Hydronephrosis - An overview

Contents

Aseptic dilatation of kidneys due to obstruction.

Etiology

Unilateral hydronephrosis:

IDIOPATHIC pelviureteric junction obstruction (M/C)
EXTRAMURAL OBSTRUCTION
- Tumour
  - From adjacent structures (Cervix, prostate, rectum, colo or caecum)
- Idiopathic retroperitoneal fibrosis
- Retrocaval/circumcaval ureter
INTRAMURAL OBSTRUCTION
- Congenital stenosis
- Ureterocele & congenital small ureteric orifice
- Inflammatory stricture
  - Following removal of ureteric calculus or repair of damaged ureter
  - Due to tuberculous infection
- Neoplasm
  - Ureter cancer
  - Bladder cancer involving ureter
INTRALUMINAL OBSTRUCTION
- Calculus in pelvis/ureter
- Sloughed papilla
  - In papillary necrosis (esp. in DM, analgesic abuse, sickle cell anaemia)

Bilateral hydronephrosis:

LOWER URINARY TRACT OBSTRUCTION
- Congenital:
  - Posterior urethral valves
  - Urethral atresia
- Acquired:
  - Benign prostatic enlargement or carcinoma of prostate
  - Postoperative bladder neck scarring
  - Urethral Stricture
  - Phimosis
Bilateral UPPER URINARY TRACT OBSTRUCTION
- Idiopathic retroperitoneal fibrosis
- Idiopathic pelviureteric junction obstruction
PREGNANCY
- Effects on ureteric smooth muscle due to high levels of progesterone

Severe long-standing hydronephrosis → Nephron destruction → Increased serum creatinine & electrolyte imbalance
Blockade → Dilated ureter & renal pelvis + medullary & cortical thinning
KIDNEY
- Calyceal dilatation + pressure atrophy
- Thin-walled, lobulated, fluid-filled sac

Unilateral hydronephrosis:

Asymptomatic
Mild pain/dull aching in loin
- Dragging heaviness worsened by excess fluid intake
Palpable kidney
Dietl’s crisis: Intermittent hydronephrosis (loin swelling) + acute renal pain
- Pain & swelling goes away as large volume of urine is passed
Antenatal detection
- By USG

Bilateral hydronephrosis:
Symptoms of bladder outflow obstruction predominate

Complications:

Imaging:

Foetuses/infants
- Prenatal ultrasound
Intravenous Urography (IVU) or Pyelography
Isotope renography: Best imaging modality
- MAG3 scan: Best for assessing renal function
- DMSA scan: Best for assessing scarring
CT Scan

The Society of Foetal Ultrasound Grading:

Grade 0 – no dilation with calyceal walls apposed
Grade 1 (mild) – dilation of the renal pelvis without dilation of the calyces nor parenchymal atrophy
Grade 2 (mild) – dilation of the renal pelvis and calyces without parenchymal atrophy
Grade 3 (moderate) – moderate dilation of the renal pelvis and calyces with blunting of the fornices and flattening of papillae
Grade 4 (severe) – gross dilation/ballooning of the renal pelvis and calyces with loss of borders between the renal pelvis and calyces and renal atrophy seen as cortical thinning

Mild cases:

Moderate-severe cases:

Pyeloplasty (Anderson-Hynes operation)
- Upper-third of ureter & renal pelvis anastomosis
  - Anastomosis protected by:
    - Nephrostomy tube
    - Ureteric stent
Endoscopic pyelolysis
- Disruption of pelviureteric junction by a balloon passed up ureter under radiographic control

Destruction of kidney: