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Treatment of Inferior Vena Cava and Renal Vein Thrombosis With Low- Molecular-Weight Heparin in a Child With Idiopathic Membranous Nephropathy

Posted on: Friday, 17 December 2004, 03:00 CST

Introduction

Nephrotic syndrome (NS) is associated with an increased tendency for thromboembolic complications in both children and adults. The reported incidence is 1.5% to 66% among children, and patients with secondary forms of nephrotic syndrome have a higher incidence of thrombotic events than children with steroidsensitive idiopathic nephrotic syndrome.1 In adults, those patients with membranous nephropathy have the greatest risk for developing thrombi.2 However, this is not true for children with idiopathic membranous nephropathy. Although deep vein thrombosis, renal artery thrombosis, and pulmonary embolism are the most common, axillary, subclavian, femoral, coronary, mesenteric, and inferior vena cava are also reported.3-5 We report a patient with membranous nephropathy who presented with fever, dehydration, and abdominal pain. An abdominal computed tomography (CT) scan showed thrombi in the inferior vena cava (Figure 1) and the right renal vein. She was treated successfully with low-molecular-weight heparin. A repeat CT scan showed complete resolution of both thrombi.

Patient Report

A 13-year-old Caucasian female presented with a 1-day history of diffuse abdominal pain and vomiting. She had a history of nephrotic syndrome secondary to idiopathic membranous nephropathy that was diagnosed 4 months before. Although she had poor compliance with nephrology follow-ups, she was doing well until 1 day previous to admission, when she started to have these symptoms. There was no history of recent illness, sick contacts, or trauma. The patient also had been afebrile until the day of admission. Her past medical history was negative other than nephrotic syndrome. Her birth history and family history were noncoiitributory.

On admission, the patient's vital signs were as follows: temperature 101.4F, pulse 125 bpm, respiration rate 20 minutes, and blood pressure 94/47 mmHg. The patient looked weak, tired, and acutely ill. Mild periorbital edema was noted bilaterally. Mucous membranes were dry. There was no murmur, click, or gallop noted with cardiac examination. The patient had clear breath sounds on both lung fields. Abdominal examination revealed a fluid wave and tenderness to palpation on all 4 quadrants. The patient described the pain as a burning sensation all over her abdomen. Her extremities showed pitting edema (2+). Pulses were adequate on both lower and upper extremities.

The pertinent laboratory results included white blood count 20,700/mm with 80% polys, 11% bands, 5% lymphocytes, and 3% monocytes. The hemoglobin was 9.8 g/dL and hematocrit and platelet count were 29% and 247,000/L, respectively. A complete metabolic panel demonstrated decreased sodium 133 meq/L, calcium 6.5 mg/dL, total protein 3.7, and albumin 1.5 g/dL. The urinalysis showed a specific gravity of 1.030, 3+ protein, and 3+ blood. The protein:creatinine ratio for this patient was 2.81. Her hepatitis panel and HIV were negative.

Figure 1. A. Midsagittal contrast-enhanced CT scan showing a 6- cm partially occluding thrombus in the inferior vena cava (black arrow). B. Axial CT scan showing a large thrombus in the inferior vena cava before treatment with low-molecular-weight heparin (white arrow).

The patient was seen by her pediatrician, and a computed tomography (CT) scan was performed at an outlying hospital before her transfer. The CT scan revealed a nonocclusive thrombus in the inferior vena cava (IVC) approximately 6 cm in length from the level of renal vessels. There was also a thrombus in the right renal vein. There was also moderate ascites as well as a pleural effusion. Thus, additional laboratory tests showed the following: prothrombin time (PT) 14 seconds with international normalized ratio (INR) of 1.28 partial thromboplastin time (PTT) 35.5 seconds, and d-dimer more than 1. Fibrinogen and factor VIII were also increased at 627 mg/dL and 350% respectively, whereas antithrombin III was decreased at 52%. The patient was admitted with a diagnosis of thrombus in the IVC and suspected peritonitis. She received 2 normal saline boluses followed by an albumin infusion at the emergency room. A blood culture was obtained and the patient was started on a cefotaxime regimen. Low-molecular-weight heparin (LMWH) was also started to treat the IVC thrombus, as recommended by hematology/oncology. Anticoagulation was monitored with anti-Xa levels.

On day 2 of hospital stay, the patient began to show clinical improvement. She was able to keep oral intake without vomiting, and the diffuse edema on her lower extremities and back started to resolve. The patient continued to have a fluid wave in the abdomen; however, no diffuse tenderness was noted with palpation.

Additional coagulation study results were as follows: slightly increased antiphospholipids antiboby level of 38.3 and lupus anti- coagulant ratio 1.36, normal protein C and S values 83 and 53, respectively, and low heparin antiXa LMWH 0.10. No prothrombin gene or factor V Leiden mutations were found.

The patient continued to improve clinically throughout her hospitalization. She remained on the cefotaxime regimen and her fever resolved after a few days. The patient was discharged to home with home LMWH therapy. Follow-up nephrology and hematology appointments were made in order to monitor her LMWH levels closely as well as ensure the resolution of the thrombus. A repeat CT scan, done 3 weeks later, revealed complete resolution of thrombus in the IVC. Thus, the decision was made to switch LMWH to coumadin and to continue anticoagulation therapy for 6 additional months.

Discussion

Patients with nephrotic syndrome who have low serum albumin, high fibrinogen levels, low antithrombin-III levels, and hypovolemia are at increased risk to develop thromboembolic events.2,6 Venous thrombosis could result in life-threatening complications. Therefore, early diagnosis and treatment are crucial.

Early treatment options include nephrectomy or thrombectomy.3 Both methods are invasive and associated with significant complications. More recently, the administration of systemic imfractionated heparin or oral coumadin has replaced nephrectomy and thrombectomy. However, the use of unfractionated heparin is associated with certain disadvantages such as unpredictable anticoagulant response or complications such as thrombocytopenia, bleeding, and osteoporosis.7 LMWH offers several advantages over unfractionated heparin. These include the following: more predictable anticoagulant response, better bioavailability, longer half-life, fewer complication rate, and convenience of subcutaneous administration.

The thrombi in our patient could have resulted from several risk factors such as hypoalbuminemia, dehydration, and increased fibrinogen levels. Her case was also complicated by the initial presentation, which was suggestive of peritonitis. Unfortunately, we were not able to obtain a sample of peritoneal fluid. However, her condition improved significantly after the administration of intravenous antibiotics.

An extensive evaluation was pursued in order to exclude additional risk factors for thrombosis and the results were normal. Although adults with membranous nephropathy have an increased risk for thrombosis, this is not the case in children. This is only the second case report of venous thrombosis in a child with membranous nephropathy. The diagnosis of renal vein thrombosis should be considered in those patients with nephrotic syndrome who present with risk factors for the development of this condition. This is valid even in children with membranous nephropathy. Our case suggests that LMWH is an effective alternative for the treatment of venous thrombosis.

REFERENCES

1. Abella EM. Hemostatic problems associated with renal disease. Int J Pediatr Hematol Oncol. 1994;1:43-51.

2. Hoyer PF, Gonda S, Barthels M, et al. Thrombocmbolic cotnplicalioiis in children with ncphrotic syndrome. Ada Paediatr Scand. 1986;75:804-810.

3. Bernard DB. Extrarenal complication of the nephrolic syndrome. Kidney Int. 1988;33:1184-1202.

4. Drijfhoul HH, Knot EAR, Cate JW. Antithrombin III metabolism in two patients with a ncphrotic syndrome caused by minimal change nephritis and primary amyloidosis. Haemoslasis. 1987;17:286-292.

5. Mehls O, Andrassy K, Koderisch J, et al. Hemostasis and thromboembolism in children with nephrotic syndrome: differences from adults. J Pediatr. 1987;110:862-867.

6. Llach F. Hypercoagulability, renal vein thrombosis, and other thrombotyc complication in nephrotic syndrome. Kidney Int. 1985;28:429-439.

7. Bromberg WD, Firlit CF. Fibrinolytic therapy for renal vein thrombosis in the child. J Urol. 1990;143:86-88.

Mari Suto, MD

Diego H. Aviles, MD

Clin Pediatr. 2004;43:851-853

Department of Pediatrics, LSU Health Sciences Center and Children's Hospital, New Orleans, USA.

Reprint requests and correspondence to: Diego H. Aviles, MD, Associate Professor of Pediatrics, Louisiana State University School of Medicine, 1542 Tulane Avenue, T8-1, New Orleans, LA 70112.

2004 Westminster Publications, Inc., 708 Glen Cove Avenue, Glen Head, NY 11545, U.S.A.

Copyright Westminster Publications, Inc. Nov/Dec 2004

Source: Clinical Pediatrics

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