Radiological Category Gastrointestinal Principal Modality 1 CT Principal

Radiological Category: Gastrointestinal Principal Modality (1): CT Principal Modality (2): Case Report # 0870 Submitted by: Patrick Marcin, M. D. Faculty reviewer: Eduardo Matta, M. D Date accepted: 12 February 2012

Case History • 71 year old female presenting with the sudden onset of left sided abdominal pain • When asked the scale from 1 to 10 she replied "bad. " The pain spreads to her back and all around her lower abdomen. It has been constant since onset and severe the entire time. She denies any fevers, recent weight changes. She is unsure if she has passed gas. • PMHx of HTN, dyslipidemia, COPD. No h/o abdominal surgery. • PE: Vital Signs: 96/77 mm/Hg, 96 bpm, 98. 5 F, 100% O 2 Sat on RA Ø General appearance: Thin woman lying motionless in bed with eyes closed appearing to concentrate on not hurting Ø Abdomen: diffuse tenderness to palpation, worse left of umbilicus, no rebound tenderness present, no peritoneal signs, no rigidity or firmness, no CVA tenderness • Pertinent Labs Ø WBC 22 with 8 bands Ø lactate 3. 6 Ø Cr 1. 7 Ø ABG 7. 26/44/163/20 base excess -7

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations CTA – Axial Arterial Phase CTA – Axial Venous Phase

Radiological Presentations

Radiological Presentations

Test Your Diagnosis Which one of the following is your choice for the appropriate diagnosis? After your selection, go to next page. • Nonocclusive Mesenteric Ischemia • Mesenteric ischemia from portal vein thrombosis • Embolic Mesenteric ischemia • Small bowel volvulus with mesenteric ischemia

Findings and Differentials Findings: The origins of the celiac axis, superior mesenteric artery and inferior mesenteric artery remain patent. However, there is nonopacification of the distal superior mesenteric artery in the region of mesenteric swirling. The proximal mesenteric veins are engorged due to obstruction more proximally by this twisted mesentery. There is borderline dilatation and fecalization of multiple loops of small bowel associated with a swirl sign centered around the root of the mesentery causing twisting and occlusion of the superior mesenteric artery as described above. No free intraperitoneal air or pneumatosis is identified. No portal venous gas is seen. Differentials: • Nonocclusive Mesenteric Ischemia • Mesenteric ischemia from portal vein thrombosis • Embolic Mesenteric ischemia • Small bowel volvulus with mesenteric ischemia

Discussion • Mesenteric ischemia is caused by a reduction in intestinal blood flow, which most commonly arises with occlusion, vasospasm, and/or hypoperfusion of the mesenteric vasculature. Other less common causes are from mechanical narrowing or obstruction. • The clinical consequence can be catastrophic, including sepsis, bowel infarction, and death, making rapid diagnosis and treatment imperative. • Intestinal Ischemia can be subdivided: Ø Acute mesenteric ischemia 1. Occlusive arterial due to emboli or thrombosis 2. Occlusive venous due to thrombosis 3. Nonocclusive due to arterial hypoperfusion ØChronic mesenteric ischemia 1. Episodic or constant intestinal hypoperfusion usually due to atherosclerotic disease.

Discussion Most common signs/symptoms • Acute ischemia ØClinical triad: Sudden onset of abdominal pain, diarrhea, vomiting ØUnremitting abdominal pain disproportionate to physical exam findings ØAbdominal distention, tenesmus, passage of bloody stool ØGuarding and rebound (infarction/perforation) ØVenous ischemia has more gradual onset • Chronic ischemia ØIntestinal angina: Postprandial abdominal pain subsiding 1 -2 hours after meal ØNausea, vomiting, diarrhea, weight loss ØIntense pain with fear of eating (sitophobia)

Discussion • High clinical suspicion is key to early diagnosis • Just as physical exam findings can be vague, and hard to pinpoint, the laboratory analysis is also nonspecific. Ø↑ WBC in 75% of cases, acidosis in 50% of cases, ↑ amylase in 25% of cases Prognosis • Acute ØDepends on promptness of diagnosis, amount of salvageable SB Ø 50 -90% mortality ØOutcomes in venous ischemia patients are generally better • Chronic • Survival dependent on degree of collateral circulation • Diagnosis requires occlusion of at least 2 major mesenteric arteries and narrowing of 3 rd artery • Infarction: 69% mortality (in recent series)

Discussion Imaging Findings on CT: • Clot or reduced lumen in SMA, SMV, or other mesenteric vessels • Segmental thickening of bowel wall (> 3 mm); average 8 mm, ≤ 20 mm • Emboli usually observed at origin of SMA or 3 -10 cm from SMA distal to middle colic artery • Lack of mucosal enhancement due to compromised arterial flow • "Misty mesentery": Mesenteric fat infiltrated by edema; more common with venous thrombosis • Increased bowel wall attenuation (venous > arterial thrombosis) due to submucosal hemorrhage or hyperemia • Pneumatosis intestinalis (venous > arterial thrombus) ØBand-like or bubble-like appearance in bowel wall ØLinear, curvilinear, or cystic gas-filled spaces ر gas in mesenteric or portal vein ØPartially fluid-filled bowel loops

Discussion Treatment • Surgical treatment ØExploratory laparotomy, bowel resection, and mesenteric bypass to reestablish blood flow ØMain treatment for acute ischemia, chronic ischemia, and complications • Endovascular intervention ØIntraarterial thrombolysis, percutaneous transluminal angioplasty ± stent placement ØThrombolytics (streptokinase, urokinase) ØVasodilators (papaverine) to reduce vasospasm • Systemic anticoagulation (warfarin, heparin) for venous occlusion

Discussion Small Bowel Volvulus • A volvulus is an acute condition in which the bowel and its mesentery twist around their own axis. It most commonly occurs in the sigmoid colon, where it can lead to intestinal obstruction. • Small bowel volvulus or midgut volvulus is common in the pediatric population, however, much rarer in adults. • There are several causes of small bowel volvulus. SBV can be categorized into two types according to causes: Ø (1) the primary form in which the small bowel volvulus occurs without any apparent intrinsic anatomical anomalies; Ø(2) the secondary type in which the small bowel volvulus is due to an anatomical abnormality, such as adhesions, mesenteric or omental defects, intestinal diverticulum and/or masses.

Discussion • The “whirlpool” sign, refers to the twisting of the mesenteric vessels seen with intestinal volvulus. On earlier images, you can trace the SMA and SMV, rotating around each other in their long axis.

Discussion • The significant degree of torsion resulted in complete occlusion of the SMA.

Diagnosis After midline incision was made, lots of inflammatory fluid and necrotic appearing bowel was identified. Here you can see one normal appearing segment of bowel which are the loops actually wrapping around the mesenteric stalk. The small bowel volvulus was rapidly reduced in a counterclockwise fashion.

Diagnosis Following this reduction, the bowel appeared to immediately have some level of recovery, although still quite dusky. The bowel was then run along its entirety. While, there were several areas that appeared threatened, there was only 1 area that appeared to be fullthickness, consistent with a gross infarct which was then resected.

Diagnosis The source or lead point of this volvulus appeared to be at the base of the small bowel, which was in the proximal jejunum. It was a large duplication cyst versus diverticulum off of the small bowel along its mesenteric border. Final Pathology: Regional cystic structure (4. 5 x 3. 0 x 2. 0), with small intestinal mucosal lining, communicating with bowel segment lumen consistent with a duplication cyst.

Diagnosis Secondary small bowel volvulus from a jejunal duplication cyst resulting in acute mesenteric ischemia.

References Li XB. Multislice computed tomography angiography findings of chronic small bowel volvulus with jejunal diverticulosis. Japan Journal of Radiology. July 2010; 28(6): 469472. Roggo A. Acute small bowel volvulus in adults. A sporadic form of strangulating intestinal obstruction. Annals of Surgery. August 1992; 216(2): 135 -141. Jeffrey RB. Ischemic enteritis. Statdx. com Tendler DA. Acute mesenteric ischemia. Uptodate. com