Causes and Management of Hydronephrosis
Etiology
- Hydronephrosis can be classified by cause, laterality, level of obstruction, and nature of obstruction, according to the American College of Radiology 1
- Malignant obstruction is a cause of hydronephrosis, from tumors of the urinary tract or adjacent structures, as stated by the American College of Radiology 1
- Strictures due to inflammation, trauma, or iatrogenic causes are a cause of hydronephrosis, as reported by the American College of Radiology 1
- Upper urinary tract infections can cause temporary obstruction due to inflammation, according to the American College of Radiology 1
- Retroperitoneal fibrosis can cause extrinsic compression of the ureters, leading to hydronephrosis, as stated by the American College of Radiology 1
- Prostatic hyperplasia can lead to bladder outlet obstruction, causing hydronephrosis, as reported by the American College of Radiology 1
- Pregnancy can cause hydronephrosis in 70-90% of pregnant patients due to mechanical compression and hormonal effects, according to the American College of Radiology 1
- Congenital anomalies, such as ureteropelvic junction obstruction or posterior urethral valves, are a cause of hydronephrosis, as stated by the American College of Radiology 1
- Mechanical compression from an enlarged uterus, pelvic organ prolapse, or other masses can cause hydronephrosis, as reported by the American College of Radiology 1
- Drug-induced hydronephrosis can occur from medications like cyclophosphamide or ketamine, according to the American College of Radiology 1
Diagnostic Approach
- Ultrasound with Color Doppler is the first-line imaging for asymptomatic hydronephrosis, which can identify and grade hydronephrosis, evaluate ureteral jets, bladder distension, and postvoid residual, as recommended by the American College of Radiology 2
- CT Urography (CTU) provides a comprehensive evaluation of the genitourinary tract with both morphological and functional information, according to the American College of Radiology 3
- MAG3 Renal Scan is the standard for diagnosing true functional obstruction versus non-obstructive dilation, as stated by the American College of Radiology 4
- CT abdomen and pelvis is particularly useful for suspected urolithiasis and when moderate to severe hydronephrosis is present, as reported by the American College of Radiology 5
- Ultrasound with Color Doppler is highly specific (94.4%) for detecting symptomatic renal stones when moderate or greater hydronephrosis is present, according to the American College of Radiology 6
- For pregnant patients, ultrasound with Color Doppler is the preferred initial imaging to avoid radiation exposure, as recommended by the American College of Radiology 7
- MRU without contrast can be used when more detailed imaging is needed during pregnancy, as stated by the American College of Radiology 7
Management
- Endoscopic dilation is a treatment option for strictures, as reported by the American College of Radiology 1
- Surgical reconstruction is a treatment option for strictures, according to the American College of Radiology 1
- Treatment of the underlying malignancy is necessary for malignant obstruction, as stated by the American College of Radiology 1
- Palliative drainage may be necessary for malignant obstruction, as reported by the American College of Radiology 1
- Medical therapy (alpha-blockers, 5-alpha-reductase inhibitors) is a treatment option for benign prostatic hyperplasia, as recommended by the American College of Radiology 3
- Surgical interventions (TURP, laser procedures) are treatment options for benign prostatic hyperplasia, according to the American College of Radiology 1
- Pregnancy-related hydronephrosis usually resolves after delivery, but temporary drainage may be needed if symptomatic or complicated, as stated by the American College of Radiology 1
- Surgical correction of the anatomical abnormality is necessary for congenital anomalies, as reported by the American College of Radiology 1