Superior mesenteric vein thrombosis with radiologically occult cause: a retrospective study of 43 cases

Understanding CT imaging findings based on the underlying pathophysiology in patients with small bowel ischemia

Because acute small bowel ischemia has a high mortality rate, it requires rapid intervention to avoid unfavorable outcomes. Computed tomography (CT) examination is important for the diagnosis of bowel ischemia. Acute small bowel ischemia can be the result of small bowel obstruction or mesenteric ischemia, including mesenteric arterial occlusion, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. The clinical significance of each CT finding is unique and depends on the underlying pathophysiology. This review describes the definition and mechanism(s) of bowel ischemia, reviews CT findings suggesting bowel ischemia, details factors involved in the development of small bowel ischemia, and presents CT findings with respect to the different factors based on the underlying pathophysiology. Such knowledge is needed for accurate treatment decisions.

Mesenteric ischemia: a radiologic perspective

Mesenteric ischemia is a broad term encompassing several clinical conditions leading to impaired vascularity of bowel loops. Absence of specific clinical presentation and a definitive laboratory marker often lead to delayed diagnosis with high morbidity and mortality in the acute setting. Imaging plays a crucial role in the diagnosis and management. Multi-detector CT (MDCT) is the first line imaging modality for the evaluation of patients with suspected mesenteric ischemia and plays an important role for assessing its severity and complications. This review article highlights the causes, pathophysiology, imaging features and possible endovascular treatment options of mesenteric ischemia.

CT manifestations of small bowel ischemia due to impaired venous drainage-with a correlation of pathologic findings

Acute abdominal pain may result from a wide variety of medical and surgical diseases. One of these diseases is small bowel ischemia, which may result in a catastrophic outcome if not recognized and treated promptly. Computed tomography (CT) by its faster image acquisition, thinner collimation, high resolution, and multiplanar reformatted images has become the most important imaging modality in evaluating the acute abdominal conditions. In this article, the author presents a description of the histology of the small bowel, pathophysiology of small bowel change, and a correlation of the pathologic and CT findings of the small bowel injuries due to impaired venous drainage. A convincing correlation of the microscopic mucosal condition with the enhancement pattern of the thickened small bowel wall on CT is useful in definitely describing the mucosal viability.

Superior mesenteric venous thrombosis complicating acute appendicitis: A case report

RATIONALE

Superior mesenteric venous thrombosis (SMVT) is a rare condition that carries high mortality. Very few cases have been reported of SMVT, complicating acute appendicitis. Early recognition requires a high index of suspicion and is crucial in successful treatment of such a life-threatening condition.

PATIENT CONCERNS

A 33-year-old male presents with a 4-day history of right lower abdominal pain, nausea and subjective fever. CT scan showed acute appendicitis and a central filling defect in the superior mesenteric vein.

DIAGNOSES

Acute appendicitis complicated by SMVT.

INTERVENTIONS

Intravenous antibiotics, appendectomy, and anticoagulation.

OUTCOMES

Repeat CT scan showed successful resolution of the SMVT at a 3-month follow up.

LESSONS

Clinical awareness and high index of suspicion are essential to diagnose and manage SMVT, a serious complication of acute appendicitis.

Treatment outcomes and risk factors for bowel infarction in patients with acute superior mesenteric venous thrombosis

OBJECTIVE

The prognosis of acute superior mesenteric venous thrombosis (SMVT) remains obscure. We aimed to investigate the treatment outcomes and possible risk factors for bowel infarction in these patients.

METHODS

We retrospectively included 66 patients with acute SMVT between January 2002 and June 2016. Each patient underwent contrast-enhanced computed tomography as part of the initial diagnosis. The standard protocol for management included a nonsurgical approach with early anticoagulation and selective exploration. For the analysis of the risk factors for bowel infarction, patients were divided into bowel resection (BR) and non-BR groups. Outcomes of interest were causes of SMVT, percentage of BR after nonsurgical treatment, and risk factors for BR.

RESULTS

Of 66 patients, 15 (23%) underwent BR; of these, 9 underwent urgent BR because of peritoneal signs and definite findings of bowel infarction on computed tomography scan, 4 underwent BR after failed anticoagulation, and 2 underwent BR because of delayed stricture. Clinically, vomiting (P = .003), abdominal distention (P = .003), rebound tenderness (P = .005), and leukocytosis (P = .001) were associated with BR. On radiologic examination, bowel wall thickening (P < .001), enhancement defects of the bowel wall (P < .001), and ascites (P = .007) were associated with BR. Twenty-seven (41%) patients presented with isolated SMVT, and the remaining patients demonstrated a coexisting portal vein (PV) thrombosis in addition to SMVT. All 15 BRs occurred in patients with combined PV thrombosis and SMVT (P < .001). Complete thrombosis of the superior mesenteric vein and PV was also associated with BR (P = .028 for superior mesenteric vein; P = .025 for PV). BR was performed in 1 (4%) of 24 patients with transient risk factors compared with 14 (33%) of 42 patients without transient risk factors (P = .006). Three patients (4.5%) died in the hospital.

CONCLUSIONS

In patients with acute SMVT, the extent of thrombus and etiology were associated with the severity of acute SMVT. Patients with transient risk factors and isolated SMVT tended to have a benign disease course. With early anticoagulation, acute SMVT does not seem to have the grave prognosis that is associated with arterial thrombosis.

Acute gastrointestinal vaso-occlusive ischemia in sickle cell disease: CT imaging features and clinical outcome

PURPOSE

The purpose of this study was to determine the incidence, specific imaging features, and outcome of gastrointestinal vaso-occlusive ischemia (GVOI) in sickle cell patients undergoing CT for acute abdominal pain.

METHODS

This HIPAA-compliant, IRB-approved retrospective study evaluated sickle cell patients with an abdominal pain crisis and acute gastrointestinal abnormalities on CT from 1/2006 to 1/2014. CT findings were divided into those compatible and incompatible with bowel ischemia or clinical diagnosis of GVOI. Two abdominal radiologists (1, 13 years' experience) reviewed the CTs for specific imaging features of ischemia. Clinical laboratory values (lactate, WBC) and outcome were recorded. Descriptive statistics and Wilcoxon-Mann-Whitney two-sample rank-sum test were performed.

RESULTS

Of 217 CTs, 33 had acute gastrointestinal abnormalities: 75% (25/33) consistent with ischemia and clinical GVOI. Complications of ischemia occurred in 16% (4/25): ileus (50%), perforation (25%), and pneumatosis (25%). In uncomplicated cases, all had bowel wall thickening: segmental 52% (11/21) or diffuse 48% (10/21). The colon was commonly involved (76%, 16/21), particularly the ascending (57%, 12/21). Most abnormalities (52%, 11/21) were in the superior mesenteric artery distribution. Average lactate (4.3 ± 4.0 mmol/L, p = 0.02) and WBC count (20.1 ± 10.4, ×1000 cells/μL, p = 0.01) were significantly higher in GVOI. Overall mortality in patients with GVOI was 17% (3/18).

CONCLUSION

GVOI is an important feature of the acute abdominal crisis in patients with sickle cell disease and can be seen in up to 75% of patients with abnormal bowel findings on CT. The diagnosis should be strongly considered in sickle cell patients with CT findings of diffuse or segmental bowel wall thickening, particularly involving the colon.

Clinical Presentation and Outcome of Mesenteric Vein Thrombosis

Mesenteric venous thrombosis (MVT) is an uncommon event. We retrospectively analyzed data for patients who were admitted with MVT between June 2005 and May 2012 in Qatar. The study included 35 patients with a mean age of 45 ± 11 years. The risk of MVT was significantly high among males who smoked and females of Arab ethnicity. The main manifestations of MVT were abdominal distension and vomiting. The major etiological factors included deficiency in protein C and S, homocysteinemia, and prior abdominal surgery. Computed tomography (CT) findings were helpful in 80% of the patients. Bowel resection with primary anastomosis was performed in 25 (71%) patients. The overall mortality rate was 17%. High index of suspicion, detection of risk factors, CT imaging, and timely intervention are essential for better prognosis.

Imaging findings of acute intravascular thrombus on non-enhanced computed tomography

Intravascular thrombosis and thromboembolism are critical diagnoses which are frequently made on contrast-enhanced computed tomography (CECT) or Doppler ultrasound. For a variety of reasons, some patients with acute intravascular pathology are imaged using CT without intravenous contrast. In the acute setting, the increased Hounsfield unit (HU) density of the thrombus compared to the blood pool allows the diagnosis to be made, or at least suggested, on non-enhanced computed tomography (NECT). The increased density of the clot is commonly referred to as the "hyperdense vessel sign." This is a well-known finding in the setting of stroke, but hyperdense vessels can also signal arterial or venous thrombosis in the chest, abdomen, pelvis, and extremities. Once a hyperdense vessel sign is noted on NECT, further exploration with CECT, angiography, or ultrasound may then be performed. Here, we present a pictorial review of the appearance of acute intravascular thrombosis as seen on non-enhanced computed tomography.

Portal vein thrombosis following laparoscopic sleeve gastrectomy for morbid obesity

A high index of suspicion is necessary to diagnose portal vein thrombosis following laparoscopic bariatric procedures.

Introduction:

Portal vein thrombosis has been documented after laparoscopic general surgery and has been uncommonly observed after laparoscopic bariatric surgery. Among bariatric operations, the sleeve gastrectomy is being performed with ever-increasing frequency. Here we report the case of a man who presented with portal vein thrombosis after laparoscopic sleeve gastrectomy.

Case Description:

A 41-y-old man underwent an uneventful laparoscopic sleeve gastrectomy for the treatment of morbid obesity, and presented on postoperative day 10 with nonfocal abdominal pain, nausea, vomiting, and leukocytosis. Computed tomography revealed portal vein thrombosis, which was found in the setting of Clostridium difficile colitis.

Discussion:

Portal vein thrombosis may be identified with increasing frequency as the number of laparoscopic bariatric operations continues to increase. A high index of suspicion is necessary to diagnose this rare, but potentially lethal, complication.

CT findings of small bowel strangulation: the importance of contrast enhancement

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.

Chronic superior mesenteric venous thrombosis revealed by diabetic ketonuria and bacteremia

We report a patient with superior mesenteric venous thrombosis presenting as diabetic ketonuria and bacteremia. The patient was a 65-year-old man with a history of diabetes mellitus, and was admitted to our hospital due to high fever. Tests revealed diabetic ketonuria and Bacteroides fragilis bacteremia. Abdominal computed tomographic scan and Doppler sonography revealed an old thrombus in the superior mesenteric vein with good flow through collateral vessels, causing the patient to have an absence of abdominal symptoms. There was no evidence of hereditary thrombophilia. The thrombus was secondary to a combination of comorbidities, including dehydration, hyperosmolarity, and diabetes mellitus.

Portal vein thrombi after ileal pouch-anal anastomosis: its incidence and association with pouchitis

PURPOSE

Portal vein thrombi (PVT) have recently been linked to ileal pouch-anal anastomosis (IPAA). We assessed the rate of PVT in patients who underwent IPAA and attempted to identify the associated features.

METHODS

We reviewed all patients who underwent IPAA at our hospital between 1997 and 2002, noting demographic, operative, and clinical data. Computed tomography (CT) scans were independently re-reviewed by two radiologists blinded to patient data. Scans were designated as positive, negative, or indeterminate for PVT.

RESULTS

A total of 112 patients underwent IPAA for ulcerative colitis, 28 (25%) of whom had a CT scan done within 8 weeks postoperatively. The indications for CT included prolonged ileus (32.1%), abdominal pain (28.6%), and fever (17.9%). On examining the CT scans, 39% were positive, 14% were indeterminate, and 46% were negative for PVT. There was no association between PVT and pelvic sepsis. Within a mean follow-up of 36.2 months, 15.4% patients without PVT had suffered pouchitis compared with 25% of those with indeterminate scans and 45.5% of those with PVT.

CONCLUSIONS

Portal vein thrombi are a common finding in the subset of patients who require a CT scan after IPAA. Patients who suffer PVT have a higher incidence of postoperative pouchitis. Thus a prospective evaluation of the risk of PVT and its association with pouchitis is warranted.

Diverticular perforation masquerading as maxillary sinusitis

Although diverticular perforation and diverticulitis is usually a straightforward diagnosis, an occasional case can be difficult. In this report, we describe a patient who initially presented with symptoms suggestive of maxillary sinusitis and hip fracture. Findings of subcutaneous craniofacial emphysema eventually led to the diagnosis of a perforated sigmoid diverticulum with abscess.

MR imaging in abdominal emergencies

The use of MR imaging in the emergency setting is evolving. Clear indications include situations in need of contrast media when iodinated contrast cannot be administered or to facilitate assessments in pregnant patients and children when exposure to ionizing radiation is considered unacceptable. The availability of rapid, motion-immune sequences now makes MR imaging a feasible study in less cooperative patients extending the range of patients for whom a diagnostic study can be achieved. Capitalizing on the unique benefits of MR imaging there is optimism that MR imaging can eliminate test redundancy and impact patient care in a cost-effective manner. Further investigations are needed to identify the diagnostic algorithms for which this favorable use holds true.

Long-term follow-up of partial thrombosis of the superior mesenteric vein in a cirrhotic patient with hepatocellular carcinoma: a case report

Superior mesenteric venous thrombosis (SMVT) is an uncommon but potentially life-threatening disorder. We describe a cirrhotic patient with hepatocellular carcinoma who had partial SMVT for at least 28 months. Our experience may help in the management of such patients. The partial SMVT was not treated at the time of discovery because there was no evidence of bowel infarction. Moreover, the patient had a tendency to bleed severely and was in a poor condition. SMVT was followed using regular ultrasonography and the pattern of SMVT did not change significantly during the follow-up period. A symptom that may have been related to SMVT was abdominal colic pain after meals, which was sometimes followed by diarrhea and / or nausea and vomiting. There was no evidence of bowel ischemia or infarction during follow-up. Abdominal discomfort can be successfully treated using anticholinergic drugs with or without analgesia.

CT depiction of portal vein thrombi after creation of ileal pouch-anal anastomosis

PURPOSE

To determine the presence and location of portal vein thrombi in patients who have undergone ileal pouch-anal anastomosis (IPAA) and who were scanned with computed tomography (CT).

MATERIALS AND METHODS

During a 4-year period, 92 of 702 patients underwent contrast medium-enhanced CT after a total proctocolectomy with an IPAA. These CT scans were retrospectively reviewed for portal vein thrombus presence, location, and occlusive nature, as well as any accompanying enhancement abnormalities of the hepatic parenchyma. Only 13 patients who had initial CT scans that were positive for thrombi underwent follow-up examinations, and these were reviewed for resolution or progression of the original findings.

RESULTS

Portal vein thrombi were present in 41 (45%) of the 92 patients; 24 (59%) of the 41 were isolated, often multiple, segmental right lobe thrombi. Five patients had both right and left segmental vein involvement. Eleven patients had various combinations of main portal vein, right and left portal vein, or segmental vein thrombi. One patient had an isolated superior mesenteric vein thrombus. Twenty-two of 25 superior mesenteric vein, main portal vein, and right and left portal vein thrombi were nonocclusive, while most (63 of 86) of the segmental vein thrombi were occlusive. Wedge-shaped, peripheral areas of hepatic parenchymal hyperenhancement that were distal to the thrombi were present in 30 (73%) of the 41 patients. Follow-up scans obtained in the 13 patients with portal vein thrombi showed thrombi resolved in five patients, progression to cavernous transformation occurred in one patient, and parenchymal enhancement changes persisted in seven patients. In the seven patients with persistent enhancement changes, four had complete resolution of thrombi.

CONCLUSION

Portal vein thrombi appear to be relatively common after IPAA surgery and are most likely segmental, multiple, and occlusive. Peripheral wedge-shaped areas of hepatic parenchymal hyperenhancement commonly accompany these thrombi.

[Mesenteric venous thrombosis complicating acute appendicitis]

Common primary surgical sources of thrombophlebitis of the mesenteric vein are diverticulitis and appendicitis. This is an acute ascending infection with septic thrombophlebitis. C.T. imaging can diagnose this complication at an early stage. Broad spectrum antibiotic therapy and heparin should be started. Surgery is performed electively to eradicate the primary inflammatory process. Early detections of septic ascending pylephlebitis and adequate treatment have decreased the mortality rate. We report a clinical case of thrombophlebitis of the mesenteric vein in acute appendicitis.