Bowel emergencies. Bruce Lehnert MD. Stomach. Gastric : Bleeding varices. Stomach

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1 Bowel emergencies Bruce Lehnert MD Stomach Gastric : Bleeding varices Stomach 1

2 Stomach Upper GI bleed Proximal to the ligament of Treitz 5X more common than lower GIB High volume Endoscopy identifies source in 95% of cases Offers therapeutic options Sclerotherapy, clipping, cautery, etc. Does not perform as well during massive bleeding May require CT for localization Stomach GIB CT technique Noncontrast Delineates high attenuation material in the bowel No oral contrast given Arterial phase Vascular malformations Arterial bleeding/vascular blush Portal venous phase Vascular blush Useful for identifying lesions responsible for bleeding» Tumors, etc. Delayed phase Late capillary phase Contrast containing blood pools in the bowel Slower bleeding detected Stomach GIB CT may outperform catheter angiography Low bleeding rates: 0.3cc/min MPRs allow for very small lesion detection Accuracy reported as high as 97% 2

3 Stomach GIB CT findings Mixed density clot in the bowel lumen pre contrast (up to 80 90HU) Linear or jet like high attenuation in the bowel lumen during arterial phase Hyperattenuating loop of bowel on portal venous or delayed phase Stomach GIB CT findings Mixed density clot in the bowel lumen pre contrast (up to 80 90HU) Linear or jet like high attenuation in the bowel lumen during arterial phase Hyperattenuating loop of bowel on portal venous or delayed phase Stomach Gastric perforation Gastric ulcer Caustic ingestion Neoplasm Ischemia Volvulus Foreign body and The Heimlich maneuver 3

4 Stomach Gastric perforation CT findings Pneumoperitoneum May be any volume but typically large for frank gastric perforation Peritoneal enhancement/inflammati on Free fluid May be complex, containing food debris Focal gastric wall thickening in setting of PUD (along greater curvature) Wall defect may or may not be visualized Ulceration may project beyond the wall of the bowel Duodenum Acute duodenal obstruction Ulcer Pancreatitis Neoplasm GIST Adenocarcinoma Metastasis Duodenal diverticulitis SMA syndrome Foreign body/bezoar Gallstone Bouveret syndrome Duodenum Acute duodenal obstruction Ulcer Pancreatitis Tumors GIST Adenocarcinoma Metastasis Lipoma Adenoma Leiomyoma Duodenal diverticulitis SMA syndrome Foreign body/bezoar Gallstone Bouveret syndrome IBD Crohn s: 5 60% duodenal involvement 4

5 Duodenum Acute duodenal obstruction SMA syndrome Compression of the 3 rd portion of the duodenum by the SMA Fat around the SMA reduced during severe weight loss, reducing angulation and distance between aorta and SMA F>M May present acutely with high grade obstruction Aorta SMA angle 15 Aorta SMA distance 8mm Duodenum Acute duodenal obstruction SMA syndrome variant Duodenum Duodenal ulcer 95% located in duodenal bulb NSAIDS, H. pylori Duodenal wall thickening Ulcer crater may project beyond the margin of the bowel Signs of perforation Inflammatory infiltration of retroperitoneal fat Extraluminal gas or contrast 5

6 Duodenum Duodenal diverticulitis Majority located along medial wall near the ampulla (70%) Diverticuli are common: 23% Diverticulitis is uncommon CT findings of diverticulitis Duodenal wall thickening Surrounding fat stranding Retroperitoneal gas Erosion into branched of the pancreaticoduodenal arteries thickening/inflammation Ischemia Crohn s Vasculitis HSP GVHD Infectious enteritis Viral CMV Bacterial Salmonella Camplyobacter Yersinia TB Whipple disease Parasitic Cryptosporidium Giardia Radiation enteritis Amyloidosis Mastocytosis Angioedema Inflammation Crohn s Recurrent segmental granulomatous inflammation Involves any part of GI tract 80% small bowel involvement 6

7 Inflammation: Crohn s Inflammation: Vasculitis Henoch Schonlein purpura Acute small vessel vasculitis Typically in children and young adults 50 70% GI involvement CT findings Multifocal bowel wall thickening Mucosal hyperemia Mesenteric edema, adenopathy, and vascular engorgement obstruction Intrinsic IBD Neoplasm Intussusception Extrinsic Adhesions Adhesive bands not visible on CT Hernia Neoplasm Intraluminal Foreign bodies Gallstones Bezoar 7

8 Simple obstruction Blocked at one or more points along course of bowel Degree of upstream dilation dependent on severity and duration High grade = 50% caliber difference between upstream and downstream bowel Closed loop obstruction Partial or complete occlusion at two adjacent points CT findings Typically fluid filled, dilated U or C shaped loops of bowel Mesenteric edema Prominent mesenteric vessels converging on the point of obstruction Volvulus may be present Beak sign Swirling mesentery Closed loop obstruction Ischemia High mortality 10% of closed loop SBO Typically the result of delayed presentation/diagnosis CT findings Thickened bowel wall Loss of mucosal enhancement (specific) Mesenteric fluid or hemorrhage Pneumatosis Portal venous gas 8

9 obstruction Intussusception Pathologic vs transient Transient Lack of upstream bowel dilation Length 3.5cm No lesion identified obstruction Intussusception Pathologic vs transient Pathologic SBO Mass, inflammation, foreign body or other lesion acting as lead point. Intussusception CT findings Target sign Early finding Outer layer:» Intussuscipiens Inner layer:» Intussusceptum Soft tissue mass Late finding Edema and mural thickening Vascular compromise 9

10 obstruction Intussusception due to Meckel s diverticulum obstruction Ileocolonic intussusception due to cecal adenocarcinoma obstruction Ileocolonic intussusception due to cecal adenocarcinoma 10

11 Inguinal Hernia Indirect hernia Passes through internal inguinal ring Lateral to inferior epigastric arteries Anterior to spermatic cord Travels adjacent to spermatic cord/round ligament Moderate risk for incarceration 15% of SBOs May contain small bowel, colon, appendix, bladder, gonads Inguinal Hernia Indirect hernia Passes through internal inguinal ring Lateral to inferior epigastric arteries Anterior to spermatic cord Travels adjacent to spermatic cord/round ligament Moderate risk for incarceration 15% of SBOs May contain small bowel, colon, appendix, bladder, gonads Femoral hernia Exits below inguinal ligament Through femoral ring and into femoral canal Medial to the common femoral vein Characteristic femoral vein compression More common in women (4:1), twice as common on the right Up to 20% incarcerate 11

12 Ventral hernias Incarceration and strangulation are common Incarceration: irreducible Associated bowel obstruction (usually SBO) Second leading cause after adhesions Narrow neck Strangulation: ischemia Usually due to closed loop obstruction in hernia Free fluid Bowel wall thickening Mesenteric edema Ventral hernias Incarceration and strangulation are common Incarceration: irreducible Associated bowel obstruction (usually SBO) Second leading cause after adhesions Narrow neck Strangulation: ischemia Usually due to closed loop obstruction in hernia Free fluid Bowel wall thickening Mesenteric edema Post colostomy internal hernia herniating through sigmoid mesentery defect created at segmental colectomy and end colostomy High grade closed loop obstruction Intestinal ischemia 12

13 infarction Numerous causes Obstruction Thromboembolism Neoplasm Vasculitis Trauma Chemotherapy Radiation Caustic ingestion High mortality infarction CT findings of ischemia Bowel wall thickening Common but nonspecific Arterial occlusion SMA occlusion is most common Portal thrombosis Mesenteric edema Pneumatosis Portal venous gas Non enhancing bowel highly specific Pneumoperitoneum infarction CT findings of ischemia Bowel wall thickening Common but nonspecific Arterial occlusion SMA occlusion is most common Portal thrombosis Mesenteric edema Pneumatosis Portal venous gas Non enhancing bowel highly specific Pneumoperitoneum 13

14 infarction CT findings of ischemia Bowel wall thickening Common but nonspecific Arterial occlusion SMA occlusion is most common Portal thrombosis Mesenteric edema Pneumatosis Portal venous gas Non enhancing bowel highly specific Pneumoperitoneum infarction CT findings of ischemia Bowel wall thickening Common but nonspecific Arterial occlusion SMA occlusion is most common Portal thrombosis Mesenteric edema Pneumatosis Portal venous gas Non enhancing bowel highly specific Pneumoperitoneum Lower GI bleed 90% colorectal 10% small bowel Diverticula (most common) Vascular malformation Angiodysplasia (2 nd most common) Varices Inflammation Neoplasm 14

15 Lower GI bleed 90% colorectal 10% small bowel Diverticula (most common) Vascular malformation Angiodysplasia (2 nd most common) Varices Inflammation Neoplasm Diverticulitis Diverticulum: mucosa and submucosa herniation through muscular layers of the wall: pseudodiverticulum Typically at site of traversing vasa recta blood vessel Diverticular bleeding Diverticulitis: occlusion and microperforation of diverticulum Diverticulitis CT findings: Bowel wall thickening (>10cm specific for diverticulitis) Pericolonic fat stranding Edema at orifice of inflamed diverticulum Complications: Abscess Fistula Mesenteric venous thrombosis Hepatic abscess Peritonitis Obstruction Hemorrhage Imaging findings overlap significantly with primary colon neoplasm. Offending diverticulum visible in only 30% of cases 15

16 Diverticulitis Complication: Coloenteric fistula Diverticulitis Complication: Colovesicular fistula Diverticulitis Complication: Tuboovarian abscess 16

17 Diverticulitis Complication: Tuboovarian abscess Diverticulitis Complication: Necrotizing soft tissue infection Diverticulitis Unusual presentation 17

18 Diverticulitis Unusual presentation Diverticulitis Unusual presentation Obstruction Adenocarcinoma Most common GI neoplasm Obesity Diet IBD Family history» Hereditary nonpolyposis colorectal carcinoma (5% of all colorectal carcinomas) Most common cause of colonic obstruction (50%) Second most common cancer mortality 18

19 Obstruction Adenocarcinoma CT findings Focal colonic wall thickening and narrowing (+/ soft tissue mass) Large lesions may appear necrotic and mimic abscess Pericolonic fat stranding» Tumor infiltration of the bowel wall Complications» Obstruction» Perforation» Intussusception Obstruction Adenocarcinoma CT findings Focal colonic wall thickening and narrowing (+/ soft tissue mass) Large lesions may appear necrotic and mimic abscess Pericolonic fat stranding» Tumor infiltration of the bowel wall Complications» Obstruction» Perforation» Intussusception Obstruction Cecal volvulus Torsion of cecum around its mesentery Abnormal retroperitoneal fixation» Long mesentery» Malrotation Pregnancy, colonoscopy 25 40% of colon volvulus cases Closed loop obstruction Ischemia Necrosis Perforation 19

20 Obstruction Cecal volvulus CT findings: Whirling mesentery (73%)» Consider variant diagnosis: cecal bascule if no whirling mesentery Severe cecal distention Ectopic cecum (LUQ) distention Distal colon decompression Obstruction Sigmoid volvulus Most common site: 60 75% High fiber diet Redundant sigmoid colon Constipation Gaseous distention Complications Strangulation» Ischemia and necrosis: 15 20% Obstruction Recurrence: 40 50% after nonoperative reduction Obstruction CT findings Northern exposure sign Air filled loop arising from the pelvis and extending cranially beyond the transverse colon Coffee bean sign U shaped closed loop obstruction Swirling mesentery 20

21 Colitis Overlap in imaging findings Immune status, clinical history Serologic, biopsy often required for specific diagnosis Many cases of infectious colitis present as pancolitis Exceptions include Salmonella, yersinia, TB, amebiasis, shistosomiasis, etc Colitis C. difficile Ubiquitous gram+ organism Overgrowth due to antibiosis Noninvasive infection injury due to toxins Majority of cases results in only mucosal injury Occasional progression to transmural injury» Toxic megacolon Colitis C. difficile CT findings Marked colonic wall thickening Decreased submucosal attenuation» Edema Mucosal hyperemia Increased colon diameter (>6cm)» Transmural inflammation Loss of haustrations Pericolonic fat stranding Ascites 21

22 Colitis CMV Herpes virus family Majority of people infected at some point Remains in latent state Serious primary infection or reactivation may occur in immune compromised patients May reactivate in IBD patients, particularly UC Pan colitis Marked wall thickening Cecum and proximal colon more severely involved Colitis Ulcerative colitis Idiopathic inflammation primarily involving colonic mucosa and submucosa. M>f Begins distally in rectum and may extend to contiguously involve entire colon and terminal ileum (ileocecal valve incompetence) Complications include Colorectal cancer Toxic megacolon Strictures Abscess (uncommon) PSC (80% of PSC patients have UC) Colitis Ulcerative colitis CT findings 95% rectal involvement» Increased perirectal fat Continuous wall thickening extending proximally from the rectum» Perianal disease less common that Crohn s Target sign» Submucosal edema» Enhancing mucosa and muscularis propria Fat halo sign» 60% of chronic cases Loss of haustration» lead pipe» Luminal narrowing Relative lack of mesenteric adenopathy compared to Crohn s 22

23 Colitis Ulcerative colitis CT findings 95% rectal involvement» Increased perirectal fat Continuous wall thickening extending proximally from the rectum» Perianal disease less common that Crohn s Target sign» Submucosal edema» Enhancing mucosa and muscularis propria Fat halo sign» 60% of chronic cases Loss of haustration» lead pipe» Luminal narrowing Relative lack of mesenteric adenopathy compared to Crohn s Pneumatosis cystoides intestinalis Circular collections of gas in bowel wall and mesentery Almost always occurs in colon Does not respect vascular territories Asymptomatic patient with very impressive imaging findings Numerous associated conditions:» Pulmonary disease» Corticosteroids Life threatening pneumatosis May be seen in setting of acute vascular or bowel pathology Mesenteric ischemia is most common identified etiology Underlying cause often not determined Degree of bowel wall gas often less impressive than pneumatosis cystoides Patient acutely ill Peritonitis Acidosis Elevated lactate (mortality 80% in setting of pneumatosis) 23

24 Suggested reading Al Hawary MM, Kaza RK, Platt JF. CT enterography: concepts and advances in Crohn's disease imaging. Radiologic clinics of North America 2013; 51:1 16 Artigas JM, Marti M, Soto JA, Esteban H, Pinilla I, Guillen E. Multidetector CT angiography for acute gastrointestinal bleeding: technique and findings. Radiographics : a review publication of the Radiological Society of North America, Inc 2013; 33: Burkhardt JH, Arshanskiy Y, Munson JL, Scholz FJ. Diagnosis of inguinal region hernias with axial CT: the lateral crescent sign and other key findings. Radiographics : a review publication of the Radiological Society of North America, Inc 2011; 31:E1 12 Rosenblat JM, Rozenblit AM, Wolf EL, DuBrow RA, Den EI, Levsky JM. Findings of cecal volvulus at CT. Radiology 2010; 256: Silva AC, Pimenta M, Guimaraes LS. obstruction: what to look for. Radiographics : a review publication of the Radiological Society of North America, Inc 2009; 29: Thoeni RF, Cello JP. CT imaging of colitis. Radiology 2006; 240: Pearl MS, Hill MC, Zeman RK. CT findings in duodenal diverticulitis. AJR Am J Roentgenol 2006; 187:W Takeyama N, Gokan T, Ohgiya Y, et al. CT of internal hernias. Radiographics : a review publication of the Radiological Society of North America, Inc 2005; 25: Ho LM, Paulson EK, Thompson WM. Pneumatosis intestinalis in the adult: benign to life threatening causes. AJR Am J Roentgenol 2007; 188: