Renal vein thrombosis

Renal vein thrombosis is rare in adults. The thrombus may occur in the inferior vena cava or in small branches of the renal vein.

Causes renal vein thrombosis

The lesion is most often unilateral. It usually occurs against the background of:

• ongoing ascending thrombosis of the inferior vena cava;
• venous congestion due to congestive heart failure in the decompensation stage;
• disorders of the blood coagulation system, conditions leading to blood thickening - nephrotic syndrome, erythremia;
• membranous nephropathy;
• antiphospholipid syndrome.

Other causes of renal vein thrombosis include kidney cancer and retroperitoneal masses. In children, renal vein thrombosis may occur as a result of severe dehydration with profuse diarrhea.

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Symptoms renal vein thrombosis

Symptoms of renal vein thrombosis are characterized by edema, venous damage to the kidney and secondary damage to the nephrons. Acute renal vein thrombosis is manifested by sharp pain in the lumbar region on the affected side, hematuria of varying intensity, with bilateral thrombosis a decrease in diuresis is possible; with right-sided damage, pain is observed in the right side.

Chronic renal vein thrombosis develops after an acute initial phase with pain and hematuria or as a primarily chronic condition. Pain, if present, is mild, dull, aching; hematuria is visually imperceptible in most cases, but proteinuria due to the developed renal venous hypertension quickly reaches the nephrotic level and leads to characteristic nephritic edema; arterial hypertension is possible, but not characteristic.

In some patients with slowly developing thrombosis, adequate blood flow through collateral vessels has time to form, and the patients do not present any significant complaints at all.

Forms

Renal vein thrombosis can be unilateral or bilateral, acute or chronic.

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Diagnostics renal vein thrombosis

If this disease is suspected, special attention should be paid to collecting the anamnesis, since isolated primary thrombosis of the renal veins is practically impossible. The question of the tendency to recurrent venous thrombosis and thromboembolism, as well as the therapy being administered, is very important. Thrombosis can be provoked by inadequate intake of anticoagulants. With an obvious clinical picture of circulatory failure, it should be borne in mind that thrombosis develops with severe right ventricular failure, which leads to stagnation of blood in the veins of the systemic circulation. Nephrotic syndrome, which can lead to venous thrombosis, should be extremely decompensated.

In both circulatory failure and nephrotic syndrome, renal vein thrombosis can be provoked by an attempt to achieve compensation by prescribing loop diuretics, especially in large doses and for a long time. Finally, any recurrent venous thrombosis without apparent cause, including renal veins, is very characteristic of malignant tumors, and the first manifestation of the disease can be thrombosis. The outcome of the disease is nephrosclerosis, but with adequate treatment, restoration of kidney function is possible.

In acute renal vein thrombosis, physical methods can detect pain in the lumbar region on the affected side and blood in the urine.

In chronic thrombosis, nephrotic-type edema is detected by examination and palpation. It is essential to pay attention to signs of venous congestion in the lower extremities, swelling of the lower half of the body, which may indicate a violation of blood outflow through the inferior vena cava, as well as developed venous collaterals of the anterior abdominal wall.

Laboratory diagnostics of renal vein thrombosis

In the general urine analysis, acute renal vein thrombosis is characterized by hematuria, which can be very pronounced. In chronic renal vein thrombosis, microhematuria is detected, and most importantly, proteinuria, which can reach nephrotic levels (more than 3.5 g / day). In patients with proteinuria, hyaline casts are naturally detected.

Determination of daily proteinuria is indicated with any increase in protein excretion to assess its actual losses. With daily proteinuria of 3.5 g or more, the probability of developing nephrotic syndrome is high. A general blood test may reveal thrombocytopenia. A biochemical blood test may reveal an elevated creatinine level (especially with bilateral thrombosis), and with nephrotic syndrome - hypoproteinemia, hyperlipidemia.

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Instrumental diagnostics of renal vein thrombosis

Survey and excretory urography in the acute phase of the disease reveals an enlargement of the affected kidney and a characteristic decrease in its function up to its complete absence. Sometimes filling defects due to blood clots are visible in the renal pelvis. Indentations corresponding to dilated collateral veins are sometimes visible along the contours of the proximal part of the ureter.

Cystoscopy, which is indicated in the presence of hematuria, can reveal the release of blood-stained urine through one of the ureters, which allows one to determine the side of the lesion and also to clearly exclude glomerulonephritis.

A coagulogram is required as soon as possible to assess hemocoagulation. Without a coagulogram, the administration of anticoagulants or hemostatic drugs in case of suspected renal vein thrombosis is contraindicated.

Ultrasound of the kidneys with Dopplerography allows for a quick assessment of the condition of the kidneys and main renal vessels. The value of this method lies in its relative simplicity and availability around the clock.

Radioisotope renography and dynamic nephroscintigraphy are performed routinely mainly to assess the symmetry of nephropathy. In chronic renal vein thrombosis, even bilateral, kidney damage is always asymmetrical, while in immune nephropathies it is always symmetrical.

CT and MRI are informative diagnostic methods.

Selective renal venography is the main diagnostic method that allows the most reliable determination of the nature and extent of damage to the renal veins, although the diagnosis can sometimes be made by performing cavagraphy.

Indications for consultation with other specialists

All individuals with suspected renal venous hypertension should consult a urologist (or, if unavailable, a vascular surgeon) and a radiologist - an angiography specialist. If the patient has proteinuria and if it is necessary to exclude glomerulonephritis, a nephrologist should be consulted.

Differential diagnosis

Acute renal vein thrombosis must be differentiated primarily from renal colic. The fundamental difference is proteinuria. Renal colic is not characterized by any significant proteinuria, while it is natural with renal vein thrombosis. Usually, the situation is resolved by performing an ultrasound (preferably with Doppler). Severe hematuria, especially with clots, may suggest a possible tumor of the kidney or urinary tract.

In case of severe proteinuria, it is necessary to exclude various forms of chronic glomerulonephritis occurring with nephrotic syndrome first of all. This issue is quite complicated, since nephrotic syndrome itself can be the cause of venous thrombosis. Severe proteinuria with scanty urinary sediment may require differential diagnosis with renal amyloidosis, especially if the patient has at least a slight decrease in glomerular filtration. Renal biopsy, which usually allows to clearly differentiate various forms of glomerulonephritis, amyloidosis, if the disease is suspected, becomes dangerous due to the high risk of bleeding from dilated intrarenal veins.

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Treatment renal vein thrombosis

Indications for hospitalization

Acute renal vein thrombosis is an absolute indication for hospitalization. If chronic renal vein thrombosis is suspected, hospitalization for inpatient examination is also indicated.

In addition, the severity of the condition of such patients with the underlying disease, against which renal vein thrombosis occurs, as a rule, also requires inpatient treatment.

In case of severe hematuria, strict bed rest is indicated.

Drug treatment of renal vein thrombosis

If the diagnosis is confirmed, it is quite legitimate to attempt thrombolysis using direct anticoagulants - sodium heparin or low-molecular heparins, such as sodium enoxaparin (Klexane) 1-1.5 mg/(kg x day). Obviously, such treatment of renal vein thrombosis is contraindicated in the presence of even slight hematuria. Thrombolysis is also effective, which can lead to restoration of kidney function. In addition to anticoagulant therapy, children are shown correction of water and electrolyte disorders.

Severe hematuria is an indication for immediate initiation of hemostatic therapy, even despite some probability of progression of venous thrombosis. Usually, etamsylate 250 mg 3-4 times a day intramuscularly or intravenously is started.

Drug treatment of chronic renal vein thrombosis is extremely difficult. If proteinuria is not immune, but is associated exclusively with renal venous hypertension, then immunosuppressive therapy (glucocorticoids, cytostatics) will be obviously ineffective. Prescribing diuretics is quite dangerous, since the thickening of the blood they cause naturally increases the risk of thrombosis progression. If absolutely necessary, diuretics can be prescribed in combination with anticoagulants. Anticoagulant therapy for chronic thrombosis should be carried out in all patients who do not have severe hematuria.

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Surgical treatment of renal vein thrombosis

Surgical treatment of renal vein thrombosis involves removing the thrombus from the renal vein and restoring its patency. If irreversible changes in the kidney occur, with severe hematuria, and also if the patient's condition is severe due to the underlying disease, nephrectomy may be required. Obviously, nephrectomy is contraindicated in the case of bilateral thrombosis.

A patient who has had renal vein thrombosis is prescribed long-term (almost lifelong) intake of indirect anticoagulants - warfarin 2.5-5 mg under the control of the international normalized ratio (INR, target INR level 2-3). It is worth noting that the entire group of indirect anticoagulants, including warfarin, has many drug interactions, which must be taken into account when prescribing any medications.

Prevention

Screening is not performed because the condition is so rare.

Renal vein thrombosis can be prevented by adequately treating the diseases that are naturally complicated by this condition - nephrotic syndrome, antiphospholipid syndrome, decompensation of circulatory failure, erythremia, etc.

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Forecast

In renal vein thrombosis, the prognosis is usually determined by the underlying disease that led to such a complication. It should be noted that this pathology develops only with a severe, extremely unfavorable course of the underlying disease.

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