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
- Tumour
- 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
- Congenital:
- Bilateral UPPER URINARY TRACT OBSTRUCTION
- Idiopathic retroperitoneal fibrosis
- Idiopathic pelviureteric junction obstruction
- PREGNANCY
- Effects on ureteric smooth muscle due to high levels of progesterone
Pathophysiology
- 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
Clinical features
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
- Impalpable kidneys: As renal failure intervenes before enlargement
Complications:
- UTI
- Postrenal Azotemia
Diagnosis
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
Management
Mild cases:
- Serial USG scans
- Operate if dilatation increases
Moderate-severe cases:
- Pyeloplasty (Anderson-Hynes operation)
- Upper-third of ureter & renal pelvis anastomosis
- Anastomosis protected by:
- Nephrostomy tube
- Ureteric stent
- Anastomosis protected by:
- Upper-third of ureter & renal pelvis anastomosis
- Endoscopic pyelolysis
- Disruption of pelviureteric junction by a balloon passed up ureter under radiographic control
Destruction of kidney:
- Nephrectomy