Tag: Abdominal Pain

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Case 41: Abdominal Aortic Aneurysm

Skyler Sloane, Benjamin Supat

An 83-year-old man presented to the emergency department with a chief complaint of acute onset lower abdominal pain radiating to the right groin. The patient reported a history of hypertension, coronary artery disease, and nephrolithiasis. 

Vitals: BP 71/51 | Pulse 84 | Temp 98.0 °F (36.6 °C) | Resp 20 | SpO2 99% on RA 

On physical exam, the patient appeared to be in obvious discomfort. There was diffuse abdominal tenderness though no rebound or guarding was observed.

A bedside FAST exam was performed. What do you see? 

Figures 1-3: This 3-view FAST exam was negative for intra-abdominal free fluid.

Next, we performed an ultrasound of the aorta.

Figure 4: Transverse aorta view. Here we can see a fusiform aneurysm. The hyperechoic vessel wall contains a less dense ring of clot surrounding the anechoic blood in the vessel.

Figure 5: Labeled image showing intramural thrombus.

The patient was given a 1L fluid bolus, 2 ultrasound-guided peripheral 14g IVs, and 2 units of emergency-release blood. The patient also got a CT angiogram which showed a large ruptured fusiform infrarenal abdominal aortic aneurysm measuring 9.2 cm by 6.0 cm with a large hematoma in the right flank and iliac fossa, which explained the patient’s symptom of flank pain. Diffuse moderate atherosclerotic vessel wall changes were also present. The patient underwent emergent endovascular aneurysm repair.

Discussion: 

An abdominal aortic aneurysm (AAA) is defined by the parameter of aortic dilation of 3 cm or greater, measured outer wall to outer wall (1). This risk of developing a AAA increases with age and is more common in males than in females. Primary relationship to a family member who has had an AAA, hypertension, and coronary artery disease are predisposing factors. Smoking and poor lifestyle are also common risk factors (2). 

There are three types of AAAs: fusiform aneurysms, saccular aneurysms, and mycotic aneurysms. Fusiform aneurysms comprise 94% of aneurysms, and they present as bulging or ballooning on all sides of the aorta. Saccular aneurysms are less common and become symptomatic at smaller sizes (on average of 5.5 cm) and present as an outpouching on one side of the aorta. Saccular aneurysms can result from a tear on the tunica media of the aortic wall, due to injury or ulceration. Mycotic aneurysms are formed due to an infection of the vessel wall that can be bacterial, viral, or fungal in nature. They can occur as a complication of endocarditis and have an increased risk of rupture. AAAs are most commonly infrarenal (80%), but some may be pararenal (3,4).

Most patients with AAAs are asymptomatic, and diagnosis is often incidental as a result of imaging with MRI, CT, or ultrasonography. AAAs can present with life-threatening complications such as thrombosis, embolization, and rupture (3). The risk of rupture increases with the size of the aneurysm. A ruptured AAA is a catastrophic medical emergency, and left untreated the mortality approaches 100%. 50% of patients die prior to hospital arrival, and another 25-50% die during surgery.  Most AAAs rupture in the retroperitoneal cavity, creating symptoms of pain, lightheadedness, and a pulsing sensation in the abdomen. Notably, up to 50% of patients with AAAs have aneurysm rupture as their primary presentation of having a AAA, and only some patients are diagnosed prior to a catastrophic event and thus have preventative measures taken (5). 

Due to the emergent need to address potential AAA and AAA ruptures, rapid diagnosis in an emergency setting is necessary. Aortic ultrasound is the primary diagnostic method for diagnosing AAAs or ruptured AAAs in an emergency setting (6). Non-radiologist-performed ultrasound for AAA is estimated to have a sensitivity of 0.975 [95% confidence interval (CI), 0.942-0.992] for AAA detection and a specificity of 0.989 (95% CI, 0.979-0.995), making it an effective diagnostic tool (7). Computed tomography angiogram is also commonly used for diagnosis and surgical planning of AAAs. However, CT is not always feasible in unstable patients (8). 

In this case, point-of-care ultrasound was a vital component in diagnosing this patient. Given a patient presentation concerning for AAA, ultrasound is a rapid and effective method to reach an early diagnosis and expedite treatment. 

References

  1. Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 Circulation. 2006; 113: e463-e654. doi:10.1161/CIRCULATIONAHA.106.174526
  2. Altobelli E, Rapacchietta L, Profeta VF, Fagnano R. Risk Factors for Abdominal Aortic Aneurysm in Population-Based Studies: A Systematic Review and Meta-Analysis. Int J Environ Res Public Health. 2018 Dec 10;15(12):2805. doi: 10.3390/ijerph15122805. PMID: 30544688; PMCID: PMC6313801.
  3. Farber, M. A.; Parodi, F. E. Abdominal Aortic Aneurysms (AAA), 2023, 2023. https://www.merckmanuals.com/professional/cardiovascular-disorders/diseases-of-the-aorta-and-its-branches/abdominal-aortic-aneurysms-aaa.
  4. Aggarwal S, Qamar A, Sharma V, Sharma A. Abdominal aortic aneurysm: A comprehensive review. Exp Clin Cardiol. 2011 Spring;16(1):11-5. PMID: 21523201; PMCID: PMC3076160.
  5. Jeanmonod D, Yelamanchili VS, Jeanmonod R. Abdominal Aortic Aneurysm Rupture. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459176/
  6. Abdominal aortic aneurysm: diagnosis and management. London: National Institute for Health and Care Excellence (NICE); 2020 Mar 19. (NICE Guideline, No. 156.) Available from: https://www.ncbi.nlm.nih.gov/books/NBK556921/
  7. Concannon E, McHugh S, Healy DA, Kavanagh E, Burke P, Clarke Moloney M, Walsh SR. Diagnostic accuracy of non-radiologist performed ultrasound for abdominal aortic aneurysm: systematic review and meta-analysis. Int J Clin Pract. 2014 Sep;68(9):1122-9. doi: 10.1111/ijcp.12453. Epub 2014 May 18. PMID: 24837590.
  8. Moxon JV, Parr A, Emeto TI, Walker P, Norman PE, Golledge J. Diagnosis and monitoring of abdominal aortic aneurysm: current status and future prospects. Curr Probl Cardiol. 2010 Oct;35(10):512-48. doi: 10.1016/j.cpcardiol.2010.08.004. PMID: 20932435; PMCID: PMC3014318.
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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

Answer:

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.

References

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. https://doi.org/10.1148/radiol.12111869

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. https://doi.org/10.1016/j.annemergmed.2020.05.017

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

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Case # 20: Right Lower Quadrant Pain

A 40 year old male presented with a 4 day history of right lower quadrant pain. He reported that the pain was at its worse when it started but gradually improved. When in the ED he noted only minimal discomfort without the help of analgesics.  He denied ever having anorexia, fever, chills, nausea, vomiting, GU complaints. During examination, he had moderate tenderness to palpation in the right lower quadrant without rebound or guarding. 

Vitals:  T 97.7F    BP 130/77    HR 66    RR 16   SP02 100%

An abdominal ultrasound of the RLQ was performed and the following images were seen. What do you see and what is your most likely diagnosis? 

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Answer and Learning Points

Answer

In both the longitudinal and transverse views, you see a tubular structure in the right lower quadrant that is non- compressible, greater than 6mm (measures 15.6 mm), and lacks peristalsis. You can also appreciate some dependent free fluid around the appendix. These findings are consistent with the diagnosis of acute appendicitis.

CT abdomen/pelvis showed a retrocecal appendix with finding of acute uncomplicated appendicitis. No bowel obstruction or intra-abdominal/pelvic abscesses. Labs showed a slight leukocytosis to 14, otherwise were reassuring. Patient was given a dose of Zosyn in the emergency department and take to the OR for appendectomy by general surgery.

Learning Points

    • Appendicitis is the most common abdominal surgical emergency that presents to the ED in western countries [1]. 
    • The sensitivity and specificity of ultrasound for the diagnosis of appendicitis appears to be around 86% and 81%, respectively, based on results from older studies [2]. 
    • Ultrasound can be used to diagnosis acute appendicitis and may be the imaging modality of choice in certain patient populations such as pregnant women and children [3]. 
    • To obtain images you can use either the linear or curvilinear probe. Ask the patient to point where exactly they hurt and place the probe there. If you don’t see it you can use the landmark of the iliac crest (most lateral), psoas muscle (posterior), and iliac artery (most medial). Move superior and inferior along the iliac artery and the appendix should be just anterior to iliac artery. If you still haven’t found it, “lawnmower” along the right lower quadrant. Look for a tubular, blind ended pouch that has no peristalsis. It should be compressible and measure <6mm in AP diameter [4]. 

References

    1. Caterino, S., et al. Acute abdominal pain in emergency surgery. Clinical epidemiologic study study of 450 patients. Ann Ital Chir. 1997; 68: 807-817.
    2. Lim H, Bae S, Seo G: Diagnosis of acute appendicitis in pregnant women: value of sonography. AJR Am J Roentgenol 1992;159(3): 539–542.
    3. Excerpt From: Mike Mallin & Matthew Dawson. “Introduction to Bedside Ultrasound: Volume 2.” Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 18th, 2020.
    4. www.5minsono.com

 

The following authors contributed to this post:

Amir Aminlari, MD; Danika Brodak, MD; Michael Macias, MD

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