|Year : 2016 | Volume
| Issue : 1 | Page : 85-87
Blocked mesocaval shunt with protein C deficiency in a child with extrahepatic portal hypertension
Nikhil Rao, Ira Shah, Sushmita Bhatnagar
Pediatric Liver Clinic, B. J. Wadia Hospital for Children, Mumbai, Maharashtra, India
|Date of Web Publication||22-Dec-2015|
1/B Saguna, 271/B St Francis Road, Vile Parle (W), Mumbai - 400 056, Maharashtra
Source of Support: None, Conflict of Interest: None
Portal vein thrombosis (PVT) is an important cause of extrahepatic portal hypertension in children. A majority of children with PVT of unknown etiology have functional protein C deficiency or abnormally elevated levels of anti-cardiolipin antibodies. We present an 8-year-old boy with portal hypertension with protein C deficiency, who underwent mesocaval shunt surgery due to recurrent episodes of bleeding esophageal varices and subsequently developed a block in the mesocaval shunt due to a thrombotic tendency.
Keywords: Mesocaval shunt, portal cavernoma, protein C deficiency
|How to cite this article:|
Rao N, Shah I, Bhatnagar S. Blocked mesocaval shunt with protein C deficiency in a child with extrahepatic portal hypertension. Med J DY Patil Univ 2016;9:85-7
|How to cite this URL:|
Rao N, Shah I, Bhatnagar S. Blocked mesocaval shunt with protein C deficiency in a child with extrahepatic portal hypertension. Med J DY Patil Univ [serial online] 2016 [cited 2020 Aug 5];9:85-7. Available from: http://www.mjdrdypu.org/text.asp?2016/9/1/85/167960
| Introduction|| |
Portal vein thrombosis (PVT) is a common cause of extrahepatic portal hypertension (EHPHT) in children in developing countries.  EHPHT has diverse etiology with perinatal risk factors like umbilical vein catheterization, or intra-abdominal sepsis seen in 50% of cases and thrombosis in others. However, hereditary or acquired coagulation disorders do not play an important role in the pathogenesis of EHPHT in children, and the etiology is not known in most cases.  Deficiencies of the natural anticoagulant proteins, protein C, protein S and antithrombin have been reported as risk factors for thrombosis.  The prevalence of protein C deficiency is estimated to be 0.2-0.5% of the general population and is associated with an increased risk of venous thromboembolism.  PVT can be one of the rare manifestations of protein C deficiency.  A portal vein thrombus leads to obstruction in the portal blood flow and increase in portal blood pressure leading to extrahepatic portal hypertension. Definite treatment of this condition is to surgically construct an artificial shunt, which connects the portal and systemic venous systems so as to drain the portal blood and relieve the portal hypertension. An example of such a shunt is a mesocaval shunt, which connects the superior mesenteric vein to the inferior vena cava. However, the outcome of shunt surgery in patients with a thrombotic tendency is not known. We present an 8-year-old boy with portal hypertension with protein C deficiency, who underwent mesocaval shunt surgery due to recurrent episodes of bleeding esophageal varices and subsequently developed a block in the mesocaval shunt.
| Case Report|| |
An 8-year-old boy presented to the surgical unit with isolated splenomegaly and hematemesis in February 2001 and was diagnosed to have EHPHT due to a portal cavernoma. He underwent regular sclerotherapy for the same, but still had hematemesis and underwent splenic artery embolization in April 2001. Surgeons decide to do mesocaval shunt surgery with splenectomy in July 2004. Postsurgery, he again had hematemesis and underwent endoscopic banding of the esophageal varix. A color Doppler done in November 2005 showed blocked mesocaval shunt and a portal cavernoma. The child was managed conservatively on propranolol. In November 2005, he was referred to the liver unit for further management. On examination, the child weighed 31 kg and height was 137 cm. Other systems were normal. Investigations showed normal liver function tests. The patient was advised regular follow-up. The patient was alright till June 2010 when he developed anemia and required blood transfusions. His color Doppler showed portal cavernoma with periportal collaterals and nonvisualization of the mesocaval shunt, inferior mesenteric vein and splenic vein. Since he had a multi-vessel block, he was suspected to have an underlying thrombotic tendency. He underwent thrombophilia workup, which revealed protein C deficiency (36% by enzyme-linked immunosorbent assay, Normal = 70-140%). Anti-cardiolipin and anti-phospholipid antibodies were normal. Protein S and antithrombin levels were normal. Urine was negative for homocysteine. Computed tomography portoenterography showed blocked mesocaval shunt with portal cavernoma. Child has now been advised repeat esophagogastroscopy. The option of a liver transplant was discussed with the parents but could not be pursued further due to nonaffordability and nonavailability of the donor.
| Discussion|| |
Protein C is a potent thrombin-dependent anticoagulant enzyme whose function is to inactivate coagulation factors V and VIII and to stimulate fibrinolysis. It is synthesized in the liver and is Vitamin K dependent. Hereditary protein C deficiency is an autosomal dominant trait and is a risk factor for venous thrombosis. Most individuals with an inherited defect have levels of protein C of around 50% of normal values, consistent with the heterozygous state. ,
It has been estimated that protein C deficiency accounts for 5-8% of unexplained venous thrombosis in young individuals.  An Indian study has found that the majority of children with PVT have functional protein C deficiency or abnormally elevated anti-cardiolipin antibodies.  Similarly, in Mexican patients with noncirrhotic PVT, 31% had protein C deficiency.  Our patient had decreased levels of protein C with normal liver functioning and normal levels of protein S, which is suggestive of heterozygous type I protein C deficiency. The hypercoagulable state caused by protein C deficiency must have been a key factor in the pathogenesis of the PVT in this patient. To reduce the portal pressure, the patient underwent mesocaval shunt surgery. However, the shunt was detected to have been blocked, and the episodes of hematemesis continued due to the failure of the shunt. The block could have been caused by a thrombus formed due to the protein C deficiency. The overall incidence of shunt thrombosis is around 10.5%. 
Prevention of recurrent thromboembolism by anticoagulation therapy with coumarin derivatives is mandatory in patients with a hereditary deficiency of protein C.  Studies in numerous series of patients with noncirrhotic PVT have demonstrated that anticoagulation is safe and effective and represents the therapy of choice.  There is no role of anticoagulation therapy in children with EHPHT as low hepatic blood flow due to PVT (low synthesis) and portosystemic shunt (increased clearance or consumption) are supposed to be responsible for low anticoagulant proteins in blood in EHPHT in children. Furthermore, deficiencies of antithrombotic factors (protein-C, protein-S, anti-thrombin III) are unlikely to be genetic in origin.  Thus, screening for thrombophilia in the first instance in children with EHPHT may still be controversial and there is no role of treatment with anticoagulation for thrombophilia in a child with EHPHT.  Furthermore, in the presence of bleeding esophageal varices, anticoagulation might actually worsen the duration and severity of bleeding episodes and hence, immediate treatment of the bleeding varices is a priority. Injection sclerotherapy may be considered, but it has been suggested that the risk of bleeding from esophageal ulcers after sclerotherapy might be increased following anticoagulation.  Hence, propranolol is preferred over sclerotherapy and is the first line method to prevent bleeding.  In a child with blocked mesocaval shunt and recurrent bleeding episodes, the role of anticoagulation is controversial.
| Conclusion|| |
Patients presenting with PVT should be investigated for underlying thrombophilic conditions like protein C deficiency. The role of anticoagulation, shunt surgery in patients with thrombophilia needs more research.
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