Isolated inferior mesenteric portal hypertension with giant inferior mesenteric vein and anomalous inferior mesenteric vein insertion.

Extrahepatic portal hypertension is not an uncommon disease in childhood, but isolated inferior mesenteric portal varices and lower gastrointestinal (GI) bleed have not been reported till date. A 4-year-old girl presented with lower GI bleed. Surgical exploration revealed extrahepatic portal vein obstruction with giant inferior mesenteric vein and colonic varices. Inferior mesenteric vein was joining the superior mesenteric vein. The child was treated successfully with inferior mesenteric - inferior vena caval anastomosis. The child was relieved of GI bleed during the follow-up.

INTRODUCTION

Portal hypertension in infancy and childhood is often caused by portal vein thrombosis, non-cirrhotic portal fibrosis, and rarely due to Budd–Chiari syndrome.[12] Primary biliary cirrhosis, biliary atresia leading to cirrhosis, and other inborn errors of metabolism are rarer causes. Extrahepatic portal vein obstruction (EHPVO) commonly presents with upper GI bleed and most prominent and predominant collaterals would be around gastroesophageal (GE) junction, retroperitoneum, and portal hilum.[3] Isolated inferior mesenteric vein portal hypertension is extremely rare.[45]

CASE REPORT

A 4-year-old girl presented with chronic anemia and malena. She was treated with multiple transfusions. The physical examination just revealed palpable spleen. The hemoglobin was 4 gm%, and platelet count, liver function tests were normal. The abdominal Doppler ultrasonography revealed thrombosis of portal vein with collaterals around portal hilum and mild splenomegaly. The thrombus in the portal vein was extending up to the liver hilum.

The patient was prepared for the surgery. The abdomen was explored by transverse supraumblical incision. It revealed giant inferior mesenteric vein measuring more than 3 cm with collaterals around the cecum and rectum [Figure 1]. Inferior mesenteric vein was found joining the superior mesenteric vein at confluence with the portal vein. The splenic vein was less than 8 mm, mild splenomegaly, and no perisplenic collaterals. Since consent for internal jugular vein graft for Rex shunt was not available and renal vein was too small, an inferior mesenterico-caval shunt was performed, in addition to splenectomy. The child was relieved of GI bleed postoperatively. No symptoms of encephalopathy and no evidence of overwhelming postsplenectomy sepsis were observed during the follow-up period of eight months.

Figure 1

Giant inferior mesenteric vein with colonic varices

DISCUSSION

Portal hypertension in children is due to extrahepatic portal vein thrombosis in 50% of cases.[6] The most common presentation of EHPVO is upper GI bleed secondary to variceal rupture at GE junction and lower esophagus. Isolated inferior mesenteric vein portal hypertension secondary to EHPVO is reported only in two cases.[45] Inferior mesenteric vein normally joins splenic vein which in turn joins superior mesenteric vein to form portal vein.[7] Inferior mesenteric vein joining superior mesenteric vein is described by anatomists.[78] Giant inferior mesenteric vein is described secondary to arteriovenous communications,[9] secondary to portal hypertension,[35] but in both of them they had varices around superior mesenteric vein axis also.

This particular case is unique with isolated inferior mesenteric vein portal hypertension with pericolic and perirectal collaterals and without perisplenic, periesophageal, retroperitoneal collaterals, and a giant (more than 3 cm in diameter) inferior mesenteric vein joining the superior mesenteric vein directly.