What is Hydronephrosis of One Kidney?

Hydronephrosis is a condition in which the kidney swells, as urine gets accumulated in the kidney instead of being flushed out of the body. While this condition can occur in both kidneys, hydronephrosis is also seen affecting only one kidney. Hydronephrosis of one kidney occurs when only one kidney is swollen, which is often a result of an underlying condition causing blockage of normal drainage of urine. It is important to understand the causes and symptoms of hydronephrosis of one kidney.

As hydronephrosis of one kidney can affect either side of the body, the condition is often seen as left or right hydronephrosis. It can occur at any age and can affect anyone, including young children and unborn babies. The main cause of hydronephrosis of one kidney is obstruction or blockage of normal flow of urine, which results in building up of urine in kidney, thus developing left or right hydronephrosis.

In hydronephrosis of one kidney, there is swelling of one kidney due to accumulation of the urine, which is waste matter, supposed to be flushed out of the body. The held up urine in left or right hydronephrosis, can be a potential risk for urinary infections.

Hydronephrosis of One Kidney

How Does Hydronephrosis of One Kidney Occur?

When urinary system is considered, the structure and function is designed to perform accurately and flush out the wastes through urine. The primary function of kidneys is to absorb essential nutrients and filter waste material and fluids to form urine. Urine is formed in left and right kidneys, which then travels down through tubes called ureters, present on both sides. These tubes reach the urinary bladder placed at the centre, which further opens into the urethra. The entire urinary tract needs to function properly to be able to remove the waste material in the form of urine.

If there is any obstruction, blockage or any conditions affecting the normal flow of urine from the kidney to the urethra, it can lead to problems. Any obstruction in the tract can cause the urine to flow backwards to reach the kidney on either side and cause left or right hydronephrosis.

What Are The Causes Of Hydronephrosis Of One Kidney?

Hydronephrosis of one kidney is the result of an underlying condition and not a condition in itself. These causes or conditions can be present in the urinary tract or other medical conditions that can exert pressure or create obstruction in the flow of urine.

Some of the common causes of hydronephrosis of one kidney are considered here

  • Blockage of the ureters can cause hydronephrosis of one kidney, due to narrowing, which can be a result of an injury or may be present since birth. Any birth defect affecting the urinary tract can cause obstruction and contribute to left or right hydronephrosis.
  • Recurrent renal infections, kidney or bladder stones can block normal passage of urine and is one of the common causes of hydronephrosis of one kidney. Kidney stones normally move, but depending on the size and their location, sometimes stones can get lodged at places, which can obstruct normal flow of urine.
  • Conditions of the urinary tract like ureteric reflux, in which the valves controlling the downward flow of urine are incompetent and results in upwards or backward flow of urine. This causes accumulation of urine in the kidney and can result in left or right hydronephrosis.
  • Certain renal conditions, previous infections, surgeries or treatment modalities like radiation, can cause scarring in the kidney or the urinary tract. This can result in blockage of the urine flow and can cause hydronephrosis of one kidney.
  • Conditions that affect the nerves supplying the urinary system can affect the flow of urine and be a cause of hydronephrosis of one kidney. These can include medical conditions, infections affecting the spine or nerves, spinal injuries, birth defects causing spinal nerve issues, tumors or other problems that can affect normal functioning of the urinary system.
  • In women, pregnancy can be a cause of hydronephrosis of one kidney, particularly in the later months. The growing fetus and the expanding womb can exert pressure on the urinary tract, thus obstructing the urine flow.
  • In men, enlarged prostate is a common cause of hydronephrosis of one kidney, particularly seen in elderly men. An enlarged prostate gland, due to prostatitis, benign enlargement or prostate cancer, can cause obstruction of flow of urine.
  • Tumors and cancers in the kidney can cause blockage of normal urinary flow and can be one of the causes of left or right hydronephrosis. Tumors or growths in the ureter or those around it can obstruct the flow of urine and can result in back flow causing hydronephrosis of one kidney. Tumors, cancers or enlarges lymph nodes around the urinary tract, particularly those affecting the kidneys, abdomen and pelvis too can cause urinary obstruction and hydronephrosis of one kidney.
  • Other causes of hydronephrosis of one kidney may include obstruction of urine from unilateral obstructive uropathy, kinking or bending of the ureters, blood clots or other rare conditions.

What Are The Symptoms Of Hydronephrosis Of One Kidney?

Hydronephrosis of one kidney is mainly a result of building up of urine in the kidney due to obstruction in the flow of urine. As urine gets accumulated in the kidney, it causes the kidney to swell and result in left or right hydronephrosis. The swollen or bulged kidney can exert pressure on the surrounding organs and structures. This gives rise to various symptoms of hydronephrosis of one kidney. The severity of symptoms varies from person to person, some may experience mild or moderate symptoms, while some cases may be severe than others. Few cases of hydronephrosis may not experience any symptoms at all.

Some common symptoms of left or right hydronephrosis include:

Changes in Urination Pattern is One of the Common Symptom of Hydronephrosis of one Kidney

Changes in pattern of urination are commonly seen in hydronephrosis. These include increased frequency or increased urgency of urination, pain before and during urination or burning urination. There may be complaints of interrupted flow of urine or some may experience incomplete voiding of urine. The passage of urine may be very weak or the person may have to strain to void even small amount of urine.

Urinary Tract Infections – Common Complaint of Hydronephrosis

Urinary tract infection is a common complaint of hydronephrosis of one kidney and is usually presented with burning urination. Other urinary complaints may also be experienced, which can include cloudy urine and painful burning sensation when passing urine. In some cases, blood may be present in urine, which may be noticed as reddish urine.

High fever with chills is also a commonly associated symptom with urinary tract infection in hydronephrosis. Nausea and vomiting are other symptoms commonly noted in urinary tract infections, related to hydronephrosis of one kidney.

Other symptoms of hydronephrosis of one kidney can be abdominal pain or pain in the back or the flank region. Such pain can begin spontaneously and may be of dull aching type. Pain in hydronephrosis of one kidney may be felt on the side of the swollen kidney. The pain can extend from the back or sides to the area around the urinary bladder.

Pressure exerted by the swollen kidney in left or right hydronephrosis, can sometimes affect other nearby organs and present with related symptoms. Swollen kidney can also exert pressure on the blood vessels and problems in filtration can, in some cases, contribute to increased blood pressure. Hydronephrosis of one kidney can sometimes result in secondary hypertension.

How is Hydronephrosis of One Kidney Diagnosed?

Complaints in hydronephrosis of one kidney include symptoms of urinary tract infections, renal stone and other renal problems. Hence, it is important to evaluate the complaints and asses the possible causes to plan proper management of left or right hydronephrosis. Proper history, clinical examination and certain investigations can help to make a diagnosis of hydronephrosis of one kidney. Clinical examination may help to determine the location, extent and severity of pain, abdominal discomfort and sometimes palpable swelling of the affected kidney.

Hydronephrosis of one kidney can be diagnosed using the following investigations.

Laboratory Tests – Blood and urine tests help to detect the presence of infection and kidney function. Urine tests help to reveal the presence of pus cells, blood in urine and crystals or any other abnormality. Presence of protein in urine, levels of serum creatinine, urea, nitrogen and other parameters related to kidney function help to determine possible abnormalities with the kidney function.

If voiding or urine is difficult, some urine may be removed using a catheter and sent for analysis.

Imaging Studies – Ultrasound of the kidneys and the abdomen helps to detect swelling in one kidney and any other abnormality in the abdomen. X-rays and other kidney scans like CT scan, MRI may be done to detect finer details and diagnose hydronephrosis of one kidney.

Intravenous pyelography (IVP) is another test done to detect the abnormality in the urinary system and find any obstruction in flow of urine. In this test, a dye is injected, which passes through the urinary system and scans are taken to note the passage through the urinary tract.

Other tests like cystoscopy, which involves visualization of the urinary bladder using a small camera may be done in some cases. For some cases, nuclear scans to detect the presence of scarring in kidney may be done, if appropriate.

What are the Treatment Options for Hydronephrosis of One Kidney?

Treatment options of hydronephrosis of one kidney depend on the underlying condition and the causes that have resulted in swelling of the kidney. The severity of the condition, presence of other medical conditions and the health status of the patient is taken into consideration. The primary aim of treatment of hydronephrosis of left or right kidney is to treat the condition causing blockage or urinary flow and restore normal functioning of the urinary system.

Some conditions maybe physiological and may not require any treatment. Hydronephrosis of one kidney in pregnancy does not usually need any treatment as the swelling is only due to growing fetus, which subsides later on. However, any other underlying cause in the pregnant woman, apart from growing fetus, may require appropriate treatment. Hydronephrosis of one kidney in babies is also usually managed without any treatment but watchful approach may be suggested.

Diagnosis of hydronephrosis of one kidney is important in deciding the treatment plan, which when promptly done, can help to effectively manage the condition.

Treatment of Hydronephrosis of One Kidney

Most conditions causing hydronephrosis may be treated with medicines, for example urinary tract infections may require anti-biotics.

For some cases, if the urine is not being passed, a catheter or tube may be placed to remove the urine through the urethra or ureteral stent may be placed to drain urine from the ureter into the urinary bladder. In some other cases, a tube (nephrostomy tube) may have to be placed in the kidney from the back and the urine is drained out of the body through the tube.

The exact type of treatment option is best decided by the treating physician, which largely depends on the cause and severity of hydronephrosis.

Some other treatment of hydronephrosis of one kidney include

  • Renal stone may require flushing out of stone through urine by increasing water intake, medications or hydrotherapy. Some severe cases of kidney stone may require surgical treatment to remove the stone causing obstruction.
  • Ureteric reflux may be treated surgically to correct the problem that is causing back flow of urine or to remove the blockage in flow of urine.
  • Surgery for hydronephrosis of one kidney may be required in case of conditions causing blockage like blood clots, scar tissue, tumors or other obstructions.

Immediate medical attention may be required in people who have only one kidney and develop hydronephrosis in that kidney. Similarly people having other major illnesses like diabetes, hypertension, auto-immune disorders, severe infections like HIV/AIDS or those who have undergone kidney transplantation may need urgent medical treatment. For severe or complicated cases, which have resulted in kidney failure, some patients may require dialysis or kidney transplant.

In cases treated with surgery or any other treatment option, anti-biotics are often prescribed to prevent or treat urinary tract infections and reduce the risk of complications.

Hydronephrosis of One Kidney in Babies & Its Treatment

Hydronephrosis of one kidney is also noted in unborn babies and is termed as antenatal hydronephrosis. This condition is usually noted during routine antenatal check-ups when ultrasound scans are done. While this may seem to be a cause of concern, it usually does not affect the pregnancy or the baby. Most of the cases of hydronephrosis of one kidney in babies, resolve during later months of pregnancy or within few months after birth of the baby. In few cases, the condition may not resolve on its own and may require treatment.

Treatment of hydronephrosis of one kidney in babies may include prophylactic use of anti-biotics to prevent urinary tract infection. Surgery may also be required in some cases to remove the obstruction or treat the underlying cause of the kidney swelling.

What are the Complications of Hydronephrosis of One Kidney?

If left untreated, hydronephrosis of one kidney can result in urinary tract infections and finally result into failure of kidney function. Long standing swelling of kidney in hydronephrosis can cause permanent damage to the kidney. This is more important in people with only one kidney as hydronephrosis in that kidney can sometimes even result in kidney failure.

However, accurate diagnosis and prompt treatment helps to resolve most cases of hydronephrosis of one kidney without any complications.

Written, Edited or Reviewed By:


Last Modified On: September 15, 2016

Pain Assist Inc.

Pramod Kerkar
  Note: Information provided is not a substitute for physician, hospital or any form of medical care. Examination and Investigation is necessary for correct diagnosis.

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