Hydronephrosis occurs when the urine made by a kidney is unable to drain steadily into the bladder. This causes the urine to ‘back up’ into the kidney and ‘swelling’ of the kidney. This can happen to one or both kidneys, depending on the cause. Sometimes the swelling is not because of a blockage, but because of reflux – when urine can flow back up from the bladder up to the kidneys.
Hydronephrosis is not a disease itself and is actually a sign of another underlying problem. The list of potential causes includes:
- Blockage of the urinary tract at birth
- Kidney stones
- Blood clot
- Scarring of the ureters (which drain urine from the kidney to the bladder)
- Tumor of the bladder or prostate, or cervix or colon
- Enlarged prostate
- Enlarged uterus from pregnancy
- Persistent urinary tract infection
- Injuries to the urinary tract from trauma or prior surgeries
The symptoms of hydronephrosis are variable, but may include back/flank, waist, lower abdominal or groin pain, pain with urination, increasing urge to urinate, incomplete urination, fever, nausea, vomiting, even unexplained itching.
Hydronephrosis maybe suspected based on history and physical exam and usually needs imaging (ultrasound, CT scan, MRI, cystogram or cystoscopy) for confirmation of its presence and assessment of its severity. The doctor may also perform blood work and urine testing to look for infection or changes in kidney function.
The treatment depends on the cause. Sometimes the hydronephrosis may resolve on its own, other times it may require antibiotic therapy, medications to help treat the underlying condition (like neurogenic bladder), insertion of catheter into the bladder, insertion of a stent or nephrostomy tube, surgery to correct a blockage, or rarely, removal of part or the entire kidney.