Renal vein thrombosis is thrombotic occlusion of one or both main renal veins, resulting in acute kidney injury or chronic kidney disease. Common causes include nephrotic syndrome, primary hypercoagulability disorders, malignant renal tumors, extrinsic compression, trauma, and rarely inflammatory bowel disease. Symptoms of renal failure and sometimes nausea, vomiting, flank pain, gross hematuria, decreased urine output, or systemic manifestations of venous thromboembolism may occur. Diagnosis is by CT, magnetic resonance angiography, or renal venography. With treatment, prognosis is generally good. Treatment is anticoagulation, support of renal function, and treatment of the underlying disorder. Some patients benefit from thrombectomy or nephrectomy.
Etiology of Renal Vein Thrombosis
Renal vein thrombosis usually results from local and systemic hypercoagulability due to nephrotic syndrome associated with membranous nephropathy (most often), minimal change disease, or membranoproliferative glomerulonephritis. The risk of thrombosis due to nephrotic syndrome appears to be proportional to the severity of the hypoalbuminemia. Overly aggressive diuresis or prolonged high-dose corticosteroid treatment may contribute to thrombosis of the renal vein in patients with these conditions.
Other causes include
Estrogen therapy
Pregnancy
Primary hypercoagulability disorders (eg, , protein C deficiency, protein S deficiency, factor V Leiden mutation, prothrombin G20210A mutation)
Renal vasculitis
Sickle cell nephropathy
Less common causes are related to reduced renal vein blood flow and include malignant renal tumors that extend into the renal veins (typically renal cell carcinoma), extrinsic compression of the renal vein or inferior vena cava (eg, by vascular abnormalities, tumor, retroperitoneal disease, ligation of the inferior vena cava, aortic aneurysm), oral contraceptive use, trauma, dehydration and, rarely, thrombophlebitis migrans and .
Symptoms and Signs of Renal Vein Thrombosis
Usually, onset of renal dysfunction is insidious. However, onset may be acute, causing renal infarction with nausea, vomiting, flank pain, gross hematuria, and decreased urine output.
When the cause is a hypercoagulability disorder, signs of venous thromboembolic disorders (eg, deep venous thrombosis, pulmonary embolism) may occur. When the cause is a renal cancer, its signs (eg, hematuria, weight loss) predominate.
Diagnosis of Renal Vein Thrombosis
Vascular imaging
Renal vein thrombosis should be considered in patients with renal infarction or any unexplained deterioration in renal function, particularly in patients with nephrotic syndrome or other risk factors.
The traditional diagnostic test of choice and the standard is venography of the inferior vena cava; this test is diagnostic, but it may mobilize clots. Because of the risks of conventional venography, magnetic resonance venography and CT angiography are being used increasingly.
CT angiography provides good detail with high sensitivity and specificity and is fast but requires administration of a radiocontrast agent, which may be nephrotoxic and should be avoided if the glomerular filtration rate (GFR) < 30 mL/minute. Magnetic resonance venography with gadolinium contrast also risks nephrogenic systemic fibrosis (NSF) in patients with decreased GFR, but can be done with group II gadolinium contrast agents if medically necessary to minimize potential risk of NSF. Doppler ultrasonography sometimes detects renal vein thrombosis but has high false-negative and false-positive rates. Notching of the ureter due to dilated collateral veins is a characteristic finding in some chronic cases.
Serum electrolytes and urinalysis are done and confirm deterioration of renal function. Microscopic or gross hematuria is often present, and serum lactate dehydrogenase (LDH) can be markedly elevated in acute renal vein thrombosis. Proteinuria may be in the nephrotic range.
If no cause is apparent, testing for hypercoagulability disorders should be initiated (see Thrombotic Disorders). Renal biopsy is nonspecific but may detect a coexisting renal disorder.
Treatment of Renal Vein Thrombosis
Treatment of underlying disorder
Anticoagulation
For acute renal vein thrombosis, thrombolysis and sometimes thrombectomy, usually percutaneous catheter-directed thrombectomy
The underlying disorder should be treated.
nephrotic syndrome) is present, indefinitely.
Patients with acute renal vein thrombosis and AKI should undergo thrombolytic therapy with or without thrombectomy. Use of a percutaneous catheter for thrombectomy or thrombolysis is currently recommended. Surgical thrombectomy is rarely used but should be considered if it cannot be treated with percutaneous catheter thrombectomy and/or thrombolysis.
Prognosis for Renal Vein Thrombosis
Death is rare and usually related to complications such as pulmonary embolism and those due to nephrotic syndrome associated with malignancy.
Key Points
The most common cause of renal vein thrombosis is nephrotic syndrome associated with membranous nephropathy.
Consider renal vein thrombosis in patients with renal infarction or any unexplained deterioration in renal function, particularly those who have nephrotic syndrome or other risk factors.
Confirm the diagnosis with vascular imaging, usually magnetic resonance venography (if GFR > 30 mL/minute) or CT angiography.
Treat the underlying disorder and initiate anticoagulation, thrombolysis, or thrombectomy.
