Category: Clinical Cases

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Case 30: Ultrasound-Guided Extraction of a Foreign Body

A 53-year-old homeless alcoholic female presented to the emergency department with a chief complaint of localized left lower quadrant abdominal pain secondary to a possible gunshot wound. She was unclear but stated she thinks some boys in a gang fired at her two days prior with a possible BB gun. Pertinent medical history included psychiatric history, morbid obesity (BMI>40), chronic alcohol abuse, sepsis and hypoxemic respiratory failure. The patient was clinically intoxicated upon arrival and therefore history was of limited accuracy. 

 

Upon arrival, patient appeared stable and vitals were as follows:

BP: 121/63 | HR: 73 | RR: 18 | T: 98.4 | Sp02: 98% on RA 

 

Physical examination revealed a 10x10 cm area of ecchymosis with a central penetrating wound about 2mm, to the left lower quadrant. The patient was tender to palpation around the affected area but there was no significant warmth or erythema to suggest infection. No palpable foreign bodies were identified. There were no signs of peritonitis: the remainder of the abdominal examination was benign and patient had active bowel sounds. She denied vomiting, hematuria, hematochezia, and melena. She also denied shortness of breath, chest pain, and back pain.  

 

To evaluate the wound for the presence of foreign bodies and for depth of penetration, bedside ultrasound was obtained. What do you see, and how would this change your patient management?

 

Figure 1: Wound prior to foreign body exploration.

Figure 1: Wound prior to foreign body exploration.

Figure 2: A hyperechoic object with reverberation artifacts and shadow seen at 1cm.

Figure 2: A hyperechoic object with reverberation artifacts and shadow seen at 1cm.

Figure 3: Removal of FB under US guidance using curved hemostats.

Figure 3: Removal of FB under US guidance using curved hemostats.

Figure 4: Extracted pellet.

Figure 4: Extracted pellet.

Answer and Learning Points

Answer:

Figure 4: Labeled ultrasound image shows hyperechoic object and reverberation artifact with shadow.

 

In these scans, an echogenic foreign body can be observed 1 cm below the epidermis with associated reverberation and mirror artifact. Using ultrasound guidance, a curved hemostat was used to remove the foreign body after local anesthetic injection. Upon contact with the forceps, the foreign body can be seen fluctuating in position. A rounded edge on the foreign body can be seen on the image.  Importantly, we clearly identified the peritoneal line to be > 4cm deeper than the foreign body and were able to safely determine the foreign body location to be significantly more superficial to the abdominal wall musculature. 

Discussion

Soft tissue foreign bodies (FB’s) are a common reason for Emergency Department visits, with open wounds producing 4,171,000 visits to United States Emergency Departments in 2020 [1]. However, retained foreign bodies account for 7-15% of cases, particularly those involving the extremities. A granulomatous tissue response commonly known as an FB reaction results as the immune system attempts to isolate the FB from the host [2]. This can lead to serious adverse complications including soft tissue inflammation and infection. The most commonly retained FB materials are metal, glass and wood. Glass accounts for half of missed FB’s on physical examination and radiographs. Although essential, a physician-performed clinical history, physical examination, and wound exploration are not sufficient to exclude a FB from differentials [2]. Thus, imaging plays an essential role in improving patient outcomes that present with FB’s. 

 

MRI is not a suitable imaging modality, as metallic contents may have hazardous movements due to the magnetic field. Computed tomography (CT) and ultrasound sonography (US) are the most effective imaging modalities. CT and US have similar sensitivity in identifying high-density objects such as stone, metal and glass [3]. Low-density foreign objects such as plastic and wood are remarkably difficult to see in techniques other than US, regardless of superficial or deep impaction. For example, radiographic images have a sensitivity of 7.4% for wood [3,4]. Sensitivity of ultrasound for FB is 80% on average, and it carries a specificity of 85%, with metals being much higher due to noticeable reverberation, and wood is more difficult to detect. However, the sensitivity of US to identify foreign bodies in soft tissues begins to decrease as the depth of the foreign body surpasses 4cm [4]. 

 

US provides a unique advantage to foreign body detection as it can provide instantaneous and simultaneous visualization of foreign bodies during extraction procedures with minimal risk and no exposure to radiation. In a study of pediatric patients presenting with an FB, sonography performed by EM physicians provided an overall sensitivity of 67% and a specificity of 96.6% [4]. US is inexpensive and provides real-time visualization, however the quality of US images is operator dependent [5].

 

Material of FB  

Ultrasound finding

Stone

Hyperechoic area with pronounced acoustic shadow

Metal

Hyperechoic area with reverberation artifacts

Glass

Hyperechoic area with comet tails; less visible than metal

Plastic

Hyperechoic area with slight acoustic shadow

Wood

Hypoechoic area with “halo” 

Table 1: A List of FB Materials and the Expected US Findings [3].

 

To perform this technique, scan use the linear probe in the area of the suspected location of the FB.  The FB can be identified by characteristic reverberation or acoustic shadowing, with additional indications being signs of infection, edema, or interruption of the fascial planes. Position the probe so that the FB is visualized in the center of the screen, and mark this area with a surgical pen. Rotate the probe 90 degrees and ensure the FB is in the middle of the US screen. Then mark this area with a surgical pen. Where these markings cross should give you the exact location of the FB such that incision and probing with forceps will result in effective removal of the FB. 

 

Removing foreign bodies is one of the least favorite procedures in the Emergency Department due to it’s difficulty and low success rates.  Bedside ultrasound is easily performed and is a useful adjunct in the accurate identification of foreign bodies and also can provide real-time guidance in foreign body removal.

References

1) Cairns C, Kang K. National Hospital Ambulatory Medical Care Survey: 2020 emergency department summary tables. DOI: https://dx.doi.org/10.15620/cdc:121911.

2) Carneiro BC, Cruz IAN, Chemin RN, et al. Multimodality Imaging of Foreign Bodies: New Insights into Old Challenges. Radiographics. 2020;40(7):1965-1986. doi:10.1148/rg.2020200061

3) Haghnegahdar A, Shakibafard A, Khosravifard N. Comparison between Computed Tomography and Ultrasonography in Detecting Foreign Bodies Regarding Their Composition and Depth: An In Vitro Study. J Dent (Shiraz). 2016;17(3):177-184.

4) Davis J, Czerniski B, Au A, Adhikari S, Farrell I, Fields JM. Diagnostic Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis. Acad Emerg Med. 2015;22(7):777-787. doi:10.1111/acem.12714

5) Rupert J, Honeycutt JD, Odom MR. Foreign Bodies in the Skin: Evaluation and Management. Am Fam Physician. 2020;101(12):740-747.

This post was written by Cameron Olandt, Rachna Subramony, MD, Skyler Sloane, and Colleen Campbell, MD.

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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 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

Answer:

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.

References

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.

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Case 27: Ectopic Pregnancy

A 43 year old female with no past medical history presents to the Emergency Department (ED) with lower abdominal pain for the last three hours. She says she knows she is pregnant from a home pregnancy test, but has not had any appointment with obstetrics and has not had an ultrasound yet. She denies any vaginal bleeding.  

Vitals: BP 120/65 mmHg, HR 85, O2 100% on RA.

She is comfortable appearing, her abdominal exam shows mild tenderness to palpation diffusely in the lower abdomen with no rebound and her pelvic exam shows a closed os with no bleeding.

Her point-of-care urine pregnancy test is positive.

You perform a trans-abdominal bedside ultrasound, what do you see?  What are your next steps?

pelvic free fluid
ectopic
positive fast

Answer and Learning Points

Answer:

The first image is a transverse view of the uterus that shows free fluid in the retcouterine pouch (Pouch of Douglas). The second image is another transverse view of the uterus that also shows free fluid in the rectouterine pouch and then fans through to scan the uterus and adnexa. From what we see there is no gestational sac in the uterus and if you look closely there appears to be a heterogenous structure in the left adnexa. The final view is a FAST view in the right upper quadrant, looking at Morrison's Pouch. We see free fluid here as well. 

These findings - a positive pregnancy test, free fluid in the pelvis and no clear intra-uterine pregnancy indicates an ectopic pregnacny until proven otherwise. The next step should be a tranvaginal ultrasound and consultation with Gynecology. 

Conclusion and Learning Points:

The transvaginal ultrasound revealed a left-sided ectopic pregnancy, as seen in the following picture. They identified a fetal pole and even a fetal heart rate in the ectopic pregnancy. The patient was taken to the operating room with Gynecology and had a salpingectomy without complications. She was discharged home three days later. 

Learning Points:

    • Any female of child-bearing age with abdominal pain should be considered for ectopic pregnancy
    • Ultrasound findings in ectopic pregnancy will not always show the ectopic itself, but rather findings suggestive of ectopic:
      • Intra-abdominal free fluid
      • No clear intra-uterine pregnancy (patients with ectopic will sometimes still have a "pseudo-gestational sac" that appears similar to a gestational sac, but there will be no yolk sac or fetal pole)
      • Heterogenous adnexal structure
    • You should not wait for B-HCG measurements to consider ectopic pregnancy, case reports have shown ectopic pregnancies with minimal HCG levels can still rupture (1)

References

1. Fu, Joyce, et al. Rupture of ectopic pregnancy with minimally detectable beta-human chorionic gonadotropin levels: a report of 2 cases. J Reprod Med. 2007 Jun;52(6):541-2.

This post was written by Charles Murchison MD and Anthony Medak MD, with further editing by Amir Aminlari MD.

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Case 26: Genicular Nerve Block for Knee Pain – A Novel Technique

A 68 year old female with no significant past medical history presents to the Emergency Department (ED) with one day of right knee pain after falling off her bicycle onto her right side. She was immediately unable to bear weight on her right leg. 

 

Vitals: T 98.3, HR 73, RR 18, BP 114/70, SpO2 99%

 

Right leg exam: mild right knee effusion. No ligamentous laxity. Tenderness to palpation over lateral joint line > medial joint line. Tenderness to palpation over proximal anterior tibia. Knee extension limited due to pain. Neurovascularly intact with soft compartments.

 

Radiographic imaging demonstrated an isolated right tibial plateau fracture depression of the lateral plateau. The patient reports she is in severe pain but dislikes taking both over-the-counter and opioid pain medications. 

What nerves may be targeted to provide pain relief to her knee while maintaining motor function? What anatomic landmarks should be used on ultrasound to identify the branches of this nerve?

Answer and Learning Points

The genicular nerves derive from various major lower extremity nerve branches (femoral, obturator, sciatic, tibial) nerves and provide sensation to the knee capsule and joint. Cadaveric studies suggest that most genicular nerves are easily identifiable landmarks that may be used for therapeutic purposes. 5  Genicular nerve blocks (GNB) are traditionally used in this setting of chronic osteoarthritis knee pain via radiofrequency ablation or perioperative knee pain via ultrasound (1-4, 9).

The use of a GNBs in the ED is a novel technique to provide motor-sparing, pain relief for acute knee pain. This 68 year old patient with an isolated lateral tibial plateau fracture reported 4/10 pain over her proximal tibia at rest and 8/10 over her proximal tibia with movement. Written informed consent was obtained for GNBs of her right knee. Anatomic landmarks for the superior lateral (Image A,B) , superior medial (Image C,D), and inferior medial (Image D,E,F) genicular nerves were identified on ultrasound.

genicular nerve block

genicular nerve block

genicular nerve block

The ultrasound probe was placed in the sagittal orientation for each site. The superior lateral genicular nerve was located on ultrasound at the junction of the lateral femoral epicondyle and the epiphysis of the shaft of the femur, adjacent to the superior lateral genicular artery (Image A,B). The superior medial genicular nerve (SMGN) can be identified on ultrasound at the junction of the medial femoral epicondyle and the epiphysis of the shaft of the femur, adjacent to the superior medial genicular artery (Image C, D). The inferior medial genicular nerve (IMGN) can be identified on ultrasound at the junction of the medial tibial epicondyle and the epiphysis of the shaft of the tibia, adjacent to the inferior medial genicular artery (Image E, F, G) (6-8).

Under ultrasound guidance and using sterile technique, the skin was first anesthetized with 1% lidocaine after each site. A 21-gauge, 2 inch echogenic needle was inserted percutaneously and advanced under ultrasound guidance using an out-of-plate technique to inject 1.5 mL of 0.5% bupivacaine around the right superior lateral, superior medial, and inferior medial genicular nerves. 

Learning points

    • Genicular nerves derive from several lower extremity nerves and supply sensory innervation to the knee. 
    • The superior lateral, superior medial, and inferior medial genicular nerves are commonly targeted for pain relief with chronic knee osteoarthritis and postoperative pain.
    • The SLGN, SMGN, IMGN are easily located on ultrasound using anatomic landmarks (junction between epicondyles and epiphysis of the femur and tibia, adjacent to paired genicular arteries).
    • To obtain the images, you can use the linear probe in the sagittal location over lateral femoral epicondyle, medial femoral epicondyle, and medial tibial epicondyle.

References

1. Ahmed, Arif. “Ultrasound-guided radiofrequency ablation of genicular nerves of knee for relief of intractable pain from knee osteoarthritis: a case series.” British Journal of Pain, vol. 12, no. 3, 2017, pp. 145-154, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6058456/. Accessed 18 November 2020.

2. Caldwell, George L. “Reduced Opioid Use After Surgeon-Administered Genicular Nerve Block for Anterior Cruciate Ligament Reconstruction in Adults and Adolescents.” HSS Journal, vol. 15, no. 1, 2019, pp. 42-50, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6384209/. Accessed 18 November 2020.

3. Cankurtaran, Damla. “Comparing the effectiveness of ultrasound guided versus blind genicular nerve block on pain, muscle strength with isokinetic device, physical function and quality of life in chronic knee osteoarthritis: a prospective randomized controlled study.” Korean J Pain, vol. 33, no. 3, 2020, pp. 258 - 266, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336352/. Accessed 18 November 2020.

4. Erdem, Yusuf. “The Efficacy of Ultrasound-Guided Pulsed Radiofrequency of Genicular Nerves in the Treatment of Chronic Knee Pain Due to Severe Degenerative Disease or Previous Total Knee Arthroplasty.” Med Sci Monit, vol. 25, 2019, pp. 1857 - 1863, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6423735/. Accessed 18 November 2020.

5. Fonkoué, Loïc. “Distribution of sensory nerves supplying the knee joint capsule and implications for genicular blockade and radiofrequency ablation: an anatomical study.” Surgical and Radiologic Anatomy, vol. 41, 2019, 1461–1471(2019), https://link.springer.com/article/10.1007/s00276-019-02291-y#citeas. Accessed 18 November 2020.

6. Güzelküçük, DemIr. “A different approach to the management of osteoarthritis in the knee: Ultrasound guided genicular nerve block.” Pain Medicine, vol. 18, no. 1, pp. 181 - 183, https://academic.oup.com/painmedicine/article/18/1/181/2924744. Accessed 18 November 2020.

7. Kim, Doo-Hwan. “Ultrasound-Guided Genicular Nerve Block for Knee Osteoarthritis: A Double-Blind, Randomized Controlled Trial of Local Anesthetic Alone or in Combination with Corticosteroid.” Pain Physician, vol. 21, 2018, pp. 41 - 51, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6058456/. Accessed 18 November 2020.

8. Protzman, Nicole. “Examining the feasibility of radiofrequency treatment for chronic knee pain after total knee arthroplasty.” PM&R, vol. 6, no. 4, 2014, pp. 373 - 376, https://pubmed.ncbi.nlm.nih.gov/24373908/. Accessed 18 November 2020.

9. Sahoo, Rajendra K. “Genicular nerve block for postoperative pain relief after total knee replacement.” Saudi J Anaesth, vol. 12, no. 2, 2020, pp. 235 - 237, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7164458/. Accessed 18 November 2020.

This post was written by Julia Sobel MD, with editing from Jessica Oswald MD, Charles Murchison MD and Amir Aminlari MD.

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Case 25: Aortic Dissection

A 44 year old male with a history of heroin abuse presents to the emergency department with altered mental status.  Per EMS, the patient was found on the street with decreased level of consciousness and poor respiratory effort.  EMS was concerned about opioid overdose, and he was treated with 4mg Narcan, with improvement in his mental status.  

Upon arrival to the ED, he was noted to be agitated and tachypneic with RR in the 40’s.  

Vitals: BP 90/65 mmHg, HR 110, O2 100% on RA, glucose 158.

He is alert and oriented to person, month, and place, but appears agitated and confused.  He denies any complaints other than shortness of breath, and states he felt fine before using heroin.  He denies any past medical history.

Exam notable for tachycardia, diffuse rhonchi throughout all lung fields, 2+ nonpitting lower extremity edema.  He is neurologically intact with 2+ pulses throughout.

A bedside echocardiogram was performed, what do you see?  What are your next steps?

PS long
dilated aortic root
aortic dissection suprasternal ultrasound
abdominal aortic dissection ultrasound
abdominal aortic dissection ultrasound
dissection to iliacs ultrasound

Answer and Learning Points

Answer:

The first two images show a parasternal long-axis view, with a dilated aortic root measuring approximately 4.2cm.  Also notice the pericardial effusion with a homogenous layer that appears fixed to the pericardium.  At the time it was unclear whether this represented a clot within the pericardial sac, or was superficial to it.

Given the dilated aortic root, a suprasternal short-axis view was obtained to assess the proximal aorta, with the short axis view seen on the third image.  A flap was visualized in the aortic lumen, significant for an ascending aortic dissection.  The dissection was then visualized in the abdominal aorta, extending distal to the common iliac arteries, seen in the last images.

The patient was placed on esmolol drip and later required vasopressor support.  CT angiography was obtained, confirming a Type A aortic dissection.  He was transferred to a nearby hospital for emergent repair of his ascending and descending aortic dissection.  

Per the operative report, the patient had developed a significant pericardial effusion by the time he reached the OR, and the visualized homogenous layer above most likely represented a blood clot within the pericardium.

Learning Points:

    • While CTA remains the gold standard for diagnosis of aortic dissection, POCUS remains a great tool for diagnosing both ascending and descending aortic dissection, particularly in the unstable patient.
    • In addition to directly visualizing the dissection flap, TTE can also be used to identify patients with high risk features, such as those with cardiac tamponade, severe aortic dilatation, severe aortic regurgitation, regional wall motion abnormalities, and decreased ejection fraction (1).
    • TTE has been shown to have a sensitivity of 78-90% and specificity 87-96% for type A dissection in older studies (2,3), and in more recent studies showing improved sensitivity up to 97-99% (1,4,5) and specificity 100% (4) with improved image quality.
    • The suprasternal notch views are particularly useful in evaluating the proximal ascending aorta, and allow the operator to assess for aortic dissection, coarctation, dilatation of the aortic arch, and retrograde flow from the descending aorta.

References

1. Sobczyk D, Nycz K. Feasibility and accuracy of bedside transthoracic echocardiography in diagnosis of acute proximal aortic dissection. Cardiovasc Ultrasound. 2015;13:15.

2. Evangelista A, Flachskamp FA, Erbel R, Antonini-Canterin F, Vlachopoulos C, Rocchi G, et al. Echocardiography in aortic diseases: EAE recommendations for clinical practice. Eur J Echocardiogr. 2010;11:645–58. doi: 10.1093/ejechocard/jeq056.

3. Nienaber CA, von Kodolitsch Y, Nicolas V, Siglow V, Piepho A, Jaup T, et al. The diagnosis of thoracic aortic dissection by noninvasive imaging procedures. N Engl J Med. 1993;328:1–9. doi: 10.1056/NEJM199301073280101.

4. Cecconi M, Chirillo F, Constantini C, Iacobone G, Lopez E, Zanoli R, et al. The role of transthoracic echocardiography in the diagnosis and management of acute type A aortic syndrome. Am Heart J. 2012;163(1):112–8. doi: 10.1016/j.ahj.2011.09.022.

5. Nazerian, P., Vanni, S., Castelli, M. et al.Diagnostic performance of emergency transthoracic focus cardiac ultrasound in suspected acute type A aortic dissection. Intern Emerg Med9, 665–670 (2014). https://doi.org/10.1007/s11739-014-1080-9

This post was written by Rachna Subramony MD, Alex Anshus MD, with editing from Sukhdeep Singh MD, Charles Murchison MD and Amir Aminlari MD.

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Case 24: Diverticulitis

 

A 56 year old male with a history of uncomplicated diverticulitis presented to the emergency room with left lower quadrant pain and loose stools for the last six days. He denies fever, vomiting or blood in hist stool 

Vitals: T 97.3   BP 152/81   HR 91       RR 18      SPO2 97% on RA

 

You physical exam shows tenderness to palpation in the left lower quadrant with no peritoneal signs. You are on the fence about getting a CT abdomen and pelvis with contrast to look for an abscess versus treating this as uncomplicated diverticulitis. You decide to throw the ultrasound probe on the area of his pain. What do we see in these images? How would this change management?

 

Answer and Learning Points

Answer:

The three videos and two images show diverticulitis with an abscess or phlegmon beneath the bowel loops. Though CT is the gold standard for diagnosing diverticulitis, ultrasound is relatively sensitive in the diagnosis and has the advantage of being cheap, fast and radiation-free (1). 

When looking for diverticulitis on ultrasound physicians will typically use a "lawn mower" approach to the left abdomen to search for areas of affected bowel. One way to get to the area of interest more quickly is simply ask the patient to point to the area of maximal tenderness and start there, similar to appendicitis or small bowel obstruction. There are a few findings on ultrasound that indicate diverticulitis (2,3):

  1. Thickening of bowel wall, typically at least 4-5mm
  2. Echogenic fat surrounding the bowel, which is representative of fat stranding seen on CT
  3. Diverticulum
diverticulitis ultrasound
Wall thickening and fat stranding

 

Ultrasound is also helpful in looking for abscess, such as in our case. We see there is an area of hypoechogenicity with no color flow, representing likely abscess adjacent to the bowel.  

 

Our patient ultimately got a CT scan that confirmed he had diverticulitis with abscess. He was admitted to medicine with GI and surgery consults following.

References

(1) Lameris, W et al. Graded compression ultrasonography and computed tomography in acute colonic diverticulitis: meta-analysis of test accuracy. Eur Radiol. 2008 Nov;18(11):2498-511.

(2) Schwerk, WB et al. Sonography in acute colonic diverticulitis. A prospective stud. Dis Colon Rectum. 1992 Nov;35(11):1077-8

(3) Mazzei M et al. Sigmoid diverticulitis: US findings. Crit Ultrasound J. 2013 Jul 15;5 Suppl 1(Suppl 1):S5.

This post was written by Charles Murchison MD, with editing from Colleen Campbell MD and Amir Aminlari MD.

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Case 23: Diastolic Dysfunction

diastolic dysfunction echo

 

A 79 year old female presented to the emergency room with worsening dyspnea on exertion.  She reported orthopnea, leg swelling, and only being able to walk a few steps without getting short of breath. She denied chest pain, fever, or productive cough, and she had been compliant with her medications. Of note, the patient was seen 3 weeks ago for chest pain, at which point she had a dobutamine stress echo that demonstrated non-reversible ischemic changes. During examination, the providers noted JVD, crackles at bilateral bases, and bilateral lower extremity pitting edema. 

 

Vitals: T 97.3   BP 152/81   HR 83       RR 18      SPO2 97% on RA

 

Your initial impression is a slamdunk heart failure exacerbation. However, a bedside ECHO is performed normal ejection fraction. This doesn’t appear to be the classic HFrEF exacerbation you’ve seen countless times before. What do we see in the echo below? What does it tell us about this patient's diastolic function?

 

diastolic dysfunction echo
e e' echo

Answer and Learning Points

Answer:

The two images above are an apical four chamber view with the doppler gait measuring mitral inflow velocity and tissue doppler, respectively. They show Grade 1 diastolic dysfunction.

Assessing for diastolic dysfunction is best achieved with an apical four chamber view and involves two measurements: mitral inflow and tissue doppler. Mitral inflow velocity is measured by placing pulsed-wave doppler at the mitral valve leaflet tips. During diastole, there are two surges of blood flow through the mitral valve. The first is Early filling immediately after the valve opens (E wave), representing ventricular relaxation. The second wave comes from the Atrial kick (A wave). In normal diastolic function, the E wave should be larger than the A wave because most of the blood enters the ventricle during relaxation, with the atrial kick subsidizing this.

Look at the diagram below to see how the E/A wave changes with the different grades of diastolic dysfunction. In our patient, the A wave was larger than the E wave so we knew this patient had grade 1 diastolic dysfunction, i.e. impaired relaxation. This happens when the stiff ventricle no longer pulls most of the blood in with relaxation (as relaxation is impaired), so the atrial kick does most of the diastolic filling. Our patient was admitted to cardiology for IV diuresis and medical optimization.

For patients whose E wave is larger than their A wave, it can be unclear whether this is a normal, pseudonormal or restrictive pattern. Tissue doppler can help further assess whether this. Place the doppler gate at the mitral valve annulus to assess left ventricular muscle relaxation. As diastolic dysfunction worsens, the ability of the left ventricle to relax will progressively worsen. Looking at the diagram below again, we see that in normal diastolic function the e' wave will be larger than the a', but as the ventricle loses its ability to relax the e' wave will get smaller. If the e' is the same size or smaller than the a' this represents diastolic dysfunction. 

diastolic dysfunction

Learning Points:

  • Heart failure with preserved ejection fraction makes up half of the patients with heart failure.
  • HFpEF can be assessed in the apical four chamber view by evaluating the mitral valve inflow at the leaflet tips and tissue doppler at the annulus.
  • The E wave is blood flow through the mitral valve during early diastole and the A wave is during the atrial kick.
  • In one study, sensitivity and specificity of diagnosing clinically significant diastolic dysfunction was 92% and 69% respectively for emergency physician conducted echocardiography (1).

References

This post was written by Megan Jackson, PGY1 at UCSD Emergency Medicine Residency Program, Charles Murchison, MD and Amir Aminlari MD

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Case # 22: Abdominal Aortic Aneurysm

abdominal aortic aneurysm

 

A 72 year old male with known abdominal aortic aneurysm (5.7 cm s/p fem-tib bypass, L AKA) presents for 3 weeks with diarrhea and mild LLQ pain. No nausea, vomiting, fever, back pain, urinary symptoms, or blood in stool. He has no localizing abdominal exam & no peritoneal signs, strong even radial pulses, and normal cardiopulmonary exam. On further chart review, patient is noted to have a 5+ cm aorta for the past 2 years, with the most recent CT scan a few weeks ago showing growth from 5.5 cm to 5.7 cm. An abdominal ultrasound is performed with the following findings.

Vitals: 

T 98.7 HR 64 BP 167/80 RR 18 O2 100%

What are we concerned about for this patient and why? What is the interpretation of the abdominal ultrasound? What are the next steps for management in the ED?

 

Courtesy of The Pocus Atlas

Answer and Learning Points

Answer:

The patient’s presenting complaints (diarrhea, mild abdominal pain) do not coincide with the classic triad of ruptured AAA (hypotension, back pain, pulsatile abdominal mass). In addition, this patient is hemodynamically stable and comfortable, which is reassuring. However, ruptured AAA can have a wide variety of presentations and should always be considered in patients with known large AAA. In addition, this patient had a known AAA >5 cm for the past two years with poor vascular surgery follow-up, and the risk for rupture for AAA’s 5.0-5.9cm increases by 5-10% each year. (1)

As this patient recently had a CT scan a few weeks ago revealing large, stable AAA, the decision was made to investigate via ultrasound rather than undergo more radiation from CT. Ultrasound is also highly sensitive and specific for detecting AAA. (2) The above images show the AAA has a large intramural thrombus with no evidence of leaking fluid nor dissection flap. The AAA is stable, measuring a similar width of 5.7 cm. The clinician can investigate further by doing a RUSH exam to reassure against intraperitoneal bleeding and other types of shock. Elective aortic surgery is recommended for patients with AAA >5.5 cm, because at this threshold the risk of rupture is greater than risk of surgery, therefore it is reasonable to consult vascular surgery for this patient in the ED. (1)

 

Learning Points

  • Ruptured AAA being a surgical emergency and nearly uniformly fatal. Risk of rupture is proportional to size of AAA:AAA rupture risk
  • Elective aortic surgery is the most effective management, however, is not recommended until the aneurysm exceeds 5.5 cm diameter. In the ED setting, it is reasonable to consult vascular surgery for an asymptomatic patient with an incidental finding of aneurysm >5.5 cm. (1)
  • A systematic review of seven studies (n=655) evaluated operating characteristics of emergency department ultrasonography for AAA. With AAA defined as >3cm dilation of aorta, the review showed that ultrasound yielded excellent diagnostic performance. (2)

  • An effective abdominal aortic ultrasound requires:

(1) Evaluation of the entire aorta from the subxiphoid area to the iliac branch bifurcation. Most abdominal aortic aneurysms lie in the infrarenal aorta.

(2) Moving bowel gas out of the way with the probe with either graded compression or curvilinear probe with larger footprint

(3) Careful differentiation aorta from IVC. The aorta will be anterior to the vertebrae and the left of the IVC.

(4) Measuring outer to outer wall. Clot can create can second inner wall and falsely decrease aortic width measurement.

References

(1) Abdominal Aortic Aneurysms (AAA) - Cardiovascular Disorders. Merck Manuals Professional Edition. Accessed July 9, 2020. https://www.merckmanuals.com/professional/cardiovascular-disorders/diseases-of-the-aorta-and-its-branches/abdominal-aortic-aneurysms-aaa

(2) Rubano E, Mehta N, Caputo W, Paladino L, Sinert R. Systematic review: emergency department bedside ultrasonography for diagnosing suspected abdominal aortic aneurysm. Acad Emerg Med. 2013;20(2):128-138. doi:10.1111/acem.12080

(3) Michelle H-B. Tips and Tricks: Big Red - The Aorta and How to Improve Your Image. ACEP Emergency Ultrasound. Accessed July 9, 2020. https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/february-2016/tips-and-tricks-big-red---the-aorta-and-how-to-improve-your-image/

This post was written by Caresse Vuong, MS4, Charles Murchison, MD and Amir Aminlari MD

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Case # 21: A 28 Year Old With Shortness of Breath

echo d sign

 

A previously healthy 28-year-old male presents to the Emergency Department complaining of one month of fatigue, shortness of breath, and dyspnea on exertion. These symptoms were preceded by symptoms of a viral illness which initially improved; however, he had recurrence of symptoms two weeks ago. He was seen at urgent care five days ago and was given steroids and albuterol without improvement. The patient otherwise denies any infectious symptoms, leg swelling, or risk factors for pulmonary embolus or deep vein thrombosis.  

VS: T: 97.7F    BP: 129/87.    HR: 109     RR: 16.    SP02: 95%

Patient is alert and oriented, non-toxic in no distress, and behaving appropriately. Cardiac exam shows a RRR, no murmurs, rubs, or gallops. Lung exam is consistent with shallow breaths and dyspnea with conversation, otherwise lungs are CTAB with no wheezing, rales, or rhonchi. The patient has no chest wall tenderness, no JVD, and no lower extremity edema.

You perform a bedside ECHO and you see the following. What do you see and what is your most likely diagnosis? What is your next step in management?

apical 4 rv strain
psla rv strain
pssa rv strain

Answer and Learning Points

Answer:

In all three cardiac views, there is dilation of the right side of the heart. In the parasternal short axis you see septal bowing into the left side of the heart, also known as the “D” sign (named after the shape of the left ventricle). These findings are indicative of elevated right sided pressure, or right heart strain, which can be seen in conditions such as acute pulmonary embolism, pulmonary hypertension, COPD, and right ventricular infarction. Given the relatively thin free wall of the right ventricle, the likely cause of right heart strain in the above scenario is an acute process.

The patient had a CT scan that revealed extensive pulmonary emboli in all segmental and subsegmental arterial divisions of the lung with findings consistent with pulmonary artery hypertension and severe right heart strain. The EKG obtained had evidence of right heart strain including right axis deviation and diffuse T-wave inversions. The patient was started on heparin and admitted to the ICU.

Learning Points

  • The reported sensitivity and specificity of echocardiography in demonstrating right heart dysfunction are around 56% and 42% respectively (1)
  • Described features of right heart dysfunction include (2)
    1. Dilation of the right ventricle
      • The RV normally appears triangular-shaped and is two-thirds the size of the LV in apical four view (3)
    1. Interventricular septal flattening
      • AKA the “D sign” on parasternal short view or paradoxical septal motion on apical four view
    1. Right ventricular hypertrophy (right ventricular free wall thickness >5mm in diastole)
      • When present, implies some degree of chronicity to the inciting hemodynamic insult
    1. Right ventricular hypokensia
      • Typically quantified as a tricuspid annular plane systolic excursion, as measured by M-mode from the apical 4 chamber view, <1.6 cm
    1. Plethoric vena cava

References

  1. He, H., et-al. Computed tomography evaluation of right heart dysfunction in patients with acute pulmonary embolism. J Comput Assist Tomogr. 2006;30 (2): 262-6.
  2. Rudski, L.G., et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. (2010) Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography. 23 (7): 685-713
  3. Mallin, 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 17th, 2020.


The following authors contributed to this post:

Danika Brodak, MD; Amir Aminlari, MD; Rachna Subramony, MD; Colleen Campbell, MD

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