Hydronephrosis is the swelling of one or both kidneys due to a buildup of urine that cannot properly drain to the bladder. This condition occurs because of a blockage or an issue that causes urine to flow backward, which increases pressure inside the kidney’s collecting system. Prompt and effective treatment is necessary to relieve this pressure, as prolonged swelling can lead to permanent loss of kidney function. The specific treatment approach for hydronephrosis varies widely, depending on the severity of the swelling and the underlying cause of the obstruction.
Initial Management and Watchful Waiting
The first step in managing hydronephrosis involves a thorough assessment to determine the extent of the swelling and the patient’s overall condition. Imaging studies, most commonly a renal ultrasound, classify the severity of the hydronephrosis as mild, moderate, or severe. This classification guides whether immediate intervention is required or if a period of observation is safe.
For mild cases, particularly those found incidentally or in temporary situations like pregnancy, doctors often recommend a course of “watchful waiting.” For example, physiologic hydronephrosis occurs in many pregnant patients and generally resolves after delivery. Similarly, many cases of mild congenital hydronephrosis in infants spontaneously resolve, sometimes within the first year of life.
During watchful waiting, patients are closely monitored with serial imaging, usually repeat ultrasounds, to ensure the condition is not worsening. Blood tests are also performed to track kidney function by measuring serum creatinine and blood urea nitrogen levels. Observation is only maintained if the patient remains asymptomatic, kidney function is stable, and there is no sign of infection or increasing severity.
Addressing the Underlying Obstruction
If the hydronephrosis is severe, persistent, or associated with declining kidney function, treatment focuses on definitively correcting the source of the blockage. The intervention is tailored to the specific cause identified through diagnostic imaging like CT urography. This definitive treatment aims for long-term resolution of the obstruction.
One common cause is a kidney stone lodged in the ureter, which can be treated using several minimally invasive techniques. Extracorporeal shock wave lithotripsy (ESWL) uses high-energy shock waves directed from outside the body to break the stone into tiny fragments that can be passed naturally. Alternatively, a ureteroscopy involves passing a thin, flexible tube up to the stone, where it can be fragmented with a laser and removed.
For a narrowing at the ureteropelvic junction (UPJ), where the kidney meets the ureter, the standard surgical correction is a pyeloplasty. This procedure involves removing the narrowed segment and reconnecting the healthy ureter to the renal pelvis, creating a wider channel for urine flow. Pyeloplasty can be performed using traditional open surgery, or more commonly, with laparoscopic or robot-assisted techniques for quicker recovery.
In cases of vesicoureteral reflux (VUR), where urine flows backward from the bladder into the kidney, management depends on the grade of reflux. Lower grades of VUR may be managed with long-term, low-dose prophylactic antibiotics to prevent urinary tract infections. More severe VUR often requires surgical repair, such as ureteral reimplantation, which corrects the angle of the ureter’s entry into the bladder to prevent backflow.
Methods for Urgent Renal Decompression
When the kidney is severely swollen, infected, or function is rapidly deteriorating, the immediate priority is to relieve the pressure. This urgent renal decompression does not fix the underlying cause but serves as a temporary measure to drain urine and protect the kidney until definitive treatment can be planned. Two primary methods are used: internal and external drainage.
Internal drainage uses a ureteral stent, a small, hollow tube placed endoscopically between the kidney and the bladder. The stent bypasses the obstruction, allowing urine to flow into the bladder and relieving pressure without an external device. Stent placement is often done via cystoscopy and is generally preferred for patient comfort because it is completely internal.
External drainage, known as a percutaneous nephrostomy, involves inserting a tube directly through the skin into the kidney’s urine-collecting system. This procedure is typically performed by an interventional radiologist and connects the kidney to an external drainage bag. A nephrostomy is often preferred when a patient has a severe infection, is too unstable for general anesthesia, or if a ureteral stent cannot be placed.
Both stents and nephrostomy tubes are temporary measures and must be followed by definitive treatment to address the root cause. The nephrostomy tube may later be converted to an internal stent once the patient’s health status has stabilized. These drainage procedures are generally performed under local or regional anesthesia, making them suitable for urgent situations.
Recovery and Long-Term Follow-Up
Following any intervention, the recovery phase focuses on managing symptoms and ensuring the kidney recovers full function. Pain is common, particularly after stent placement or surgery, and is typically managed with oral pain relievers. If infection was present, a course of antibiotics is administered to clear the infection, which is important in cases of infected hydronephrosis.
For patients who underwent temporary decompression, the ureteral stent or nephrostomy tube must be removed or exchanged according to a set timeline. Stents are usually removed via a brief outpatient procedure once the underlying obstruction is resolved. Nephrostomy tubes are similarly removed when they are no longer necessary, often after the patient has recovered enough to undergo definitive surgery.
Long-term monitoring is a fundamental part of the recovery process to confirm that the obstruction is permanently resolved and that kidney function is preserved. Follow-up imaging, such as ultrasound or a specialized renal scan, is performed at intervals like three to six months post-procedure. These scans ensure the swelling has resolved and that the kidney is draining correctly, helping to catch any recurrence early.