinus to perirenal space

3. Column of Bertin - Renal Pseudotumor, at jxn of mid & upper 1/3
N renal cortex interposed between pyramids, protrudes into sinus
isoechoic & continuos w other cortex, diplaces sup & middle calyces
sharply defined medial margin

4. Duplication Artifact - interface of liver & fat or spleen & fat
can cause appearence of upper pole thickening

CYSTIC RENAL DISEASE
Can cause Polycythemia

1. Simple Renal Cysts - occur in 50%, ovoid w thin walls
inc thru transmission w no internal echoes
inc w age, never occur before 30yrs
Rim or punctate calc poss, wall <1mm thick

Nephrogenic Cyst - #1, cortical w no collecting sys comm
"Beak" sign - any slow growing proc w intrarenal origin
can have thin filamentous septa, inc protien may make dense
DDx - Auto dom polycystic is never unilat

Pyelogenic Cyst - rare, tic from central collecting sys
common in kids w tuberous sclerosis, Von Hipple & Turner's

2. Atypical Renal Cysts - w septation, calc or minimal echoes
Most still benign, CT evaluation esp if thick irreg walls - Bx
Hyperdense cyst on CT may be hemmorhagic or rare renal cell
US will help in this DDx, hem cysts hypo, renal cell hyper
Pseudoaneurysm or spleenorenal shunt - can sim on US
Careful F/U adequate if no thick wall

3. Auto Dominant Polycystic Kidney Dz - Adult, asymtomatic
Cysts form in all structures derived from blastema
DO NOT communicate, ALWAYS bilat
Bilat renal enlargement, numerous variable cysts
Sx variable between famalies, sim within a family
Progressive Renal Failure in most, Acute poss w obs or inf
Mild to massive Nephromegaly, mult col sys defects
Inc cortical echogenicity, 50% have LIVER involved, 80% HTN
Berry Aneurysms seen in 15%, freq cause of mortality, panc cysts 9%
DDx - mult simple cyst in elderly, usually no renal enlargement
4. Auto Recessive Polycystic Kidney Dz - neonatal & juvenile forms
Neonatal Form - usually die at birth, lg bilat echogenic kid
Striations from Ectatic & dilated collecting ducts key finding
Crowded in medulla but cystic up to outer cortex
reverses N US appearance - hypo cortex, hyper medulla
Sunburst pattern full thickness, contrast moves slowly
Oligohydramnios - pulm hypoplasia, potter facies
Minimal Liver component, microscopic biliary duct dil

Juvenile Form - I' manifestation is LIVER Dz
Biliary ductal ectasia sim to Caroli's Dz
periportal fibrosis, portal htn & varices
Subclinical Nephromegaly w mild renal tubular ectasia
loss of cortical medullary distinction
cortex echogenic, rarly visible cysts
Disorganized collecting system seen on IVP
NO assoc w berry aneurysms

5. Medullary Cystic Kidney - Rare, auto dom adult, rec in child
Chronic Interstitial Nephritis, fibrosis of medulla
Collecting ducts & tubules entraped & obs w fibrosis
Cysts are II' & not neccesary for Dx, 2mm cysts poss
Cysts lined w epithelium from collecting ducts & tubules
Small, Smooth Kidneys & Sx unique among the cystic Dz's
inc echogenicity causes pyramids to blend w sinus fat
Salt wasting, Azotemia, Polyuria, & Anemia
Urinary Sediments common - rare in cystic Diseases
Assoc w Renal Osteodystrophy or II' Hyperparathyroidism

6. Medullary Sponge Kidney - not hereditary, usually not clinically sig
Ectatic collecting tubules best seen on excretory urography
Mult small communicating cysts, create "Bouquet of Flowers"
Calc - can be extensive in cysts, usually smaller than cysts
unlike regular nephrocalcinosis these disappear P contrast
Ca+ stone develop in 10%, infection & papillary nec increased
Striated appearance to pyramids on IVP
benign tubular ectasia has sim appearance on IVP
** Caroli's - associated in 80%

7. Multicystic Dysplastic Kidney - #1 neonatal palpable mass
Congenital but NOT hereditary, most unilateral, bilat = Fatal
ureteral bud may fail to meet metanephric blastema
End stage becomes atrophic mass, 30% have ring calc in adults
apparent renal agenesis or hypoplasia in an unDx adult
1/3 have abnormality in contralateral kidney, UPJ most common
Pelvoinfundibular Type - No connection ever develops
lg cysts from ureter bud surrounded by dysplastic tiss
"Cluster of Grapes", Develop rim calc
Hydronephrotic Type - Early connections but obs interupts proc
Some nephrons form, remainder of buds become cystic, variable
Can have segmental form, usually assoc w duplicated sys
may sim cystic mass, rare, always think neoplasm 1st

8. Aquired Cystic Kidney Disease - 90% of dialysis pts, any prolonged uremia
small & echogenic, variable cysts, curvilinear calc from intracyst hem
usually not apparent until 2-3yrs on dialysis, rarely hemorrhage
Cortical irregularity may sim mass, up to 40% have assoc mass
Only .33% ever develop metastatic renal cell ca

9. Pyelocalyceal Diverticulum - fluid filled mass in pelvis
Communicates to fornix, slow filling & washout w poss stasis & inf
Congenital Type - from cystic wolfian duct remenant
Aquired Type - from abcess or cyst ruptured into calyx
Often have sm stones or milk of calc forming fluid levels
Multiloculated Cyst seen in child, simple cyst not before 30y/o
Complicated by infection, hem & TCC, may sim Ca esp when lg

10. Congenital Megacalyces - inc number & dil of calyces in mosaic pattern
renal enlargment w prominent fetal lobulation

11. Multilocular Cystic Nephroma - Cystic Hamartoma
Large, usually >10cm, Bipahsic dist, 3mo old male, adult female
Mixed cystic w echogenic septations, see section on Solid Tumors
tends to herniate into the renal pelvis

12. Hydatid Cyst - much less common than liver, 50% don't calcify


BOSNIAK CLASSIFICATION OF RENAL CYSTS
Category I - Thin well defined wall, anechoic, non-enhanceing, water
Category II - septa <1mm, <3cm in size, thin rim calc, high density
no follow up neccessary if only one seen, f/u if 2 or more
Category III - indeterminate change, thick wall or septa, septa calc
must be surgically resected
Category IV - Clearly malignant lesion - must be a cyst predominately

RENAL MASSES

BENIGN RENAL MASSES
most sm, originate from mysenchyme, incidental at autopsy
ie fibroma, myomas, lipomas & angiomas

1. Angiomyolipoma - Hamartoma w Vasc, Musc & Fat, No malig potential
Most asym, 3:1 female 40-60y/o, 15% mult (Tuberous Sclerosis)
80% of tuberous sclerosis pt's have mult, cysts also
Most pt's w Angiomyolipoma do not have tuberous sclerosis
Only sm portion grows intrarenal, most grows into adj fat
well circumscribed but no capsule, most contain fat
NO tumor vascularity, good prognosis if <4cm in size
Vasc lacks N elastic layer or organized outer Sm musc
MUST excise if >4cm, fragile vasc predisposes to hem
CT showing fat in a echogenic renal mass is pathognomonic
Intensly enhancing, fat attenuation in 95%, NO calc
Wilms & teratoma can also have fat but very, very rare
US - "Tip of the Iceberg" due to blending w adj fat
Most Echogenic of tumors, Hyper or isoechoic to sinus fat
Hem may cause heterogenity or dec echogenicity
Angio - mult ectatic & aneurysmal vessels in 50%, NO A-V shunt

Myelolipoma - marrow elements & fat, not muscle
some debate about whether marrow can have endocrine activity

2. Adenoma - Benign Epithelial neoplasm of Prox tubule
small uniform cells w scant cytoplasm, size not sig to malignancy

Oncocytoma - made up of prox tubular cells, rare variant adenoma
Large uniform cells w abundant cytoplasm & mitochondria
White Central Stellate scar on histo, seen in old age
Stellate central scar more easily seen w CT than US, neither diagnostic
Angio - characteristic "spoke wheel" pattern of vessels
Tc-99m DMSA - cold lesion like most neoplasms, tubules do not fxn
Dx - needle Bx is NOT adequate due to sampling error

Both - Asym w rare hematuria, well defined if <5cm
grade I benign resectable, grade II more aggressive
Calc rare, isoechoic, sim RCC on US - MUST BX
Angiography - 25% show a spoke wheel pattern, freq in RCC
dense homogeneous blush diff from RCC's inhomo blush
Nucs - the only tumors that may take up radionucleitide
3. Multilocular Cystic Nephroma - cystic Hamartoma
Cyst variable w expansile growth, rare malig degen
mult noncommunicating fluid loc
thick pseudocapsule of fibrosis
Biphasic dist - Occurs in males <4y/o or females >20y/o
50% in young boys w elements of Wilm's
50% female adults, may be cystic lymphangioma, same histo
Large at discovery, 10-20cm, considered a true neoplasm
usually asym, pain, hematuria, infection poss
Plain Film - may show curvilinear septal calc
US - large cysts w thick highly echogenic septa
CT - septa may enhance, tends to herniate into renal pelvis
Angio - hypovascular
DDx - cystic Wilm's, multiloc cyst, echinococ, RCC, pyelo
DX only w Bx, No assoc w HTN

4. Hemangiopericytoma - Juxtaglomerular Tumor or Reninoma
elevated venous renin & II' aldosterone, young women
aldosterone causes Na+ retention & K+ excretion, HTN
Small solitary & usually located just beneath capsule
sharp margination w pseudocapsule & Freq Hem
US - echogenic Subcapsular mass, usually <2-3cm
Angio - enhance less than parenchyma, hypovascular
renal vein renin measurements diagnostic
Resection curative, they do not met, Curable cause of HTN
R/O renin tumor of lung, liver & orbit

5. Mesoblastic Nephroma - Fetal renal hamartoma, palp in neonate
connective tissue growing between nephrons, resec currative
Rarely calc, hem or nec, distorts calcices on IVP
#1 renal neoplasm in first few months

6. Peripelvic Cysts & Renal Pelvis Lipomatosis - distort sinus fat
Freq seen on IVP, US can Dx w confidence & R/O neoplasm


MALIGNANT RENAL TUMORS

1. Renal Cell Carcinoma - 85%, 6th decade, 2:1 male, usually lg
Hypoechoic to N cortex, can be Hyper, 40% have Cysts, Nec or hem
Tumor Vascularity in 90%, RI<.40, 5% avascular
HTN results from vascular shunting, 4% get polycythemia
Most Renal adenoca displaces tissue (Ball), papillary type
Aggressive type infiltrates, NONPAPILLARY type
Most solid Benign Tumors cannot be distinguished
Angiomyolipoma w fat in tumor is the exception
DDx Trans cell, met, lymphoma, leukemia
Always evaluate contralat kid, renal vein & retroperitoneum
Tumor thrombus is echogenic & expansile
Adrenal mets in 25%, bone & lung #1
30% w mets at Dx, <2% bilat unless w von-Hippel Lindau
IVP - Always enhaces less than N tissue
periph cortical mass may not distort calyces & pelvis
Vermian filling defects in pelvis - tumor induced vasc
CT - mult distrophic calc in 20%, do Pre & post contrast
Nec & hem freq, asses fat planes, renal vein & nodes
Subcapsular hem may be presenting sign
Retroperitoneal bleed also, think RCC in older man
Angiomyolipoma more freq cause in young female
Cystic w or w/o mural nodule poss, cysts can coexist also
Central scar - sim oncocytoma
US - equal to CT for assesing renal V thrombosis, Budd-Chiari poss
25% have renal vein involvement at nephrectomy
Polycythemia assoc in 4% due to tumor prod of erythropoietin
Abnormal liver fxn tests seen even w/o mets, alk phos & PTT elevated

Stage I - inside capsule (75% 5yr), II - within girodas fascia (50% 5yr)
IIIa - local venous extention (25% 5yr), IIIb - local nodes (15% 5yr)
IIIc - both venous & local nodes, IV - outside girodas fascia (<5% 5yr)

Self-Healing Hypernephroma - RCC that has outgrown it's blood supply
Hypovascular, undergoes cytic degeneration & forms peripheral calc
very difficult to DDx from calc cyst, even w gross pathologic inspection

Pearl - check for bone mets, check chest X-ray & do renal venogram
Risk Factors for RCC
Von Hippel-Lindau Syn - RCC in 25%, often bilat
70% have renal cysts, Hemangioblastomas of CNS, pheochromo
Aquired Cystic Kidney Dz - occurs in 50% on dialysis
10% will develop RCC, 80% by 7yrs but most die before
Also inc w Auto Dom Polycystic Kidney Dz & other cystic Dz
Papillary Renal Ca - Adenoma, Histo identical to RCC, 5% of renal Ca
If >3cm consider malignant, may met even before
Asym but may have painless hematuria
Hypo or isoechoic to renal cortex, well defined
CT more sensitive but still nonspecific, Hypovascular

2. Wilm's Tumor - #1 malig abdomimal tumor in kids <10, 50% @ 3yrs
Arise from primitive metanephric blastema, most cortical
arise anywhere along ascent of kid or in pelvis, rare
Sx - Hematuria freq but rarely gross
Hypertention due to renin secreted by tumor, not mass eff
US - freq shows wedge of residual N tissue, 5% bilat, 5% calcify
12cm average on presentation, 90% palpable
always evaluate for renal vein invasion, freq cystic components
CT - sharp margination, hem, nec & heterogenity common
Bulky cortical mass usually spares collecting sys, strechs it
Sharply delineated by pseudocapsule
sim RCC in both CT & US, good vs bad histology not defined
6% migrate up IVC and form cast, rarely obs
Risk Factors - 33% w Bilat sporadic aniridia
Beckwith-Wiedmen Syn - macrosomia, macroglossia, omphalocele
Hemihypertrophy 5%
Stage I - within capsule, II - local extension to nodes or vessels, complete excision
III - not totally resectable, peritoneal implants etc, IV - mets, V - bilat (5%)
20% of mets to lung, rarely go to bone & brain
5yr survival 90%, 100% for stage I, 50% for stage IV
prognosis improves if detected before age 2
Prognosis - Most dependent on histology, 90% have favorable type
Triphasic - primitive blastema, stroma & epithelial cells
Unfavorable - clear cell, rhabdoid, anaplastic & sarcomatous characteristics
DDx - Neuroblastoma presents earlier, invades form outside
also NB accum MDP radiotracer & secretes catecholamines

Nephroblastomatosis - residual metanephric blastema past 36wk
only found isolated if diffuse bilat bumpy enlarged kids, flank mass
found in 30% of pts w Wilm's, 100% if bilat Wilm's
inc risk for Wilm's but most regress rather than evolve to Wilm's
Contrast CT diagnostic - Does NOT enhance, isodense to cortex
Clear Cell Sarcoma of Kidney - 4% distinct from Wilm's
Bone metastisis is main distinguishing factor
Never multicentric or bilat, worse prognosis than Wilm's

Rhabdoid Tumor of the Kidney - occur in younger than Wilm's
lg mass arising centrally, Mets to Brain distinguishing
Freq crescent of subcapsular fluid assoc
also assoc w I' PNET (medulloblastoma)
Histo shows bundles of filamentous cytoplasmic inclusions

Drash Syndrome - Wilm's, pseudohermaphrodite & nephritis

3. Mesoblastic Nephroma - most common renal neoplasm in infancy
Infiltrative growth of mature spindle cells entrap nephrons
NO capsule, unsharp margins often replacing >60% of kidney
most present w incidental mass at birth
HTN due to renin, hypercalcemia & CHF due to AV shunting
US - classically shows well defined concentric rings
CT - irreg attenuation, entraped nephrons show irreg enhance
Excellent prognosis except in few atypical cellular cases

4. Multilocular Cystic Renal Tumor - Cystic Nephroma
solitary multiseptated noncomm cysts, Septa thin, enhance
usually a asym mass, must be resected
Cystic Partially Diff Nephroblastoma - any frag of blastema
identical on imageing

5. Transitional Cell Carcinoma - 90% col sys tumors, 8% of Renal
Infiltrates from pelvis along nephrons, Reniform enlargement
Hypo or isoechoic, distorts architecture & sinus fat
NO abn vasc assoc, rarely invades veins
HEMATURIA early, usually present small but bulky poss
Asym hydronephrosis, Frags can also sim anechoic stones
Rare in children, occur older than wilm's at 10yrs
assoc w Tuberous Sclerosis & Von Hippel-Lindau Syn
presents smaller than wilm's, freq bilat
Risk Factors - Phenacotin (analgesic abuser), aniline dye, smoker
DDx - lymphoma, mets, squamous cell, infil RCC & bacterial
Papillomas - benign relative of TCC, smooth & rounded
Histo difficult to distinguish, may recur, poss premalig
6. Squamous Cell Carcinoma - Sim but more invasive than TCC
Also invades renal parenchyma from pelvis
Chronic irritation causes luekoplakia or squamous metaplasia
premalignant, IVP & CT more sensitve than US

7. Renal Sarcomas - rare as primary, arise from assoc mysenchyme
fibrosarc, liposarc, myosarc etc, frequently in pelvis

8. Renal Lymphoma - primary rare, from hematogenous or direct extention
50% get bilat enlarged kidneys, involved in end stage, rarely cause of death
Renal impairment usually due to nodes obstructing outflow
NonHodgkins #1, enlarged w mult bilat hypoechoic masses
lymphomatous masses can produce post acoustic enhancement
Often multiple, margins less distinct than cysts
Burkitt's Lymphoma - renal involved in 30%, aggressive
males under 10yrs, infiltrate diffusely

9. Renal Metastases - Freq seen at autopsy but 4x <RCC in living
lung & melenoma freq infil peripelvic space
colon usually lg solitary echogenic masses
most sm, 50% multifocal w poor margins, Hypoechoic
All enhance on CT

Renal Leukemia - similar to lymphoma, cause of enlargment unkn
freq renal involvement during active stages
strongly consider if invasion of renal pelvis present
nodes along walls of pelvis actually involved

RENAL INFECTION AND INFLAMMATORY DISEASE

1. Acute Pyelonephritis - ascending UTI, urinary statsis or iatro
G- esp E coli #1 cause, female 15-30yrs, diabetes predisposes
Usually unilat, Dx clinical, US to R/O obs or abcess
NO abn on US usually, enlargement & hypoechoic II' edema
boundry between sinus fat & parenchyma may blur
IVP - abn in 50%, linear radial zone of lost enhancement
often has lobar or sublobar dist, sim infarct, malig
US - usually Hypoechoic, may be focal but indistinct
CT - Focal Scar poss w retraction of cortex & papilla resulting
Renal vein thrombosis Or Renal infarction poss

Acute Bacterial Nephritis - actually just severe diff pyeloneph
Entire kidney infil w PMN's, enlarged & hypoechoic on US
Small Smooth Unilat - pap nec & Permanant damage usually
Phlegmatous mass results if not Tx, must resect
Present w failure if bilat
IVP - shows dec enhancement early, retention later
Calyces & pelvis collapsed by swelling
loss of blood flow indicates interstitial process
sim infil transitional cell & lymphoma
DMSA - remains gold standard for perfusion study, dec uptake

4. Emphysematous Pyelonephritis - seen w diabetes, obs & immunesup
Fulminate necrotizing process, usually E. coli
50% mortality - DO NOT miss on plain film
Unilat #1, NO response to Abx due to ischemia, Nephrectomy
US - "dirty" shadowing produced by gas, may sim bowel

5. Pyogenic Abcess - result of acute bacterial nephritis, retrograde G-
Staph Aureus (G+) abcesses can be caused by hematogenous seeding
freq extention to perinephric space, rare comm to collecting sys
IVP - focal enlargment, subcapsular extention creates concave
Angio - can have neovascularity, simulates RCC
US - poorly marginated, debri & fluid filled w echogenic foci
sim cysts & masses, rapid sequential changes pathog
CT - best for evaluating perinephric space invasion, seen in 50%
most pyogenic abcesses do NOT calcify, TB does calcify
Microabcesses often result from rare hematogenous pyelo
Puss & WBC often absent from urine specimen by abcess onset
6. Pyonephrosis - Puss in the collecting system, assoc w obs
Echogenic Debris seen in dilated collecting sys
may need aspiration for Dx, must be drained for Tx

7. Xanthogranulomatous Pyelonephritis - rare, severe chronic renal infec
Chronic supparative granulomatous infection w diffuse involvement
Charactrized by partial or complete replacement of the kidney
named for the lipid laden macrophages assoc w this
Middle age females & diabetics
70% have stones esp staghorn & recurrent UTI, E. Coli poss, Proteus #1
most assoc w chronic obstruction, extrarenal extention freq
Enlarged kidney w dil irreg calyces, punctate calc poss
Hepatic dysfunction may be assoc, resolves after Tx

8. Tuberculosis - aquired by hematogenous spread, 75% unilat initially
Caseating granulomas & abcesses w fibrosis & cortical destruc
Cortical Embolic Lesions - extend to pyramids & ulcerate to calyx
#1 cause of diffuse renal calc in nonfunctioning kidney
Autonephrecty freq, "putty kidney", amorphous smudgy calc
Infundibular Stenosis - due to collecting sys involvement
ureteric granulomas may obs, frequently calcify
Bladder involment follows, NO calc, irreg thickening sim TCC
Atypical Mycobacterium - produce same changes, more difficult to Tx

9. Fungal Dz - candidiasis #1, usually hematogenous seeding
only seen in immunecomp, post-surg or w underlying renal dz
sim bacterial nephritis & abcess
Fungus balls may produce obs w resulting failure & anuria

10. Renal Parenchymal Malakoplakia - Assoc w G- UTI, immunecomp
most malikoplakia occurs in bladder & dist collecting sys
impared intracellular bacterial killing
US - nonspecific hypoechoic masses when renal
diffuse renal enlargement & distortion of calyces

11. AIDS - 50% w inc renal cortical echogenicity relative to liver
drugs cause tubular nec, but this is not cause of echogenicity
PCP can cause diffuse calc

12. Diabetes - up to 60% of pts w Acute Pyelonephritis are diabetic
XGP is a common sequelae of chronic obs & superimosed infection
CHRONIC ATROPHIC PYELONEPHRITIS
Reflux Nephropathy, NOT an infection
water-hammer effect from intrarenal reflux main cause of damage
Focal Cortical Scar - overlies a dilated calyx, sm kidney
Polar cortex most effected, does NOT occur after age 4
Squamous Cell Ca - can cause chronic pyelonephritis
assoc w Schistosomiasis & follows squamous metaplasia
DDx - treated acute bacterial nephritis, renal TB or pap nec
papillary necrosis usually has sloughed papilla in calyx

Ask-Upmark Kidney - HTN caused by a kidney w segmental hypoplasia
probably due to reflux scar, congenital abn possible
diffuse hyperplasia of juxtaglomerular cells in affected kidney

RENAL TRAUMA
Blunt Injuries - 80%, 2/3 to kidney vs collection sys

1. Subcapsular Hematoma - most common, occur II' to minor trauma
kidney intact, presents w gross or micro hematuria
Interstitial edema leads to dec renal blood flow
CT is method for initial eval, asses fxn & images whole abd
US cannot distinguish hematoma from urinoma acutely
Perinephric Hematoma - fat infiltrated & bubbly in appearance

2. Renal Fracture - linear defect, subcapsular blood
assoc w severe trauma, avul of vessels, rare

3. Vessel Avulsion - #1 cause of nonvisualization of kid post trauma
Infarction - wedge defect, global if major art avulsed

4. Page Kidney - perinepheric hematoma or urinoma presses on vasculature
HTN results within 1yr, Tx w nephrectomy

RENAL CONGENITAL ABNORMALITIES
10% of all people have some degree of anomalous anatomy
50% w severe anomalies have VATER assoc syndrome
Vertebral, Anal, Tracheal, Esophageal, Radial bone & Renal

1. Supranumerary Kidney - rarest renal malform, below N kidney
no physical connection, drains into N ureter distally

2. Agenesis of the Kidney - more common, male 2:1, L>R
Ureteric bud & metanepheric blastema do not fuse
if bilat present in utero w oligohydramnios & pulm hypoplasia
Potter facies - beak nose, receding chin, low ears
Genital anomalies also assoc, cryporchad, bicornate uterus
ipsilat Adrenal is disk shaped in paraspinous region

3. Compensatory Hypertrophy - response to loss of opposite kidney
Younger pt w renal loss has Hyperplasia of glomeruli up to age 6
Hypertrophy is predominant after that up to age 40
assoc w inc renal art size & dilation of collecting sys for inc flow
may be up to 5 vert bodies in length

4. Renal Hypoplasia - congenitally sm kidney, rare
most sm smooth kidneys are aquired from vasc, inflam or obs
Reduced in size by 50%, fewer calices (N 10-14)
NORMAL function

5. Renal Dysplasia - Ectopic insertion of its ureter
grossly distorted w poor fxn in addition to sm size

6. Rotational Anomalies - Does not complete 90' medial rotation
freq assoc w ectopic & fused kidneys
rarely over rotate, face post or lat

7. Ectopic Kidneys - permanent location below N most common
can be behind bladder or across midline freq fused to N kid
Blood supply from LOWER aorta or Iliacs
Renal Ptosis is variant w N ureter & arterial origin
IVP - kidney difficult to see due to bony pelvis, malrotated
8. Fusions of the Kidney - lower pole most common, horseshoe
Vasc supply to isthmus variable, often aberant aorta branches
Neoplasm can hide from IVP in isthmus
Malrotation present to some degree
mild dilation due to ant angulation, inc stones & infec
superior, middle or total fusion into "ring" rare
Pancake - both in pelvis & fused at upper & lower poles
Cross Fused Ectopia - upper pole of ectopic fused to lower N
more prone to trauma

9. Unipapillary Kidney - N in many small mammals including monkeys
rare in humans & usually assoc w significant urinary anomaly
hypoplastic w freq contralat anomalies as well

10. Polycalicosis - larger than N number of calices, N size & fxn

11. Aberrant Renal Papilla - causes a filling defect which sim neo
No minor infundibulum or formed calix, oval defect in pelvis
smoother than TCC & fixed unlike stone, obl veiws helpful

12. Congenital Megacalices - unilat enlargement w no pelvis dil
most probably aquired II' to obs or infection

RENAL VASCULAR ULTRASOUND
Resistive Index = s-d/s, gives diastolic flow assesment
Pulsatility Index = s-d/Mean
Dist branches of Art have few anastamosis, Dec branches w age
Dist veins have mult anastamosis
Anomalous Veins often run longitudinal - Sim lymphadenopathy
Spectral Broadening - assoc w turbulent flow

1. Renal Art Perfusion - low-impedence system, constant diast flow
Branching from main is segmental - intralobar - arcuate - intralobular
RI > .7 seen more w tubulointerstitial Dz than Glomerular
difference >.1 side to side indicates unilat dz
Small renal art can result from any cause of atrophy

2. Renal Artery Occlusion - enlarge initially, echogenic & sm late
Segmental infarct - hypoechoic mass at 24hrs, consolidates
focal enlargement of renal parenchyma, NO effect on collecting sys
low density area w rim enhancement in 50%
echogenic scar in weeks, sim neoplasm
Stenosis - velocity >180 indicative of 60% occlusion
Renal/Aortic ratio - velocities diff >3.5 = Stenosis

Renal Artery Thrombosis - acute w flank pain & hematuria
Doppler shows no flow, echogenic material in art, NO fxn on CT
Kidney may appear N initially, prior infarcts freq
Angio - collateral flow poss to capsular artery
1st 4 lumbar arteries, lower intercostals & adrenal arteries
Etiology - aneurysm, polyarteritis nodosa, dissection II' to trauma

3. Renal Vein Thrombosis - can be acute or chronic if partial obs
flank pain & hematuria often assoc w fever & leukocytosis
Renal Neoplasm - causes 50%, RCC especially prone to this
retroperitoneal malig, dehydration, nephrotic syn, AMYLOID
transplant, IVC thrombosis & membranous glomerulonephritis
Also seen in infants of diabetic mothers
Inc risk assoc w Diabetes, SLE, Trauma & Sarcoid
large edematous hypoechoic kidney, corticomed jxn indistinct
thrombus & lack of flow in vein, tumor thrombus more hyper
CT - shows prolonged angiographic phase of nephrogram
IVP - dense nephrogram, striations, enlarged & dec excretion
US - peaked systolic flow w plateau-like reversed diastolic flow
Cellular infil of cortex occurs P 1-3wks, inc echogenicity
Parenchymal fibrosis eventually causes shrunken hyper kid
Collaterals develop within 24hrs, can cause vasc impression
4. Congenital Arteriovenous Malformation - synonymous w Hemangioma
Always central, present as mass lesions at tip of pappilla
Massive Hematuria is characteristic
Shunting very rare & minimal when does occur
Cirsoid Type - cluster of multiple dilated vessels
Cavernous Type - lg arterialized chamber, presents large
present w calcified wall, Early Draining Vein

5. AV Fistulas - low resistance art flow pattern & inc turbulance
arterialization of venous flow
Post Bx #1, ruptured aneurysm or RCC also, all are aquired
Polyarteritis Nodosa - freq sm aneurysms which prog to fist

Trueta Phenomenon - dec cortical flow w shunt of art blood to vein
dec cortical blush, assoc w hypovolemic shock & vasoconstrictor drugs
No fistula can be demonstrated, shunting is the apparent mechanism

6. Renal Vein Varices - Any cause of inc Pres, fistula freq
"nutcracker" SMA & aorta, splenorenal shunts
IVP - Present as vermiform mass, filling defect can sim TCC
Easily compressed w distention, retrograde often needed

7. Pseudoaneurysms - Pulsitile flow & characteristic swirling
Avascular cystic areas can have color "splashes", no swirl
can cause subcapsular hematoma w parenchymal comp & fxn loss
may coexist w AV Fistula P Bx

8. Renal Artery Stenosis - occurs in 5% HTN pts, renin released
Angiotensin II inc causes vasoconstriction
ACE inhibitors (captopril) remove eff vasoconstriction
relieves HTN but may cause dec cortical perfusion
Aldosteron also inc causeing further HTN
Atherosclerosis in 2/3, Fibromuscular dysplasia #2
Aneurysms, vasculitides, NF-2, infarction & parenchymal dz
May cause atrophy of affected kidney, <9cm
Doppler detects prox in 80%, distal in 95%, mult in only 20%
Peak-sys freq shift in renal art 3.5:1 w aorta, ?useful
Rounded & delayed systolic peak seen dist to stenosis
NO method predicts wheather angioplasty will improve HTN

Fibromuscular Dysplasia - involves dist 2/3 of art, prox 1/3 spared
Medial Fibroplasia causes 70% but can originate in any layer
#1 cause of HTN in children & young adults, 3:1 female
9. Renal Artery Aneurysm - Saccular form occurs at branches
Fusiform type occur post-stenotic
Atherosclerosis most freq cause, rarely rupture, 75% calc
Fibromuscular Hyperplasia - Distributes in center of artery
Occurs in young women, severe refractory HTN
Freq dissection & infarction, Aneurysms result
Resulting cluster of collateral vessels can sim AVM
Angiomyolipoma - aneurysms in 50%, freq multiple
other neoplasm such as RCC also
Mycotic - rare, thoracic aorta, SMA & MCA involved

Collagen Vascular Dz - cause necrotizing angitis of med & small vessels
Multiple aneurysms near corticomedullary jxn, may hemorrhage
intense inflam results in microinfarcts, patchy nephrogram
SLE - aneurysm in 50% but kidneys involved in 100%, often to ESRD
genetic predisposition & more common in blacks
Polyarteritis Nodosa - seen in 80%, can spontaneously regress
hypersensitivity angitis & Drug abuse
Scleroderma - NO aneurysms, necrosis of arterioles mostly
Progessive Systemic Sclerosis - onset early, simulates malignant HTN
spotty nephrogram w no aneurysm diagnostic of scleroderma

10. Renal Contusion - Causes blood in interstitium, diffuse edema
Compression reduces nephrogram, squeezes collecting sys
Preserves reniform shape

11. Vasa Recta - capillary plexus, follows loop of henle into medulla
from efferent arteriol of juxtaglomerular sys, 1-2% of blood flow

MEDICAL RENAL DISEASE
Acute - freq large bilat kidneys, long DDx, require Bx
Bx required for N or >12cm kidney w supected med renal Dz
Chronic - small bilat kidneys, need long term maintenance
kidney <9cm considered end-stage, no Bx would be helpful
measurements of cortical thickness unreliable
accentuated corticomedullary definition & inc echogenicity
ALWAYS asses for Pre-Renal failure - vein or art thrombosis

1. Acute Tubular Necrosis - #1 cause of renal failure, reversible
Toxic or Ischemic, causes widespread tubular epithelial damage
heavy metals, Abx, anesthetics & solvents
Myoglobinuria causes 5%, even sm amts cause chronic failure
follows rhabdomyolysis from trauma, etoh, fever, stroke
Abrupt & severe onset of Tubular cell necrosis, cellular casts in UA
US - often N P ischemia, mild echogenicty or enlargement
Toxic causes freq cause enlargement, echogenic cortex
hypoechoic pyramids accentuates corticomedullary jxn
increased RI freq

2. Acute Cortical Necrosis - irreversible nec II' to hypoperfusion
shock, hem, sepsis, burns, RVT, severe dehydration
Necrosis of cortex & tubular cells w interstitial infil
Medullary & superficial cortex supplied by capsule spared
US - Hypoechoic initially due to edema, minimal enlargement
CALC seen as early as 24hrs at jxn of necrotic & N tissue
CT - No perfusion to cortex, hyperperfusion of medulla
"tram trac" Calc of cortex

3. Acute Glomerulonephritis - Autoimmune induced glomerular damage
Collagen vasc Dz's ie lupus, Poststrep glomerulonephritis
Goodpasture's Syn & rapidly progressive glomerulonephritis
Sx - hematuria, HTN, axotemia & RBC Casts
US - N early, enlarged & Echogenic appearance develops quickly
inc cortical echogenicity w medullary sparing pominent
hypoechoic cortical foci from vasculitis induced ischemia

4. Interstitial Nephritis - WBC infil causing echogenic kids
Pyelonephritis when infectious, Drugs etc can also cause it
5. Nephrocalcinosis - calcium deposits in the renal parenchyma
US less sensitive than CT though more sensitve than film
shadowing may be seen even if calc not present, less likely
Percutaneous Removal - only contraindicated w bleeding diathesis
Lithotripsy - freq hematuria, use a stent if stone >2cm
Renal Tubular Acidosis - #1 cause in neonates

Renal Stones - arise in collecting sys, percipitants
rarely cause failure unless only one kidney
ALL cause post shadowing on US despite composition
Calcium Oxalate - 35%, radioopaque, usually idiopathic
can be assoc w sarcoid, cushings, crohn's, milk alkali etc
Struvite - 15%, mildly opaque, Magnesium ammonium phosphate
Alkaline infected Urine, esp proteas prod urease, inc ammonia conc
Uric Acid Stones - 7%, radiolucent, purine metabolism disorder
Hyperuricemia - II' due to Crohn's, chemo or lymphoma causes 40%
I' gout causes only 20%, All have Acidic Sterile Urine
Gout can be caused by any form of renal failure, polycystic etc
Tx w sodium bicarbonate infusion thru renal pelvis, raise urinary PH
Cystine Stones - 3%, mildly opaque, II' to auto dom cytinuria
these stones occur in ACIDIC urine
Xanthine Stones - rare, assoc w Oxalosis, see below

Parenchymal Nephrocalcinosis - diffuse & bilat
Hypercalcemic states, HPT, vit D intoxication, bone malig etc
Cortical Calc - Cortical Nec, Glomerulonephritis & Oxalosis
Medullary - Hypercalc states & renal tubular acidosis
Focal & unilat calc usually II' to infection or neoplasm

Medullary Calcinosis - hypercalcemia & medullary sponge kid
Distal Tubular Acidosis can also cause medullary calc
Echogenic pyramids w or w/o shadowing, opposite N hypo app
interstitium 1st due to lymphatic Ca+ overload
these deposits act as nidus, stones eventually extruded
Medullary pyramid echogenicty w/o calc can be seen
hyperkalemia & primary aldosteronism
medullary sponge kid has mult ectatic tubules, min calc

Primary Oxalosis - rare hereditary disorder, die in childhood
xanthine to uric acid conversion interupted, part of purine metabolism
diffuse bilat calc at corticomedullary jxn & involves both
Aquired Oxalosis - assoc w sm bowel Dz (Crohn's) or bypass surg
diffuse cortical calc causes inc echogenicity, diff to DDx
advanced cases may cause a WES type appearance on US
5. Primary Amyloidosis - unrelated to other Dz processes
Unknown etiology, Kidneys involved in 40%, Nephrotic Syn
Amyloid deposits in glomeruli, arteries & interstitium in 40%
Nephrotic Syndrome - Protien loss not relative to severity of deposites
protien lossed due to breaks in tubular epi & podocytes

Secondary Amyloidosis - assoc w chronic Dz of many kinds
80% involves kidneys, US findings similar in both I' & II'
renal enlargement in acute stages, progresive dec
Chronic - inc cortical echogenicity & corticomed accentuation
Both can cause Renal Vein Thrombosis

6. Renovascular Hypertension - 45% of pt's w malig htn
Renal Art Stenosis - juxtaglomerular release renin
angiotensinogen from liver cleaved to angiotensin I
converting enzyme in lung changes to angiotensin II
vasocontricts efferent arteriols, release aldosterone
Worsening renal fxn w use of ACE inhibitors is diagnostic
Captopril Renal Scintigraphy - 25-50mg given oral
MAG3 performed 60min later, give lasix 20min into scan
Know the Grade 1-3 appearance of time-activity curves
basically flatens intial N peak worse w each grade
Hypertensive IVP - renal size diff of >1.5cm, delayed excretion
causes inc contrast concentration, dec urine Na+
Captopril also accentuates this
Vermiform collaterals may be seen impressing pelvis
Angiography - gold standard for anatomic stenosis, HTN cause?
Renal vein renins >1.5 diff between sides, not popular now
pressure diff should also be measured
Intervention w uncontrolled HTN, plasty, stent or surg
B-blockers inhibit renin release
Use stents 10-15% larger than art, neointimal growth
Eventual diffuse nephron atrophy, Sm Smooth kidneys result
"Page" Kidney - HTN resulting from compression on the kidney
usually a perinepheric process such as hematoma, urinoma or tumor
Fibromuscular Dysplasia - string of pearls, female predominance
involves mid to dist portion or renal art (atherosclerosis usually prox 1/3)
all layers can be involved but media most common, PTA Tx of choice

7. Renal Tubular Acidosis - inability of kidney to excrete H+, alkaline urine
metabolic acidosis, hyperchloremia, hypercalcemia, K+ depletion
assoc w HPT, vit D intoxication
#1 cause of nephrocalcinosis in neonates

8. Sickle Cell Dz - causes smooth enlarged kidneys & renal failure
Perirenal Hematoma - assoc w renal infarct, Clubbing of calyces
Papillary Necrosis - II' to thrombosis of small vessels
Pyelonephrosis & urine concetration abnormalities
Priapism - due to venous outflow defects

9. Arteriolar Nephrosclerosis - one of the few causes of bilat sm kidneys

MISCELLANEOUS RENAL DISEASES

OBSTRUCTION
Acute Obstructive Nephropathy - dilation w renal fxn impairment
5% of renal failure, malig, surg, calc, prostate
IVP - most sensitive sign is widening of Calyceal angle
Chronic results in Rim Sign due to thin atrophic cortex
US - sensitive unless obscured by staghorn or oliguria
Mild hydronephrosis - minimal sep of renal sinus fat
Moderate hydro - anechoic urine seperates entire sinus
Severe hydro - extensive seperation of sinus & calices
also see thinning of parenchyma
UPJ formed at site where peristalsis creates apposition
if pelvis not conical a good bolus cannot form, fxn obs
ureter peristalsis becomes irreg, N is 2-4X per minute
eventually stops if chronic
Look for vicarious contrast excretion in GB or colon at 24hrs
Extravasation - may occur, most likely at Fornix

Chronic Obstruction - dil to certain point then equil obtained
initially P >20mmhg but gradually dec back to N <15, dil same

False-Postive for Obs - pelvocaliectasis does not equal obs
overhydration, full bladder, extrarenal pelvis, vasc, cysts
up to 50% of grade I hydornephrosis Dx may be N
Reevaluate after voiding, equivocal cases evaluate w IVP
Diuretic - during IVP or Nuc scan clears dil sys if no obs

False-Negative for Obs - occurs in <1%, usually w min dilation
Staghorn calc can obscure the dilated system
Decompressed system from tubular back flow or calyx rupture
Hyper-acute obs may not yet have dil, esp if dehydrated
RI >.7 or difference of >.1 indicates pathology, consider obs


DILATATION WITHOUT RENAL FAILURE
Obstructive Uropathy - dilatation without renal deficit

1. Hydronephrosis of Pregnancy - 85%, R>L due to uterus pressure
hormonal relaxation of ureters also contributes, peeks at 25w

2. Congenital UPJ Obs - common congenital anomaly
Failure rare, usually undiagnosed until adulthood
Pelvocaliectasis w abrupt cutoff at UPJ, sim cystic mass
DDx from multicystic dysplastic Dz diff in older adults
#2 site for calculi obs, Ureterovesicle jxn #1

3. Congenital Megacalices - abn # & timing of ureteral cell div
calices increased in size & #, medullary thickening, N cortex
Renal fxn N, tends to have decreased ability to concentrate
Stasis causes inc susceptibility to stones & infection
IVP shows polygonal or faceted calices, sim papillary nec

4. Acute Flank Pain - IVP ideal for eval unless preg or poor fxn
US localization of hydro on side of pain suggests stone


PAPILLARY NECROSIS
Ischemic Necrosis of Medulla, loops of Henle & vasa recta

1. Etiology - "POSTCARD"
Pyelo, Obs, Sickle, TB, Cirrhosis, ASA, Renal v thrombosis, Diabetes
Analgesic Nephropathy - Present w gross hematuria, HTN & renal insuff
Inhibits prostiglandin reg of blood flow to papilla
collecting ducts spared early, henle most sensitive
May pass renal tissue (renal colic), 4:1 female
Papillary Necrosis progresses to scar & renal atrphy
predisposes to TCC & to a lesser degree squamous cell ca
Sickle Trait - predisposes, homozygous don't have time
Diabetes Melitis - only when assoc w overwhelming infection
used to be I' cause
Hypotension, dehydration in infants & hemophilia

Focal or Unilat Causes - necrosis of affected ray
Granulomatous infection & drug abusers #1 focal etiologies
UTI, Renal Vein Thrombois & Obstruction

2. Findings
IVP - Smudging of papilla earliest sign, contrast in rays
Calc at hyperemic Zone, sloughed triangular rings of calc
Nephrocalcinosis in semilunar ring also poss
irreg forniceal blunting, residual of viable medulla
Obs from sloughed papilla
Eventually evolve to smooth blunted calyces

US - cystic collection in pyramid or cyst replaceing pyramid
can mimic hydronephrosis when severe
sloughed papilla may calc & sim stone


EFFACED PELVOCALYCEAL SYSTEM
Always attempt to distend pelvocalyceal sys

1. Global Enlargement - due to edema or renal failure
Oliguria can also contribute in renal failure, acute or chron

2. Sinus Lipomatosis - stretches calyces, usually insig
obesity, endocrine, aging or renal wasting
Staghorn calc can induce massive fat prolif in sinus

3. Renal Sinus Mass - parapelvic cyst #1, can sim fat or hydroneph

RENAL TRANSPLANT EVALUATION

1. Perinepheric Fluid Collections - 50% due to surg, Bx or reject
Lymphoceles - #1, occur in 20% at 1-3wks, med or inf to kid
Septations & debris freq, usually asym, may obs if lg
freq recurrance P drainage, surg resection if symptomatic

Urinomas - early postoperative complication, 1-2wks
surg error, vasc compromise & rupture, post obs etc
usually at lower pole or near bladder, NO septations
aspirate for DDx form lymph etc

Hematomas - less common, usually immediate post op
Variable w debris or septations, may be subcapsular

Abcess - usually infection in preexisting fluid collection
occur 4-5wks P transplant, "dirty" post shadowing pathog

2. Obstruction - ureteroneocystostomy site freq edematous post op
mild self limiting obs
True obs occurs later due to stricture, rejection, clots etc
Overly distended bladder creates FUNCTIONAL obs

3. Rejection - more severe & acute has greater changes
3 different phases, all cause loss of perfusion & allograft enlargement
Hyperacute - Ab present at time of transplant, occurs in 1-12hrs
Thrombosis of vasc bed, functional destruction
marked enlargement of kid, Cortex HYPOechoic
loss of corticomedullary distinction
scattered parenchymal hemorrhage seen as heterogen echogen
Doppler - absent or reversed diastolic end-flow, RI >.90
Acute - cellular response occurs in 1-3wks
accelerated form poss in 1day, allograft still enlarges
sensitized lymphocytes destroy cells w/o help from humoral Ab
hypoechoic medullary pyramids, thickened uroepithelium
Chronic - humoral Ab response over months to years
damages endothelial & interstitial cells
occurs in all to some degree
US - doppler shows progressive dec in diastolic flow
can haver reveresal of diastolic flow
systolic flow peaks not affected
absent arterial signal due to thrombosis
NUCS - no flow in early phase, no excretion
4. Acute Tubular Necrosis - presents concurrant w rejection
US - NO features DDx from Hyperacute or acc rejection
NUCS - show N perfusion but delayed tubular clearance
Always to some degree w cadaver kid, never w relative transplant

5. Cyclosporin Toxicity - Usually causes NO changes in allograft
may enlarge, but cortex HYPERechoic, pyramids prominent
Simulates ATN - N perfusion but no excretion

6. Vascular Complications
Renal artery Stenosis - 10%, at anastamosis or II' to reject
Complete art occlusion - severe acute vascular rejection
Lack of doppler flow may simply be severe hypofxn not obs
Renal Vein Thrombosis - rare, usually in early post-op period
Arterial resistance inc marked due to no capsular coll V

7. Transplant Related Masses - Epstein-Barr virus Lymphoma
Augmented by cyclosporin & OKT3, develop in 6mo P transplant
Also inc susceptablility to Squamous Cell Ca of skin

ANATOMY & CONGENITAL DEFECTS OF THE URETERS

URETER ANATOMY
Exits post to vessels, tunnel laterally into trigone
Collecting tubules come from same ureteric bud
N peristalsis begins at UPJ, pacemaker probably in pelvis
occurs 5-10 times per min in either direction
stones & vaginal stim inc peristalsis, infection decreases it
Descend lat to spinous processes, if medial abnormal
think retroperitoneal fibrosis or circumcaval ureter on R

CONGENITAL DEFECTS

1. Circumcaval Ureter - medial deviation of R mid ureter
IVC develops from R post cardinal V not supracardinal
CT shows ureter passing post & medial to IVC
Prox ureter dilates, may become tortuos w reverse J shape

2. Valves, Strictures & Folds - Rare in ureter
Diaphragm may be seen w prox dilation
Transverse ureteral Folds - redundant mucosa in lumen
disappear w age & are not obstructive

3. Ectopic Ureteral Orifice - insertion other than trigone
reflux or obs may result, severe renal dysplasia may result
Posterior Urethra - most common site in males, usually obs
seminal vesicles or ejaculatory ducts, no incontinence
Females - vestibule or vagina, usually incontenent

4. Ureterocele - Focal dil of dist ureter within the bladder wall
Orthotopic Form - occurs in N postition in trigone, Adult
"cobra head" appearance, project into bladder, often asym
when assoc w duplication occurs in lower moeity
Pseudoureterocele - aquired due to Ca occluding UVJ
ureteroceles in older pts must be evaluated
5. Duplicated Collecting System - abn ureteral bud, most asym
Partial Dup results from branching of bud before joining
Complete dup results from 2 seperate buds, join seperatly
lower sys inserts in trigone, possible slight sup lat
Upper sys inserts med & inf to lower sys, usually smaller

Weigert Meyer Rule
Lower Moiety - usually shorter submucosal tunnel, cranial lat
REFLUX in 30%, may lead to reflux nephropathy
Upper Moiety - Ectopic & Obstructed, caudal & med insertion
Ureterocele Possible
above urogenital diaph in male, female incontinence
insertion to seminal ves creates multicystic mass
Freq stenosis and obstruction w resulting hydronephrosis
poss only lower sys vis, fewer calices, deviated pelvis
Drooping Lilly sign - compression of lower moeity calyx

Ectopic Ureterocele - 99% assoc w complete duplication, UPPER sys
focal submucosal dilation of ureter within bladder wall
50% term in bladder & do not reflux
50% term in urethra, patulous orifices reflux w void
may dilate & obs adjacent lower pole moiety insertion
can also prolapse & cause bladder outlet obs
may present as mass protruding from vagina
6. Vesicoureteral Reflux - failure of UVJ valve
more freq in infants due to thinner bladder wall, rare in blacks
Adults - due to persistent short submuc seg & obtuse angle
Inflam of bladder wall can alter valve mech, infectious etc
Nuerogenic bladder, altered ureter peristalsis, transplant
Severe - detrusor contraction fills ureter rather than void
ureters thin & stretch, become flaccid

Reflux Nephropathy - Chronic Atrophic Pylonephritis, high Pressure I'
Pyelocaliectasis - dilation of prox system, NO assoc papillary calc
Dilation resolves w correction but calices clubbed perm
Medullary loss & cortical thinning as in chronic obs
GFR drops, proteinuria & HTN if not corrected
Parenchymal scarring II' to backflow into tubules & cortex
intrarenal reflux not uniform thru kidney, often subtle
vasc comprimise probable leads to scaring
permenant marked FOCAL thinning of cortex
Multifocal Scars at diff stages poss
Reflux Atrophy - sm smooth kid resulting from water-hammer
occurs when no infection complicates process
Most occurs during infancy when most susceptable
Remains I' cause of transplant in children
IVP - dec # of nephrons causes faint nephrogram, NOT prolonged

Hutch Diverticulum - ext bladder tic w ureter insertion
does not develop until adult, #2 in adults for reflux

Screening - after 1st UTI in infant male, post ureteral valves
girls older than 2yrs can have 2-3 w/o concern, debatable
radionucleitide cystogram has lower dose but less specific
IVP shows changes of Reflux Nephropathy most effectively
VCUG & IVP ideal combo for Dx

Grade I - reflux to part of ureter, no dilation
Grade II - reflux filling of entire system
Grade III - entire sys filled w mild dilation
Grade IV & V - progression from moderate to severe dilation
7. Ureteropelvic Junction Obstruction - many causes, one congen
Abnormallity in musculature at UPJ, dec number & maloriented
Prox renal pelvis dilated, freq abn musculature as well
Variable renal fxn w intermittent Sx often positional
distal ureter N

8. Nonobstructive Dilation - mult physiologic & congen causes, Reflux

Diabetes Insipidus - Caused by diminished ADH production
High Flow State results due to inability to concentrate urine
volume overwhelms peristalsis, calyces, ureter & bladder dilate

Congenital Megaloureter - dil due to abn distal ureter, 3:1 left, 20% bilat
Aperistaltic segment which does not expand for urine passage
Flouro - active peristalsis in dil segment, NO tortuosity or angulation
does usually allow passage of a catheter for retrograde
often asym but may have mild obstructive renal atrophy
N renal fxn in all but most severe cases
very slow if any progression of dilation
NO reflux or stenosis on involved side, contralat poss
Contralat agenesis, ectopia, duplication or ureterocele assoc

Post-Obstructive Atrophy - freq assoc w loss of renal fxn

Pregnancy - mechanical & hormonal, resolves in 6wks
think UTI if seen beyond 6wks

9. Ureteral Herniation - sciatic, inguinal or femoral poss
Sciatic #1, hairpin turn seen lat into sacrosciatic notch
Inguinal & femoral rare, but more likely to obs, can't vis
Internal herniation into fold of peritoneum between iliacs
cause sharp angulations

10. Vascular Impressions - N vasc, tortuos collateral or anuerysm
Ovarian Vein Syndrome - R side obs esp during pregnancy
late stages of preg due to uterus & iliac vessels not ov V

11. Prune Belly Syndrome - Eagle-Barret syn, sporadic & all male
Triad - Massively distended ureters cause pressure atrophy of abd wall
dilated bladder prevents testis from descending bilat
Functional abnormality of bladder emptying most common cause
chronic urinary tract problems, patent urachus, dysplastic kidneys
Obs of urethra - less freq, assoc w malrotation, atresia, CHD, CAM
death shortly after birth, post urethral valves rare

NON-NEOPLASTIC URETER PROCESSES

MURAL DISEASES OF THE URETER

Ureteral Diverticula - Rare, 2 distinct subtypes
Incomplete Duplication - solitary & unilateral
involves all layers or ureter, may be very long
Hyperplastic - buds of ureteral epithelium
usually does NOT project thru all layers of wall
Multiple & bilateral, less than 2mm in dia
High assoc w TCC
Periurethral Cysts - aquired diverticula of female urethra
probably occur II' to infection of periuretheral glands

Suburothelial Hemorrhage - hem into ureteral wall, very rare
assoc w coagulopathy, present w hematuria
IVP shows irreg filling defect, CT shows hem in wall

Amyloidosis - long irregular segments of ureteral narrowing
present w obs, no specific imaging findings

Crohn's - fistula from term ileum can extend to or displace
almost always right sided, may cause fistula
disrupted enteric absorbtion of Ca+ & oxalate causes Stones

TB - #1 cause of multiple strictures
hematogenous but most are from old calcified lung dz, years later
occurs downstream from renal involvement
creates cavities in the kidneys, can simulate papillary necrosis

Schistosomiasis - frequently causes calc of ureter when involved
TB & chronic pyelonephritis can also cause calc but rare

Endometriosis - long smooth stricture of distal ureter
stricture is not as long as would be expected w TB

BENIGN EPITHELIAL DZ OF THE URETER
1. Ureteritis Cystica - mult sm epithelial cysts in adults
occur II' to inflammation, UTI present or in HX
Brunn's Nests - growth of uroepithelium into tunical propria
Usually unilateral & in PROXIMAL 1/3
forms tiny pockets, mult diverticuli
Pyeloureteritis Cystica - pelvis involved as well
No clinical sig, may cause hematuria
DDx - hem into wall due to trauma, inc PT etc, transient
Aquired Diverticuli - continum w Uretritis cystica, Inc TCC

2. Malacoplakia - inflam process more often seen in bladder
soft subepithelial plaques, periph hyperemia, central ulcer
Michaelis-Gutman Bodies seen in large histiocytes, PAS positive
flatter than cystica, resolve w UTI Tx, 4:1 women
more freq distal, rare assoc w obs or stricture, not premalignant

3. Leukoplakia - more common in bladder & pelvis
Sqaumous metaplasia of urothelium, keratinizes & desquamates
Desquamated tissue may cause obs, mimics TCC

4. Stevens-Johnson Syn - erythema multiforme bullosa
large bulla can form in the ureter, may sim air bubbles

TUMORS OF THE URETER
80% of epithelial neoplasms in ureters are malignant
I' ca more common distal & in bladder, 30% multicentric

1. TCC - #1, 80% papillary, mural initially w irreg & thickening
Plaque possible w applecore appearance, worse prognosis
Goblet sign - sm papillary tumor in lumen distends DISTAL ureter
distended portion folds around mass & dist N ureter
5% assoc w bladder involvement, 25% multicentric in ureters
DDx - stones, look for calc or shadow on US, dislodge also
Clots resolve spontaneously, sloughed papillae
Transitional Cell Papilloma - benign variant consedered premalignant

2. Squamous Cell Ca - assoc w long hx of stones, luekoplakia etc
Sim to TCC radiologically, less likely to be polypoid
Schistosomiasis is predisposing

3. Mesenchymal Tumors - sarcoma of ureteral wall rare
Leiomyosarc, lymphosarc, hemangiosarc & spindle cell sarc
usually large at discovery

4. Fibroepithelial Polyp - fingerlike polyps of fibrovasc stroma
Not an epithilial neoplasm, probably inflammatory
covered by benign epithelium, asym or mild hematuria
rare obs, NO malig potential, young to mid adult
sim vermiform clot which usually resolve spontaneously

5. Mets - freq assoc w local extention or lymphadenopathy

6. Endometriosis - cyclic changes seen, may cause notching

RETROPERITONEAL TUMORS
Arterial supply usually from lumbar intercostals

1. Mesenchymal Tumors - Most not distinctive
Liposarcoma - variable fat element unique, hypovascular
If well diff fat seen in child it is a benign Lipoma
Leiomyosarcoma - may arise from or invade IVC
often simulates an intrarenal mass
Malignant Fibrous Histiocytoma - #1 in late adulthood
Lymphangioma - Acutually a congenital malformation, not tumor
Obs of lymphatic of groin & retroperitoneum
Tubular fluid filled structure
Usually on L where cisterna chyle located
Rhabdomyosarcoma - 15% occur in the lower GU tract in childhood
can present as a "cluster of grapes" protruding from vagina

2. Neural Crest Tumors - 80% of Paragangliomas adrenal
of the remainder 80% are retroperitoneal along parasym chain
50% malig - aggresiveness only defined by invasion
Variable secretion of Epi, Norepi & Metabolites
Paragangliomatosis - diffuse involvement of entire chain

3. Nerve Sheath Tumors
Schwannoma - Neruilemmoma, well encapsulated & homogeneous
No radiologic DDx from NF, germ cell etc
Neurofibroma - often expand neuroforamen

4. Germ Cell Tumors - only Teratoma distinctive, freq fat
"Shard like" calc, teeth rare, nodule on wall of cyst

5. Retroperitoneal Fibrosis - mult etiology, inflammatory process
Enhances particularly at periphery suggesting progression
Can form apparent mass over aorta & ureters, stops at iliacs
Ureters narrowed & drawn INWARD, seen in less than half of pts
severe failure can accompany minimal Dz, disrupts peristalsis
Poss etiology for hydronephrosis in Crohn's Dz
Methysergide & LSD are drugs implicated in etiology

6. Pelvic Lipomatosis - benign prolif of fat, elongates sturctures
Variant in young black males can be aggressive
causes inflam in bladder & colon
Ureters can be deviated either medial or lateral

RETROPERITONEAL SPACES
Retroperitoneal fibrosis II' to tumor, hematoma or ergot-alkaloids

1. Ant Pararenal Space - between post parietal peritoneum & ant renal fascia
contains the pancreas & retroperitoneal GI tract (Duo & Colon)
processes can communicate across midline via pancreas

2. Perirenal Space - ant border is Gerota'a facia & post is Zuckerkandl's fascia
medial borde5the great vessels
contains adrenals, kidney's, prox collecting sys & renal vessels

3. Post Pararenal Space - lies between post renal fascia & transversalis fascia
contains only fat

ADRENAL GLAND
G) Zona Glomerulosa - excretes aldosterone, salt control
F) Zona Fasiciulata - excretes Cortisol, sugar control
R) Zona Reticularis - excretes androgens, sex control (17-ketosteroids)
Medulla - paraganglionic cells excrete epi & norepi
Adenoma's - 2-5cm, well differentiated & hyper T2, Most nonfunctioning
seen in 2% of all autopsies, esp elderly obese diabetic women
Lung cancer the most common met

1. Cushing's Syndrome - excess cortisol
Moon face, buffalo hump, gynecomastia, hirsutism, diabetes
Precocious puberty in children, early physis fusion
Pituitary Cushings - 75% of cushing's due to pit adenoma
Basophilic adenomas of the ant pit gland
Causes diffuse or macronodular hyperplasia of adrenal
Ectopic ACTH from thymus etc causes 3%
Adrenal Hyperplasia - primary type causes 8% of cushings
Adrenal Adenoma - <4cm, accouts for 15% of cushings
Adrenal Carcinoma - >4cm, 5% of cushings

2. Addison's Dz - insuff cortisol, not a radiologic Dx
Assoc Small gland indicates adrenal atrophy
poss due to autoimmune, 25% have calcified adrenals
Assoc lg gland indicates inflam process or hem
Granulomatous Dz - TB or histo
Mult types of bacterial or viral infection

3. Conn's Syndrome - Hyperaldosteronism, most due to pit adenoma
HTN caused by Na+ retention, K+ dumped, low renin levels, weakness
Surgery usually curative if nodule identified
Adrenal Hyperplasia - causes 20%, DDx w adrenal vein sampling
often includes cells thruout retroperitoneum
Aldosterinoma - usually subcapsular, <3cm, 95% unilat in 30y/o
HTN from Hypernatremia & Hypokalemia causes dec Renin levels
adrenal vein sampling easily distinguishes from pheo or neuroblastoma
Nucs - Iodocholesterol scan can help loc hyperfxn region
CT - mult renal cysts assoc, resolve w Tx

II' Aldosteronism - caused by excessive secretion of RENIN
4. Pheochromocytoma - Adrenal medullary sym paragang cell, Chromaffin
Rule of 10 - 10% calc, 10% are extra adrenal, 10% bilat, 10% malig
2nd most common site is aortic bifurcation (organ of Zuckerkandel)
CT - well encapsulated & usually 4-5cm at presentation
Hypervasc but contrast can precipitate HTN crisis
premedicate w alpha-blocker phentolamine
Dx w 24hr urine vanilmandelic acid, plasma levels variable
Glucagon stim test also
Assoc w MEN II, Neurofibromatosis 1% & vonHippel Lindau 10%

5. Neuroblastoma - #1 abdominal mass in infancy, 12%
25% <1yr, 50% before 2yrs, 90% before 8yrs, equal sex incidence
may present intruterine, catecholamine excess in mother
Neural crest origin, sm round cells, central neurofibrillary tangles
30% adrenal, 10% bilat, can occur anywhere in sym chain
CT - lobulated & heterogeneous, 70% have stippled calc
30% invade kidney & retrocrural nodes at Dx
extend across midline in 50%
NUCS - take up I-123 MIBG & Tc-99m MDP
Stage I - limited to organ, II - does not cross midline
III - cross midline, IV - mets to nodes, liver & bone
IVs - mets but NO bone involvement, best prognosis?
Mets - 60% to bone, 40% to nodes, 10% to lung & liver
Blue-berry Muffin Syndrome - mult mets to skin
Hutchinson Syndrome - extensive skeletal mets esp to skull
Younger pts much more likely to survive, 60% <1yr, 10% >2yr
overall 80% survivial for stage I, 10% for stage IV
Ganglioneuroblastoma - more mature form, sim age range, rare
tends to occur in post mediastinum & abdomen
Ganglioneuroma - benign differentiated form, .02% convert to this
occur primarily in older pts, 60% <20yrs though
Ganglioneuromatosis - GI form assoc w MEN IIb

6. Myelolipoma - rare, bone marrow tiss which may bleed, most asym
US - may show echogenicity but often too small to see fat component
CT - shows fat component w HU of -20, fat is diagnostic
does not need resection if fat can be demonstrated
must DDx from retroperitoneal lipoma or liposarcoma
myeloid elements or contrast may obscure fat & prevent Dx
Angio - NOT vascular, DDx from vascular renal angiomyolipomas
Endocrine abnormalities NOT assoc sez ACR #22 & Amis
7. Precocious Puberty - Adenoma of Zona Reticularis
Congenital adrenal hyperplasia also poss
Low Aldosterone assoc

8. Hemangioma - can create lg peripheral enhanced lesion
Look for phleboliths

9. Adrenal Cyst - usually congenital or post traumatic, most asym
Low density w peripheral calc poss

10. Wolman Dz - Auto rec lipomatosis, pediatric, death by 2-3mo
accum of fat in viceral foam cells
extensive punctate calc thruout bilat enlarged adrenal glands
hepatosplenomegaly & generalized osteoporosis

11. Adrenal Calcification - usually due to neonatal hem, small & atrophied
25% of Addison's Dz, also small atrophied gland
Enlarged & calcified is bad - 30% of cortical carcinoma
Adenoma's rarely calcify
DDx - lymph node or pancreatic calc


ADRENAL ADENOMA Vs METASTISIS
Adenomas - occur in up to 85% of N population, mets <1%
slow or no growth, very rare to grow >5cm
CT - very low density usually, should be <20, Dr. Amis asked me this on orals
MRI - Chemical Shift Imaging w In Phase/Opposed Phase scans
adenomas contain some fat so it is hypointense out of Phase
Fat suppresion shows dark center w residual bright rim

Mets - occur in 25% of pts w epithelial primaries
Rapid doubling time, often >5cm
CT - tend to be denser
MRI - Chemical Shift Imaging shows no signal change
Bright/Bright Bad - no fat content when bright on opposed phase
no change w fat suppresion scan

MULTIPLE ENDOCRINE NEOPLASIA
Familial Auto Dom adenomatous hyperplasia
cells of principle organs all derived from neural crest
Amine Precursor Uptake & Decarboxylation - APUD cells

MEN I - Wermer Syndrome, PPP occurs in 40%
Parathyroid Hyperplasia, 90%
Pancreatic Islet Cell tumor, 80%
Gastrinoma #1, insulinoma or VIPoma
Pituitary Adenoma, 40%
Assoc - Adrenal Cortical tumors & thyroid tumors seen in 20%
carcinoid, lipoma, thymoma & Menetrier's also

MEN IIA - Sipple Disease, PMP
Parathyroid Hyperplasia - can also be adenoma but less common
Medullary Carcinoma of Thyroid
Pheochromocytoma - often bilateral
Assoc - Carcinoid tumors & Cushings

MEN IIB - Mucosal Neuroma Syndrome, GMP
Ganglioneuromatosis - oral & intestinal, usually 1st manifestation
thickened plaque like colonic wall, dil & abn haustra
thickened lips due to submucosal nodules
Medullary Carcinoma of Thyroid
Pheochromocytoma

INFLAMMATORY PROCESSES IN THE BLADDER

1. Brunn's Nests - #1 pathological change assoc w chronic inflam, 90%
solid nests of urothelial cells lying in the lamina propria
Assoc w Pelvic Lipomatosis & any cause of inflam
Cystitis Cystica - nests of cells undergo cystic degeneration
Cystic rests develop causing mult filling defects, thickening
Cystitis Follicularis - cysts assoc w submucosal lymphoid aggregates
especially in children w UTI
Cystitis Glandularis - metaplasia to glandular structures
mucin secreting, precancerous
Hemorrhagic Cystitis - assoc w Cyclophosphamid Tx

2. Luekoplakia - keratinizing squamous metaplasia, premalignant
80% caused by chronic infection, assoc w stones in 40%
1:1 sex dist in renal pelvis, but 4:1 male in bladder

3. Malakoplakia - atypical granulomatous Rxn to UTI
Female age 40-60 w E. Coli infection, cannot diff from TCC
Michaelis-Gutman inclusion bodies seen in cells

4. Emphsematious Cystitis - Gas within badder & wall
Assoc w DM & ascending coliform infection
Not a surgical emergency, give Abx & control diabetes

5. Crohn's Dz - TI may fistulize to bladder
actually more common to have fistula from colon tic rupture

6. Shistosomiasis - Hematobium variant from africa lays eggs here
diffuse stranded calc, thickening & metaplasia of wall
Inc Squamous cell Ca

BLADDER NEOPLASMS

1. Benign - very rare and cannot be distinguished from malig
Usually Non epithelial, Leiomyoma #1, Hemangioma
Pheochromocytoma, Nephrogenic Adenoma, Fibroepithelial polyp
Papilloma - assoc w external involvement

2. Transitional Cell Ca - 90% in adults, smoking inc risk 5x
60% present w painless hematuria & frequency
Risk Factors - Aniline Dye, pelvic rad & employees in plastic industry
Irreg filling defect, NO calc, US & IVP do not show extent
CT - shows mass, extent into perivesc fat & nodes
most common in post lat aspect near trigone
Cloacogenic Ca - origin at pectinate line, most are transitional cell

3. Squamous Cell Ca - 8% in adults, assoc w chronic inflam
UTI, Calculi, Schistosomiasis, Chronic instrumentation

4. Adenocarcinoma - <2%, assoc w urachal cysts mostly

5. Sarcoma - non-epithelial neoplasm very rare

6. Rhabdomyosarcoma - #1 in child, poor prognosis
2:1 male, 75% occur in children <5yrs, 25% of all child sarcomas
20% occur in bladder at trigone, 30% occur in head & neck
present as Large intraluminal filling defects
Embryonal Rhabdomyosarcoma - most common subtype, >50%
"Sarcoma Botryoides" cluster of grapes most freq app
Alveolar Rhabdomyosarcoma - worst prognosis
Peomorphic Rhabdomyosarcoma - occur mostly in adults
Angio - very vascular tumors

7. Endometriosis - urinary tract involved in 2%, bladder #1 site
present w monthly hematuria, DDx from Ca diff, MRI helpful

8. Urachal Carcinoma - adenoca which invades from outside, 75% male
Present w mucous in urine, poorer prognosis than TCC
70% calcify, less than 1% of TCC calcifies

DDx for filling Defect - Neoplasm, stone, clot, fungus ball
Sloughed papilla, Endometriosis

BLADDER TRAUMA

1. Intraperitoneal Rupture - 20%, surgical emergency if in peritoneum
rupture occurs at the ureterovesicular jxn
lap belt injury in child, bladder protrudes from pelvis

2. Extraperitoneal Rupture - 80%, usually close to base of bladder
loss of obturator fat planes, upward displacement of ileal loops
Tx w decompression & medical manage
usually a urethral injury assoc

BLADDER OUTPOUCHINGS

1. Congenital Bladder Diverticulum - "Hutch" diverticulum
herniation of mucosa thru detrusor musc
Assoc w ureteral obs & reflux

2. Acquired Bladder Diverticulum - Usually caused by obs
Assoc w BPH, Prostate Ca, Neropathic Bladder, Urethral stric
Stasis leads to infection, stones, bleeding, inc Ca
may cause ureteral obs & reflux

3. Urachal Cyst - Persistent connection of bladder to umbilicus, Allantois
Only present when infected, Fist or tic much less common
Cyst epithelium undergoes metaplasia to glandular epi
85% of Urachal Carcinoma is Adenoca, freq dystrophic Calc
IVP - best seen in prone position, occurs on superior margin
Urachus usually patent in prune belly syn

4. Bladder Hernias - usually thru inguanal or femoral rings
Paraperitoneal most common, intraperitoneal or extraperitoneal poss
can present as a scrotal mass

5. Bladder Extrophy - complete defect in urogenital sinus & overlying bone
IVP - distal ureters are "hockey stick" shaped
Rectus Abdominus muscles & pubic symphysis widely seperated
Epispadius - lesser degree of the same process, less spread of the symphysis
post urethral valves, cryporchad, vaginal stenosis, bifed clitoris also assoc
Assoc w Adenoca of bladder not TCC

6. Pear Shaped Bladder - due to lat pressure, lymphoma, pelvic lipomatosis
pelvic hematoma, hypetrophied ileopsoas muscles
IVC thrombosis - also causes vasc notching of the ureters, good for DDx

URETHRA
exits from inf trigone, females may have promenince
Post Urethra - 3cm, transitional eipthelium, TCC poss
Prostatic - Verumontanum within, entry for ejaculatory ducts
Membranous Urethra- 1cm segment traversing the urogenital diaphragm
starts at end of verumontanum & ends at cone of bulbous urethra
External Sphincter - within urogenital diaphragm
Ant Urethra - stratified columnar epi, squamous cell poss
Bulbous portion - prox dilation P leaving pelvis
Cowper's glands empty into porximal bulbous urethra
Pendulous - penile portion, glands of littre seen along dorsal portion
Fossa Navicularis - dilated distal 2cm of penile urethra

Posterior Urethral Valve - #1 cause of outflow obs
Mucosal flap at jxn of membranous to ant urethra
VCUG - shows dilation of prostatic portion
Assoc w reflux, hydronephrosis & renal dysplasia
Type I - #1, fold from inf verumontanum dist to mem urethra
Type II - verumontanum prox to bladder neck
Type III - horizontal membrane at level of origin of mem urethra
#1 cause of Urine Ascites in a newborn, rupture at fornix of calyx

Anterior Urethral Valve - obs w prox dilation, rare
sim Wide mouth dist urethral diverticulum

Trauma - blunt or surgical #1, develop rapidly to stricture
Type I Injury - prostatic urethra stretched but not torn
Type II - rupture between prostate & urogenital diaphragm
urine leaks extraperitonealy, does not leak into perineum
Type III - tear extends into urogenital diaphragm
leaks into both spaces
Rupture inferior to urogenital diaphragm
Buck's facia contains hem, if this is ruptured scrotum swells

Stricture - post trauma #1 cause, develop rapidly
Congenital Stricture - do occur w short seg involved
Inflam stricture #2 - Gonococcus, TB, Shisto, usually bulbous
begins in glands of littre, beaded long seg strictures
Squamous Cell Ca - rare, most commonly II' to mult strictures

Urethral Diverticuli - most commonly due to trauma from foley
almost all are in the ant urethra
Urethral Atresia - Assoc w prune belly, rare

Condyloma Acuminata - inflammatory papilloma, assoc w ext warts
cannot DDx from Ca, can degen to Squamous Cell Ca

Urethral Carcinoma - 80% Squamous, 15% TCC
Decrease risk if strictures resected
Squamous Cell Ca - 80% of urethral carcinoma, ant due to epi type
60% in bulbous urethra, 40% in penile
TCC - also occurs but rare, occurs in post urethra
60% bulbomembranous, FEMALES more common due to irritation

Glands of Littre - located in pendulous penile urethra
can become infected, esp w gonococci

Cowper's Glands - lie along bulbous urethra
empty into proximal bulb, preejaculatory spuge

Detrusor-Bladder Neck Dysynergia - cord lesion at T7 or level of conus
detrusor musc contracts but bladder neck & ext sphincter don't relax
VCUG - minimal opening in post urethra

Detrusor-Sphincter Dysynergia - cord lesion between pons & conus
Detrusor contracts, bladder neck relaxes but ext sphincter won't relax
VCUG - balloning of prox prostatic urethra, narrowed dist half

Periurethral Cyst - aquired diverticuli of female urethra
probably result from infection of the periurethral glands

Bilateral Obstruction - #1 cause is tumor
extention from prostate, colorectal or gyn neoplasms

Renal Sinus Hemorrhage - most due to anticoag therapy
soft tissue density seen in renal sinus & suburothelium.

CONTRAST AGENTS
Best attenuation at 70kVp
All contrast agents are filtered by the glomerulus
hyperosmolar contrast draws fluid out of renal parenchyma
this causes inc vasodilation & transient inc in blood flow
peak excretion at 3min

1. Ionic Contrast
Sodium Salts - reabsorbed in prox tuble, result in less urine vol
Iodine concentration increases, better for IVP?
Meglumine Salts - Not reabsorbed, inc vol of urine
Iodine concentration decreases
less toxic to endothelium & neural tissue than Na+ salts
Heart Cath - both ionics induce V-fib if used alone
must have Na+/meg mix, even better is Non-Ionic

2. Non-Ionic Contrast - low osmolality, results in less urine vol
Iodine concentration increases
fewer EKG changes & decreased endovascular disruption

3. Renal Failure - inc in assoc w myeloma or hypergammaglobulinemia
Diabetes & hyperuricemia also

4. Uricosuric - ALL contrast agents precipitate urate
can cause acute acute urate nephropathy
can also precipitate Bence Jones protiens seen w mult myeloma

5. Pheochromocytoma - arterial contrast injection can cause HTN crisis
pretreat w alpha-blocker phentolamine


ACUTE CONTRAST REACTIONS
Uticaria - watch, benedryl, zantac
Facial Edema - O2, monitor, Epi 1:1000 .1ml SQ
Bronchospasm - Epi SQ first, then Epi 1:10,000 1ml IV, CODE if sat <90
Hypotention w Tachy - Trendelenberg, O2, LR, Epi, Epi
Hypotention w Brady - Trendelenber, O2, LR, Atropine 1mg IV X 2
never give <.5 of atropine IV, it may have a reverse effect
Hypertention - Hydralazine 5mg IV
Pheochromocytoma Contrast Rxn - Phentolamine 5mg IV
Seizure - Valium 5mg IV
Edema - Lasix 40mg IV, Morphine 2mg IV