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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

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.

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Medical Editor:

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.

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In this Article

• What is hydronephrosis?
• What causes hydronephrosis?
• What are the symptoms of hydronephrosis?
• When should I seek medical care for hydronephrosis?
• How is hydronephrosis diagnosed?
• What is the treatment for hydronephrosis?
• What are the complications of hydronephrosis?
• Can hydronephrosis be prevented?
• Hydronephrosis At A Glance
• Patient Comments: Hydronephrosis - Treatment
• Patient Comments: Hydronephrosis - Cause
• Hydronephrosis Index

There are numerous conditions that will cause hydronephrosis. Sometimes the diagnosis is relatively easy. For example, when a patient has symptoms and signs of writhing flank pain and blood in the urine, and he or she has a family history of kidney stones, the clinical diagnosis of renal colic from a kidney stone may be considered but still needs to be confirmed. Sometimes the diagnosis is difficult and is found during the evaluation of a patient who complains of weakness and is found to be in kidney failure.

The diagnosis begins with taking a history of the signs and symptoms that the patient experiences. The health care practitioner may want to 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.