Antenatal Hydronephrosis

What is it?

Antenatal hydronephrosis refers to the swelling of a baby’s kidneys detected during pregnancy. This condition occurs when urine builds up in one or both kidneys due to an obstruction, abnormal development, or a reflux of urine. It is typically diagnosed through prenatal ultrasound and is one of the most common abnormalities detected in pregnancy.

Causes:

1. Ureteropelvic Junction (UPJ) Obstruction: Blockage where the kidney meets the ureter, the tube that carries urine to the bladder.

2. Vesicoureteral Reflux (VUR): Urine flows backward from the bladder to the kidneys, leading to swelling.

3. Posterior Urethral Valves (PUV): A blockage in the urethra (only in males), causing urine to back up into the bladder and kidneys.

4. Multicystic Dysplastic Kidney (MCDK): The kidney develops abnormally with cysts, which may obstruct normal urine flow.

5. Other Obstructions: Abnormalities in the bladder or ureters that block the normal flow of urine.

Symptoms (in the baby after birth):

- Abdominal Swelling: May be visible in severe cases.

- Urinary Tract Infections (UTIs): Frequent UTIs after birth can be a sign of urinary system abnormalities.

- Pain During Urination: Indicating possible obstruction, though babies may not express this clearly.

- Blood in the Urine: May occur if the condition leads to irritation in the urinary system.

Diagnosis:

1. Prenatal Ultrasound: Detects swelling in the kidneys, often during the second trimester.

2. Postnatal Ultrasound: Performed after birth to check if the swelling persists and to assess kidney function.

3. Voiding Cystourethrogram (VCUG): A special X-ray test to check for vesicoureteral reflux (VUR) after birth.

4. Renal Scan: Used to evaluate how well the kidneys are functioning and to identify blockages in the urinary system.

Treatment:

- Observation: Mild cases may resolve on their own before or shortly after birth, requiring only close monitoring with regular ultrasounds.

- Antibiotics: Prophylactic antibiotics may be prescribed to prevent UTIs in babies with hydronephrosis.

- Surgical Intervention: In severe cases or if the hydronephrosis is caused by an obstruction like UPJ obstruction or PUV, surgery may be required to correct the abnormality and restore normal urine flow.

- Pyeloplasty: Surgery to correct UPJ obstruction.

- Valve Ablation: A procedure to remove the blockage in cases of PUV.

- Treatment of VUR: Depending on the severity, vesicoureteral reflux may be managed with antibiotics or, in more serious cases, surgery.

Prognosis:

- Mild to Moderate Cases: Often resolve spontaneously and may not require treatment beyond monitoring.

- Severe Cases: If untreated, severe hydronephrosis can lead to kidney damage or impaired kidney function, especially if associated with frequent infections or untreated obstructions.

Side Effects and Complications:

- Kidney Damage: Persistent hydronephrosis can lead to impaired kidney function or kidney failure in severe cases.

- Infections: Recurrent UTIs can result from urine reflux or obstruction, potentially damaging the kidneys over time.

- Surgical Risks: If surgery is required, complications such as bleeding, infection, or recurrence of the obstruction can occur.

- Renal Scarring: Prolonged untreated obstruction or reflux can lead to scarring in the kidneys, which may affect long-term kidney health.

Early detection and monitoring of antenatal hydronephrosis are crucial to ensure appropriate management and to minimize the risk of long-term kidney damage.