Month: December 2024

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Case 41: Abdominal Aortic Aneurysm

Skyler Sloane, Benjamin Supat

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

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

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

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

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

Next, we performed an ultrasound of the aorta.

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

Figure 5: Labeled image showing intramural thrombus.

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

Discussion: 

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

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

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

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

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

References

  1. Hirsch AT, Haskal ZJ, Hertzer NR, et al. ACC/AHA 2005 Circulation. 2006; 113: e463-e654. doi:10.1161/CIRCULATIONAHA.106.174526
  2. Altobelli E, Rapacchietta L, Profeta VF, Fagnano R. Risk Factors for Abdominal Aortic Aneurysm in Population-Based Studies: A Systematic Review and Meta-Analysis. Int J Environ Res Public Health. 2018 Dec 10;15(12):2805. doi: 10.3390/ijerph15122805. PMID: 30544688; PMCID: PMC6313801.
  3. Farber, M. A.; Parodi, F. E. Abdominal Aortic Aneurysms (AAA), 2023, 2023. https://www.merckmanuals.com/professional/cardiovascular-disorders/diseases-of-the-aorta-and-its-branches/abdominal-aortic-aneurysms-aaa.
  4. Aggarwal S, Qamar A, Sharma V, Sharma A. Abdominal aortic aneurysm: A comprehensive review. Exp Clin Cardiol. 2011 Spring;16(1):11-5. PMID: 21523201; PMCID: PMC3076160.
  5. Jeanmonod D, Yelamanchili VS, Jeanmonod R. Abdominal Aortic Aneurysm Rupture. [Updated 2023 Aug 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459176/
  6. Abdominal aortic aneurysm: diagnosis and management. London: National Institute for Health and Care Excellence (NICE); 2020 Mar 19. (NICE Guideline, No. 156.) Available from: https://www.ncbi.nlm.nih.gov/books/NBK556921/
  7. Concannon E, McHugh S, Healy DA, Kavanagh E, Burke P, Clarke Moloney M, Walsh SR. Diagnostic accuracy of non-radiologist performed ultrasound for abdominal aortic aneurysm: systematic review and meta-analysis. Int J Clin Pract. 2014 Sep;68(9):1122-9. doi: 10.1111/ijcp.12453. Epub 2014 May 18. PMID: 24837590.
  8. Moxon JV, Parr A, Emeto TI, Walker P, Norman PE, Golledge J. Diagnosis and monitoring of abdominal aortic aneurysm: current status and future prospects. Curr Probl Cardiol. 2010 Oct;35(10):512-48. doi: 10.1016/j.cpcardiol.2010.08.004. PMID: 20932435; PMCID: PMC3014318.
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Case 40: Rare Ocular Condition Diagnosed by Point-of-Care Ultrasound

Skyler Sloane & Andre Velazquez

A 73-year-old male presented to our emergency department with a chief complaint of new intermittent double vision for the past two weeks. The patient noticed that he saw double when looking at signs on the freeway. These were new symptoms he had not experienced in the past. The patient reported a history of hypertension, hyperlipidemia, and recently diagnosed prostate cancer. The patient also confirmed a history of ocular migraine. The patient denied current headaches, new floaters or flashes, curtains, or clouds in his vision.

Upon arrival, vital signs were: BP 131/91 | Pulse 107 | Temp 97.8 °F (36.6 °C) | SpO2 98% 

Visual acuity: OD 20/20 and OS) 20/20. Pupil light reaction from 3 mm to 2 mm bilaterally. Extraocular movement was full and normal in both eyes. Finger counting was normal in both eyes. The right eye had an intraocular pressure of 13 mmHg and the left eye had an intraocular pressure of 14 mmHg. The bedside anterior segment exam was normal. 

We performed a bedside ultrasound while waiting for an ophthalmology consult and obtained the following images of the left eye. 

Figure 1: Ultrasound of the left eye. 

Figure 2: Labeled ultrasound of the left eye showing asteroid hyalosis (hyperechoic free-floating particles in the vitreous chamber). 

In the obtained images, we see hyperechoic free-floating particles in the vitreous chamber as we scan through the eye. From these images, we reached a diagnosis of asteroid hyalosis. This was later confirmed by ophthalmology through a dilated fundus exam. 

Asteroid hyalosis (AH) is an uncommon degenerative condition that is characterized by the formation of asteroid bodies (AB), comprised of calcium and phospholipids within the vitreous chamber (1). The greatest prominent risk factor is age (2). 

Asteroid hyalosis is benign and asymptomatic in most cases and is not a viable cause for the diplopia that our patient presented with (1). Ophthalmology reported no evidence of strabismus or nystagmus. Additionally, the optic nerve was observed to be sharp and perfused. They postulated that the complaints could be explained by superior oblique myokymia vs retinal hemifield slide. Given the patient’s history of recently diagnosed prostate cancer, brain imaging was recommended to rule out intracranial pathology. Brain imaging revealed no evidence of acute infarct, hemorrhage, or mass. A follow-up with ophthalmology revealed ocular misalignment with a small esotropia in the left eye and a left abduction deficit. The ophthalmologist postulated that this could be due to minor six nerve palsy. This esotropia was found to be the cause of the ocular diplopia.

Asteroid hyalosis can mimic vitreous hemorrhage on ultrasound. Both conditions may show hyperechoic echogenicities swirling in the vitreous chamber in a washing machine or snow globe motion (3). Asteroid particles are composed of calcium linked to phospholipids and often take on an intensely hyperechoic appearance on ultrasound due to their density (2). Conversely, vitreous hemorrhage often appears less hyperechoic than asteroid particles and can have a less granular appearance (4). Differentiating between asteroid hyalosis, a benign and largely asymptomatic condition, and vitreous hemorrhage, a more serious condition that may require emergent intervention is critical. 

Figure 3: Vitreous Hemorrhage: diffuse mobile opacity often referred to as a “snow globe” appearance that is made apparent by side-to-side movement of the eye.

We presented this case to raise awareness of the utility of point-of-care ultrasound in rapidly diagnosing rare ocular diseases. Furthermore, this case is significant because asteroid hyalinosis is a relatively rare disease that is infrequently observed in the emergency department. 

References: 

  1. Scott, D. A. R., Møller-Lorentzen, T. B., Faber, C., Wied, J., Grauslund, J., & Subhi, Y. (2021). Spotlight on Asteroid Hyalosis: A Clinical Perspective. Clinical Ophthalmology, 15, 2537–2544. https://doi.org/10.2147/OPTH.S272333
  2. Duong R, Abou-Samra A, Bogaard JD, Shildkrot Y. Asteroid Hyalosis: An Update on Prevalence, Risk Factors, Emerging Clinical Impact and Management Strategies. Clin Ophthalmol. 2023 Jun 20;17:1739-1754. doi: 10.2147/OPTH.S389111.
  3. Gros EC, Mccafferty LR. Asteroid Hyalosis: A Mimicker of Vitreous Hemorrhage on Point of Care Ultrasound: A Case Report. POCUS J. 2023 Nov 27;8(2):113-115. doi: 10.24908/pocus.v8i2.16391.
  4. De La Hoz Polo M, Torramilans Lluís A, Pozuelo Segura O, Anguera Bosque A, Esmerado Appiani C, Caminal Mitjana JM. Ocular ultrasonography focused on the posterior eye segment: what radiologists should know. (2016) Insights into imaging. 7 (3): 351-64. doi:10.1007/s13244-016-0471-z
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Case 39: Superficial Thrombophlebitis

Aastha Shah

A 57-year-old male with a past medical history of HIV, hyperlipidemia (on a statin), chronic obstructive pulmonary disease (COPD), lumbar stenosis, and chronic diastolic heart failure presented with a chief complaint of pain and swelling in the right inguinal region for the past 3 days. The patient reported a similar presentation in the past, during which he was told that he had a hernia. He denies associated symptoms such as fever, chills, nausea, vomiting, abdominal distention, constipation, or urinary changes. He passed stool normally this morning and has no history of prior abdominal surgeries.

Vitals: BP: 135/84 mmHg | Pulse: 84 bpm | Temp: 97.4 °F (36.3 °C) | Resp: 16 | Wt: 75.7 kg (166 lb 14.2 oz) | SpO2: 98%

On physical examination, the patient appeared in no acute distress. Cardiovascular exam revealed a regular rate and rhythm without murmurs. Lungs were clear to auscultation and the abdomen was soft, nondistended, and non-tender. A firm, localized swelling and tenderness was noted in the right inguinal region. There was no redness, induration, or drainage at the site. No testicular swelling or tenderness was observed. The remainder of the physical exam, including neurologic and extremity exams, was unremarkable.

A bedside ultrasound was performed over the area of swelling.

Figure 1: Non-occlusive superficial venous thrombus in the right inguinal region.

Discussion

Deep vein thrombosis (DVT) is a common condition, with an annual incidence rate estimated at about 1 in 1,000 adults. The risk of DVT increases with age, and other risk factors include immobility, recent surgery, trauma, malignancy, and certain medical conditions like HIV, COPD, and heart failure, which this patient has.

The differential diagnosis for DVT includes a variety of conditions that may present with
unilateral leg pain and swelling. These include cellulitis, muscle strains, Baker's cyst, venous
insufficiency, or even superficial thrombophlebitis, which was seen in this patient. Superficial venous thrombosis (SVT) is generally considered less dangerous than DVT, as SVT does not carry the same risk of pulmonary embolism, but it can still cause significant discomfort and complications if left untreated.

On physical exam, patients with DVT typically present with unilateral leg swelling, pain, and
tenderness. Other findings can include warmth, erythema, and distended superficial veins. In this case, the patient had localized swelling and tenderness in the right inguinal region without any associated redness or warmth, which is consistent with superficial venous thrombosis rather than DVT.

Ultrasound is the gold standard for diagnosing both DVT and SVT. Bedside ultrasonography
performed by emergency physicians can achieve sensitivities of 95% and specificities of 96%, making it a highly reliable tool for assessing DVT at the point of care (1). However, variability in ultrasound protocols has been noted across institutions. As reported by the Society of Radiologists in Ultrasound, discrepancies between protocols can lead to underdiagnosis or unnecessary testing, as highlighted in one case where a patient presented with calf DVT that was missed on initial imaging but later identified during follow-up scans (2). This underscores the need for standardized, comprehensive duplex ultrasound protocols to ensure accurate diagnosis.

When performing a point-of-care ultrasound (POCUS) exam for DVT, compression should be applied to the femoral vein just above and below the saphenofemoral junction, above and below the bifurcation of the common femoral vein into the deep femoral vein and femoral vein, and to the popliteal vein extending up to the trifurcation into the calf veins (3-point compression protocol). In this patient, the femoral vein was visualized during the POCUS, but the clot was superficial and located away from the femoral vein.

Treatment for DVT typically involves anticoagulation to prevent clot extension and pulmonary embolism. For superficial venous thrombosis, treatment is less aggressive and usually involves conservative management, such as compression stockings, nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief, and in some cases, anticoagulation if the thrombus is near a deep vein or extensive. If the thrombus extends or becomes symptomatic, more aggressive measures, such as surgical intervention or thrombolytic therapy, may be required.

References:

  1. Baker M, Anjum F, dela Cruz J. Deep Venous Thrombosis Ultrasound Evaluation.
    StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available
    from: https://www.ncbi.nlm.nih.gov/books/NBK470453/.
  2. Needleman L, Cronan JJ, Lilly MP, et al. Ultrasound for Lower Extremity Deep Venous
    Thrombosis: Multidisciplinary Recommendations From the Society of Radiologists in
    Ultrasound Consensus Conference. Circulation. 2018;137(14):1505-1515.
    doi:10.1161/CIRCULATIONAHA.117.030687.

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