Hydronephrosis and Kidney

Hydronephrosis

Definition

Hydronephrosis is the swelling of the kidneys when urine flow is obstructed in any of part of the urinary tract. Swelling of the ureter, which always accompanies hydronephrosis, is called hydroureter. Hydronephrosis implies that a ureter and the renal pelvis (the connection of the ureter to the kidney) are overfilled with urine.

Description

The kidneys filter urine out of the blood as a waste product. It collects in the renal pelvis and flows down the ureters into the bladder. The ureters are not simple tubes, but muscular passages that actively propel urine into the bladder. At their lower end is a valve (the ureterovesical junction) that prevents urine from flowing backward into the ureter. The bladder stores urine. The prostate gland surrounds the bladder outlet in males. Urine then flows through the urethra and out of the body as a waste product.

Because the urinary tract is closed save for the one opening at the bottom, urine cannot escape. Instead, the parts distend. Rupture is rare unless there is violent trauma like an automobile accident.

Obstructed flow anywhere along the drainage route can cause swelling of the upper urinary tract, but if the obstruction is below the bladder, the ureterovesical valve will protect the upper tract to a certain extent. Even then, with no place to go, the urine will back up all the way to its source. Eventually, the back pressure causes kidney function to deteriorate.

Obstruction need not be complete for problems to arise. Intermittent or partial obstruction is far more common than complete blockage, allowing time for the parts to enlarge gradually. Furthermore, if a ureterovesical valve is absent or incompetent, the pressure generated by bladder emptying will force urine backward into the ureter and kidney, causing dilation even without mechanical obstruction.

Causes and symptoms

Causes are numerous. Various congenital deformities of the ureter may sooner or later produce back pressure. Kidney stones are a common cause. They form in the renal pelvis and become lodged in the kidney, usually at the ureterovesical junction. In older men, the continued growth of the prostate gland leads commonly to restricted urine flow out of the bladder. Prostate cancer, and cancer anywhere else along the urine pathways, can obstruct flow. Pregnancy normally causes ureteral obstruction from the pressure of the enlarged uterus (womb) on the ureters.

Symptoms relate to the passage of urine. Sometimes, urine may be difficult to pass, irregular, or uncontrolled. Pain from distension of the structures is present. Blood in the urine may be visible, but it is usually microscopic.

In all cases where bodily fluids cannot flow freely, infection is inevitable. Symptoms of urinary infection may include:

• painful, burning urine
• cloudy urine
• pain in the back, flank, or groin
• fever, sweats, chills, and generalized discomfort

Patients often mistake a serious urinary infection for the flu.

Kidney Cyst

Kidney Cysts

A cyst is a collection of fluid. Kidney cysts are very common (a third of us have one) and usually cause no problems. Occasionally, a cyst can increase in size and produce pain and a high blood pressure due to compression of the rest of the kidney. The first-line treatment of such a cyst is to drain it under a local anaesthetic as most will not re-fill. If the cyst does re-fill and continues to cause symptoms it is best dealt with by an operation.

The kidneys lie high in the abdomen, below the diaphragm and as a result can only be reached by traditional surgery through a large incision. The laparoscopic operation is performed through 3 x 5-10 mm cuts near the rib cage.

Although laparoscopy is a type of keyhole surgery, the view obtained is much better than looking through a keyhole. Modern equipment produces a wide, bright, clear and magnified view of the operation. The gas used to distend the abdomen during laparoscopy also greatly reduces bleeding during surgery.

Kidney Creatinine

Kidney function tests check how well the kidneys filter and transport waste materials from the blood into the urine.

Who is a candidate for the test?

Kidney function tests are usually ordered when a healthcare provider suspects a disease that may be affecting the kidneys. These tests are also used to monitor someone who already has kidney disease.

How is the test performed?

There are four major tests. Each test is described more fully in separate articles in this encyclopedia. They are:

 creatinine

 creatinine-urine

 creatinine clearance

 BUN

Creatinine and BUN are blood tests that measure metabolic breakdown products in the body. It is the role of the kidney to get these waste products into the urine. When the kidney does not work properly, these products are not put into the urine and the levels become elevated in the blood.

Urine creatinine measures the amount of creatinine that is excreted into the urine.

Creatinine clearance is a fairly precise way to estimate the exact amount of function a kidney has compared to normal. Any of these tests may be ordered to help measure kidney function. Which one is used often depends on the disease that is suspected.

Kidney Malfunction And Blood Tests

The kidneys have an important role of maintaining the balance of body fluids within the human body. They regulate the electrolyte concentrations, blood volume and also blood pressure.

They receive unfiltered blood from the heart and the filtration of blood is carried out within the kidneys and then the filtered blood is sent back to the heart. The kidney function involves removal of metabolic waste from the blood stream, regulating water balance in the body and maintaining acidity and alkalinity of body fluids.

An individual can live with one kidney as the renal tissue available in one kidney is sufficient to carry out its function. When the functioning tissue gets reduced it leads to kidney malfunction.

Blood urea nitrogen (BUN) is a blood test conducted to asses functioning of the kidneys. Urea is a waste product of the protein metabolism and formed in the liver. The kidneys filter urea from the blood and this gets excreted in the urine. BUN normal range is 7-20 mg/dl and if the result of the blood test shows a higher figure, then kidney malfunction is a possibility.

Serum creatinine is another blood test used for evaluating the kidney function. Creatine is a molecule used for energy production in muscles. About 2 percent of the body creatine gets converted to creatinine on a daily basis. Creatinine is transported to the kidneys through the blood stream. The kidneys carry out the filtration of creatinine for disposal in the form of urine. As the muscle mass remains unchanged, the creatinine level also remains unchanged on daily basis.

Hence, creatinine level test conducted on blood can reveal any malfunction of kidneys. The normal level of creatinine is 0.6-1.2 mg/dl for adult males and 0.5-1.1 mg/dl for adult females. The creatinine level in the blood will tend to rise if the kidney function has deteriorated.