Epiploic Appendagitis vs Diverticulitis

Epiploic Appendagitis vs Diverticulitis: Making the Radiologic Distinction
Matt Baker, MSIII
Gillian Lieberman, MD
November 16, 2009
Agenda
• Case Presentation
• Diverticulitis
– Anatomy
• Differential Diagnosis
– Epidemiology
– Pathophysiology
• Epiploic Appendagitis
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Anatomy
Epidemiology
Pathophysiology
Clinical presentation
Radiologic appearance
Treatment
– Clinical presentation
– Radiologic appearance
– Treatment
• Differentiating the Two
• The Importance
• Case Resolution
Our Patient Ms. J: Clinical Presentation
39 year old woman h/o diverticulitis
LLQ abdominal pain for 24 hours
Pain is sharp, 9/10, persistent, non‐radiating
Denies any N/V, diarrhea, constipation, F/C
On exam: afebrile and exquisitely tender in the LLQ, with some guarding to light palpation; no rebound
• WBC: 6.9 w/normal differential
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Differential Diagnosis for a Female Patient with LLQ Pain
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Diverticulitis
Ischemic colitis
Bowel obstruction
Regional enteritis
Ureteral colic
Torsion/rupture of an ovarian cyst or tumor
Ectopic pregnancy
PID
A CT was obtained to help narrow the differential…
Our Patient Ms. J: Abdominal CT Report
• IMPRESSION:
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Stomach, duodenum, and small bowel normal caliber
Celiac, SMA, and IMA are patent
Pelvic organs unremarkable
Well‐defined focus of fat within the LLQ demonstrates surrounding fat stranding
• Inflammation is adjacent to the sigmoid colon with diverticula
• No inflamed diverticula are identified
• Colon is non‐distended
• No free air
• Small amount of fluid in the cul‐de‐sac is likely physiologic
• Final read: Epiploic appendagitis versus diverticulitis
Before interpreting Ms. J’s abdominal CT, let’s learn about epiploic appendagitis and diverticulitis, and how they are diagnosed radiologically…
Anatomy: Epiploic Appendages
• Visceral peritoneal outpouchings
containing fat and blood vessels
• Located on the serosal
surface of the colon
• Most common in sigmoid colon and cecum
• Usually 1‐2 cm thick and 2‐5 cm long
A cross‐sectional diagram of the colon, showing the relationship between epiploic appendices (A), colic artery (B), straight artery (C), mesocolon (D).
Source: http://www.eurorad.org/case.php?id=1113
Epiploic Appendages on Pathology
Pathologic specimen
Source: http://ect.downstate.edu/courseware/haonline/imgs/00000/8000/700/8736.jpg
Normal Epiploic Appendages in Patients with Ascites on US
Ascites
Ascites
*
Ultrasound with power Doppler
Vriesman AC. Abdominal Imaging. 2002; 27: 20-28.
*
Ultrasound
McClure MJ. Clinical Radiology. 2001; 56: 819-827
Normal Epiploic Appendages in Patients with Ascites on CT
Ascites
Ascites
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Sigmoid colon
Sigmoid colon
*
CT pelvis without IV contrast
Almeida AT. American Journal of
Roentgenology. 2009; 193: 1243-1251.
CT pelvis with IV contrast
Singh AK. RadioGraphics. 2005; 25: 1521-1534.
Ascites
CT pelvis with PO contrast
Vriesman AC. Abdominal Imaging. 2002; 27: 20-28.
Primary Epiploic Appendagitis
• Caused by appendageal torsion or spontaneous venous thrombosis
• Leads to ischemic or hemorrhagic infarction
• Associated with obesity and heavy or unaccustomed exercise
• Incidence in men = women
• Has been reported in 2.3‐7.1% of patients clinically suspected of having diverticulitis*
*Vriesman AC. Abdominal Imaging. 2002; 27: 20-28.
Epiploic Appendagitis Clinical Presentation
Acute focal abdominal pain, often LLQ
Worsens with abdominal stretching and cough
Nausea and vomiting rare
Bowel function usually unchanged
PE: focal abdominal tenderness; may have signs of peritonitis
• Low‐grade fever may be present
• WBC count is often normal
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Menu of Radiologic Tests
• Computed Tomography (CT): the mainstay for diagnosing epiploic appendagitis
– Confirms the fatty nature of the lesion
– Highlights fat stranding
– Fast, effective, gives a lot of information
• Ultrasound (US): useful, but used less today
– Correlates location of lesion with location of maximum tenderness
• Magnetic Resonance Imaging (MRI): not as useful as CT, rarely used
Epiploic Appendagitis on CT
• Ovoid pericolic lesion of fat density
– Fat in lesion: ‐60 Hounsfield units
– Normal peritoneal fat: ‐120 Hounsfield units
• Hyperattenuating ring sign
– 2‐3 mm hyperdense rim surrounding ovoid lesion
– Represents inflamed visceral peritoneum
• Surrounding inflammatory changes
– Fat stranding, thickened parietal peritoneum
– Mild local thickening of adjacent colonic wall; asymmetric
• Central dot sign
– Central hyperattenuating round area or linear area
– Represents engorged or thrombosed central vessels or central area of hemorrhage that is fibrosed, calcified
Epiploic Appendagitis on CT: Companion Patient 1
Parietal peritoneal thickening
Coronal CT with IV contrast
PACS, BIDMC
Fat-density ovoid lesion surrounded
by hyperattenuating ring of thickened
visceral peritoneum
CT pelvis with IV contrast
PACS, BIDMC
Epiploic Appendagitis on CT: Companion Patient 2
Coronal CT with IV and PO contrast
PACS, BIDMC
Fat-density ovoid lesion with
hyperattenuating ring and
surrounding inflammation
CT pelvis with IV and PO contrast
PACS, BIDMC
Epiploic Appendagitis on CT: Central Dot Sign
Thick arrow: pericolonic fatty
lesion surrounded by
hyperattenuating ring
Thin arrow: central
hyperattenuating area
corresponding to thrombosis
and hemorrhagic changes
Open arrow: very mild
thickening of colonic wall
CT pelvis with IV and PO contrast
Almeida AT. American Journal of Roentgenology. 2009; 193: 1243-1251.
Epiploic Appendagitis on US
Non‐compressible hyperechoic ovoid mass
Site of maximum tenderness
Devoid of blood flow on Doppler US
Lesion often circumscribed by a hypoechoic
rim from inflamed visceral peritoneum
• May contain central hypoechoic areas of hemorrhage
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Epiploic Appendagitis on US
A hyperechoic fatty mass is
surrounded by a hypoechoic
rim of thickened visceral
peritoneum
Ultrasound
Vriesman AC. Abdominal Imaging. 2002; 27: 20-28.
Color Doppler
shows that the mass
is avascular
Ultrasound
Almeida AT. American Journal of Roentgenology.
2009; 193: 1243-1251.
Ultrasound with power Doppler
McClure MJ. Clinical Radiology. 2001; 56: 819-827
Epiploic Appendagitis on
Barium Enema
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No role in the diagnosis of epiploic
appendagitis, as it does not provide adequate information.
Extrinsic compression from
mass effect is seen on the
lateral wall of the
descending colon
Frontal radiograph with barium enema
Son HJ. Journal of Clinical Gastroenterology. 2002; 34(4): 435-438.
Treatment
• Self‐limiting with spontaneous resolution
• Symptoms usually subside within a week
• Conservative treatment is sufficient
– Analgesics
• Ibuprofen and acetaminophen/codeine
– Hospitalization and/or antibiotics not required
• Patients advised to seek medical attention if symptoms worsen
Now let’s learn about diverticulitis and its radiologic appearance…
Anatomy: Diverticular Disease
• Diverticula: sac‐like protrusions of colonic mucosa and submucosa
• Diverticulosis: presence of uninflamed diverticula
• Diverticulitis: inflammation of diverticula, often w/ gross or microscopic perforation
• Majority of diverticula located in distal descending and sigmoid colon
Source: http://www.puristat.com/images/diverticulitis‐illust605.jpg
Diverticulitis
• Classically: Obstruction ‐> Focal inflammation ‐> Diverticular distention ‐> Localized ischemia ‐> Perforation
• Can occur without obstruction: Dehyrated
Stool ‐> Increased intraluminal pressure ‐> Erosion of diverticular wall ‐> Inflammation and necrosis ‐> Perforation
• Associated with obesity, lack of physical activity, and decreased dietary fiber intake
• Prevalence dramatically increases with age
Diverticulitis Clinical Presentation
Acute focal abdominal pain, often LLQ
Nausea and vomiting
Diarrhea
PE: focal abdominal tenderness; signs of peritonitis
• Fever
• Elevated WBC count
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Menu of Radiologic Tests
• Radiograph: used to exclude other pathologies, such as obstruction
– Free air may be seen with perforated diverticula
• CT: test of choice
– Very high sensitivity and specificity
• Contrast enema: used less today
– Barium contraindicated if perforation is suspected
• US: High‐resolution, compression US useful additional tool for monitoring evolution over time
Diverticulitis on CT
• Paracolic fat stranding
• Ill‐defined or blurry diverticula in area of inflammation
• Mild bowel wall thickening
• Localized pericolic pockets of gas
• Complications: abscess, fistula, obstruction
Diverticulitis on CT: Companion Patient 3
Thickened bowel wall
Fuzzy diverticulum with
surrounding fat stranding
CT abdomen with PO contrast
PACS, BIDMC
Diverticulitis on CT: Companion Patient 4
Localized gas collection
and nearby fat stranding
Diverticula
Diverticulum
Coronal CT with IV and PO contrast
PACS, BIDMC
Localized gas collection
and nearby fat stranding
CT pelvis with IV and PO contrast
PACS, BIDMC
Treatment
• Uncomplicated diverticulitis
– Bowel rest and antibiotics for 70‐100% of patients
• Inpatient versus outpatient management
– Up to 30% will require surgery during initial attack
– Dietary recommendations
• Clear liquids only; advance diet slowly
– Elective surgery for some
• Complicated diverticulitis
– Obstruction, perforation, abscess formation, or fistula formation
• Surgery or percutaneous intervention
Back to our Patient Ms. J
• 39 year old woman with a h/o diverticulitis
• 9/10 LLQ abdominal pain for the last 24 hours
Before looking at her current CT, let’s examine her CT from 2006…
Our Patient Ms. J: 2006 CT of Diverticulitis
Fuzzy
diverticula
Fat stranding
Fuzzy
diverticula
Coronal CT with PO contrast
CT pelvis with PO contrast
PACS, BIDMC
PACS, BIDMC
Our Patient Ms. J: Current CT
Diagnosis: Epiploic Appendagitis
Uninflamed
diverticula
No bowel wall
thickening
Coronal CT without contrast
PACS, BIDMC
Fat-density ovoid lesion with
hyperattenuating ring and central dot
sign with surrounding inflammation
CT pelvis without contrast
PACS, BIDMC
Keys to Differentiating Epiploic
Appendagitis from Diverticulitis
Epiploic Appendagitis
Diverticulitis
Inflammatory changes in the pericolic fat
Inflammatory changes in the pericolic fat
Minimal colon wall thickening; often asymmetric
Segmental wall thickening and hyperemia of the colon
Diverticula are absent or uninflamed
Inflamed diverticula in the involved segment
1.5‐3.5 cm diameter fat density lesion abutting anterior colonic wall
No distinct fatty lesion
Color Doppler signal low or absent
Color Doppler signal usually increased
Clinically do not appear seriously ill
Clinically appear ill, often with N/V, fever, and an elevated WBC count
PE: Localized tenderness, usually without rigidity
PE: Localized tenderness, often with frank peritonitis
Typically younger patients
Incidence increases with age; typically older patients (>50 years)
The Importance of Making the Diagnosis Radiologically
• Clinical presentations largely indistinguishable • Diagnosis can be confidently made with CT
• Can avoid unnecessary hospitalization and overuse of hospital resources
• Treatment is dramatically different
– Can result in surgery
– Unnecessary antibiotic use
Hospital Course for Our Patient
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Given one dose of antibiotics in the ED
Admitted to surgery service
NPO/IVF
Antibiotics continued
Symptoms improved the next day
– Discharged with 2 weeks of Cipro/Metronidazole
– Ibuprofen and acetaminophen for pain
– Complete resolution over the next week
Conclusion: Our patient avoided unnecessary surgery, but still received antibiotics!
References
Almeida AT. “Epiploic Appendagitis: An Entity Frequently Unknown to Clinicians—Diagnostic Imaging, Pitfalls, and Look‐Alikes”. American Journal of Roentgenology. 2009; 193: 1243‐1251.
Garg AG. “Inflammatory Fatty Masses of the Abdomen”. Seminars in Ultrasound CT and MRI. 2008; 29: 378‐
385.
Gelrud A. “Epiploic appendagitis”. UpToDate. www.uptodate.com. Accessed 11/13/09.
McClure MJ. “Radiological Features of Epiploic Appendagitis and Segmental Omental Infarction”. Clinical Radiology. 2001; 56: 819‐827
Molla E. “Primary epiploic appendagitis: US and CT findings”. European Radiology. 1998; 8: 435‐438.
Osada H. “Multidetector computed tomography diagnosis of primary and secondary epiploic appendagitis”. Radiation Medicine. 2008; 26: 582‐586.
Rao PM. “Primary Epiploic Appendagitis: Evolutionary Appearances in CT Appearance”. Radiology. 1997; 204: 713‐717.
Rioux M. “Primary Epiploic Appendagitis: Clinical, US, and CT Findings in 14 Cases”. Radiology. 1994; 191:523‐
526.
Sandrasegaran K. “Primary Epiploic Appendagitis: CT diagnosis”. Emergency Radiology. 2004; 11: 9‐14.
Singh AK. “Acute Epiploic Appendagitis and Its Mimics”. RadioGraphics. 2005; 25: 1521‐1534.
Singh AK. “CT Apperance of Acute Appendagitis”. American Journal of Roentgenology. 2004; 183: 1303‐1307.
Sirvanci M. “Primary epiploic appendagitis CT manifestations”. Journal of Clinical Imaging. 2000; 24: 357‐361.
Son HJ. “Clinical Diagnosis of Primary Epiploic Appendagitis”. Journal of Clinical Gastroenterology. 2002; 34(4): 435‐438.
Vriesman AC. “Epiploic appendagitis and omental infarction: pitfalls and look‐alikes”. Abdominal Imaging. 2002; 27: 20‐28.
Young‐Fadok T. “Epidemiology and Pathophysiology of colonic diverticular disease”. UpToDate. www.uptodate.com. Accessed 11/13/09.
Zissin R. “Acute epiploic appendagitis: CT findings in 33 cases”. Emergency Radiology. 2002; 9: 262‐265.
Acknowledgements
• Dr. Julia Rissmiller
• Dr. James Kang
• Dr. Gillian Lieberman
• Maria Levantakis
Philomath, Oregon