|Year : 2007 | Volume
| Issue : 1 | Page : 26-28
Isolated portal vein thrombosis in nephrotic syndrome
J Varghese1, A Mathew1, NV Seethalekshmy2, G Kurian1, VN Unni1
1 Department of Nephrology, Amrita Institute of Medical Sciences, Kochi, India
2 Department of Pathology, Amrita Institute of Medical Sciences, Kochi, India
V N Unni
Dept of Nephrology, Amrita Institute of Medical Sciences and Research Centre, Elamakkara P.O, Cochin - 682 026
Source of Support: None, Conflict of Interest: None
Venous thrombosis is a known complication in the nephrotic syndrome, with the renal vein being the most frequent site. It can also occur in other parts of the venous system. Here, we describe a case of isolated portal vein thrombosis in a patient with nephrotic syndrome, which resolved with treatment.
Keywords: Nephrotic syndrome, portal vein thrombosis
|How to cite this article:|
Varghese J, Mathew A, Seethalekshmy N V, Kurian G, Unni V N. Isolated portal vein thrombosis in nephrotic syndrome. Indian J Nephrol 2007;17:26-8
| ~ Introduction|| |
Venous thrombosis has been recognized in nephrotic syndrome since the year 1840, when Rayer described an association between renal vein thrombosis and the nephrotic state. Although many decades earlier, renal vein thrombosis had been thought to be the cause of nephrotic syndrome, today it is clear that venous thrombosis is a complication of the nephrotic state. ,,,, Various factors lead to the prothrombotic state that is seen in nephrotics. Further, treatment with corticosteroids is known to predispose to venous thrombosis.  Isolated portal vein thrombosis occurring in nephrotic syndrome is rare indeed.
| ~ Case Report|| |
A 45-year-old male, presented with a history of abdominal pain and distension since 20 days. He had noticed frothing of his urine 3 weeks prior to this complaint and had consulted a primary care physician; he was investigated and found to have proteinuria, hypoalbuminemia, hypercholesterolemia, and pedal oedema. He had no past history of a similar complaint and had no symptoms of a systemic disease.
On clinical examination, he had marked generalized oedema; blood pressure was 110/70 mm of Hg; his abdomen was distended, with wall oedema and ascites, but there was no organomegaly and there were no distended veins on the abdominal wall. Plasma albumin was 1.6 gm/dl, 24-h urinary protein was 5.5 gms, and total serum cholesterol was 491 mg/dl. The hemoglobin was 15.2 g/dl with a hematocrit of 48%. Serum creatinine was 1.8 mg/dl. Liver function tests, including serum bilirubin, transaminases, and alkaline phosphatase were normal. HbsAg and anti-HCV were negative, serum complement levels were normal, and the peripheral smear appeared normal, with no evidence of any hemoparasite.
Ultrasound and Doppler study of the abdomen showed that both kidneys were normal, with no evidence of renal vein thrombosis; the liver showed subtle changes in echotexture and there was evidence of portal vein thrombosis involving the main trunk with extension into the right and left branches. Doppler study of pelvic and other veins, including the inferior vena cava, were normal. CT scan of the abdomen [Figure - 1] showed thrombosis of the main portal vein with partial recanalization of the branches.
The patient was investigated for a prothrombotic state: PT 12.3s (INR 0.93), APTT 33s, antithrombin III 47 (normal 80-120), Protein C 129 (normal 70-130), Protein S 18 (normal 65-140), anticardiolipin antibodies IgG and IgM were negative, APLA was negative, lupus anticoagulant was negative, factor V mutation was not detected, and homocysteine levels were normal. No cause could be detected for the portal vein thrombosis other than the nephrotic state. Kidney biopsy was done and light microscopy revealed normal glomeruli with mild mesangial expansion; immunofluorescence was negative, suggesting minimal-change disease.
He was given oral prednisolone (1 mg/kg/day) and low molecular weight heparin for 8 weeks. His abdominal pain improved and the edema decreased and he was discharged. After 4 weeks on steroids, he achieved complete remission of his nephrotic state. His oedema disappeared, serum albumin became normal, cholesterol levels came down to normal, and urinary protein loss was nil. A repeat CT scan of the abdomen after 8 weeks showed recanalization of the portal vein branches [Figure - 2] with normal blood flow, and heparin was discontinued. Subsequently, on follow-up, steroids were tapered and stopped.
| ~ Discussion|| |
The pathogenetic mechanisms responsible for venous thrombosis in the nephrotic syndrome include, 1) urinary loss of clotting inhibitors, zymogens, and plasminogen; 2) increased hepatic synthesis of fibrinogen and lipoproteins, and cofactors like factors V, VII, and VIII; 3) excessive platelet aggregation; 4) hemoconcentration due to loss of fluid from the intravascular compartment; and 5) the effects of drugs (diuretics and steroids). ,,,
The common sites of venous thrombosis are the renal veins, the central veins leading to the extremities, the peripheral veins and the cerebral venous sinuses. Arterial thrombosis has been described in the coronary, mesenteric, and femoral arteries. ,, The majority of the patients with venous thrombosis in nephrotic syndrome are asymptomatic. Although it is felt that the incidence of venous thrombosis is maximum in membranous nephropathy, it has been well described in minimal-change disease, membranoproliferative glomerulonephritis, and in amyloidosis. 
Portal vein thrombosis is diagnosed when it develops in the trunk of portal vein.  It can extend to involve the right and the left branches as well as the segmental intrahepatic branches; it can also spread in the opposite direction to involve the splenic vein or the superior mesenteric veins. , Some of the known causes of portal vein thrombosis include primary myeloproliferative disorders (polycythemia vera or essential thrombocythemia), antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria, hyperhomocysteinemia, factor V Leiden mutation, and protein C, S, and antithrombin III deficiency. ,,, Other risk factors for thrombosis include oral contraceptives, pregnancy, focal inflammatory lesions, and inflammatory bowel disease. 
Nephrotic syndrome is associated with both arterial and venous thrombosis, which affects 10% of adults and 2% of children. , The frequency of this complication has increased with the use of steroids and diuretics.  Nephrotic patients have an increase in whole blood viscosity due to hemoconcentration, which is related to increased fibrinogen levels.  There are also increased levels of von Willebrand factor, and factors V, X, and VII. The immensely complex balance of coagulant and fibrinolytic and regulatory proteins is disturbed in the dysproteinemia of the nephrotic state. ,, The hyperlipidemia associated with nephrotics also contributes to thrombosis by causing platelet aggregation.
Portal vein thrombosis, as an isolated site of thrombosis, is uncommon in nephrotic syndrome.  A literature search for isolated portal vein thrombosis in nephrotic syndrome showed only a few case reports. ,, Infection, as a predisposing factor, has been mentioned as a precipitating cause for thrombosis in nephrotics. 
Our patient had nephrotic syndrome with a severe hypoproteinemic state, along with hyperlipidemia, which could have predisposed to portal vein thrombosis. Resolution of the hypoproteinemia led to recanalization of the thrombosed veins. Low molecular weight heparins could have helped in faster recanalization of the thrombosed portal vein.
| ~ References|| |
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[Figure - 1], [Figure - 2]
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|[Pubmed] | [DOI]|