What Are the Signs & Symptoms of a Blood Clot in the Kidneys?

Renal vein thrombosis is a rare condition in which a blood clot forms in the renal vein, blocking the flow of blood from the kidneys to the heart. This can lead to kidney failure or another condition known as pulmonary embolism, in which all or part of the clot breaks off and travels to the lungs. Renal vein thrombosis typically occurs gradually in adults. However, the disease progresses much faster in children and poses a greater threat to their health.

A person who has renal vein thrombosis may experience pain in the upper back, a decrease in urine production or have blood in the urine. Chest pains and shortness of breath are symptoms that may occur if the clot has traveled to the lungs. Other symptoms include high blood pressure, fever, a sharp pain along one side of the body or an enlarged kidney. Some people will develop renal vein thrombosis and not have symptoms at all.

Dehydration, which can reduce blood volume and cause clotting, is the leading cause of renal vein thrombosis among babies and children. Among adults, the causes include any trauma to the back or abdomen that leads to scarring, which traps blood in the renal vein. Other conditions that can lead to clotting include kidney tumors in the renal vein that block blood flow. Nephrotic syndrome, a condition in which the kidneys are damaged, is another cause.

A physician can determine if a patient has renal vein thrombosis by manually checking the patient's abdominal area for signs of an enlarged kidney and by listening to the abdomen with a stethoscope to detect any unusual sounds that may indicate a blockage of blood flow in the renal vein. Blood and urine tests can also reveal the problems with clotting. A patient who has nephrotic syndrome may have an unusually high level of protein in the urine and high levels of cholesterol in the blood.

Anyone who is having symptoms of renal vein thrombosis should get medical help immediately. Babies and children will need emergency care if they have a fever of 102 degrees or higher, a sudden swelling in a leg or any other symptoms of this condition. Parents should also watch for signs of dehydration. This includes crying without tears, extreme weakness, sunken cheeks and abdomen and light-headedness. Other warning signs include excessive thirst, dark urine and dry mouth.

Intravenous fluids are the typical treatments for patients who develop renal vein thrombosis due to dehydration. In other cases, the treatment is focused on preventing the clot from traveling to the lungs, where it be life threatening. Blood thinners can help smooth out the clots. Sometimes, doctors will surgically remove the clot or the damaged section of the kidney. They will then open the blocked vein using flexible tubing. Some patients will need bed rest for a while.