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Case 33: Parotid Mass
A 73-year-old male with a past medical history including atrial fibrillation and hypertension presented to the ED for admission for planned resection of a parotid mass with ENT. He first noted pain to his right cheek several months prior. Over this period, a mass was noted. The mass continued to grow over time, raising concern for malignancy, and the decision was made to pursue resection of the mass. On presentation, he endorsed significant pain to the right parotid area, but denied any fever, chills, chest pain, SOB, nausea, vomiting, abdominal pain, or dysuria. On physical exam, gross observation revealed diffuse swelling of the patient’s right cheek just anterior to the right tragus with marked tenderness to palpation. The remainder of his exam was unremarkable.
Vitals:
BP 160/81 | Pulse 75 | Temp 97.4 °F (36.3 °C) | Resp 20 | Ht 5' 11" (1.803 m) | Wt 87.7 kg (193 lb 5.5 oz) | SpO2 98% | BMI 26.97 kg/m²
Point of care ultrasound was performed to visualize the mass (right side) and compare it to the contralateral, non-diseased glandular tissue (left side). The following scans were obtained:
Figure 1: Left parotid, transverse view
Figure 2: Left parotid, sagittal view
Figure 3: Right parotid with mass, transverse view
Figure 4: Right parotid with mass, sagittal view
Discussion
The parotid gland can often be elusive on account of its relatively unremarkable echogenicity. However, using anatomical landmarks, finding the gland and its surrounding structures can be quick and easy. The technique used for obtaining our bedside images for this case is summarized below:
Figure 5: Scan plane used to obtain sagittal view of the parotid
Figure 6: Scan plane used to obtain transverse view of the parotid
Figure 7: Labeled Anatomy of Parotid Gland (image from teachmeanatomy.info)
The superficial location of the parotid necessitates a high-resolution linear probe for optimal scan resolution. We found that the base of the tragus was an easy and reliable landmark to use as a starting waypoint for obtaining either the transverse or sagittal plane views. This positioning allows for identification of the parotid gland as it wraps around the angle of the mandible. The transverse plane is particularly useful for visualization of the accessory parotid gland, which is known to be the landmark for the parotid (Stenson’s) duct.2,3 In fact, ultrasound has been shown to successfully diagnose parotid duct obstruction.4 The sagittal plane can be useful when searching for an optimal cross-section of Stenson’s duct, especially when it is dilated (e.g. in the case of an obstructing stone). Should the duct prove difficult to locate, the course and angle of Stenson’s duct may be approximated by drawing an imaginary line from the base of the tragus to the upper lip.5 Though we were unable to obtain optimal imaging of Stenson’s duct with this patient, we were able successfully locate the accessory parotid gland using the technique described above.
Figure 8: Left parotid gland (PG) with labeled accessory lobe (AL) noted to be just medial and separate from the main gland in the transverse plane
Overall, this case was an excellent exercise in using anatomical landmarks for localization of the parotid gland, review of notable anatomy, and comparison with diseased tissue. This patient underwent successful right superficial parotidectomy in the following days and was discharged on post-op day 1. The pathology report was concerning for high grade carcinoma with localized spread but clean margins. No lymph node involvement.
References
1. The parotid gland. TeachMeAnatomy. (n.d.). https://teachmeanatomy.info/head/organs/salivary-glands/parotid/
2. Parotid gland- normal. ULTRASOUNDPAEDIA. (n.d.) https://ultrasoundpaedia.com/parotid-gland-normal/
3. Human Anatomy Lessons. (2022, August 5). Parotid gland. Learn Human Anatomy. https://humananatomyonline.in/2022/08/05/parotid-gland/
4. Goncalves, M., Mantsopoulos, K., Schapher, M., Iro, H., & Koch, M. (2021). Ultrasound in the diagnosis of parotid duct obstruction not caused by sialolithiasis: diagnostic value in reference to direct visualization with sialendoscopy. Dentomaxillofacial Radiology, 50(3), 20200261.
5. Jones J, Howden W, Yu Y, et al. Parotid gland. Reference article, Radiopaedia.org (Accessed on 21 Sep 2023) https://doi.org/10.53347/rID-10448
This post was written by Henry Horita, Lainey Yu, MD, Ben Supat, MD, MPH, and Sukh Singh, MD. Posted by Ben Supat, MD, MPH.
Case 32: Perforated Gallbladder
A 77-year old man presented to the emergency department with a complaint of appetite loss over the past 15 days. He reported ongoing symptoms for the past 5 months. However, over the previous 15 days, his appetite had been so poor that he only drank 1-2 nutrition drinks per day. He reported a 10-15 lbs weight loss paired with fatigue and weakness. He denied nausea, vomiting, abdominal pain, fevers, and chills. The patient reported normal bowel movements. He denied any significant medical history and had no records in our EMR. He reported an unremarkable colonoscopy 7-8 years ago.
Upon physical examination, he was non-toxic in appearance. Vitals were as follows:
BP: 155/89 | HR: 105 | RR: 16 | T: 99.8 F | Sp02 100% on RA |
The patient had no masses, no hepatomegaly, no flank pain, and no tenderness to the abdomen upon palpation. Laboratory evaluation included a CBC which was remarkable for an elevated white blood count of 23,200 with a left shift. The chemistry panel was notable for normal ALT, AST, bilirubin, and creatinine.
Bedside ultrasound was performed, and the following images were obtained. In examining these images, what do you notice and how would this change your patient management?
Answer and Learning Points
Figure 3: Thickened gallbladder wall and echoic sludge around the cholelithiasis. Gallbladder wall perforation can be visualized at the 2 o’clock position.
Figure 4: Gallbladder wall perforation visualized at the 11 o’clock position.
Figure 5: CT image demonstrating gallbladder wall perforation at the 2 o’clock position as well as pericholecystic fluid.
In the images above, a thickened gallbladder wall with “hole-signs” can be seen, indicating perforation.
Discussion
Biliary pathology is the third most common cause of acute abdominal pain presenting to the ED [1]. Unfortunately, labs and clinical exam findings, either alone or in combination, are insufficient to reliably rule out biliary pathology [2]. Point-of-care ultrasound (POCUS) in the ED can detect cholelithiasis with a sensitivity and specificity of 89.8% and 88.0%, respectively [3]. Regarding the detection of cholecystitis, ED POCUS features a sensitivity and specificity of 87% and 82%, respectively [4]. In this case, we visualized a perforation and abscess outside the inflamed wall of the gallbladder, illustrating the accuracy and utility of POCUS as a diagnostic tool.
How to best visualize the gallbladder:
1. Subcostal sweep: With the marker dot to the patient’s head, place the probe in the subxiphoid/epigastric area. Next, slide the probe slowly to the patient’s right flank until the gallbladder is visualized or one has determined that another view is necessary.
2. Subcostal fanning: With the marker dot to the patient’s right, place the probe in the RUQ abdomen, where one would palpate for a non-ultrasound Murphy’s sign. Fan cephalad to look for the gallbladder in the area under the anterior ribs.
3. X-7: Start subxiphoid and move the probe approximately 7 cm to the patient’s right, scan in transverse orientation transverse below or through the ribs. If scanning through the ribs, one may need to rotate the probe slightly clockwise to align the probe with the intercostal space.
4. Mid-axillary longitudinal view: Obtain a view of Morrison's pouch as you would when completing a FAST (marker dot toward the patient’s head, patient supine, and probe placed in the mid axillary line). Remember, the kidney is retroperitoneal. After identifying the hepatorenal interface, slowly fan anteriorly until the gallbladder is directly under the probe. The common bile duct will be parallel and superficial to the portal vein. The inferior vena cava, with its characteristic respiratory variation, will be deep to the portal vein. Use color flow to differentiate the structures, as the common bile duct will not have color flow.
5. Roll the patient: If the above does not yield satisfactory views, roll the patient into a left lateral decubitus position. This will bring the gallbladder to a more anterior location and likely improve visualization of the GB when the steps above are repeated in this new patient position.
Normal Findings:
The upper limit of normal for the adult common bile duct is 6mm up to the age of 60. After this, the upper limit of normal rises an additional 1mm for every decade of life after 60 (e.g. 7mm at 70 years of age). Remember, there is a band of connective tissue called the main lobar fissure (MLF) that anchors both the portal triad and the neck of the gallbladder. Therefore, if you see the portal triad, you can then find the main lobar fissure emanating from the portal triad and track it to the neck of the gallbladder. The converse is true when locating the portal triad after identifying the gallbladder (follow the gallbladder neck, then trace the MLF to the portal triad).
During the examination, measure the thickness of the anterior gallbladder wall. The posterior wall is subject to posterior acoustic enhancement, which may yield an inaccurate measurement. A normal gallbladder wall thickness should measure less than 3 millimeters (mm). This measurement serves as a baseline for evaluating potential abnormalities.
Signs of Cholecystitis:
Cholecystitis can be diagnosed by observing gallbladder wall thickening greater than 3mm, pericholecystic fluid collection, gallbladder distension, and the presence of a sonographic Murphy's sign (positive when the point of maximal tenderness is identified by pressing the abdomen with the ultrasound probe while the gallbladder is centered on the screen) [5].
The presence of gallstones within the gallbladder lumen can be detected through ultrasound. Gallstones are typically visualized as rounded structures with an bright, anterior outer layer and associated acoustic shadowing (similar to bone). When the stones occupy most of the lumen of the gallbladder, or a gallbladder is contracted around one or more stones, one may appreciate a “Wall Echo Sign”, where the shadowing from the stones obstructs visualization of the posterior wall of the gallbladder. Note that non-calcified stones will not produce shadowing artifacts behind them.
The significance of sludge in ultrasound imaging of the gallbladder can vary depending on the clinical context. Sludge itself can be a precursor to the formation of gallstones. It may indicate an imbalance in the components of bile, such as excess cholesterol or insufficient bile salts, which can lead to the development of gallstones over time. Perforation can be diagnosed by observing gallbladder wall discontinuity or disruption, pericholecystic fluid collection or abscess formation, and signs of free fluid in the abdominal cavity [6].
POCUS is a powerful diagnostic modality for identifying biliary pathology, including cholecystitis, cholelithiasis, and perforation of the gallbladder wall. By following the scanning technique outlined above and identifying findings consistent with biliary pathology, clinicians can obtain accurate diagnoses and facilitate appropriate patient management. POCUS is a valuable tool to use in conjunction with a patient's clinical history, physical examination, and other diagnostic modalities to ensure comprehensive assessment and optimal healthcare outcomes.
References
1) Cervellin, Gianfranco, Riccardo Mora, Andrea Ticinesi, Tiziana Meschi, Ivan Comelli, Fausto Catena, and Giuseppe Lippi. 2016. “Epidemiology and Outcomes of Acute Abdominal Pain in a Large Urban Emergency Department: Retrospective Analysis of 5,340 Cases.” Annals of Translational Medicine 4 (19): 362.
2) Trowbridge, Robert L., Nicole K. Rutkowski, and Kaveh G. Shojania. 2003. “Does This Patient Have Acute Cholecystitis?” JAMA: The Journal of the American Medical Association 289 (1): 80–86.
3) Ross, Marshall, Michael Brown, Kyle McLaughlin, Paul Atkinson, Jenny Thompson, Susan Powelson, Steve Clark, and Eddy Lang. 2011. “Emergency Physician-Performed Ultrasound to Diagnose Cholelithiasis: A Systematic Review.” Academic Emergency Medicine: Official Journal of the Society for Academic Emergency Medicine 18 (3): 227–35.
4) Summers, Shane M., William Scruggs, Michael D. Menchine, Shadi Lahham, Craig Anderson, Omar Amr, Shahram Lotfipour, Seric S. Cusick, and J. Christian Fox. 2010. “A Prospective Evaluation of Emergency Department Bedside Ultrasonography for the Detection of Acute Cholecystitis.” Annals of Emergency Medicine 56 (2): 114–22.
5) Simeone, J. F., J. A. Brink, P. R. Mueller, C. Compton, P. F. Hahn, S. Saini, S. G. Silverman, G. Tung, and J. T. Ferrucci. 1989. “The Sonographic Diagnosis of Acute Gangrenous Cholecystitis: Importance of the Murphy Sign.” AJR. American Journal of Roentgenology 152 (2): 289–90.
6) Sood BP, Kalra N, Gupta S, et al. Role of sonography in the diagnosis of gallbladder perforation. J Clin Ultrasound. 2002;30(5):270-274. doi:10.1002/jcu.10071
This post was written by Cameron Olandt, Ben Supat, MD, MPH, and Colleen Campbell, MD. Posted by Ben Supat, MD, MPH.
Case 31: A Man with Shortness of Breath
A 77-year-old patient presented to a rural Emergency Department with a chief complaint of shortness of breath a day prior to presentation. Patient also reported that he fell several weeks ago and hurt his ribs. He was subsequently admitted to the hospital and was ultimately treated for pyelonephritis. He endorsed being more sedentary than usual for the next several weeks. On the day of presentation he was lying in bed when he began to suddenly feel short of breath. He denied feeling any chest pain, lightheadedness, dizziness, nausea, vomiting, diarrhea, diaphoresis, jaw or arm pain. His shortness of breath had self resolved prior to coming into the emergency department. On physical examination, the patient was alert and had mild respiratory distress. He was tachycardic and also found to have inspiratory crackles in the right lower lung fields. The remainder of the physical exam was within normal limits.
Upon arrival, vitals were as follows:
BP: 92/70 | HR: 118 | RR: 18 | T: 98.2 | Sp02: 80’s% on RA to 90% with 15L NRB
Point of care ultrasound was performed and the following images were obtained. In these images, what do you notice and how does this change your patient management?
Figure 1: Parasternal Short Axis view of the left ventricle at the mid-papillary level
Figure 2: A normal parasternal Short Axis view of the left ventricle at the mitral valve level.
Figure 3: Our patient’s Parasternal Short Axis view of the D-sign in the left ventricle.
View shown in the image above is the parasternal short axis. To perform this technique, use the phased array transducer and place it around the 4th intercostal space, next to the sternum, with the probe marker to the patient’s right shoulder. For example:
![Figure 4: Placement of probe for Parasternal Long Axis view [1].](https://emultrasound.sdsc.edu/wp-content/uploads/2023/06/Screen-Shot-2023-06-29-at-3.56.20-PM-300x256.png "Screen Shot 2023-06-29 at 3.56.20 PM")
Figure 4: Placement of probe for Parasternal Long Axis view [1].
![Figure 5: Standard long axis view of the left ventricle at the mitral level [2].](https://emultrasound.sdsc.edu/wp-content/uploads/2023/06/image-asset.gif "image-asset")
Figure 5: Standard long axis view of the left ventricle at the mitral level [2].
Clockwise rotation of the probe (90 degrees) where the indicator is pointing towards the patient's left shoulder will provide a short axis view of the left ventricle. Normal parasternal short axis view in a patient without cardiac dysfunction will include the right ventricle sitting as a semi-circle on top of the circular left ventricle. For example:
![Figure 6: Placement of probe for Parasternal Short Axis view [1].](https://emultrasound.sdsc.edu/wp-content/uploads/2023/06/Screen-Shot-2023-06-29-at-4.00.16-PM-300x250.png "Screen Shot 2023-06-29 at 4.00.16 PM")
Figure 6: Placement of probe for Parasternal Short Axis view [1].
![Figure 7: Standard short axis view of the left ventricle at the mitral level [2].](https://emultrasound.sdsc.edu/wp-content/uploads/2023/06/ezgif.com-gif-maker4.gif "ezgif.com-gif-maker+(4)")
Figure 7: Standard short axis view of the left ventricle at the mitral level [2].
In our case, the right ventricle is pushing down on the left ventricle, indicating increased right sided pressures. This is the classic “D-sign” of the left ventricle, the septum has become straight due to the right sided pressures.
Classically, the apical four view is used to diagnose elevated right sided pressures by comparing chamber sizes. However, this view can be challenging at times. In our case, we show the effectiveness of diagnosing right sided pressures using a parasternal short axis view [Figure 3].
Discussion
We typically observe indications of increased pressures in the pulmonary artery and strain on the right side of the heart. These indications can be identified through the presence of reduced movement in the right ventricular wall, enlargement of the right ventricle and right atrium, abnormal motion of the septum during systole, and a dilated inferior vena cava that does not collapse during respiration.
In our case, POCUS utilizing the parasternal short axis view of the heart indicated the “D-sign”. In a normal heart with proper physiological functioning, the pressure in the left ventricle is higher than the pressure in the right ventricle. As a result, during systole the left ventricle maintains a round shape, causing the intraventricular septum to bulge into the right ventricle. However, if the right ventricle pressures are elevated, the septum becomes straight, changing the shape of the left ventricle into a "D".
Case Conclusion
Visualization of the D sign led to a high concern for pulmonary embolism. Management of the patient’s hypotension was transitioned from fluid resuscitation to vasopressors, on which he was stabilized. He was then taken for a STAT CTA, showing a large saddle pulmonary embolus. The patient was treated with thrombolytics, and he was transferred to a tertiary care center for higher level of care. There, the patient underwent thrombectomy with removal of significant clot burden as below:
Figure 8: Clots retrieved post-thrombectomy.
His clinical status continued to improve and he was discharged on hospital day 7 with no residual complications.
In this case, recognition of the D-sign allowed for prompt and effective management of a critically ill patient, and the patient made a full recovery. Key clinical advantages were expediting a difficult diagnosis in a patient who was reportedly asymptomatic at the time of presentation, a rapid transition from fluid resuscitation (which could have worsened his right heart strain) to vasopressor support, and early imaging and thrombolytics before his clinical picture could worsen.
References
1) Lee V, Dinh V, Ahn J, Deschamps J, Genoba S, Lang A, Tooma D, White S, Krause R. Cardiac Ultrasound (Echocardiography) Made Easy: Step-By-Step Guide. POCUS 101. https://www.pocus101.com/cardiac-ultrasound-echocardiography-made-easy-step-by-step-guide/#Step_1_Parasternal_Long_Axis_PSLA_View. (Accessed May 30, 2023)
2) “Normal Cardiac Anatomy.” n.d. TPA. Accessed August 1, 2023. https://www.thepocusatlas.com/normal-cardiac-anatomy/normal-parasternal-long-axis-plax-view.
This post was written by Cameron Olandt, Dr. Daniel Brownstein, Dr. Andrew Lafree, Dr. Colleen Campbell, and Dr. Sukhdeep Singh. Posted by Dr. Ben Supat.
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 2: A hyperechoic object with reverberation artifacts and shadow seen at 1cm.
Figure 3: Removal of FB under US guidance using curved hemostats.
Figure 4: Extracted pellet.
Answer and Learning Points
Answer:
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.
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?
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.
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?
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.
Does adding M-mode to B-mode improve accuracy in diagnosing pneumothorax?
Background
Ultrasound has been shown to be superior to supine chest x-ray in the diagnosis of pneumothorax, with one recent systematic review demonstrating 91% sensitivity using ultrasound compared to 50% using chest x-ray.1 CT scan remains the gold standard in diagnosis but is often not feasible in unstable trauma patients. Ultrasound is recommended by ATLS guidelines for use in trauma patients as part of the eFAST protocol. There are three main described ultrasound findings in pneumothorax: lung sliding, B-lines, and the lung point. While B-mode (2D mode) is commonly described, many resources also suggest the use of M-mode (motion mode).
This study evaluates whether the addition of M-mode to B-mode impacts the sensitivity, specificity, and accuracy of bedside ultrasound in the diagnosis of lung sliding. Previous studies have evaluated the accuracy of M-mode on cadaveric subjects2, but no previous studies have investigated the accuracy of M-mode + B-mode compared to B-mode alone in live human subjects.
Does adding M-mode to B-mode improve accuracy in diagnosing pneumothorax?
Avila, J et al. Does the Addition of M-Mode to B-Mode Ultrasound Increase the Accuracy of Identification of Lung Sliding in Traumatic Pneumothoraces?. J Ultrasound Med, 37: 2681-2687
Clinical Question
Does the addition of M-mode to B-mode improve accuracy in identifying lung sliding? Does this vary by ultrasound experience and level of training?
Methods & Study Design
Design:
Survey
Population:
Emergency Physicians including residents, fellows, and attending physicians
Intervention:
Hemithorax anterior lung field ultrasound scans were performed on 15 patients who had a unilateral pneumothorax confirmed by CT scan. B-mode and corresponding M-mode images were obtained for each patient, with one scan on each side, producing scans of 30 lungs. These images were incorporated into a 30-question quiz in which respondents were asked to identify the presence or absence of lung sliding. One version of the quiz contained B-mode clips alone and one version contained B-mode and M-mode clips for each lung. Respondents were randomized to one of the two quizzes. The quiz was sent to EM residency directors for distribution. One hundred forty physicians responded and were randomized.
Outcomes:
Sensitivity, specificity, and accuracy of the diagnosis of lung sliding, and association with respondent ultrasound experience and level of training.
Results
Overall, the addition of M-Mode to B-Mode resulted in unchanged sensitivity, 93.1% vs 93.2%, improved specificity from 89.8% to 96% (P < 0.0001), and improved accuracy from 91.5% to 94.5% (p=0.0091).
In subgroup analysis, there was no significant difference in accuracy, sensitivity, or specificity when adding M-mode for physicians with more than 250 ultrasound scans previously performed. For physicians with less than 250 total scans previously performed, use of B-mode + M-mode increased accuracy from 88.2% to 94.4% (P = 0.001) and increased specificity from 87.0% to 97.2% (P < 0.0001) compared with B-mode alone. For resident physicians, the addition of M-mode to B-mode significantly improved accuracy from 89.6% to 94.6% (P = 0.0016) and specificity from 87.9% to 95.9% (P < 0.001) for resident physicians. There was no significant improvement for fellows and attending physicians.
Strengths and Limitations
Strengths:
The authors describe methods in detail, including how the ultrasound scans were performed, number of sites scaned, and the type of machine, probe, and settings used. They also collected detailed information on level of ultrasound experience which helps generalize results among emergency physicians with varying levels of ultrasound experience. Ultrasound results were compared to the gold standard of CT scan.
Limitations:
The survey was sent out to residency program directors to distribute to residents, fellows, and attendings, which excludes the large number of practicing emergency physicians in the community. Community physicians may have different levels of experience and formal training with ultrasound and would be an important group to include in terms of study generalizability. Additionally, the sample size was relatively small (140 total participants) and included many more residents (92) than fellows/attendings (48). The images used also did not capture the absence or presence of B-lines, which could also impact interpretation and management. This study evaluated interpretation only and did not evaluate image acquisition, which could impact the outcomes measured and would be more helpful for practical application. Finally, there may be a difference in clinical significance between pneumothorax diagnosed with x-ray or bedside ultrasound versus CT scan– CT may identify more smaller and less clinically relevant pneumothoraces which may be missed on ultrasound.
Author's Conclusions
“The addition of M-mode images to B-mode clips aids in the accurate diagnosis of lung sliding by emergency physicians. The subgroup analysis showed that the benefit of M-mode US disappears after emergency physicians have performed more than 250 US examinations.”
Our Conclusions
The addition of M-mode to B-mode can improve accuracy in identifying lung sliding when evaluating for pneumothorax when performed by emergency physicians with less training or ultrasound experience. Given this benefit, more junior physicians could be encouraged to add M-mode to their evaluation for pneumothorax, especially as the additional image acquisition required is relatively quick.
The Bottom Line
Adding M-mode to B-mode when using ultrasound to evaluate for pneumothorax improved accuracy amongst emergency physicians with less US experience.
Authors
This post was written by Julie Westover, MS4 at UCSD School of Medicine, with editing by Ben Liotta, MD and Amir Aminlari, MD.
References
Avila, J., Smith, B., Mead, T., Jurma, D., Dawson, M., Mallin, M. and Dugan, A. (2018), Does the Addition of M-Mode to B-Mode Ultrasound Increase the Accuracy of Identification of Lung Sliding in Traumatic Pneumothoraces?. J Ultrasound Med, 37: 2681-2687. https://doi.org/10.1002/jum.14629
1. Alrajhi K, Woo MY, Vaillancourt C. Test characteristics of ultrasonography for the detection of pneumothorax: a systematic review and analysis. Chest 2012; 141:703–708.
2. Adhikari S, Zeger W, Wadman M, Walker R, Lomneth C. Assessment of a human cadaver model for training emergency medicine res- idents in the ultrasound diagnosis of pneumothorax. Biomed Res Int 2014; 2014:724050
Can Junior EPs Use E-Point Septal Separation to Accurately Estimate Left Ventricular Function?
Background
Point-of-care echocardiography can provide a rapid and accurate assessment of left ventricular function, which is valuable in differentiating causes of hypotension and dyspnea at bedside. Visual estimation of LV function by experienced practitioners has been shown to correlate well with quantitative estimates. However, the number of examinations required before a practitioner is qualified to visually estimate LV function accurately is unknown. Although there are various comparable parameters for assessing LV function, mitral valve E-point septal separation (EPSS) is an easy-to-obtain measurement inversely correlated with LV function. EPSS is an M-mode measurement of the minimum distance between the anterior mitral valve leaflet and the interventricular septum during diastole. Despite its applicability, the reproducibility and accuracy of EPSS as a bedside tool for evaluating LV function in less experienced emergency physicians has yet to be established.
Can Junior Emergency Physicians Use E-Point Septal Separation to Accurately Estimate Left Ventricular Function in Acutely Dyspneic Patients?
Clinical Question
This study aims to determine if novice emergency physicians (PGY 3 and PGY 4) are able to obtain EPSS measurements and determine if these measurements correlate to echocardiographic visual estimations of LV function by experienced emergency physicians.
Methods & Study Design
Design:
Prospective observational study of correlation between EPSS to visual estimation and LV function in patients who present to ED with chief complaint of acute dyspnea.
Population:
Convenience sampling of 70 subjects enrolled in the ED from July 2008 and July 2009. Criteria for enrollment included age > 18 years, chief complaint of dyspnea, ED length > 2 hours, no history of trauma, and normal mental status. Patients with known history of mitral valve repair or replacement, aortic insufficiency, or mitral stenosis were excluded.
Intervention:
12 senior residents (PGY 3 and PGY 4) in EM residency program with variable levels of ultrasound experiences (70 to 150 total ED ultrasound examinations; average of fewer than 25 cardiac examinations) performed transthoracic echocardiogram of patients with chief complaint of acute dyspnea. Ultrasound examination included subcostal, parasternal long axis (PLAX), parasternal short axis, and apical four chamber views. Six-second video clips in parasternal short and long axes were obtained. M-mode measurements of EPSS were recorded in PLAX orientation after all video clips were obtained and calculated during diastole. All examinations were performed without the presence of experienced emergency physicians (EPs).
Outcomes:
One of two experienced EPs reviewed stored video and visually estimated LVEF. Two board-certified cardiologists subsequently reviewed one-half of the video clips and estimated LVEF, blinded to both junior EPs’ EPSS measurements and visual estimations by experienced EPs.
Results
58 out of 70 enrolled subjects had complete echocardiographic studies recorded.
Concordance rates between EPSS measurements by EPs and cardiologist for LVEF were acceptable with kappa for visual LVEF estimation of 0.75 (95% CI = 0.48 to 1.00).
Spearman correlation analysis revealed significant correlation (p = -0.844, p< 0.001) between novice physicians’ measurements of EPSS and visual estimation of LVEF by experienced EPs.
Strengths and Limitations
This study compared EPSS measurement by junior EPs with visual assessment by experienced EPs showing a strong correlation. Experienced EPs were not blinded to results, which may have induced bias, but the authors find this less likely given what they interpret as good agreement on visual estimations between experienced EPs and blinded cardiologists. It is debatable whether the agreement between EPs and cardiologists with kappa of 0.75 represents good agreement. This study utilized a convenience sampling design due to logistical constraints, which may impact the generalizability of its results. Many subjects were excluded for incomplete ultrasound views, but authors note that junior EPs were actually able to assess EPSS for all subjects, further supporting the use of this measurement even when other views are difficult to obtain.
Authors Conclusions
PGY 3 and PGY 4 EM residents were able to obtain measurements of EPSS that correlated closely with visual assessments of LVEF by experienced emergency physicians with extensive point-of-care ultrasound and echocardiography experience. EPSS can serve as a quantitative alternative to visual estimation of LVEF in dyspneic ED patients.
Our Conclusions
Rapid assessment of LVEF with bedside echocardiography can provide useful clinical information in the acutely dyspneic patient. The level of expertise required to accurately visually assess a LVEF is unknown. This study supports EPSS as a useful quantitative addition to visual estimation of LVEF in patients with acute dyspnea for novice emergency physicians with less echocardiography experience. The level of correlation between EPSS and visual estimation was not perfect, suggesting use of EPSS as an addition to rather than replacement for standard visual estimation.
The Bottom Line
EPSS can serve as a quantitative addition to qualitative visual estimation of LVEF with bedside echocardiography, especially for less experienced EM practitioners.
Authors
This post was written by Eugene Han, MS4 at UCSD School of Medicine, with editing by Ben Liotta, MD and Amir Aminlari, MD.
References
1. Secko MA, Lazar JM, Salciccioli LA, Stone MB. Can junior emergency physicians use E-point septal separation to accurately estimate left ventricular function in acutely dyspneic patients? Acad Emerg Med. 2011 Nov;18(11):1223-6. doi: 10.1111/j.1553-2712.2011.01196.x. Epub 2011 Nov 1. PMID: 22044429.
2. McKaigney CJ, Krantz MJ, La Rocque CL, Hurst ND, Buchanan MS, Kendall JL. E-point septal separation: a bedside tool for emergency physician assessment of left ventricular ejection fraction. Am J Emerg Med. 2014 Jun;32(6):493-7. doi: 10.1016/j.ajem.2014.01.045. Epub 2014 Feb 3. PMID: 24630604.
3. Shahgaldi K, Gudmundsson P, Manouras A, Brodin LA, Winter R. Visually estimated ejection fraction by two dimensional and triplane echocardiography is closely correlated with quantitative ejection fraction by real-time three dimensional echocardiography. Cardiovasc Ultrasound. 2009 Aug 25;7:41. doi: 10.1186/1476-7120-7-41. PMID: 19706183; PMCID: PMC2747837.
4. McGowan JH, Cleland JG. Reliability of reporting left ventricular systolic function by echocardiography: a systematic review of 3 methods. Am Heart J. 2003 Sep;146(3):388-97. doi: 10.1016/S0002-8703(03)00248-5. PMID: 12947354.
5. Jacob M, Shokoohi H, Moideen F, Pousson A, Boniface K. An Echocardiography Training Program for Improving the Left Ventricular Function Interpretation in Emergency Department; a Brief Report. Emerg (Tehran). 2017;5(1):e70. Epub 2017 Jun 15. PMID: 29201952; PMCID: PMC5703747.