Urinary Tract Obstruction

Dr. Rajalakshmi VK (AIIMS)MBBS

July 06, 2020

July 06, 2020

Urinary Tract Obstruction
Urinary Tract Obstruction

Our urinary system comprises the kidneys, ureters (narrow tubes), bladder and urethra which work together to produce and flush the urine out of the body.

The function of the kidneys is to filter the blood and remove the excess water in order to maintain the electrolyte balance in the body. The two kidneys are connected to the bladder with the help of two tube-like structures called the ureters. The bladder is the organ where the urine is stored. From the bladder, the urine passes out of the body through another tube-like structure called the urethra. 

Whenever there is a hindrance or blockage anywhere in this tract, the urine gets trapped in the body. This condition is known as urinary tract obstruction (UTO). The obstruction can be partial or complete, on one side or both, on the upper tract or lower. 

UTO can have various causes such as kidney stones, narrowing of the ureter or urethra (strictures), neurogenic bladder or due to the pressure to the adjacent structures by the growing foetus (during pregnancy) or tumours. 

A person with UTO may present with pain in the abdomen especially during urination, blood in urine, retention of urine in the body and others. Patients with chronic UTO may be asymptomatic sometimes—that is, they do not present with any symptoms—until they develop complications such as urinary tract infections or renal failure.

Diagnostic tests such as urinary tract CT scan, cystoscopy and MRI scans are required to find out the source and site of obstruction.

The first step towards the treatment of UTO is to relieve the pressure from the bladder by draining the urine and treating the pain with the help of procedures like nephrostomy (for upper UTO) or cystostomy (for lower UTO). Once emergency treatment is given, the source of the obstruction is treated. The treatment of UTO involves drug therapy and other surgical treatments.

Types of urinary tract obstruction

The function of the urinary system is to remove waste products from the body, regulate the water and salt balance, and to store and transport urine out of the body. The urinary tract is divided into two parts: the upper urinary tract and the lower urinary tract. 

The upper urinary tract consists of the kidneys and ureters. The human body has two kidneys and each kidney has its own ureter. The ureter is a tube-like structure which transports urine from each kidney to the bladder. 

The lower urinary system consists of the bladder, a tube called the urethra, urinary sphincter (muscular structures that control the release of urine from the urethra) and the prostate in men. These structures help in transporting the urine from the bladder out of the body. 

After filtering blood, the kidney sends the extra water to the bladder with the help of ureters, in the form of urine. This urine is then removed from the body with the help of urethra.

Urinary tract obstruction (UTO) is divided into two main types: upper urinary tract obstruction and lower urinary tract obstruction.

  • Upper urinary tract obstruction, also known as the supravesical urinary tract obstruction, involves any obstruction in the kidneys, at the junction of ureter and kidneys or in the ureter.
  • Lower urinary tract obstruction, also called bladder outlet obstruction or infravesical urinary tract obstruction, involves any obstruction in the bladder or urethra.

Symptoms of urinary tract obstruction

A person with urinary tract obstruction may present with some common symptoms such as:

  • Pain in the abdominal region
  • Reduced urine production
  • Difficulty in urinating
  • Blood in the urine
  • Persistent urinary tract infections
  • High blood pressure (hypertension)

Often people with upper urinary tract obstruction remain asymptomatic, but others may show the following signs:

  • Severe pain in the abdomen during urination, often on the same side of the obstruction
  • Blood in the urine
  • High blood pressure
  • Fever and chills along with the other symptoms which may indicate urosepsis (sepsis due to urinary tract infection)
  • Nausea and vomiting
  • High levels of urea in the urine (uremia) which may indicate bilateral urinary tract obstruction

The common signs of lower urinary tract obstruction are:

  • The constant feeling that you need to urinate because you haven't been able to pee properly (urine retention)
  • Pain in the lower abdomen near the hips 
  • Mild swelling in the lower abdomen  
  • Trouble in starting urination (urinary hesitancy)
  • Weak urine flow
  • Prolonged micturation (longer time for urination)
  • Excessive urination at night (nocturia)
  • High levels of urea in the urine (uremia) which may indicate bilateral urinary tract obstruction

Causes of urinary tract obstruction

The causes of urinary tract obstruction can be different for the upper and lower urinary tract. 

The causes of upper urinary tract obstruction are:

  • Kidney stones (Nephrolithiasis) 
  • Urothelial cancer (a type of bladder cancer)
  • Blood clots
  • Narrowing of the ureter (ureteral stricture) 
  • Pregnancy 
  • Cancerous mass such as cervical cancer, ovarian cancer or colon cancer
  • Aneurysms (bulge) of the aorta and iliac artery
  • Endometriosis 
  • Crohn disease (inflammation of the bowel)
  • Diverticulitis (inflammation of a part of the intestine)
  • Retroperitoneal fibrosis (collection of fibrous tissue between the stomach and intestine)
  • The ureter gets tied up accidentally during a surgery

The potential causes of lower urinary tract obstruction are:

  • Urothelial cancer
  • Bladder dysfunction due to nerve damage seen in case of spastic neurogenic bladder and flaccid neurogenic bladder
  • Enlarged prostate 
  • Posterior urethral valves (obstructive membranes in the urethra, near the bladder)
  • Narrowing of the urethra (urethral stricture)
  • Obstruction in the lower urinary tract due to a kinked or plugged catheter

Urinary tract obstruction diagnosis

In order to diagnose an obstruction in the urinary tract, the doctors may have to perform certain tests and scans to be able to reach a diagnosis:

  • Blood test: Complete blood count (CBC) would help the doctor to find out if there is infection in the body.
  • Urine tests: Urine test would indicate the level of creatinine in the urine, which could be a sign of kidney damage.
  • Ureteroscopy: Ureteroscopy is a procedure in which a camera is sent down into the ureter, to look for any blockages. It is usually an outpatient procedure in which the urologist uses a catheter and a special camera.
  • Ultrasound: An ultrasound of the retroperitoneal area (area behind your abdominal organs) would help the doctor visualise the kidneys and ureters.
  • Voiding cystourethrogram: Voiding cystourethrogram is a test done to find out the abnormal urine flow. In this test, the doctor inserts a small tube (catheter) through the urethra and injects a radio-opaque dye into the bladder. Then the doctor takes X-rays of the kidneys, ureters, bladder and urethra before and during urination.
  • Cystoscopy: With cystoscopy, the doctor visualises any abnormality in the urethra and bladder. In this test, the doctor inserts a small tube with a camera and light into the urethra or through a small incision in the lower abdomen. 
  • CT scan: A CT scan of the lower abdomen is done to visualize any obstruction in the kidneys, ureter and bladder.
  • Magnetic resonance imaging (MRI): An MRI scan of the abdomen is done to see the deeper tissues of the organs in the urinary system.

Treatment of urinary tract obstruction

The treatment for urinary tract obstruction is based on the underlying cause of the obstruction. The treatment may include the following:

  1. Emergency treatment for urinary tract obstruction
  2. Drug therapy for urinary tract obstruction
  3. Invasive treatment of upper urinary tract obstruction
  4. Invasive treatment of lower urinary tract obstruction

Emergency treatment for urinary tract obstruction

1. Nephroureterectomy

It is a procedure done to remove the entire affected kidney along with its adjoining ureter. This is only done if the draining kidney is non-functional or is posing the threat of sepsis which can be fatal.

2. Relieving the pressure

Since the urine gets collected in the urinary tract, it is essential to relieve the pressure. This is done when

  • There is complete obstruction of the urinary tract  
  • The obstruction is leading to renal failure 
  • There are fever, infection and refractory pain (uncontrollable pain) along with the obstruction

For relieving the pressure caused due to an upper urinary tract obstruction, ureteral stenting is performed. A ureteric stent is a thin, flexible plastic tube which is also known as a J-J stent or double-J stent because it is curled at both ends. This curling up of the tube prevents any damage to the kidney and the bladder. The stent is placed in such a manner that its upper-end sticks into the kidney and its lower end stays in the urinary bladder.

For relieving pressure caused due to lower urinary tract obstruction, urethral catheterization is done with a Foley’s catheter. In this procedure, a tube called Foley’s catheter is inserted into the bladder through the urethra.

When there is a complete obstruction and Foley’s catheter is not helpful, suprapubic urethral catheterization is done. In this type of catheterization, a tube-like structure is inserted directly into your bladder by making a small hole in the abdomen. 

Once the emergency situation is handled and the complete obstruction has been managed, the urologist can treat the underlying cause.

Drug therapy for urinary tract obstruction

All the patients receive primary treatment which involves the administration of analgesics such as non-steroidal anti-inflammatory drugs (aspirin and ibuprofen) or morphine (given intravenously). The patients are also given antibiotics prophylactically, even in the absence of infection.

Invasive treatment of upper urinary tract obstruction

Following treatment procedures are used for upper urinary tract obstruction:

1. Nephrolithiasis or kidney stones

For the treatment of kidney stones, the following procedures are used:

  • For nephrolithiasis, doctors initially treat the condition conservatively with pain controlling medications and other medications such as alpha-blockers and calcium channel blockers which can help relieve the condition. 
  • Patients with stones of size greater than 10 millimetres (mm) which do not pass even after four to six weeks and clinical symptoms such as vomiting, anuria (no passage of urine), unbearable pain, sepsis may require invasive treatments such as shock wave lithotripsy (SWL). In SWL, the doctor administers a series of shock waves to break the kidney stone which can then travel through the urinary tract and pass from the body more easily.
  • For patients with harder stones which are larger than 1.5 cm, ureteroscopy (examining the uterus using a small telescope) is done to find out the actual location of the stones. After that percutaneous nephrolithotomy is done to remove the stones, where the surgeon enters the kidney by making a small incision in the back. Then the surgeon inserts a nephroscope (a miniature fiberoptic camera) and other small instruments such as a tube into the hole to remove the entire stone.
  • Rigid and firm stones can also be removed laparoscopically (through keyhole surgery).  

2. Ureteral stricture

Ureteral stricture means narrowing of the tube which connects kidneys and the bladder. The following treatments are used to relieve stricture in the ureter(s):

  • Transluminal balloon dilation: This treatment is done in the case of short strictures. In this procedure, the doctor inserts a balloon into the ureter along with a catheter (tube) and then the narrowed portion is widened by inflating the balloon. The doctors may use stents to prevent the ureter from narrowing again. 
  • Endoureterotomy: This process is mostly used if balloon dilation fails. It can involve the use of lasers and stents to relieve the stricture.
  • Laparoscopic surgery: Laparoscopic surgery is only done if other less invasive measures fail.

3. Pregnancy

If the obstruction is present due to pregnancy but the patient has no signs of infection, then no treatment is given. Most of these obstructions resolve spontaneously after delivery. But if the pregnant woman presents with signs of infection, then the obstruction is treated with the help of antibiotics, fluid therapy and ureteral stenting. 

4. Unknown mass in the abdomen 

If the mass is malignant, then the cancer is treated accordingly. Meanwhile, the obstruction is treated with the help of ureteral stenting or nephrostomy tubes. Nephrostomy is a procedure in which a tube is inserted through the skin into the kidney to directly drain the urine.

5. Aneurysm

In case of an aneurysm, the treatment involves surgical removal of the aneurysm followed by repair of the artery or vein. 

Invasive treatment of lower urinary tract obstruction

Following treatment procedures are used for lower urinary tract obstruction:

1. Bladder stone

For the removal of the bladder stone, one of the following procedures may be used:

  • Urine pH: Sometimes the doctor may alkalinize (increase the pH) your urine with potassium citrate so that the stones get dissolved in the body.
  • Transurethral cystolitholapaxy: In this procedure, the surgeon inserts a small tube with a camera at the end (a cystoscope) from the urethra, up into the bladder. While the camera helps to locate the bladder stones, either lasers or ultrasound waves are transmitted from the cystoscope to break up the stones into smaller pieces, which can be washed out of the bladder with urine.
  • Percutaneous suprapubic cystolitholapaxy: In this procedure, the tube with the cystoscope is inserted by making a small cut in the skin of the lower abdomen and the stones are removed by making another cut in the bladder.
  • Suprapublic cystostomy:suprapubic cystostomy is done in the case of large intact stones. It is quite similar to percutaneous suprapubic cystolitholapaxy, but in this surgery, the cut is comparatively larger.

2. Bladder dysfunction due to neurological damage (neurogenic bladder) 

Doctors may give the patient medications such as alpha-blockers and other cholinergic drugs to help increase the flow of urine. Other treatments for a neurogenic bladder are:

  • Intermittent self-catheterization: In this procedure, a plastic tube called a catheter is placed from the urethra into the bladder to allow the urine to drain freely out of the bladder. Once the bladder is empty, the tube is removed.
  • Bladder augmentation: Bladder augmentation is done so that the bladder can store larger amounts of urine without leading to high pressures or urine leakage.
  • Urinary diversion: Urinary diversion is a surgical procedure in which the surgeon reroutes the normal flow of urine out of the body when urine flow is blocked in the normal route. It is done as a last resort when all the other treatments fail. 

3. Urethral stricture

Urethral stricture means narrowing of the tube which helps to pass the urine from the bladder. In case of short strictures, transluminal balloon dilation, urethrotomy (a surgical procedure to widen the urethra) and urethral stents are used to widen the urethra. For long strictures, urethroplasty is done where the entire urethra is replaced or reconstructed surgically.

Medicines for Urinary Tract Obstruction

Medicines listed below are available for Urinary Tract Obstruction. Please note that you should not take any medicines without doctor consultation. Taking any medicine without doctor's consultation can cause serious problems.

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