Urinary tract obstruction

Recent and novel data on urinary tract obstruction

Urinary tract obstruction (UTO) is a major risk factor for end-stage renal disease (ESRD). A recent study found that UTO accounts for up to 40% of all new cases of ESRD in the United States.

UTO can be difficult to diagnose, especially in the early stages. Current diagnostic methods are often invasive and/or expensive. Researchers are developing new, non-invasive diagnostic tools, such as blood tests and urine tests, that could help to identify UTO earlier.

There is a growing interest in the use of minimally invasive surgery to treat UTO. Minimally invasive surgery can be less painful and have a shorter recovery time than traditional open surgery. However, more research is needed to determine the long-term efficacy of minimally invasive surgery for UTO.

Here are some specific examples of recent and novel data on UTO:

A new study has identified a panel of urinary extracellular vesicles (sEVs) that may be used to diagnose UTO in a non-invasive way. sEVs are small particles that are released by cells into the surrounding fluid. They contain a variety of molecules, including proteins, RNA, and DNA. Researchers found that the levels of certain sEV proteins were significantly higher in patients with UTO than in healthy controls. They also found that these sEV proteins could be used to distinguish between different types of UTO, such as upper tract obstruction and lower tract obstruction.

Another study has shown that artificial intelligence (AI) can be used to improve the diagnosis of UTO on ultrasound images. AI algorithms were able to identify UTO with greater accuracy than human radiologists. This suggests that AI could be used to help diagnose UTO more quickly and accurately in the future.

Researchers are also developing new minimally invasive treatments for UTO. One promising new treatment is called endopyelotomy. Endopyelotomy is a procedure in which a small incision is made in the renal pelvis (the area where urine collects in the kidney) to relieve the obstruction. Endopyelotomy can be performed using a flexible camera and surgical instruments inserted through the urethra.

Overall, there is a growing body of recent and novel data on UTO. This research is leading to the development of new, non-invasive diagnostic tools and minimally invasive treatments for UTO.

Dilated kidney (hydronephrosis)

Additional information:

Causes of hydronephrosis:

• Kidney stones

• Prostate enlargement

• Tumors of the urinary tract

• Strictures (narrowings) of the urinary tract

• Congenital (birth) defects of the urinary tract

• Symptoms of hydronephrosis:

• Flank pain (pain in the side or back)

• Painful urination

• Frequent urination

• Blood in the urine

• Fever

• Complications of hydronephrosis:

• Kidney stones

• Urinary tract infections

• Kidney damage

• Kidney failure

Treatment for hydronephrosis:

Treatment for hydronephrosis depends on the underlying cause and the severity of the condition. In some cases, hydronephrosis may resolve on its own without treatment. However, in other cases, treatment is necessary to relieve the obstruction and prevent further kidney damage.

Common treatments for hydronephrosis include:

1. Ureteral stenting: A thin, flexible tube is inserted into the ureter to bypass the obstruction.

2. Nephrostomy: A tube is inserted through the skin into the kidney to drain urine.

3. Surgery: Surgery to remove the obstruction or to repair a congenital defect of the urinary tract.

Prognosis for hydronephrosis:

The prognosis for hydronephrosis depends on the underlying cause and the severity of the condition. If the obstruction is relieved early, most people will make a full recovery. However, if the obstruction is not relieved or if there is significant kidney damage, kidney failure may develop.

Prevention of hydronephrosis:

There is no surefire way to prevent hydronephrosis. However, there are some things you can do to reduce your risk, such as:

• Drink plenty of fluids throughout the day.

• Avoid straining during urination.

• Eat a healthy diet to reduce your risk of kidney stones.

• Get regular checkups and see your doctor if you have any symptoms of hydronephrosis.

Causes of urinary tract obstruction

Urinary tract obstruction can be total or partial, affect one or both sides, and develop quickly (acute) or slowly (chronic). The most common causes vary by age group:

Children: Structural abnormalities, such as birth defects, such as posterior urethral valves (valves on the inside of the back of the urethra) and other strictures that narrow or block the ureter or urethra.

Young adults: Kidney stones, ureter stones, or stones in any other part of the urinary tract.

Older adults: Benign prostatic hyperplasia (BPH) or prostate cancer, tumors, and stones.

Other common causes of obstruction include:

Stricture (narrowing caused by scar tissue) of the ureter or urethra after radiation therapy, surgery, or other procedures performed on the urinary tract.

Ureter polyps

Blood clot in the ureter

Tumors of the ureter or surrounding tissues

Disorders of the muscles or nerves of the ureter or bladder (may be due to medications with anticholinergic effects, birth defects, or spinal cord injury)

Fibrous tissue formation (scarring) in or around the ureter after surgery, radiation therapy, or taking medications (including methysergide)

Swelling of the lower end of the ureter toward the bladder (ureterocele)

Tumors, abscesses, and cysts of the bladder, cervix, prostate, or other pelvic organs

Large mass of stool blocked in the rectum (rectal overload)

Hydronephrosis (dilation of the kidney) can develop in both kidneys during pregnancy as the expanding uterus compresses the ureters. Hormonal changes during pregnancy can also worsen the disorder by reducing contractions of the muscles that normally allow urine to flow through the ureters. This condition, called hydronephrosis of pregnancy, usually resolves by the end of pregnancy, although the pelvis and ureters may remain slightly dilated.

Symptoms of urinary tract obstruction

Symptoms vary depending on the cause, location, and duration of the blockage. Sudden obstruction that expands the bladder, ureter, and/or kidney is often painful. A rapidly enlarging kidney can cause renal colic, which is characterized by excruciating pain in the flank (the area between the ribs and the hip) on the affected side. The pain may come and go every few minutes and may spread to one testicle or the vaginal area. People may also experience nausea or vomiting.

Obstruction of a ureter does not necessarily reduce the amount of urine passed. However, if the obstruction affects the ureters coming from both kidneys or the urethra, it can stop or reduce urine flow. Obstruction of the urethra or bladder neck can cause pain, compression, and dilation of the bladder.

People with slowly progressive obstruction that causes hydronephrosis may be asymptomatic or experience episodes of dull, aching pain in the flank on the affected side. Sometimes, a kidney stone can temporarily block the ureter and cause intermittent pain.

Hydronephrosis can also cause nonspecific intestinal symptoms such as nausea, vomiting, and abdominal pain. These symptoms are sometimes seen in children with hydronephrosis caused by a congenital malformation called ureteropelvic junction obstruction (UPJO), in which the junction between the ureter and the renal pelvis is too narrow.

People with a urinary tract infection (UTI) may experience purulent urine, fever, and bladder or kidney discomfort.

Diagnosis of urinary tract obstruction

Early diagnosis of urinary tract obstruction is important, as most cases can be cured and late treatment can cause irreversible kidney damage. Doctors may suspect obstruction based on symptoms such as renal colic, bladder distention, or decreased urine volume. In rare cases, they may be able to feel an enlarged kidney, usually in infants, children, or thin adults. Sometimes, bladder distention can be seen in the lower abdomen, just above the pubic bone.

Diagnosis of urinary tract obstruction is made through a series of tests, including:

Bladder catheterization: A hollow, flexible tube is inserted through the urethra into the bladder to drain urine. If a large volume of urine drains from the bladder, this suggests that the obstruction is at the level of the bladder neck or urethra. Before performing bladder catheterization, many doctors perform an ultrasound to determine if the bladder contains a large volume of urine.

Bladder catheterization

Imaging tests: Imaging tests may be performed to identify signs of obstruction, such as hydronephrosis or the site of obstruction. Ultrasound is often the first imaging test performed, as it is non-invasive and accurate. However, ultrasound is not always accurate in locating the site of the obstruction.

Ultrasound of the urinary tract

Computed tomography (CT) scan is another option. CT scans are fast and extremely accurate, especially for identifying stones. However, CT scans involve exposure to radiation. Magnetic resonance imaging (MRI) is also available, but it is not as accurate as ultrasound or CT scans for detecting kidney stones. MRI may be used if it is important to avoid exposing the patient to radiation and the site of obstruction cannot be clearly visualized by ultrasound.

Other imaging tests, such as voiding retrograde urethrocystography (VCUG), may be performed to identify the site of obstruction, most commonly in children with bladder or urethral obstruction. VCUG uses x-rays to visualize the bladder and urethra after a radiopaque contrast dye is injected into the bladder through a catheter.

Endoscopy

Endoscopy may be used to examine the urethra, prostate, and bladder with a special flexible or rigid endoscope (cystoscope). A longer rigid or flexible endoscope (ureteroscope) may be inserted into the ureters or kidneys to identify sites of obstruction. Sometimes, the cystoscope, ureteroscope, or both may also be used to remove objects causing the blockage.

Blood and urine tests

Blood and urine tests are performed to assess kidney function and identify any signs of infection. Blood tests may reveal elevated levels of blood urea nitrogen (BUN) and creatinine if the obstruction has completely blocked both kidneys for several hours. Urinalysis may show white and red blood cells if the cause of the obstruction is a stone or tumor, or if there is an infectious complication of the obstruction.

Prognosis of urinary tract obstruction

The prognosis for urinary tract obstruction depends on the severity and duration of the obstruction, as well as the underlying cause. If the obstruction is relieved promptly, kidney damage is usually reversible. However, if the obstruction is not relieved for a prolonged period of time, kidney damage may be irreversible. The prognosis is also better for patients with a single kidney obstruction than for patients with bilateral kidney obstruction.

Treatment of urinary tract obstruction

Treatment for urinary tract obstruction is aimed at addressing the underlying cause of the blockage. For example, if the urethra is blocked by a benign enlarged prostate, treatment may include medications, surgery, or dilation of the urethra with dilators. Stones that are blocking the flow of urine through the ureter or kidney may be removed using lithotripsy or endoscopic surgery.

If the underlying cause of the obstruction cannot be corrected quickly, the urinary tract may be drained to prevent kidney damage. In cases of acute hydronephrosis, urine that has accumulated above the point of obstruction can be drained through a flexible tube inserted into the kidney through the back (nephrostomy tube) or by inserting a flexible plastic tube that connects the bladder to the kidney (ureteral stent). If the urethra is the site of the blockage, a soft rubber catheter may be inserted into the bladder to drain urine.

Blockages that cause chronic hydronephrosis usually do not require emergency care, but they should be monitored closely. If complications of urinary tract obstruction develop, such as urinary tract infection or acute kidney failure, immediate intervention is required.

Source: https://www.urologicaldiagnosis.online/