DISORDERS OF URETER – Causes and Risk Factors, Classification, Pathophysiology, Clinical Manifestations, Diagnostic Evaluations and Management

URETERAL STRICTURE

A ureteral stricture is characterized by a narrowing of the ureteral lumen, causing functional obstruction. The most common cause of ureteral stricture is ureteropelvic junction (UPJ) obstruction, which is characterized by a congenital or acquired narrowing at the level of the UPJ.

CAUSES AND RISK FACTORS

Strictures can have several origins:

• They may develop after treatment for another urologic condition. Individuals who have undergone ureteroscopic or percutaneous kidney treatment for stones or tumors, pelvic radiation therapy or urinary diversion surgery may develop ureteral strictures. After these procedures, scar tissue may obstruct the ureter.
• Other surgeries in the vicinity of the ureters can cause stricture formation, such as gynecologic or vascular surgery procedures.
  
• Strictures may occur after passage of kidney stones or as a result of certain cancers
  
• External traumatic injury can cause strictures
  
• In children, congenital anomalies may result in strictures
  

CLASSIFICATION

Ureteral strictures may be classified as extrinsic or intrinsic, benign or malignant, and iatrogenic or non-iatrogenic. Extrinsic malignant strictures include those caused by primary or metastatic cancer. Primary pelvic malignancies, particularly cancers of the cervix, prostate, bladder, and colon, frequently cause extrinsic compression of the distal ureter. Retroperitoneal lymphadenopathy, caused by a wide range of malignancies, particularly lymphoma, testicular carcinoma, breast cancer, or prostate cancer, may cause proximal to midureteral obstruction. Extrinsic benign compression due to idiopathic retroperitoneal fibrosis may also cause unilateral or bilateral ureteral obstruction, leading to azotemia.

 

PATHOPHYSIOLOGY

Ureteral strictures are typically due to ischemia, resulting in fibrosis. Wolf and colleagues define a stricture as ischemic when it follows open surgery or radiation therapy, whereas the stricture is considered nonischemic if it caused by spontaneous stone passage or a congenital abnormality. Less commonly, the etiology is mechanical, such as from a poorly placed permanent suture or surgical clip.

Pathologic analysis of the strictures reveals disordered collagen deposition, fibrosis, and varying levels of inflammation, depending on factors such as etiology and interval since the causative insult. The resulting ureteral obstruction may vary widely from mild, causing only asymptomatic proximal ureteral dilation and hydronephrosis, to severe, causing complete obstruction and subsequent loss of renal function.

Some patients with ureteral strictures are asymptomatic others are symptomatic only during periods of diuresis or develop severe renal colic. The degree of symptoms correlates poorly with the degree of obstruction; at times, severe obstruction is asymptomatic or silent. Renal failure and azotemia may be due to bilateral strictures, such as in cases of bilateral ureteroenteric strictures, external compression due to retroperitoneal malignancy, or retro-peritoneal fibrosis; recovery depends on the duration of ureteral obstruction.

 

CLINICAL MANIFESTATIONS

• Blood in the semen
• Bloody or dark urine
  
• Decreased urine output
  
• Decreased urinary stream
  
• Difficulty urinating
  
• Discharge from the urethra
  
• Frequent or urgent urination
  
• Inability to urinate (urinary retention)
  
• Enlarged (distended) bladder
  
• Incontinence
  
• Painful urination (dysuria)
  
• Pain in the lower abdomen
  
• Pelvic pain
  
• Slow urine stream (may develop suddenly or gradually)
  
• Spraying of urine stream
  
• Enlarged or tender lymph nodes in the groin (inguinal) area
  
• Enlarged or tender prostate
  
• Hardness (induration) on the under surface of the penis
  
• Redness or swelling of the penis
  

 

DIAGNOSTIC EVALUATIONS

• A detailed patient history and physical examination
• Urinalysis
  
• Urine culture and sensitivities
  
• Serum electrolytes with serum blood urea nitrogen and creatinine
  
• Ureteroscopy
  
• Renal ultrasonography
  
• Computed tomography
  
• Intravenous pyelography
  
• Retrograde pyelography
  
• Nuclear medicine diuretic scan
  

MANAGEMENT

No accepted medical treatment of ureteral strictures currently exists. The surgical approach used depends primarily on the location of the ureteral stricture.

1. Balloon Dilation: The most common initial management of benign ureteral strictures is balloon dilation, followed by stent placement for 4-6 weeks.
2. Endoureterotomy: Endoscopic surgery to open a stricture in a ureter. Ureteral incisions can be performed with an endoscopic cold knife, a small (3F) electrocautery probe, or holmium. YAG laser. This procedure is also commonly performed for benign strictures and boasts a higher success rate than balloon dilation.
   
3. Ureteral Metal Stents: Metal stents, which have been used to treat end-stage malignant disease, provide proximal decompression, although recurrence of the obstruction is possible
   
4. Transureteroureterostomy: Transureteroureterostomy (TUU) is a urinary reconstruction technique that is used to join one ureter to the other across the midline. It offers patients with distal ureteral obstruction an option to live without external urostomy appliances or internal urinary stents. TUU is also used in undiversion procedures when the surgeon wants to avoid the pelvis because of previous trauma, surgery, or radiation therapy. TUU can be combined with other procedures, such as cutaneous ureterostomy, in extreme cases
   
5. Ureteroneocystostomy: surgical reimplantation of the ureter into the bladder is necessary in cases of congenital anomaly or damage to the ureter secondary to pelvic surgery or irradiation. If there is total obstruction of the ureter, a percutaneous needle nephrostomy should be attempted, and surgical repair should be delayed until ideal conditions for repair are achieved. Every hour that the kidney remains totally obstructed, progressive damage to the kidney occurs​
   

NURSING MANAGEMENT

To decrease the risk of perioperative infection, the patient should have a sterile urine culture prior to surgical or endoscopic treatment. Perform a preoperative mechanical and antibiotic bowel preparation in patients in whom an ileal ureter substitution is a possibility. Antibiotics are used perioperatively and may be continued for 24 hours or until drains are removed.

Drains are left in place until output is minimal (< 30 ml/d) or the drainage is confirmed to be serum, which is accomplished by checking the drain creatinine level. In patients who received an endoureterotomy, stents are left in place for 4-6 weeks. In patients who received anastomotic repairs, stents are left in place for 10-21 days. If a nephrostomy tube was placed in the patient, it is typically removed last because it can be used to perform antegrade nephrostography to confirm patency.
 

DISORDERS OF URETER – Causes and Risk Factors, Classification, Pathophysiology, Clinical Manifestations, Diagnostic Evaluations and Management  - URETERAL STRICTURE