• Medical Author:
    Benjamin Wedro, MD, FACEP, FAAEM

    Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

When should I seek medical care for hydronephrosis?

A person with acute hydronephrosis usually develops significant pain and needs emergent help with pain control.

Blood in the urine is never normal and should not be ignored. Most often in women, it is due to a bladder infection, but other causes include kidney stones, tumors, and occasionally is associated with appendicitis.

Individuals who have the diagnosis of hydronephrosis who develop a fever need to be seen immediately. If a urinary tract infection occurs and there is decreased urine flow, there is the risk of becoming very ill by developing bacteremia (blood stream bacterial infection).

Hydronephrosis is a true emergency in patients with only one kidney and should the person believe that the lone kidney is at risk, urgent medical care should be accessed.

How is hydronephrosis diagnosed?

The diagnosis begins with taking a history of the symptoms that the patient experiences. The health care practitioner will ask questions that will direct whether further tests need to be ordered. Reviewing the patient's past medical history and family history may be helpful.

Depending upon the situation and whether there is acute onset of symptoms, physical examination may reveal tenderness in the flank or where the kidneys are located. The bladder may be found to be distended when the abdomen is examined. Usually, in males, a rectal examination is done to assess the size of the prostate. In women a pelvic examination may be performed to evaluate the uterus and ovaries.

Laboratory tests

The following laboratory tests may be ordered depending upon what potential diagnosis is being considered.

  • Urinalysis to look for blood, infection or abnormal cells
  • Complete blood count (CBC) may reveal anemia or potential infection
  • Electrolyte analysis may be helpful in chronic hydronephrosis since the kidneys are responsible for maintaining and balancing their concentrations in the blood stream.
  • BUN (blood urea nitrogen), creatinine and glomerular filtration rate (GFR) are blood tests that help assess kidney function.

Imaging Studies

CT scan of the abdomen can be performed to evaluate the kidney anatomy and make the diagnosis of hydronephrosis. It also may allow the health care practitioner to look for the underlying cause including kidney stones or structures that are compressing the urinary collecting system. Depending upon the situation and the health care practitioner's concerns, the CT may be done with or without contrast dye injected into a vein, and with or without oral contrast (that the patient drinks) to outline the intestine. Most commonly, for kidney stones, neither oral nor intravenous contrast is needed.

Ultrasound is another imaging study that can be done to look for hydronephrosis. The quality of the test depends upon the skill of the ultrasonographer to evaluate the structures in the abdomen and retroperitoneum. Ultrasound is also useful in women who are pregnant where radiation concerns exist.

Intravenous pyelography (IVP) has mostly been replaced by CT scanning but does have a role in diagnosing some patients and its use is now limited.

KUB X-rays (an X-ray that shows the kidney, ureter, and bladder) are used by some urologists to classify a kidney stone as radiodense or radiolucent and may use KUB X-rays to determine if the stone is able to migrate down the ureter into the bladder.

Medically Reviewed by a Doctor on 9/2/2016

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