Case 29: Perforated Diverticulitis

A 37-year-old female presented to the emergency room with severe, radiating bilateral flank pain lasting one week. Pain was constant and pressure-like. Patient had a past medical history significant for constipation, ovarian cysts, diverticulitis, and a colonic polypectomy. She denied fever, vomiting, and denied melena and hematochezia. Patient had no dysuria, frequency or hematuria. She denied vaginal discharge or odor. Patient was seen and treated by her primary care provider with ciprofloxacin and metronidazole for presumed diverticulitis. When pain failed to improve two days later, patient presented to the Emergency Department.

Upon arrival, her vital signs were as follows:

T 98.2 | BP 109/73 | HR 71 | RR 16 | SPO2 99% on RA |

Her physical exam revealed left paraumbilical and left lower-quadrant tenderness. No masses were palpated. A bedside ultrasound of the abdomen is performed, and the following images were obtained. In examining these images, what do you notice and how would this change your patient management?

Diverticulitis itop GIF
Diverticulitis cropped view itop GIF

Answer and Learning Points


In these images/videos, a thickened bowel wall is observed in the distal descending colon and proximal sigmoid. Extensive pericolonic fat stranding is represented by the hyperechoic fat deep to the bowel, with no drainable abscess found.

In the emergency setting, computed tomography (CT) scans are highly accurate and remain the most widely used modality to diagnose diverticulitis, with an overall accuracy of 99% [1]. CT can assist in planning if surgical intervention is needed. An estimated 15-20% of all patients admitted with either complicated or uncomplicated diverticulitis will require surgical intervention during their initial admission, yet that likelihood increases to upwards of 50% for those with complicated diverticulitis [2]. However, concerns of radiation exposure and extended length of stays have led to increased use of point-of-care ultrasound (POCUS) [3].

Cohen et al found that POCUS performed by ultrasonographic-trained emergency physicians, physician assistants, and ultrasonographic fellows had both high sensitivity (92%) and specificity (97%) for diagnosing acute diverticulitis [3]. However, the usage of POCUS for diverticulitis by EM physicians is a new application and not a current widespread practice.


There are 3 POCUS indicators of acute diverticulitis, namely:

1) Thickened bowel wall greater than 5mm surrounding an adjacent diverticulum

2) enhancement of surrounding pericolonic fat

3) sonographic tenderness to palpation [3]


To perform this technique, place the curvilinear probe on the patient in the areas of tenderness and compress the bowel wall. The bowel will be found just deep to the peritoneal line. In diverticulitis, the bowel will appear with a thickened wall >4 mm with a visible diverticulum.

Surrounding hypoechoic edema is often visible. Perforation may appear contiguously to the diverticulitis. Normal bowel will compress fully with the ultrasound probe.


CT Image


This patient received a CT that confirmed acute flare of diverticulitis with contained perforation involving a short segment in the distal descending colon and proximal sigmoid, with no drainable abscess at this time. She was admitted to medicine with GI and surgery consults following.


1) Sai, V. F., Velayos, F., Neuhaus, J., & Westphalen, A. C. (2012). Colonoscopy after CT diagnosis of diverticulitis to exclude colon cancer: a systematic literature review. Radiology, 263(2), 383–390.

2) Wieghard N, Geltzeiler CB, Tsikitis VL. Trends in the surgical management of diverticulitis. Ann Gastroenterol. 2015;28(1):25-30.

3) Cohen, A., Li, T., Stankard, B., & Nelson, M. (2020). A Prospective Evaluation of Point-of-Care Ultrasonographic Diagnosis of Diverticulitis in the Emergency Department. Annals of emergency medicine, 76(6), 757–766.

This post was written by Cameron Olandt and Colleen Campbell MD RDMS.

Case 28: Nah-bscess

A 35 year old male with a history of IV drug use and HIV on ART presents to the emergency department with pain and redness of his left upper extremity for a few days. He denies systemic symptoms or prior history of abscess.

Vitals: Temp 98.5, HR 93,  BP 122/75, RR20

Physical Exam: Notable for a large, well circumscribed area of induration, erythema, warmth, and  tenderness on the left upper arm. Distal to the lesion, there is intact cap refill and 2+ radial pulse.

A bedside ultrasound was performed. What do you see?


cobblestoning and fluid collection
turbulent flow within fluid collection
pulsatile flow
continuous flow
continuous lumen

Answer and Learning Points


Image 1 is a transverse view of the LUE and demonstrates cobblestoning in the subcutaneous tissue which is suggestive of cellulitis. There is no fluid tracking on the fascial planes, fascial thickening, hyperechoic gas or dirty shadowing to suggest necrotizing fasciitis.

Image 1 also demonstrates a well-circumscribed, anechoic fluid collection concerning for an abscess. However, the lumen-like and well-demarcated appearance deep to the area of cobblestoning also suggests a blood vessel, and so we imaged it with color and pulse-wave doppler.

Image 2 use color doppler and demonstrates turbulent flow within the fluid collection. Superficial and medial to the fluid collection, a vessel can be appreciated with flow towards the ultrasound probe.

Image 3 and 4 use pulse wave doppler and demonstrate areas of both pulsatile and continuous flow in various parts of this structure.

Image 5 demonstrates continuity between a distal pulsatile vessel and the proximal fluid collection. The fluid collection likely represents an arterial aneurysm or arteriovenous fistula, as opposed to an abscess. Taking into consideration the patients history of IV drug use, trauma from repeated injections may have created abnormal structures within the patient’s vasculature.

Conclusion and Learning Points:

1. When there is concern for cellulitis, POCUS is a useful tool to quickly evaluate for drainable fluid collections, as well as to evaluate for necrotizing fasciitis.

2. When evaluating a possible abscess, it is important to confirm that the collection has no pusatility or flow before attempting drainage.


1. Bystritsky R, Chambers H. Cellulitis and Soft Tissue Infections. Ann Intern Med. 2018 Feb 6;168(3):ITC17-ITC32. doi: 10.7326/AITC201802060. Erratum in: Ann Intern Med. 2020 May 19;172(10):708. PMID: 29404597.

2. Paz Maya S, Dualde Beltrán D, Lemercier P, Leiva-Salinas C. Necrotizing fasciitis: an urgent diagnosis. Skeletal Radiol. 2014 May;43(5):577-89. doi: 10.1007/s00256-013-1813-2. Epub 2014 Jan 29. PMID: 24469151.

This post was written by Jeff Hendel, MS4 and Ben Liotta, MD, with further editing by Sukh Singh, MD.

Can Fluid Accumulation on Ultrasound Diagnose Necrotizing Fasciitis?

necrotizing fasciitis


Necrotizing fasciitis (NF) is rapidly progressing, severe soft tissue infection with a mortality rate of 19.3% with treatment and significantly higher without treatment (1). Early diagnosis is essential to prompt surgical intervention and reduce morbidity and mortality. However, treatment can often be delayed because no laboratory or imaging test can definitively diagnose NF. Contrast-enhanced CT shows the best accuracy, but again is not perfect and can be difficult to obtain in unstable patients. MRI is similarly accurate, but even less feasible in the Emergency Department. Ultimately, it remains a surgical diagnosis.

Ultrasonography is a rapid, bedside, and non-invasive tool that has potential to accelerate assessment of patient with clinical suspicion for NF. There are ultrasonographic findings associated with NF diagnosis, including irregularity or thickening of deep fascia, subcutaneous emphysema, and fluid accumulation along the deep fascial plane (2-13). Considering this condition’s rapid progression, ultrasonography may enable physicians to quickly gauge disease severity and triage accordingly, prompting earlier surgery and bettering patient outcomes.

The Relationship Between Fluid Accumulation in Ultrasonography and Diagnosis and Prognosis of Patients with Necrotizing Fasciitis


Clinical Question

What is the relationship between ultrasonographic finding of fluid accumulation along the deep fascia and diagnosis and prognosis of necrotizing fasciitis?

What ultrasonographic findings are significantly different between NF patients and non-NF patients?

What is the ultrasonographic-detected depth of fluid accumulation along the deep fascia that offers the greatest accuracy to diagnosis of NF?

Is there a difference in the prognosis between NF patients with fluid accumulation compared to NF patients without fluid accumulation? 

Methods & Study Design

• Design 

Retrospective study with prospective enrollment

• Population 

This study was conducted at Chang Gung Memorial Hospital, a suburban academic tertiary care hospital.

Inclusion criteria: patients who visited the ED from February 2015 – November 2016 with clinical suspicion of NF of limbs based on symptoms and clinical signs (severe pain out of proportion, skin findings, rapid progression, crepitus, skin bullae, necrosis, or ecchymosis).

NF group: discharge diagnosis of NF, confirmed by pathology report showing necrosis after surgical intervention

Non-NF group: did not have surgical intervention or whose pathology report did not support NF diagnosis

Exclusion criteria: patients with ED visits between 24:00 – 7:00, non-lesion side also has fluid accumulation, age <18yo, prior antibiotics or debridement, lesions involving trunk area

• Intervention 

Ultrasonographic exam within 1 hour after ED arrival completed by one of three experienced emergency physicians who received an 8-hour basic and soft-tissue ultrasonographic training before the study

Orthopedic consult for surgical opinion

• Outcomes  

  • Diagnostic markers: irregularity or thickening of deep fascia, fluid accumulation, subcutaneous emphysema, subcutaneous cobblestone
  • Reasonable cutoff value of fluid accumulation along deep fascial plane for diagnosing NF according to receiving operating characteristic (ROC) curve
  • Prognostic markers: length of stay (LOS) in hospital, mortality, amputations, number of operations


Ultrasound finding of fluid accumulation and irregular or thickened fascial layer were significantly different between NF and non-NF groups. All patients who had subcutaneous emphysema were in the NF group.

The best cutoff point of fluid accumulation to diagnose NF was 2mm, which had the best accuracy (72.7%), with sensitivity of 75%, a specificity of 70.2%, a positive predictive value of 71.7% and a negative predictive value of 72.7%.

NF patients with fluid accumulation had longer length of stay than NF patients without fluid accumulation (average: 39 days vs. 23 days). Number of operations were not significantly different between NF patients with and without fluid accumulation. All NF patients who had an amputation or died had fluid accumulation.


Overall mortality between NF and non-NF groups showed no significant difference.

Strength & Limitations


  • Sample size was larger than other studies investigating ultrasonographic findings for NF diagnosis.
  • Study had a comparator groups with clear definitions (NF vs. non-NF).
  • Ultrasound training was standardized and assessed with inter-rater reliability between three emergency physicians as 100%.


  • Small, imbalanced sample of NF patients for sensitivity and specificity analysis of fluid accumulation for amputation and mortality. 
  • Study excluded patients with truncal soft tissue infections.
  • Study excluded patients with prior antibiotics or debridement, which may have been NF patients with higher severity and worse prognosis.
  • Patient population were from south Taiwan exclusively.
  • NF patients had higher prevalence of specific co-morbidities (diabetes mellitus, liver cirrhosis, and alcohol use disorder), which could be confounding. 

Authors Conclusion

“The ultrasonographic finding of fluid accumulation along the deep fascia with a cutoff point of more than 2 mm of depth may aid in diagnosing NF. For the prognosis of NF, when fluid accumulation was present along deep fascia on ultrasound, patients with NF had longer lengths of hospital stays and were at risk of amputation or mortality. Ultrasonography is a point-of-care imaging tool that facilitates the diagnosis and prognosis of NF.” (14)

Our Conclusion

Consistent with prior studies and case reports (2-13), this study supports the role of ultrasound in the diagnosis of NF. Trained emergency physicians were able to successfully use ultrasound to detect significant imaging differences in NF patients, including fascial irregularity and deep fascial fluid accumulation. In comparison to Yen et al., this study suggests an even lower cutoff point of fluid accumulation along the deep fascia (2mm vs 4mm) for the highest diagnostic accuracy. We would caution that the finding of "fluid accumulation" was somewhat difficult to interpret in their study.

Further studies with larger sample sizes need to be completed. However, with the diagnostic and prognostic trends seen in this study, ultrasound should be considered as a timely, efficient imaging modality that can help identify patients with clinical suspicion of NF and accelerate OR intervention.

The Bottom Line 

Ultrasound is a viable imaging modality for patients with clinical suspicion of NF that could potentially expedite surgical intervention, though imaging findings may not be as easy to interpret as the authors lay out.


This post was written by Caresse Vuong, Charles Murchison MD and Amir Aminlari MD.


  1. Khamnuan P, Chongruksut W, Jearwattanakanok K, Patumanond J, Yodluangfun S, Tantraworasin A. Necrotizing fasciitis: Risk factors of mortality. Risk Manag Healthc Policy 2015;8:1–7.
  2. Castleberg E, Jenson N, Am Dinh V. Diagnosis of necrotizing fasciitis with bedside ultrasound: The STAFF exam. West J Emerg Med 2014;15:111–113.
  3. Tsai CC, Lai CS, Yu ML, Chou CK, Lin SD. Early diagnosis of necrotizing fasciitis by utilization of ultrasonography. Kaohsiung J Med Sci 1996;12:235–240.
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  6. Bernardi, Emanuele, Antonello Iacobucci, Letizia Barutta, Elisa Pizzolato, Virna Olocco, and Bruno Tartaglino. “A-Lines in Necrotizing Fasciitis of the Lower Limb.” Journal of Ultrasound in Medicine 33, no. 11 (2014): 2044–46. 
  7. Chao, H. C., M. S. Kong, and T. Y. Lin. “Diagnosis of Necrotizing Fasciitis in Children.” Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine 18, no. 4 (April 1999): 277–81. 
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  10. Kehrl, Thompson. “Point-of-Care Ultrasound Diagnosis of Necrotizing Fasciitis Missed by Computed Tomography and Magnetic Resonance Imaging.” The Journal of Emergency Medicine 47, no. 2 (August 2014): 172–75. 
  11. Shyy, William, Roneesha S. Knight, Ruth Goldstein, Eric D. Isaacs, and Nathan A. Teismann. “Sonographic Findings in Necrotizing Fasciitis.” Journal of Ultrasound in Medicine 35, no. 10 (2016): 2273–77. 
  12. Hanif, Muhammad A., and Michael J. Bradley. “Sonographic Findings of Necrotizing Fasciitis in the Breast.” Journal of Clinical Ultrasound: JCU 36, no. 8 (October 2008): 517–19. 
  13. Valle Alonso, Joaquín, Ganapathiram Lakshmanan, and Yasser Saleem. “Use of POCUS Ultrasound in Sepsis, Bedside Diagnosis of Necrotizing Fasciitis.” QJM: An International Journal of Medicine 110, no. 10 (October 1, 2017): 687–88. 
  14. Lin, Chun-Nan, Cheng-Ting Hsiao, Chia-Peng Chang, Tsung-Yu Huang, Kuang-Yu Hsiao, Yi-Chuan Chen, and Wen-Chih Fann. “The Relationship Between Fluid Accumulation in Ultrasonography and the Diagnosis and Prognosis of Patients with Necrotizing Fasciitis.” Ultrasound in Medicine & Biology 45, no. 7 (2019): 1545–50. 


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