Symptoms and Causes of Hydronephrosis: What You Need to Know

One of the most common signs of hydronephrosis is pain in the flank or lower back. This discomfort can range from a dull, persistent ache to sudden, intense episodes known as renal colic. In severe cases, the pain may be so overwhelming that individuals struggle to find relief, sometimes even rolling on the ground due to its intensity. When only one kidney is affected, the pain typically occurs on one side of the back. However, if both kidneys are involved, the discomfort may be felt on both sides.

Recognizing the Warning Signs

If the condition progresses or becomes complicated by a urinary tract infection (UTI), additional symptoms may develop. These include fever, frequent urination, urgency, and a burning sensation during urination—classic indicators of urinary irritation. Left untreated, these infections can worsen and lead to more serious complications such as sepsis, especially in individuals with weakened immune systems.

Understanding the Underlying Causes

Hydronephrosis often results from a blockage in the ureter, the tube that carries urine from the kidney to the bladder. When this passage is obstructed, urine backs up into the kidney, causing it to swell. Common causes of such obstructions include kidney stones, congenital narrowing of the ureter, or inflammation due to recurrent infections. Structural abnormalities present from birth can also contribute to impaired urine flow.

Tumors and Other Serious Conditions

In some cases, hydronephrosis may be linked to tumors—either within the urinary tract or in surrounding organs—that compress the ureter. When cancerous growths or large benign masses press against the urinary pathway, they restrict normal drainage and lead to fluid buildup. Patients with tumor-related hydronephrosis may notice blood in their urine, medically referred to as hematuria. This symptom can appear suddenly or recur over time, warranting immediate medical evaluation.

Why Early Diagnosis Matters

Identifying the root cause is essential for effective treatment. Simply managing pain or treating secondary infections won't resolve the underlying issue. Diagnostic tools such as ultrasound, CT scans, or MRI imaging help doctors pinpoint the location and nature of the obstruction. Once diagnosed, treatment options vary depending on the cause—ranging from minimally invasive procedures to remove stones, to surgical intervention for tumors or strictures.

Early detection not only improves outcomes but also helps preserve kidney function. Chronic or untreated hydronephrosis can lead to permanent kidney damage, reduced filtration capacity, and in extreme cases, kidney failure. Therefore, anyone experiencing persistent back pain, changes in urination patterns, or unexplained fevers should seek prompt medical attention.

Staying informed about the symptoms and potential causes of hydronephrosis empowers individuals to take charge of their health. With timely care and appropriate interventions, most people can recover fully and avoid long-term complications.