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UCSF Benioff Children’s Hospital Oakland UNDERSTANDING Hydronephrosis: Prenatal Diagnosis

Hydronephrosis Overview

Hydronephrosis is dilation of the , specifically the (place where urine is stored after its production). This can be the result of an anatomic abnormality in the urinary tract or can be a variant of normal. Hydronephrosis secondary to obstruction is typically at the level of the kidney (uretero-pelvic junction obstruction, or UPJ) or the bladder (uretero- Figure 1 vesical junction obstruction or megaureter). Please see Figure 1.

How is Hydronephrosis What, if any, other test should be When should these diagnosed? done? tests be performed Hydronephrosis is usually • VCUG (voiding cystourethrogram): This study gives if a prenatal diagnosed in one of two ways. us important information regarding the shape and ultrasound showed 1. A prenatal ultrasound size of the bladder, the bladder neck (or opening) and hydronephrosis? (ultrasound during ) the tubes that drain the urine from the kidneys into If your newborn baby had may reveal a with dilated the bladder, called . It allows us to diagnose hydronephrosis (kidney, kidneys. This occurs in 1 per reflux (the abnormal back-flow of urine from the , or bladder dilation) 100 . bladder into the ureter and up to the kidney). It also noted on a screening pre- 2. An ultrasound done as a gives us additional anatomic information about the natal ultrasound, a repeat routine evaluation for another (urine tube which takes urine from the bladder ultrasound should be medical problem, such as outside the body) to make sure no blockage is conducted in the first few a or present (posterior urethral valves). weeks of life. It is normal incontinence, may also reveal • Kidney (Renal) Scan: This test may be done for a newborn to make less hydronephrosis. depending on the history of urinary tract infection(s), urine in the first day of life. result of VCUG, and/or the severity of the If the ultrasound is done too Once hydronephrosis is noted, hydronephrosis. It is used to better demonstrate early, it may falsely appear whether is it during pregnancy the actual function and/or drainage of the kidneys. that the hydronephrosis is or later, additional tests are often A kidney scan can also show if there is kidney gone. Certain conditions required in order to find out the damage and/or scarring that may have resulted from seen on the ultrasound may significance of the hydronephrosis. a previous urinary tract infection or long-standing warrant a more expeditious These tests are important because hydronephrosis. Two types of renal scans are work-up and we will let you children with hydronephrosis may typically performed depending on the diagnosis. know if this is necessary have an anatomic abnormality 1. Lasix Renogram or MAG-III diuretic renogram to (for example, in the event of or urinary tract blockage. Early test for significant blockage in the urinary tract, severe hydronephrosis in both diagnosis and treatment of a OR kidneys or a dilated bladder). potential urologic abnormality can 2. DMSA renal scan to test for scarring or damage prevent urinary tract infections to the renal tissue (more common in patients with and permanent kidney damage or ). scarring.

Fetal Medicine Program Department Department 510-428-3156 510-428-3402 510-428-3335 Understanding Hydronephrosis: Prenatal Diagnosis

How is hydronephrosis graded Why does hydronephrosis occur? and why is this important? There are numerous reasons why hydronephrosis occurs. Potential diagnoses: Hydronephrosis is graded on a scale from 1. Vesicoureteral reflux zero to four, with one being the mildest 2. Non-obstructive hydronephrosis form and four being severe. Please see 3. Ureteropelvic junction (UPJ) obstruction Figure 2. The degree of hydronephrosis 4. Ureterocele is used to assist in decision making with 5. Posterior urethral valves regard to treating the underlying cause 6. Ureterovesical junction (UVJ) obstruction of the hydronephrosis and the ultimate 7. Megaureter prognosis of patients. More severe grades 8. Multicystic Dysplastic Kidney of hydronephrosis are associated with closer 9. Ectopic ureter pediatric urology follow-up. For example, 10. Neurogenic/nonneurogenic bladder grade III and IV hydronephrosis (not due to vesicoureteral reflux) typically require a renal This list is quite extensive, but most often the cause of the hydronephrosis is scan. from one of the first three (in bold) diagnoses. The special x-ray tests mentioned previously will help us to find the cause of the hydronephrosis. Figure 2 (SFU Grading of Hydronephrosis) Will my child require any medication to assist in treating the hydronephrosis?

Grade 0 If your newborn needs antibiotics, he or she will be given a low dose once a day. The pediatrician taking care of your baby in the delivery hospital will prescribe these antibiotics. The types of antibiotics prescribed are specific to the urinary tract with few, if any, side effects. The type and amount of antibiotics will change as your child gets older and gains weight. The goal of giving your baby antibiotics is to prevent kidney infections that may occur as a result of hydronephrosis. Once Grade I the special x-ray tests have been completed, we will be able to estimate the total time of antibiotic treatment.

Will the hydronephrosis go away or will my child require Grade II surgery? Typically, non-obstructive hydronephrosis (ie., hydronephrosis secondary to dilation at the ureterovesical junction, the place where the ureter meets the bladder) and grade 1 to 3 hydronephrosis secondary to uretero-pelvic junction type hydronephrosis do not need surgical intervention and resolve over time. The Grade II timing of resolution depends on the severity of the hydronephrosis and is different for each child. Children diagnosed with dilation from uretervesical junction abnormalities called megaureters rarely if ever need surgical repair. Children with grade IV hydronephrosis (severe) are the most likely to require surgery to prevent renal damage and recurrent infection. Grade III

Grade IV