Symptoms of Hydronephrosis

Hydronephrosis is a secondary condition wherein one or both kidneys become swollen, usually due to a build-up of urine that failed to drain into the bladder. Hydronephrosis can also affect people of all ages. The condition doesn’t cause any long-term problems when treated or diagnosed; however, if left untreated the kidneys may become scarred. While this is only true in the rarest of cases, it can lead to kidney failure. There aren’t many unique symptoms of hydronephrosis, so it is best to be diligent and take action if multiple general symptoms present.

Frequent Urination

Frequent urination can be frustrating to experience and tends to be unrelated to water intake. It isn’t life-threatening, but it may indicate an underlying condition. Frequent urination is usually a symptom of infections of the urinary tract (UTI), kidneys, or bladder.

Unsuccessful Urge to Urinate

Somewhat related to frequent urination, needing to urinate more often and not being able to can also be a symptom. Medical professionals know it as an overactive bladder, and usually diagnose it from a collection of symptoms including nighttime urination or incontinence. Having that “gotta go!” feeling is a hallmark of hydronephrosis and UTIs.

Flank Pain

As fluid builds up in the kidneys, they become swollen. The blockage or obstruction makes it difficult to urinate, and the more the kidneys swell, the more they press against other organs. One of the main symptoms of hydronephrosis is a pain in the flank or the side of your back, under your lower ribs. This pain may travel to the groin or stay localized, but generally means you should see a doctor.


Nausea is when you feel the urge to vomit, often without actually vomiting. Bouts of nausea can be acute, or they can last a long period. Nausea affects many people from time to time, it’s only when it accompanies other symptoms that you should see a doctor.

Blood in Urine

The scientific term for blood in the urine is hematuria. There are two types of hematuria: gross and microscopic. Only gross hematuria is a symptom of hydronephrosis. In other words, if you can see blood in your urine, it is probably a sign that something is going on with your kidneys. Blood in the urine won’t appear bright red, but rather a light red or pink. In rarer cases, the blood will show up as a murkier shade of brown. Generally, if you see blood in your urine, see a doctor.

Abdominal Pain

Hydronephrosis can cause pain or bloat in the abdomen. While flank pain is the most common pain-related symptom, in some cases it presents in the abdomen first. This is usually categorized as a stomach ache that doesn’t go away. If the pain is consistent and unexplained, your doctor may schedule a CT scan of your abdomen to rule out or diagnose more severe conditions.


Technically, fever is a body temperature measurement that registers as being above normal. Normal body temperature tends to be around 98.6 degrees F. Anything above normal but below 100.4 is a low-grade fever. Because fever is usually a response to infection, in this case, it may indicate a kidney or bladder infection. Therefore, if the fever presents with any other symptoms relating to urination, hydronephrosis is possible.

Pain When Urinating

Painful urination is the most common symptom of a urinary tract infection. It usually presents as a sore or a burning sensation when you urinate. Because the function of the urinary tract is to remove waste and bacteria from the body, a blockage can cause infection. In response, patients can dread and put off urinating, which may make the infection worse.

Severe Pain

While hydronephrosis doesn’t always cause pain or causes only mild pain, in some cases the pain is more severe. The flank pain in this instance can make the individual literally writhe in agony. This is a rare symptom of hydronephrosis, and definitely requires medical attention.

Cloudy Urine

Urine color can vary depending on your water intake, with normal urine appearing to be a light straw color. Just because you don’t have visible blood in your urine doesn’t mean you don’t have hydronephrosis. Cloudy urine could be a sign of this, as cloudy urine is as abnormal as pink urine. Essentially, if your urine is not clear, you may have an infection.