Renal Vein Thrombosis: Causes, Symptoms & Treatment

Renal vein thrombosis is when a blood clot forms in a vein of the kidney. It is one of the vascular diseases and is usually the result of cancer.

What is renal vein thrombosis?

Renal vein thrombosis is a vascular disease. A thrombus forms in the renal vein (renal vein). Because of this vascular occlusion, blood stasis occurs within the kidney. In most cases, thrombosis of the renal vein manifests itself only very discreetly. Sometimes the disease is completely asymptomatic. A life-threatening complication of renal vein thrombosis is pulmonary embolism. Here, the blood clot travels from the renal vein via the right heart to the lungs, where it blocks a pulmonary artery. Despite this risk, patients with renal vein thrombosis are not usually operated on. Treatment is by medication with anticoagulants.

Causes

Thrombosis is always caused by a triad of decreased blood flow, increased coagulability of the blood, and damage to the inner lining of the vessel. This triad is also called the Volhard triad. The main cause of renal vein thrombosis is cancer. In most cases, this is renal cell carcinoma or another tumor from the retroperitoneal space. Second most common cause of renal vein thrombosis is nephrotic syndrome. Nephrotic syndrome is a symptom complex of proteinuria, hypoproteinemia, hyperlipoproteinemia, and edema. The syndrome usually develops on the basis of glomerulonephritis. Other causes of renal vein thrombosis include dehydration (for example, due to severe diarrhea or vomiting), metabolic disorders such as homocystinuria, autoimmune diseases, or thrombophilia. Renal vein thrombosis can also result from blunt trauma. Blunt trauma usually occurs in accidents. However, blows, abuse, or entrapment can also cause blunt trauma and, therefore, renal vein thrombosis. Some renal vein thrombosis also occurs without a known cause. This form is also known as idiopathic renal vein thrombosis. In general, the risk of renal vein thrombosis is significantly increased after a previous kidney transplant.

Symptoms, complaints, and signs

Renal vein thrombosis is often asymptomatic or very discrete. The most common symptom is pain in the flank area. Seventy-three percent of all patients with renal vein thrombosis experience flank pain. In 36 percent of cases, there is bloody urine (macrohematuria). The amount of urine drops to less than 200 milliliters per square meter of body surface. In medical terminology, this condition is called oliguria. Increased amounts of proteins are also excreted with the urine (proteinuria). Due to the loss of protein, water accumulation occurs in the tissues. These edemas often appear around the eyes. These complaints are accompanied by non-specific symptoms such as fatigue, nausea, fever or loss of appetite. In 50 percent of all patients, trembling of the hands (asterixis) is also found. If the thrombus dissolves spontaneously, the symptoms change. Some of the symptoms recede. However, if irreversible vascular damage has occurred, some of the symptoms may persist even after the clot dissolves.

Diagnosis and disease progression

Often, renal vein thrombosis is diagnosed only when renal values suddenly worsen in patients with nephrotic syndrome or when renal failure occurs. Laboratory tests may reveal a reduction in renal function. The glomerular filtration rate (GFR) is decreased. The creatinine concentration in the blood, on the other hand, is increased. Increased urinary substances remain in the blood. In individual cases, there may be a deficiency of protein-S or antithrombin in the blood. Red blood cells (erythrocytes) and proteins are found in the urine. To assess the extent of protein excretion, the so-called albumincreatinine quotient is determined in the urine. The concentration of albumin blood proteins in the urine is measured and related to the creatinine concentration in the urine. If the albumin-creatinine quotient is above 30 milligrams per liter, kidney disease is present. This form of pathological protein excretion is also known as albuminuria. The diagnosis is confirmed by imaging procedures such as Doppler ultrasound, computed tomography, magnetic resonance imaging, and arterio- and venography.Older studies report that 8 to 27 percent of all renal vein thromboses recur. However, more recent studies refute these findings. According to them, recurrent thrombosis occurs rather rarely. Patients who develop renal vein thrombosis on the ground of nephrotic syndrome do not have a reduced life expectancy. In contrast, life expectancy is decreased in patients with cancer. Patients treated with warfarin rather than Marcumar have a better prognosis.

Complications

The subsequent course of renal vein thrombosis depends on the progression of causative factors and whether the thrombosis is treated. If left untreated, one of the most serious complications is the possibility of pulmonary embolism. This happens when the blood clot (thrombus) breaks loose in the renal vein, travels from there to the right ventricle of the heart, and is then pumped into the pulmonary circulation, where it causes blockage of a pulmonary artery. Typically, renal vein thrombosis covers a wide range of symptoms. In some cases, the symptoms are below the threshold of perception, so usually no treatment is given either. If thrombosis presents with clear specific symptoms such as pain in the affected flank and bloody urine, further progression may lead to renal failure if left untreated. However, there are also known cases in which the blood clots have dissolved spontaneously and the symptoms have improved virtually by themselves. The extent to which symptoms resolve after spontaneous dissolution of the thrombus or after successful intervention depends on whether the kidney has already been irreversibly damaged. Treatment of the thrombus usually consists of attempting to dissolve the blood clot by administration of heparin. In severe cases in which the thrombus can be precisely localized, surgical removal of the clot may also be considered.

When should you see a doctor?

Renal vein thrombosis develops slowly and does not produce definite symptoms until the late stages. A physician must be consulted if pain occurs in the hips and back behind the lower ribs. If accompanying fever, nausea and vomiting, and blood in the urine are noticed, medical advice is required. If a pulmonary embolism is suspected, which manifests itself by sudden chest pain and shortness of breath, the emergency physician must be called. People suffering from cancer, especially carcinomas of the kidney cells and nephrotic syndromes, are among the high-risk patients. There is also an increased risk after surgical interventions as well as thromboembolism, which is why patients must inform the doctor immediately in these cases. Infants suffering from sepsis, cystic kidneys or dehydration must be presented to the pediatrician if signs of renal vein thrombosis appear. Renal vein thrombosis is treated by the general practitioner or a nephrologist. Individual symptoms may be evaluated and treated by urologists, gynecologists, gastroenterologists, and venous disease specialists.

Treatment and therapy

Surgical removal of the blood clot is possible. However, because of the potential complications, this surgical procedure is rarely performed. Usually, anticoagulants are used for therapy. Anticoagulants are drugs that inhibit blood clotting. They are therefore also called anticoagulants. In renal vein thrombosis, the anticoagulants heparin and Marcumar are used. Heparins are multisugars that inhibit the clotting cascade in the blood. The protease inhibitor antithrombin III circulates in the blood and can inhibit activated clotting factors such as thrombin or factor Xa. Both factors cause the blood to clot. Heparin binds to antithrombin III, causing it to bind much faster to the clotting factors and inactivate them. This is why heparin is used to treat thrombosis. Marcumar also has an anticoagulant effect. It reduces the amount of clotting factors II, VII, IX and X. With the help of heparin and Marcumar, the thrombus in the renal vein should dissolve. Treatment must be continued for at least six months. To prevent further thrombosis, lifelong treatment with the anticoagulant drugs may be required.

Outlook and prognosis

The prognosis of renal vein thrombosis must be determined according to the individual causative findings.However, it is a serious disease that can basically be fatal if the course of the disease is unfavorable. It is a medical emergency requiring the fastest possible action to ensure the survival of the affected person. The risk of renal vein thrombosis is significantly increased in people who have had a kidney transplant. If the transplant succeeds without further complications, recovery is possible. The affected person is nevertheless bound to lifelong medical control due to the health issue at hand. If the thrombosis was caused by a violent event, there is a good chance of recovery in the further course. The prerequisite for this is that there are no further external influences in this region of the body. The prognosis is worse in patients who have been diagnosed with cancer. If this is causally responsible for the development of the thrombosis, the overall situation must be examined more closely. If the cancer can be treated successfully, the further outlook improves and relief from the symptoms can be expected. In an advanced stage, however, a shortening of life is to be expected. If severe diarrhea and dehydration are present, this is also a medical emergency. If this can be treated successfully, a cure is possible.

Prevention

Renal vein thrombosis can be prevented only by early treatment of the underlying disease.

Follow-up care

Because of the fairly high recurrence rate of up to 27 percent, follow-up is certainly warranted. This recurrence of renal vein thrombosis is usually due to deeper thromboses in the leg veins, which may also be evident in the renal veins. Other follow-up measures depend on the symptomatology and cause of the renal vein thrombosis. If, for example, dehydration or deficiency symptoms were the cause, these must be urgently compensated for during or after treatment. Good water intake and a vitamin-rich diet increase blood and vascular health and can restore damaged tissue accordingly. It also reduces the chance that thrombosis will recur. Follow-up in this manner is most useful in older patients. In younger patients, renal vein thrombosis usually has other causes. Treatment with anticoagulants also entails follow-up. Imaging techniques and blood tests can be used to evaluate the success of the therapy. If surgical measures become necessary, appropriate follow-up care must be provided. This is usually necessary in the case of cystic kidneys or cancer. Depending on the patient’s condition, follow-up care may also take place as an inpatient. In the case of cancer in children, in which nephroblastoma in particular is often the causative factor, follow-up examinations that are carried out again and again are sometimes useful. If renal vein thrombosis has been treated and the underlying cause eliminated, follow-up is often no longer necessary.

What you can do yourself

In renal vein thrombosis, the patient has few options for self-help. In most cases, there are other underlying conditions that must be treated and therapized for improvement to occur. Although there is little the patient can do to change the situation physically, there is much he can do to improve his vitality and well-being. With a healthy and balanced diet he supports his immune system. This provides the organism with more defenses in the fight for a cure. Sufficient exercise and a continuous supply of oxygen also help to mobilize one’s forces. Overweight or a strong increase of the own weight are not recommended. The body’s own weight should be within the recommendations of the BMI. The consumption of harmful substances such as nicotine, alcohol or other drugs should be refrained from. These trigger weakening of the patient and lead to an increase in symptoms. With an optimistic basic attitude, the affected person can do a lot for himself. Leisure activities should be organized despite all adversities. As a result, the motivation to live increases and feelings of happiness are produced. For help and support, advice can be sought from other sufferers in self-help groups or Internet forums. The mutual exchange can improve the handling of the complaints in everyday life.