Superior mesenteric vein thrombosis as a complication of acute appendicitis : report of a case
A 45-year-old man whose BMI was 23.2 kg/m2 visited our outpatient clinic primarily due to fever and abdominal pain. Although mild pain was noted in the right lower abdominal region, there was no other symptom including rebound tenderness, and the patient was prescribed drugs and allowed to go home. After 2 days, pain of the right lower abdomen was slightly alleviated, but a fever above 39 °C persisted. The patient consulted the emergency outpatient clinic of our hospital. Blood tests showed high values indicating inflammatory reaction, and abdominal ultrasonography and contrast-enhanced CT showed enlargement of the appendix. The patient was immediately admitted.\nOn admission, the body temperature was 39.0 °C, the abdomen was flat, pain in the right lower abdominal region was mild, and no rebound tenderness was noted. On the blood tests at the outpatient visit 2 days before, the WBC was 8,300/μl, and CRP was 7.5 mg/dl, but they were exacerbated to 11,000/μl and 34.13 mg/dl, respectively. Also, the platelet count was reduced to 75,000/μl, and liver dysfunction was suggested by increases in the AST 71 IU/l, ALT 58 IU/l, T-Bil 2.5 mg/dl, and LDH 303 IU/l. Abdominal contrast-enhanced CT showed increased radiodensity of the enlarged appendix and surrounding adipose tissue (Fig. ).\nAfter admission, as abdominal findings were unremarkable despite of fever and blood test results. Decreases in the platelet count, mild increases in the transaminase levels, and increases in the total bilirubin level were noted. We suspected other diseases, for example, viral infection and blood disease as a cause of inflammation. We initially planned to manage the acute appendicitis conservatively with the possibility of taking into consideration of emergency surgery.\nDetailed examinations were performed. Blood cultures were negative. Tests for viral infections such as cytomegalovirus and EB virus infections were negative, and for fungal infection was negative too. As an empiric treatment, meropenem (MEPM) was administered at 0.5 g × 3/day. The fever, high inflammatory reaction, and liver dysfunction were temporarily alleviated, but the WBC and fever elevated again on the 5th hospital day. Abdominal contrast-enhanced CT was performed again, and the result showed no remarkable changes in appendicitis. However, a vine-like low-density area along the ileocolic vein (ICV) and defects in the lumen of the SMV and dendritic low-density area of the portal vein in S5 of the liver were recognized (Fig. ). We suspected the occurrence of SMVT and PVT induced by inflammation extending from protracted appendicitis. We carried out appendectomy by laparotomy on emergency.\nIntraoperatively, the appendix adhered to the surrounding tissues but could be detached. The mesoappendix was markedly thickened, and there were findings suggestive of abscess formation in the mesoappendix. No sign of edema, congestion, or necrosis was noted in the large intestine, small intestine, and mesentery. Therefore, only an appendectomy was performed.\nHistopathological examinations indicated the diagnosis of phlegmonous or gangrenous appendicitis. Abscesses were noted in the mesoappendix, and fibrinoid necrosis was observed in the vascular wall, particularly the venous wall, in the mesoappendix. No clear thrombus, suppurating thrombus, or biofilm was found in the blood vessels.\nThe postoperative course was uneventful, and improvements were observed in inflammatory reaction, platelet count, transaminase levels, and total bilirubin level. Postoperatively, heparin administration was started at 16,000 U/day, and heparin was substituted for warfarin with the resumption of oral nutrition. On the 7th postoperative day, regression and alleviation of SMVT and PVT were confirmed by abdominal contrast-enhanced CT.\nOn abdominal contrast-enhanced CT on the 48th postoperative day, no sign of recurrence of SMVT or PVT was noted, but the SMV was atrophied (Fig. ). Oral warfarin administration was discontinued half a year after surgery. The blood AT III activity, protein C antigen and activity levels, and antinuclear antibody level were measured after surgery. As these parameters were all within the normal range, abnormality of the congealing fibrinogenolysis system was excluded.