Hydronephrosis

Hydronephrosis is a disorder of the kidneys, the organs that remove liquid waste, or urine, from the body. In patients with hydronephrosis, a blockage or other problem with the flow of urine causes the kidneys to overfill and swell. Hydronephrosis may occur in one or both kidneys and in people of all ages, including unborn babies. Depending on its causes and severity, hydronephrosis is generally highly treatable.

Background

Most people have two kidneys, bean-shaped organs about the size of a fist. The kidneys are located near the bottom of the rib cage, with one kidney on each side of the spine. Kidneys are an essential part of the urinary tract, the physical system that removes liquid waste, or urine, from the body.

The kidneys begin the process of creating urine by filtering used and unneeded materials from the bloodstream. This fluid waste material gathers in the renal pelvis, a part of the kidney, and then travels via a small tube known as the ureter. From there, the urine collects in the bladder. When the bladder is full, the urine passes through another narrow tube, the urethra, from which it leaves the body.

Kidneys are essential to the healthy functioning of the body. In humans, kidneys can filter about two hundred quarts of blood each day. From this, all but about two quarts are cleaned and reused, while the remainder is passed out of the body as urine. This process is necessary to keep the blood, and ultimately, the entire body free of waste and contaminants.

At times, the urinary system can be disrupted, leading to potentially serious problems. One such disruption is known as hydronephrosis, a condition in which urine stops passing along the correct route out of the body. In hydronephrosis, urine may be blocked from leaving the body or flow from the bladder back to the kidney. In either case, the kidney becomes overfull of urine.

Overview

Hydronephrosis refers to the swelling of one or both kidneys caused by urine being trapped in the kidney due to a blockage or other drainage problem. People of all ages may experience hydronephrosis, including unborn babies. Hydronephrosis among fetuses may even be discovered in the womb through ultrasounds.

In many cases, mild forms of hydronephrosis do not cause noticeable symptoms. More severe cases often lead to pain, either at all times or during urination. The pain may be in the flank (side and back of the body) near the kidneys or travel through the groin and abdomen. Other urinary problems may also be symptoms of hydronephrosis. These problems include urgent or frequent urination or pain while urinating. Sometimes, more generalized symptoms include fever, nausea, and vomiting.

If a medical expert suspects hydronephrosis, the next step is often an ultrasound. This device creates an image of the kidneys through sound waves. Other means of examining the kidneys include magnetic resonance imaging (MRI), computerized tomography (CT), or a camera called a cytoscope that is inserted into the body. Additional tests that may provide evidence of hydronephrosis include blood and urine tests to determine how well the kidneys are functioning. Signs such as blood in the urine, infection, or urinary stones can be related to hydronephrosis cases.

Hydronephrosis results from disturbances to the system that drain urine from the kidneys. There are two main types of disturbance. One is a blockage within the urinary tract that reduces or stops the passage of urine. The blockage may occur between the kidney and ureter or between the ureter and bladder. The second main type of disturbance involves urine that is already in the bladder flowing backwards into the kidney, causing the kidney to become overfull and swell. This opposite flow is clinically termed vesicoureteral reflux.

The disturbances behind hydronephrosis may have several origins. Some of these include kidney stones, blood clots, or tumors in the pelvis or abdominal region. Other cases may stem from pregnancy, inflammation due to urinary tract infections, or scar tissue resulting from prior surgeries or injuries. Many of these causes develop through life experience, but some are present from birth.

Patients with hydronephrosis may have a wide variety of treatment options. Treatment plans generally vary significantly based on the causes and severity of the disorder in the individual. In patients with mild cases of hydronephrosis, treatment may not be necessary. Doctors may recommend simply monitoring the situation with the expectation that it will probably correct itself in a short time. This is often the case for people whose hydronephrosis is caused by another temporary condition, such as pregnancy.

Generally, patients who receive treatment for their hydronephrosis undergo three main processes. The first is generally to drain the affected kidney, removing the built-up urine and relieving the swelling. In many cases, this can be accomplished with a thin tube called a urinary catheter that is inserted into the body either through the urethra or a small incision and allows fluid to drain out. In severe cases, this drainage must be done quickly to minimize potential damage to the kidney.

The next main process involves treating the cause or causes of the hydronephrosis. For example, if a tumor or an enlarged prostate is causing the blockage, surgery or other forms of therapy will generally be applied to remove or reduce their size. In cases in which kidney stones are causing obstruction, different forms of treatment to break up the stones and avoid future stones will be applied. If the urinary channels are too narrow to allow drainage, doctors may elect to insert wideners called stints to restore proper urine flow.

The third main process relates to dealing with any damage to the kidney. If a kidney is severely damaged, doctors may elect to remove it. Humans generally have a pair of kidneys, but in most cases one would suffice. People who have lost a kidney generally function perfectly well with their other, remaining kidney.

In all patients with hydronephrosis, doctors may prescribe medications such as antibiotics that will help reduce the likelihood of infection. An infection of the urinary tract will cause additional problems and likely complicate the original case of hydronephrosis and any established treatment plans. Patients should discuss the medications with their doctor to be prepared for possible side effects and take their medicine as directed.

Bibliography

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