What Is Neonatal Hydronephrosis?
The urinary system contains organs that are designed to perform their specific functions. Kidneys, ureters, urinary bladder, and urethra are the crucial organs of the urogenital system. The kidneys are bean-shaped organs present on either side of the body, below the rib cage. They consist of three main parts, the renal cortex, medulla, and pelvis. The renal cortex filters the blood, the medulla forms urine, and the pelvis drains the urine from the kidneys to the ureters.
The condition in which the renal pelvis becomes enlarged is known as hydronephrosis. It can affect both infants and adults. When the enlargement of the renal pelvis occurs in babies before or after birth, it is known as neonatal hydronephrosis. The condition can be diagnosed before birth with the help of an ultrasound. Mild hydronephrosis will subside without any treatment. However, surgical intervention is required if the hydronephrosis is due to urinary tract obstruction.
What Are the Causes of Hydronephrosis in Newborns?
Sometimes, the doctors are unable to find the cause of neonatal hydronephrosis, and it resolves without any treatment. However, there are several causes of hydronephrosis in newborns. The causes of neonatal hydronephrosis have been described below:
1. Transient Hydronephrosis - Transient hydronephrosis occurs when the urinary tract is underdeveloped or narrow. As the baby undergoes growth and development, the urinary system matures, and transient hydronephrosis gets resolved. It has been reported that most babies born with hydronephrosis usually show transient hydronephrosis. The condition subsides when the child is around three years of age.
2. Congenital Defects - The defects present by birth are known as congenital defects. If the defects are present in the urinary system by birth, hydronephrosis can occur. However, it subsides as the organs mature but becomes severe sometimes. The defects are mainly present in the tubes that carry urine from the kidneys to the bladder (ureters). The ureteral defects have been described below:
- Ureteropelvic Junction Obstruction - The urine drains through the renal pelvis into the tubes known as ureters. The junction where the ureters meet the kidneys is known as the ureteropelvic junction. If the blockage is present at this junction by birth, the urine returns to the kidneys, causing them to swell, resulting in hydronephrosis.
- Vesicoureteral Reflux - When there is a change in the path of urine, that is, it flows from the bladder to the ureters and the kidneys; the condition is known as vesicoureteral reflux. It is commonly seen in children and infants and increases the risk of urinary tract infections.
3. Urinary Tract Obstruction - The urinary tract can be divided into two parts, the upper and the lower. The upper urinary tract consists of kidneys, and the ureters, whereas the lower consists of the urinary bladder and the urethra. The most common cause of neonatal hydronephrosis is lower urinary tract obstruction. Either the junction between the urethra and the bladder is blocked, or the urethra is blocked due to the presence of posterior urethral valves. They are abnormal tissue folds that obstruct the urethra. Posterior urethral valves are commonly seen in babies and block the flow of urine outside the body. As a result, the urine flows back to the kidneys, resulting in hydronephrosis.
4. Prune Belly Syndrome - In this condition, the muscles present within the stomach are either entirely or partially absent, resulting in a characteristic 'prune' like or wrinkled appearance in the belly. It is one of the causes of the retention of urine in the body.
5. Spina Bifida - It is a congenital defect in which the spinal cord does not form completely. As a result, the nerves that control the urinary bladder fail to transmit signals to the brain resulting in urinary retention. If the urine remains retained in the body, the pressure on the kidneys increases resulting in hydronephrosis.
What Are Some of the Signs and Symptoms of Neonatal Hydronephrosis?
The baby does not present with any symptoms of mild hydronephrosis. In some babies, the presence of swelling and pain in the abdomen and lower back is seen. The risk of urinary tract infections increases in such infants. The following symptoms are seen if the baby develops a urinary tract infection:
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Presence of only fever at times.
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The baby remains irritated due to abdominal pain and is reluctant to eat. As a result, the growth of the baby is poor.
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As the child is not eating correctly, loss of weight, weakness, and exhaustion occurs.
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The urine smells bad.
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Vomiting and diarrhea are commonly seen.
What Methods Are Used to Diagnose Hydronephrosis in Newborns?
Hydronephrosis can be diagnosed before the baby is born with the help of an ultrasound. Prenatal testing and ultrasound are a part of routine checkups during pregnancy. The diagnostic methods have been described below:
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Medical History - The medical history provides a better understanding of the general health of the patient. As the baby will not be able to describe his condition, the doctor asks the parents questions related to the symptoms observed in the baby, the time of their onset, and changes in the behavior of the baby.
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Physical Examination - The doctor inspects and palpates the abdomen of the baby to check the swelling. A mass can be felt in the abdomen due to the enlargement of the kidney and the urinary bladder.
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Imaging Tests - The following imaging tests are usually recommended to diagnose the causes of hydronephrosis:
- Ultrasound - It is an imaging test used to diagnose hydronephrosis even before the baby is born. The advantage of the procedure is that the patient is not exposed to the X-rays, so it can be easily carried out in pregnant females. The doctor moves a device known as a transducer over the abdomen of the patient. Sound waves reach the body through the device, and images are obtained on the computer screen. The kidneys appear enlarged if the fetus is suffering from hydronephrosis.
- Voiding Cystourethrogram - This test is mainly done to check if the patient is urinating correctly or if there is any backflow of urine from the bladder to the kidneys. In this procedure, a tube is passed into the bladder of the patient, and a solution is injected through this tube into the bladder. X-rays are then taken from different angulations to monitor the functioning of the bladder. The doctor will check if any amount of solution is flowing back to the kidneys or if any blockage is present in the passage of urine.
- Radionuclide Cystogram - It is a diagnostic test that determines whether the child is suffering from hydronephrosis or not. In this procedure, radioactive material is inserted through a tube into the urethra of the child. The images are then obtained with the help of a gamma camera as the liquid flows into the urinary tract.
How Is Neonatal Hydronephrosis Managed?
The treatment of hydronephrosis depends upon the severity and the causes. The treatment options mainly include the wait and watch approach, removal of the cause, and surgery. The treatment options have been described below:
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Wait and Watch Approach - If a baby is born with hydronephrosis, the doctors might suggest the parents wait for some time before any treatment. It is because transient hydronephrosis will subside as the organs of the urinary tract mature. Therefore, no treatment is required because the condition returns to normal as the baby grows.
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Prevention of Urinary Tract Infection - If the child is likely to develop urinary tract infections, the doctor recommends antibiotics to treat them. If a child is two months old or above, antibiotics are administered by mouth as liquids (syrups). If a child is reluctant to take medications and is continuously vomiting, the drug is injected into the body through the veins. The infection usually subsides in two to three days, but the entire course of antibiotics needs to be completed. The commonly used antibiotics are listed below:
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Cefixime.
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Cefprozil.
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Cephalexin.
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Amoxicillin and Clavulanic acid.
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Trimethoprim.
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Surgery - If the above methods fail to treat hydronephrosis, surgery is required to remove the underlying cause. The most common surgical method used to treat hydronephrosis is pyeloplasty. It has been described below:
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Pyeloplasty - It is a procedure in which the ureters are repaired surgically to treat ureteropelvic junction obstruction. First, a small cut is made in the region below the ribs of the baby. Next, the obstructed portion of the ureters is removed, and the remaining part is attached to the renal pelvis. A small silicone tube, known as a stent, is left in place for a few days to facilitate the drainage of urine.
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What Are the Complications of Neonatal Hydronephrosis?
If hydronephrosis is left untreated for long, the following complications arise:
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Urinary Tract Infections - The risk of urinary tract infections in hydronephrosis increases because the urine remains in the body. As a result, the bacteria enter the body quickly and cause infections.
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Kidney Damage - If the hydronephrosis is left untreated, scarring of the kidneys occurs, which can cause permanent damage to the kidneys.
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Kidney Stones - When the urine is unable to flow through the body, the salts and minerals present in the urine clump together to form masses or stones. These stones obstruct the flow of urine, which increases the pressure on the kidneys resulting in their damage.
Conclusion:
Hydronephrosis is characterized by the swelling of the kidneys, and when it occurs in newborns, it is known as neonatal hydronephrosis. The condition might be present even before the baby is born and diagnosed on ultrasound. If the child is suffering from transient hydronephrosis, no treatment is required because it will subside as he grows. However, treatment is required if the baby develops hydronephrosis due to urinary tract obstruction. As the babies are unable to express their symptoms, the condition goes unnoticed, resulting in severe complications. Therefore, the parents must consult the doctor at the earliest so that the condition can be diagnosed and treated on time. Both surgical and non-surgical options help to save the kidneys of the child so that he lives a healthy life ahead.
