PYLEPHLEBITIS COMPLICATING PERIDIVERTICULITIS WITHOUT HEPATIC ABSCESS: EARLY DETECTION WITH CONTRAST-ENHANCED CT OF THE ABDOMEN

dangerous complication of inflammatory abdominal processes, mainly appendicitis (1) and diverticulitis (2). Many abdominal and extra-abdominal conditions can lead to portal or mesenteric vein thrombosis (3): it has been reported as a complication of hypercoagulation disorders, trauma, cirrhosis, or after splenectomy. It is called pylephlebitis or ascending septic thrombophlebitis when this thrombophlebitis is septic, quite often associated with a primary gastro intestinal inflammatory source. This unusual condition had a reported mortality of more than 50% before the era of the antibiotics. We report here a case of peridiverticular inflammation in the sigmoid, with ascending thrombophlebitis of the sigmoid and inferior mesenteric vein, and distal embolus in the left portal vein.

Pylephlebitis is a very rare and dangerous complication of inflammatory abdominal processes, mainly appendicitis (1) and diverticulitis (2). Many abdominal and extra-abdominal conditions can lead to portal or mesenteric vein thrombosis (3): it has been reported as a complication of hypercoagulation disorders, trauma, cirrhosis, or after splenectomy. It is called pylephlebitis or ascending septic thrombophlebitis when this thrombophlebitis is septic, quite often associated with a primary gastro intestinal inflammatory source. This unusual condition had a reported mortality of more than 50% before the era of the antibiotics. We report here a case of peridiverticular inflammation in the sigmoid, with ascending thrombophlebitis of the sigmoid and inferior mesenteric vein, and distal embolus in the left portal vein.

Case report
A 76-year-old lady was admitted for altered clinical status, left flank and left lower abdominal pain, fever (39°C). Blood tests showed highly elevated CRP levels (320 mg/l). In her past history one episode of peridiverticulitis two years earlier, treated without surgery. The abdominal CT performed at admission in the emergency department revealed a large air collection just close to the sigmoid colon, with infiltration of the adjacent fat. The sigmoïd veins were thrombosed, as was the inferior mesenteric vein upto the lower portal vein. And the left intrahepatic portal vein was also thrombosed.

Discussion
Pylephlebitis was a dread-full and often lethal complication of some cases of appendicitis before the utilization of the antibiotics. Diverticular disease has replaced appendicitis as the most common cause of pylephlebitis, with other possible sources including appen-cutaneous injections of low molecular weigth heparin (LMWH) were started, leading to early biological response (CRP levels at day 4 lowered to 40 mg/l) and slower clinical response. No hepatic abscess developed and the patient left the hospital after 20 days, still on oral antibiotic and anticoagulation therapy.

PYLEPHLEBITIS COMPLICATING PERIDIVERTICULITIS WITHOUT HEPATIC ABSCESS: EARLY DETECTION WITH CONTRAST-ENHANCED CT OF THE ABDOMEN
Pylephlebitis is a very rare and dangerous complication of inflammatory abdominal processes, mainly appendicitis (1) and diverticulitis (2). We describe a case of peridiverticular inflammation leading to a extensive phlebitis of the adjacent sigmoid vein, extending to the inferior mesenteric vein up to the proximal portal vein, with distal embolus into the left portal vein. Contrast CT and multiplanar reconstructions allowed early diagnosis, and with antibiotic and anticoagulation therapy, no liver abscess developed.
Key-words: Abdomen, acute conditions -Thrombophlebitis.   1D) and central or peripheral zones of low attenuation secondary to decreased intrahepatic blood flow. With early medical treatment, those abnormalities will subside, but untreated can lead to one or more hepatic abscess. Long term antibiotic therapy is recommended, especially in case of if liver abscess, often with drainage of these abscesses. Anticoagulotherapy remains controversial but is often used: it did not prevent cavernous transformation branches of the mesenteric vein or the portal vein. Scanning can be performed at the "portal" phase 70 sec after intravenous injection of iodinated contrast at a rate of 2 or 3 cc/sec but false positive diagnosis of venous thrombosis have been made when scanning was initiated too early after contrast injection. This can be avoided with a "biphasic injection of iodinated contrast" (60 cc at a rate of 2 cc/sec, 30 sec of pause followed by a second injection of 60 cc at a rate of 3 cc/sec and than 20 cc of saline), as in our patient, which allows nice depiction of the arterial vessels with at the same time complete filling of the veins ( Fig. 1 and  2A). Diagnostic CT findings are to be searched in close vicinity to the sigmoid colon (thrombosed branch of the inferior mensenteric vein (Fig. 1A) and distally: segmentally thrombosed portal branch ( Fig. 2A) or liver abcess. Sequential reading of the axial and coronal slices allows precise analysis of the vessels involved by the thrombus, but, in small vessels such as the inferior mesenteric vein, curved reconstruction can help in recognizing the vessels and their continuity ( Fig. 2A,  B).

Conclusion
Unenhanced MDCT can detect acute diverticulitis with a very high accuracy, but complications such as venous thrombosis and portal vein emboli could be difficult to diagnose without intravenous injection. In this case, early diagnosis and early treatment may have helped avoiding the development of intrahepatic abscesses. Multiplanar and curved reconstructions can help recognizing the small thrombosed veins.

Bibliography
of the portal vein in some series (3).
Doppler ultrasound of the main portal vein and branches is very reliable but the analysis of the mesenteric veins is limited in the evaluation of these patients due to its operator dependency and inability to accurately depict vascular anatomy in the presence of overlying bowel gas (radiographics). Especially when, as in our patient, the clinical symptoms are in the left lower quadrant and not in the right hypochondrium.
It was claimed that low-dose unenhanced multi-detectors CT has a diagnostic performance similar to that of contrast-enhanced standarddose multi-detector row CT in patients suspected of having acute diverticulitis (4) but t it's accuracy to exclude this type of serious complicated should still be scrutinized. CT with intravenous injection of iodinated contrast is superior to non contrast CT to detect thrombosis of the