A Case of Isolated Unilateral Right Renal Vein Thrombosis Associated with Bilateral Pulmonary Embolism Treated with Rivaroxaban a Direct-Acting Oral Anticoagulant

Background

Renal vein thrombosis is a rare clinical condition, with an etiology that varies according to patient age. In the elderly, renal vein thrombosis occurs in patients following trauma, infection, or malignancy. In young adults and children, renal vein thrombosis can be associated with nephrotic syndrome, especially membranous glomerulonephritis [1,2]. Usually, most cases of renal vein thrombosis are bilateral, but in unilateral cases of renal vein thrombosis, the left renal vein is more frequently involved than the right renal vein [1,2].

This report is of a case of unilateral renal vein thrombosis affecting the right renal vein complicated by bilateral pulmonary embolism in a previously healthy adult woman without comorbidities.

Case Report

A 44-year-old woman who was previously healthy presented to the emergency room with dyspnea of recent onset associated with compressive chest pain. Her past surgical history included two births by cesarean section. In the emergency room, her blood pressure was 170/110 mmHg, her temperature was 37°C, her heart rate was 110 bpm, and her oxygen saturation was 85% while breathing ambient air.

Physical examination was unremarkable for cardiopulmonary findings, and she had a regular pulse, and normal bilateral air entry on chest auscultation. Laboratory studies showed a white blood cell (WBC) count of 15×109/L, hemoglobin of 13.3 g/dl, a creatinine of 0.78 mg/dl, C-reactive protein (CRP) of 2, a troponin of 7 ng/l, and a positive D-dimer test. The electrocardiogram (ECG) showed T-wave inversion in the anteroseptal ECG leads and sinus tachycardia. Chest X-ray showed no acute cardiopulmonary abnormalities. Transthoracic echocardiography performed in the emergency room showed a dilated right ventricle with pulmonary arterial hypertension of 45 mmHg, a normal left ventricular ejection fraction of 65%, with no wall motion abnormalities. Pulmonary computed tomography (CT) angiography showed bilateral proximal pulmonary embolism with an abnormal renal cortex (Figure 1).

Investigations of an underlying cause of bilateral pulmonary embolism in a previously healthy woman included tests for acquired or inherited coagulopathy, and mammography and bilateral lower extremity duplex ultrasonography, which were all normal. However, enhanced CT of the abdomen and pelvis showed a thrombus in the right renal vein extending into the lumen of the inferior vena cava (Figure 2).

The patient was diagnosed with renal vein thrombosis with bilateral pulmonary embolism. She was treated successfully by oxygen support and intravenous heparin infusion followed by treatment for one year with rivaroxaban, a direct-acting oral anticoagulant (DOAC). At three-month follow-up after discharge from hospital, her oxygen saturation was 97% in room air, and she was performing her normal daily activities without limitations.

Discussion

The management of renal vein thrombosis has progressed from invasive strategies such as nephrectomy or thrombectomy to medical treatment. The treatment of renal vein thrombosis depends on the underlying etiology. The majority of cases of renal vein thrombosis reported in the literature were associated with nephrotic syndrome. Atorvastatin, angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers in cases of nephrotic syndrome complicated with renal vein thrombosis may slow the progression of kidney injury and reduce proteinuria [3,4]. Also, steroids, cyclosporine, and immunosuppressive therapies have benefits in the treatment of membranous glomerulonephritis, and surgery is used only for cases of renal vein thrombosis associated with early-stage renal cell carcinoma [3,4].

There are clinical guidelines for thrombolysis in renal vein thrombosis, but there are guidelines for the management of pulmonary thromboembolism and pulmonary hypertension. For cases of renal vein thrombosis with recurrent thromboembolic events despite medical therapy, an inferior vena cava filter placed below or above the renal veins may be considered [3].

Some studies recommend the use of warfarin for prevention of thromboembolism in patients with renal vein thrombosis [7]. A recent study established the efficacy of using the direct-acting oral anticoagulant (DOAC), apixaban, as a prophylactic treatment for thromboembolic events in cases of nephrotic syndrome [5]. Previous studies have shown that anticoagulation either by warfarin or novel oral anticoagulants (NOACs) should be initiated when renal vein thrombosis is complicated with pulmonary embolism or other thromboembolic events. Minimum duration of treatment for one year is recommended or until resolution of nephrotic syndrome [3–9].

In this case report, the unusual characteristics of renal vein thrombosis were found, and the case was unilateral, affecting the right renal vein, complicated by bilateral pulmonary embolism. This patient did not have nephrotic syndrome. Given the lack of clinical management guidelines, and taking into consideration previously published studies, rivaroxaban was used as it was previously described in patients with nephrotic syndrome and coagulopathies [8,9]. In this case, heparin infusion followed by treatment with rivaroxaban for one year was chosen, with a good outcome at three-month after discharge from hospital.

Conclusions

In this case, unilateral right renal vein thrombosis in a previously healthy 44-year-old woman was diagnosed after bilateral pulmonary embolism and managed by intravenous heparin infusion and direct oral anticoagulation (DOAC) with rivaroxaban with good clinical outcome.