Obstructive Uropathy
Definition
Obstruction of Urinary Tract
Lead to Renal Impairment
Classification
Causes – Congenital, Acquired
Duration – Acute, Chronic
Degree – Partial, Complete
Level – Upper Urinary Tract, Lower Urinary Tract
Anatomy
Aetiology (Causes)
Congenital Acquired
Congenital Narrowing
Meatal stenosis
Distal urethral stenosis
Posterior urethral valve (PUV)
Ectopic ureters
Ureterocoeles
Ureterovesical (VUJ)
Ureteropelvic Junctions (PUJ) Stenosis
Urethral stricture (Infection, Injury)
Benign Prostatic Hyperplasia (BPH)
Prostate Cancer
Bladder Tumour
(Bladder neck, Ureteral orifices)
CaP, Cervical cancer (CaCx)
(extension into base of bladder
occluding ureters)
S2-S4 Sacral Root Damage
Spina Bifida
Myelomeningocoele
Compression of Ureters at Pelvic Brim
by metastatic nodes from CaP, CaCx
Ureteral Stones
Vesicoureteric Reflux (VUR) Retroperitoneal Fibrosis
Malignant Tumour
Pelvi-Ureteric Junction (PUJ) Obstr.
Pregnancy
Neurogenic Bladder
Stones
VUR
Staghorn Calculi
Bilateral VUR due to PUV
Bilateral VUR 2° to
Prune Belly Syndrome
Bladder Outlet Obstruction (BOO)
Tumours
Stricture
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Pathophysiol ogy
Obstruction, Neuropathic Bladder Dysfunction
have same effects on GUT
Lower Tract Upper Tract
(Ureter, Kidney)
Distal to Bladder Neck
Severe external urinary
meatal stricture
BPH
Bladder
BPH
Lower Tract Changes (Bladder)
Obstruction
↓
↑ Hydrostatic Pressure
↓
Dilation of Urethra
↙ ↓ ↘
Diverticulum Prostatic Duct Dilation Infected Urine
↓
Extravasation
↓
Periurethral Abscess
2 Stages
Compensation Decompensation
Bladder musculature Hypertrophy
(to balance ↑ urethral resistance)
Decompensation of
Detrusor Muscle results in
presence of Residual Urine (RU)
after voiding
Trabeculation of Bladder Wall
Cellules
Diverticula
Mucosal changes
Trabeculation of Bladder Wall
Normal Mucosa – Smooth
Hypertrophy ↓
Individual muscles bundle become taut
↓
Coarse interwoven appearance
Trigonal muscle, Interureteric ridge Hypertrophy
↓
↑ Resistance urine flow in Intravesical ureteral segments ↓
Functional obstruction of VUJ
↓
Back Pressure on Kidney
↓
Hydroureter, Hydronephrosis
Obstruction ↑ in the presence of Significant Residual Urine
Cellules
Mucosa between Superficial Muscle Bundles is Pushed
↓
Formation of Small Pockets (Cellules)
Diverticula
Cellules force through entirely the musculature of Bladder Wall
↓
Saccules ↓
Diverticula
May be embedded in Perivesical Fat or covered by Peritoneum
(depending on location)
Unable to expel content efficiently into Bladder after 1° obstruction has been removed
(No Muscle Wall)
Upper Tract Changes
Hydroureter (HU)
Hydronephrosis (HN)
Ureter
Early Stages Late Stages
Intravesical Pressure is Normal when
Bladder fills
Pressure ↑ only in Voiding
Decompensation + Residual Urine
↓
Added Stretch Effec t ↓
Incompetence of VUJ valves
↓
VUR
↓
Further Hyd roureteronephrosis
Pressure is not Transmitted to
Ureters, Renal Pelves because
competence of VUJ valves
Trigonal Hypertrophy
↓
↑ Resistance Urine Flow
↓
Progressive Back Pressure on
Ureter, Kidney
↓
Hydroureter, Hydronephrosis
2° to Back Pressure
(due to reflux, obstruction)
↓
Ureteral Musculature Thickens
(push urine downward by peristaltic
activity – Compensation Stage)
↓
Elongation, Tortousity of Ureter
Fibrous tissue band formation ↓
Further Angulate Ureter
(during contraction) ↓
2° Ureteral Obstruction
At this stage, removal of obstruction below
may not prevent Kidney from undergoing
progressive obstruction
Ureteral Wall Attenuated
(due to ↑ Pressure)
↓
Contractile Power is Lost
(Decompensation stage)
↓
Severe Ureteral Dilatation
(like Bowel Loops)
Kidney
Normal Kidney Pressure ≈ 0
When Pressure ↑ - Pelvis, Calyces Dilate
(depend on duration, degree, site)(the higher, the greater effect on Kidney)
If Intrarenal Pelvis - Parenchyma affected (compared to extrarenal)
Early Stage Later Stage
Pelvic musculature Hypertrophy
(to force urine past obstruction)
Muscle become Stretched
↑ Atonic (Decompe nsated)
Progression of Hydronephrotic Atrophy
Earliest change – Calyceal Hydronephrosis
With ↑ Pressure, Normal Concave Calyx
become Flattened then become Convex (clubbed)
Renal Parenchymal changes due to
• Compression atrophy (from ↑ Intrapelvis Pressure)
• Ischaemic Atrophy (from Haemodynamic changes)
(manifested in Arcuate vessels that run at base of Pyramids) → Spotty Atrophy
Tubules become Dilated
Cells Atrophy from Ischaemia
Hydronephrosis (unusual type of Pathologic change)
Only in Unilateral Hydronephrosis
Advanced stages of Hydronephrotic Atrophy is seen
Eventually, Kidney become
Completely Destroy ed
Appears as Thin-Walled Sac filled with Clear Fluid, Pus
↑ Intrarenal Pressure
Cause Suppression of Renal Function
The Closer Intrapelvic Pressure approaches Glomerular Filtration Pressure
The ↓ Urine can be secreted
GFR, RBF ↓
Concentrating Power is Gradually Lost
Urea/Creatinine Ratio ↓ (compared to Normal Kidney)
Completely Obstructed Kidney
Continue to secrete Urine (which is reabsorbed via Tubules, Lymphatics)
(Normally – other secreting organs – cease sec reting when completely obstructed)
Intrapelvic Pressure ↑ Rapidly
↓
Extravasation of Urine from Renal Pelvis into Parenchymal Interstitium
(reabsorbed by lymphatics)
↓
↓ Intrapelvic Pressure
(Allow Further Filtration)
Compensation
Markedly Hydronephrotic Kidney continue to Function
Does not contain true urine (only H2O, Salts)
As Unilateral Hydronephrosis Progress
Normal Kidney undergo compensatory hypertrophy (Maintain Total Renal Function)
Successful Anatomical Repair of Obstruction of Kidney
Fail to Improve Powers of Elimination
If Both Kidney Equally Hydronephrosis
Strong Stimulus Continually Exerted on Both to Maintain Maximum Function
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Clinical Features
Loin Pain (due to Capsule Stretch, Presence of Calculus, Infection)
Ureteric, Renal Colic
Complete Anuria
Complete Bilateral Obstruction
Complete Obstruction of Single Functioning Kidney
Polyuria
Partially Obstruction – impairment of Renal Tubular Concentrating Ability
Hematuria (Microscopic/ Occult)
Urinary Stones
Malignancy
Infection
Uraemia
Bilateral Obstruction, Obstruction of a solitary Kidney
Results in
• Weakness
• Pallor
• Weight Loss
• Peripheral Edema
• Mental status change
Investigations
KUB X-Ray
Renal Function Test (RFT)
Urine
Full Microscopic Examination (FEME)
Culture, Sensitivity (C&S)
Ultrasound
KUB
Urinary Tract
Intravenous Urography (IVU)
CT Urography/ CT Renal Protocol
Retrograde Pyelography (RPG)
Antegrade Pyelography (APG)
DTPA
DMSA
Treatment
Aims
Relieve Obstruction
Treat Underlying Cause
Prevent, Treat Infection
Relief Symptoms
Preserve Renal Function
Depend on
Degree of Obstruction
Renal Impairment
Infection
Site of Obstruction
Expeditious Intervention, Hospitalization
Complete Obstruction
Obstruction of a Solitary Kidney
Infection (Fever, Leukocytosis, Bacteriuria)
Azotemia
Uncontrolled Colic Pain
Nausea, Vomiting, Dehydration
Medical Treatment
Analgesics Antibiotics
Voltaren Bactrim
Pethidine Trimethoprim
Zinnat
Ciprobay
Recovery of Function
Depend on
Degree of Obstruction
Duration of Obstruction
Prevent Renal Impairment
Relief of Complete Urinary Obstruction should be achieved expediently
Decompress Urinary System Temporarily
Temporary Drainage device
Until Management can be executed
Obstruction & Infection
Urological emergency
Require
• Immediate relief
(Foley Catheter, Ureteral Stent, Percutaenous Nephrostomy Tube)
• Broad spectrum Antibiotics (prevent Life-threatening Urosepsis)
Relieve Obstruction (Decompress Upper Tract Obstruction)
Ureteral Stent Percutaenous Nephrostomy
Small tube
Renal Pelvis → Bladder
(placed endoscopically, with
Fluoroscopic guidance )
Small Tube
Placed through Flank
Directly into Renal Pelvis
(percutaneously by Urologist,
Interventional Radiologist) Performed in Operating Room (OR)
Under Local Anaesthesia (LA)
Adequate Sedation
Require only Local Anaesthesia (LA)
Complications
Pyelonephritis, Pyonephrosis
(eg. gross pus within obstructed renal pelvis of a funtionless kidney)
Abscess formation
Urosepsis
Urinary Extravasation with Urinoma Formation
Urinary Fistula Formation
Renal Parenchymal Loss
(long term obstruction leading to renal insufficiency, failure)
Pyonephrosis
Prognosis
Depend on
Cause
Site
Degree (partial, complete)
Duration of Obstructive process
Presence of Concomitant Infection
Favourable Prognosis Expected if
Renal Function Good
Obstruction Corrected
Infection Eradicated
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