Bacteroides fragilis bacteremia associated with portal vein and superior mesentery vein thrombosis secondary to antithrombin III and protein C deficiency: a case report.

Hypercoagulability is one of the causes of portal vein and superior mesentery vein thrombosis. We report a case of Bacteroides fragilis bacteremia associated with portal vein and superior mesentery vein thrombosis secondary to antithrombin III and protein C deficiency. The patient presented with high fever for more than 3 weeks. Abdominal sonography revealed a liver cyst of 1.7 cm in diameter over segment 4 and a renal stone of 0.7 cm in size over the lower portion of the right kidney but no evidence of hydronephrosis. Elevation of liver enzymes was also noted. Intermittent fever was noted despite treatment with ceftriaxone and doxycycline. On Day 15 of hospitalization, blood culture revealed B. fragilis, which prompted further investigation of the source of intraabdominal and pelvic infection. Abdominal computed tomography revealed portal vein and superior mesentery vein thrombosis. Endoscopic studies of the gastrointestinal tract showed no tumor or diverticulum. Study of coagulation factors disclosed deficiency of antithrombin III and protein C. Clinicians should remain aware of the need to promptly search for a portal or mesentery vein thrombosis in cases of Bacteroides bacteremia of unknown origin.