Hydronephrosis is the dilatation of the renal pelvis or calyces, which can be associated with obstruction. It has various causes including extramural obstruction from aberrant vessels or tumors, intramural obstruction from congenital issues or tumors, and intraluminal obstruction from stones or papillary necrosis. Bilateral hydronephrosis can result from urethral obstruction or issues affecting both kidneys. Imaging studies are used to diagnose and characterize hydronephrosis. Long term obstruction can lead to thinning of the renal parenchyma and loss of kidney function.

1. Hydronephrosis
SUNILKUMAR.P

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Definition
• Hydronephrosis is the aseptic dilatation ofthe
renal pelvis or calyces.
• It may be associated with obstruction butmay
be present in the absenceofobstruction.
• There is accompanied destruction of kidney
parenchyma.

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4. Types of Obstruction
• SUDDEN
• INSIDIOUS,
• PARTIAL or COMPLETE,
• UNILATERAL or BILATERAL;

6. Obstructive lesions of the
urinary tract

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Etiology
• It canbe Unilateral orbilateral.
• Unilateral maybe extramural, intramural or
Intraluminal
• Bilateral causesare either congenital or
acquired

8. Unilateral hydronephrosis
• Bysome form of ureteric
obstruction, with theureter
above the obstructionbeing
dilated.
Causes
A. Extramural obstruction
B. Intramural (in thewalls)
C. Intraluminal
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Causesof Unilateral hydronephrosis
A. Extramural
1. Obstruction byAberrant renal vessels(vein or
artery). It is common on leftside.
2. Compression by growth ( CAcervix, carcinoma
rectum)
3. Retroperitoneal fibrosis (Ormond disease)
4. Retrocaval ureter

10. B.Intramural
1. Congenital PUJobstruction
2. Ureterocele
3. Neoplasm of ureter
4. Narrow ureteric orifice
5. Stricture ureter following removal of stone,pelvic
surgeries or tuberculosis of ureter.
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11. C.Intraluminal
1. Stone in the renalpelvis
2. Sloughed papilla in papillary necrosis
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12. Bilateral Hydronephrosis
• Result of urethral obstruction ; butmay also
be causedby one of the lesions described
above occurring on both sides
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Causesof Bilateral hydronephrosis
A. Congenital
• Congenital stricture of external urethral meatus, pin-hole
meatus.
• Congenital posterior urethral valve.
B. Acquired
• BPH
• Carcinoma prostate
• Postoperative bladder neckscarring
• Inflammatory / traumatic urethral stricture
• Phimosis
• Carcinoma cervix
• Bladder carcinoma

14. Classification
• Classification I
—UnilateralHN
—Bilateral HNwithout renalfailure
—Bilateral HNwith renalfailure
• Classification II
– Intermittent HN
– Persistent HN
• Classification III
– HNonly
– HNwith hydroureter
• Classification IV
– Extrarenal pelvic HN(80%)
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15. PATHOHYSIOLOGY

20. MORPHOLOGICAL FEATURES
The pathologic changes vary depending
upon whether the obstruction is sudden and
complete, or incomplete and intermittent.

21. Gross findings
 The kidneys may have moderate to marked
enlargement
 Extra renal hydronephrosis
 Dilatation of renal pelvis medially in the form
of sac
 Atrophy of renal parenchyma
 Advanced stage is called intra renal
hydronephrosis

24. Microscopic findings
• The wall of hydronephrotic sac is thickened due
to fibrous scarring and chronic inflammation.
•There is progressive atrophy of tubules and
glomeruli along with interstitial fibrosis.
• Pyonephrosis.

25. Laboratory Studies
Urinalysis----- Hematuria
Pyuria
CBC---- Leukocytosis
Biochemical--- Elevated BUN, creatinine,
hyperkalemia.

26. Imaging studies
1. USG
2. CT SCAN
3. MRI SCAN
4. diuretic renography
5. radionuclide renal scanning
6. perfusion pressure flow studies
7. A voiding cystourethrography (VCUG) is performed to
detect VUR
8. Gravity-assisted drainage imaging
9. Magnetic resonance urography (MRU)