Summary about Disease
Fetal hydronephrosis refers to the dilation or swelling of one or both of the fetal kidneys' renal pelvis (the part of the kidney that collects urine) detected during prenatal ultrasound. It is a relatively common finding, affecting approximately 1-5% of pregnancies. In many cases, it resolves spontaneously before or shortly after birth. However, in some instances, it can indicate an underlying urinary tract obstruction or abnormality that may require further evaluation and treatment. The severity of hydronephrosis is graded based on the degree of dilation.
Symptoms
Fetal hydronephrosis itself does not cause any symptoms in the pregnant mother. It is detected during a routine prenatal ultrasound. After birth, if the hydronephrosis is significant and untreated, potential symptoms in the infant could include:
Urinary tract infections (UTIs)
Failure to thrive
High blood pressure
Blood in the urine (hematuria)
Abdominal or flank pain (in older children)
Causes
The causes of fetal hydronephrosis can vary. Common causes include:
Transient or Physiologic Hydronephrosis: This is the most common cause, where the dilation is mild and resolves on its own. It may be due to the normal development of the fetal urinary system.
Ureteropelvic Junction Obstruction (UPJ Obstruction): A blockage at the point where the ureter (the tube that carries urine from the kidney to the bladder) joins the renal pelvis.
Vesicoureteral Reflux (VUR): Urine flows backward from the bladder into the ureters and kidneys.
Posterior Urethral Valves (PUV): A flap of tissue in the urethra (the tube that carries urine from the bladder out of the body) that obstructs urine flow, found only in males.
Megaureter: An abnormally wide ureter.
Duplicated Collecting System: The kidney has two separate collecting systems, which can sometimes lead to obstruction or reflux.
Medicine Used
4. Medicine used There are typically no medications used prenatally to treat fetal hydronephrosis. Management focuses on monitoring the condition with serial ultrasounds. *Postnatally*, medications might be used to treat complications or underlying causes:
Antibiotics: For treating urinary tract infections.
Antihypertensives: To manage high blood pressure, if present.
Specific medications: If the hydronephrosis is related to a rare condition, specific medications for that condition may be needed. Surgery may be necessary to correct underlying structural abnormalities.
Is Communicable
Fetal hydronephrosis is not communicable. It is not an infectious disease and cannot be spread from person to person. It arises from developmental or structural issues within the fetus.
Precautions
Prenatal:
Regular Prenatal Care: Attend all scheduled prenatal appointments and ultrasounds to monitor the baby's development and detect any potential problems early.
Follow Doctor's Recommendations: Adhere to your doctor's advice regarding diet, lifestyle, and any necessary tests or procedures. Postnatal (if hydronephrosis persists after birth):
Monitor for UTIs: Watch for signs of urinary tract infections, such as fever, irritability, poor feeding, or changes in urine odor or color.
Follow-Up Care: Attend all scheduled follow-up appointments with the pediatrician or a pediatric nephrologist/urologist.
Administer Medications as Prescribed: If antibiotics are prescribed, give them exactly as directed to prevent antibiotic resistance.
How long does an outbreak last?
Fetal hydronephrosis is not an "outbreak" so that question is not applicable. For those cases of hydronephrosis that resolve spontaneously, it may resolve by the third trimester or sometime after birth. For those cases that require intervention, the condition is addressed in an ongoing basis.
How is it diagnosed?
Prenatal Ultrasound: This is the primary method of detection. Hydronephrosis is typically identified during a routine second-trimester ultrasound (around 18-22 weeks of gestation).
Postnatal Ultrasound: If hydronephrosis is detected prenatally, a repeat ultrasound is usually performed after birth to assess its severity and determine if it has resolved.
Voiding Cystourethrogram (VCUG): This test is used to evaluate for vesicoureteral reflux (VUR). It involves inserting a catheter into the bladder and filling it with a contrast dye. X-rays are taken while the bladder is filling and during urination to visualize the flow of urine.
Renal Scan (MAG3 Scan or DMSA Scan): These nuclear medicine scans assess kidney function and drainage.
Other tests: Depending on the suspected underlying cause, other tests such as blood tests, urine tests, or genetic testing may be performed.
Timeline of Symptoms
Fetal hydronephrosis itself is asymptomatic during pregnancy for the mother. The timeline of potential postnatal symptoms depends on the severity and underlying cause.
Asymptomatic: Many cases resolve spontaneously without ever causing any symptoms.
Infancy: If significant hydronephrosis persists, symptoms like UTIs can appear in infancy.
Childhood: In some cases, symptoms may not become apparent until later in childhood, such as abdominal pain or high blood pressure.
Important Considerations
Severity Grading: Hydronephrosis is graded from mild to severe. Mild cases often resolve on their own. More severe cases require closer monitoring and potential intervention.
Specialist Consultation: If fetal hydronephrosis is detected, a consultation with a pediatric nephrologist or urologist is often recommended to discuss the findings, potential causes, and management options.
Parental Anxiety: Prenatal diagnosis of fetal hydronephrosis can cause anxiety for parents. It's essential to provide them with accurate information, reassurance, and support. Understanding the condition and potential outcomes can help alleviate some of their concerns.
Long-Term Follow-Up: Even if hydronephrosis resolves, long-term follow-up may be recommended to monitor kidney function and detect any potential problems later in life.
Bilateral vs. Unilateral: Hydronephrosis can affect one kidney (unilateral) or both kidneys (bilateral). Bilateral hydronephrosis is often associated with more severe underlying conditions.