superior mesenteric vein ( smv ) thrombosis caused by appendicitis is a very rare entity in the recent times due to improved high quality imaging techniques and use of broad spectrum antibiotics . however , it is important to be aware of the possibility of smv thrombosis while managing patients with appendicitis as the mortality rate in smv thrombosis associated with intra - abdominal infection was reported to be 30%-50%,1,2,3 with smv thrombosis possibly causing intestinal edema , congestion , and necrosis . moreover a 21-year - old male was transferred to the emergency department with a chief complaint of lower abdominal pain , nausea , and fever for 4 days . he had no past medical history or had not undergone any examination for assessing the coagulation status . he denied any family history of deep vein thrombosis or other coagulation disorder . on arrival , his body temperature was 39.1 , pulse rate was 104/minutes , respiratory rate was 18/minutes , and blood pressure was 108/49 mmhg . blood analysis showed a white blood cell count of 10,870/l ( neutrophils 91.8% ) , platelet count of 80,000/l , c - reactive protein level of 14.94 mg / dl , erythrocyte sedimentation rate of 17 mm / hr , total bilirubin level of 2.6 mg / dl , aspartate aminotransferase level of 47 iu / l , alanine aminotransferase level of 67 iu / l , and prothrombin time of 13.1 seconds ( international normalized ratio 1.36 ) . on the computerized tomography ( ct ) scan , appendicitis with a periappendiceal abscess and a non - occlusive thrombus in the smv were noted ( fig . systemic intravenous antibiotics were started ( ceftriaxone 2 g daily+metronidazole 500 mg thrice daily ) . the patient underwent emergent laparoscopic appendectomy and monitoring for the occurrence of bowel infarction was performed . the fibrinogen degradation product level was < 5 g / ml ( normal < 5 ) , and d - dimer level was < 0.20 mg / l ( normal < 0.5 ) . antithrombin iii ( 104% , normal 80 - 120% ) , protein c activity ( 86% , normal 70 - 130 ) , protein s activity ( 91% , normal 77 - 143 ) , and homocysteine levels ( 10.92 umol / l , normal 5.08 - 15.40 ) were within their normal ranges . the lupus anticoagulant screening test was negative and the level of anti - phospholipid antibodies ( ig g 3.2 gpl / ml , normal<10.0 ; igm 1.0 mpl / ml , normal < 10.0 ) was below the normal range . on the 7th postoperative day , follow - up ct scan was performed and it showed a nearly occlusive thrombus in the smv . systemic antibiotic therapy was continued for 1 week , and it was substituted with oral antibiotics ( cefaclor 250 mg thrice daily ) , which were administered for 3 weeks . on the 45th postoperative day , follow - up ct scan demonstrated dissolution of smv thrombosis ( fig . diverticulitis is the most common cause , followed by appendicitis , cholecystitis , pancreatitis , tumors , and abdominal and pelvic infection.5 the primary source of infection was detected in 70% of the cases.6 causative microorganisms are identified often , and e. coli , bacteroides fragilis , proteus mirabilis , klebsiella pneumoniae , and enterobacter spp . are the most common pathogens.1,7 however , in this case , microorganisms were not identified in blood culture . recently , blood culture has become a very important test due to the resistance to antibiotics as antibiotic regimen could be reassessed for de - escalation . the incidence of smv thrombosis caused by appendicitis was approximately 0.4% before 1950 , following which it has become an extremely rare entity because of adequate antibiotic use and prompt surgical treatment.8 the mortality rate was as high as 80%,7,9 and it has decreased to 30%-50% ; however , it is still high enough for considering this entity important . removal of the source of infection and a course of systemic broad spectrum antibiotics effective against common causative organisms are essential . although stlitzenberg et al.10 reported about interval appendectomy and nishimori et al.2 reported about appendectomy with thrombectomy by using fogarty catheter , emergency appendectomy is usually recommended.11 in this case , emergent appendectomy without manipulating smv thrombosis was performed . ceftriaxone and metronidazole were administered for 1 week for gram - negative bacilli and anaerobes , and oral cefaclor ( 2-generation cephalosporin ) was used consecutively for 3 weeks . the duration of use of antibiotics was determined based on previous studies.3,12,13 the use of anticoagulation therapy in the treatment of pylephlebitis is the most controversial issue . some reports recommended using anticoagulation therapy to reduce the recurrence rate and mortality rate of pylephlebitis.2,14,15 however , crowe et al.16 reported that anticoagulation therapy is not necessary for pylephlebitis when the primary disease such as appendicitis or diverticulitis is well - controlled . in this case , after the follow - up ct scan performed on the 7th postoperative day revealed aggravation of smv thrombosis which was nearly occlusive , anticoagulation therapy was started . patient recovered without any catastrophic complications such as intestinal ischemia or necrosis , but early initiation of anticoagulation therapy could lead to safer management . in conclusion , smv thrombosis is a very rare complication of appendicitis ; but it can lead to catastrophic consequences . smv thrombosis can be treated successfully with emergency appendectomy , broad - spectrum antibiotics , and anticoagulation therapy .
superior mesenteric vein ( smv ) thrombosis caused by acute appendicitis is a very rare entity nowadays . 
 we report a successfully treated case of a 21-year - old man with smv thrombosis associated with severe acute appendicitis . 
 intravenous heparin was administered , and it was later substituted with warfarin . 
 systemic antibiotic therapy was continued for 1 week , and it was substituted with oral antibiotics , which were administered for 3 weeks . on the 45th postoperative day , follow - up 
 computed tomography scan demonstrated dissolution of smv thrombosis . 
 anticoagulation therapy was maintained for 3 months . 
 he was discharged without any complications . 
 smv thrombosis can be treated successfully with emergency appendectomy , broad - spectrum antibiotics , and anticoagulation therapy .