Year : 2006 | Volume
: 16 | Issue : 4 | Page : 951--952
Radiological quiz - abdomen
SZ Abbas, M Rashid, SN Abbas, IA Khan
Dept. of Radiodiagnosis, JN Medical College, AMU, Aligarh, India
S Z Abbas
Department of Radiodiagnosis, JNMC, AMU, Aligarh, Aligarh - 202002
|How to cite this article:|
Abbas S Z, Rashid M, Abbas S N, Khan I A. Radiological quiz - abdomen.Indian J Radiol Imaging 2006;16:951-952
|How to cite this URL:|
Abbas S Z, Rashid M, Abbas S N, Khan I A. Radiological quiz - abdomen. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Feb 19 ];16:951-952
Available from: http://www.ijri.org/text.asp?2006/16/4/951/32397
A 22 year old male patient who has suffered blunt trauma in a severe motor vehicle accident was brought to Emergency Section of our Hospital in an unconscious state. Patient was afebrile with a shallow and rapid respiration (R/R - 40/min) and his systolic B.P was 60mmHg. Physical examination revealed multiple abrasions over Right upper abdomen. Chest radiograph revealed fracture of Right 6th and 7th rib anteriorly but no evidence of pneumothorax or hemothorax. Cervical and pelvic roentography were unremarkable. IV fluids were administered and patient was screened by ultrasonography (FAST Scanning) which revealed intraperitoneal fluid collection. Following are the Contrast Enhanced CT abdomen images of the patient [Figure 1][Figure 2][Figure 3]. What is your diagnosis?
View AnswerSHOCK BOWEL
CECT scan of the abdomen shows fluid filled small bowel loops with diffuse thickening of the bowel wall with increased postcontrast enhancement. Ascending and descending colon appear normal. Also seen are hyperenhancing adrenals, flattened inferior venacava and slightly small calibre of aorta. There is also an associated hemoperitoneum.
Patient was taken up for emergency laparotomy which showed a mesenteric tear. However the bowel did not showed any abnormality intraoperatively.
Shock bowel complex is an infrequently encountered entity found on computed tomography in victims of severe trauma. Severe circulatory blood loss with hypovolaemic shock, most often seen as a result of trauma, leads to reflex reduction in circulation in an attempt to sustain circulatory volume and cardiac output. These compensatory mechanisms result in the characteristic imaging findings on CT.,
Bulkley et al.  performed studies of bowel hypoperfusion in a canine model which indicated that the bowel mucosa becomes increasingly permeable to albumin and other macromolecules when blood flow is reduced to a point at which oxygen consumption is 50% or less of normal. This increased permeability is evident as early as 1 hr of ischemia. The CT appearance of the small bowel in our patients is consistent with increased permeability leading to wall thickening, increased enhancement with IV contrast material (due both to slowed perfusion and interstitial leak of molecules of contrast material), and accumulation of intraluminal fluid (probably due to failed resorption capacity) . The recovery of a normal morphologic appearance, as well as apparent function of the small bowel in all surviving patients, indicates the ability of the human small bowel to tolerate prolonged periods of hypoperfusion resulting from splanchnic vasoconstriction caused by hypovolemic shock. The failure of the colon to show similar changes on CT scans suggests a much lower metabolic oxygen demand or perhaps less efficient shunting of blood away from the large bowel. ,
Other processes can lead to diffuse abnormalities of the small bowel occurring after trauma, like diffuse small-bowel edema can result from aggressive volume resuscitation and increased central venous pressure . In such cases, the patients are likely to show other signs of elevated central venous pressure including an enlarged inferior vena cava, periportal lymphedema, and possibly accumulation of retroperitoneal fluid ,. These patients do not exhibit increased contrast enhancement of the small-bowel wall. These signs would not be expected in a hypoperfused person, except in cases of tension pneumothorax, cardiac tamponade, or other severe impairment of cardiac function, in which both systemic hypoperfusion and central venous hypertension can coexist. Other lesions that could have a similar CT appearance to shock bowel include diffuse on extensive small-bowel contusion on diffuse bowel ischemia related to vascular occlusion, rather than hypoperfusion that may occur from blunt abdominal trauma.
In the setting of abdominal trauma, early abdominal and pelvic CT scan can show diffuse abnormalities due to hypovolemia that occasionally may alert clinicians of unsuspected shock . Recognition of these signs as distinguished from injured viscera is important in order to avoid unnecessary laparotomy .
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