Month: April 2026

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Case 69: Expedited Workup for a Low-Risk Pulmonary Embolism

Julia Kelly, Cameron Smyres

A 62-year-old man who was recently diagnosed with colon cancer presents to the ED after being diagnosed with a pulmonary embolism on outside CT imaging. The patient had a CT scan of his chest for cancer staging and an incidental PE was found. He was told to seek care at the ED. The patient is asymptomatic, and specifically denies chest pain, dyspnea, acute leg swelling and otherwise feels at his baseline. He denies any recent travel and has no history of blood clots in the past.

Vitals: BP 106/70 | Pulse 55 | Temp 98 °F (36.7 °C) | Resp 19 | Wt 79.8 kg (176 lb) | SpO2 98%

Physical Exam: The patient is not in acute distress, lying in bed and breathing comfortably on room air. Lungs are clear to auscultation bilaterally. 1+ pitting edema noted in shins bilaterally. The remainder of the exam is normal.

Labs: CBC with stable chronic macrocytic anemia (Hgb 11.7). CBC, PT and PTT wnl.

Figure 1: Parasternal long (no RV dilation)
Video 1: Parasternal short (no D sign present, symmetric squeeze of LV)

ED Course: Limited bedside cardiac ultrasound showed grossly normal heart function, without pericardial effusion or right ventricular dysfunction. No evidence of right heart strain. PE team was consulted who did not recommend formal echocardiogram based on patient’s lack of symptoms, hemodynamic stability, and reassuring bedside ultrasound. Patient was started on Eliquis and referred to PE clinic for outpatient follow up.

Discussion:

Pulmonary embolism (PE) is a potentially life-threatening diagnosis that can present with a variety of symptoms, from asymptomatic to sudden hemodynamic collapse. Approximately half of PEs are diagnosed in the emergency care setting,4 making rapid identification and risk stratification especially important. Mortality can reach up to 25-50% in massive PE without prompt treatment. POCUS has been shown to be highly sensitive for large PEs and in those with abnormal vital signs.1

A rapid bedside tool, POCUS can play an important role in risk stratification of patients with PEs by evaluating for right heart strain, though data shows its utility in diagnosing PE itself might be more limited5. Pulmonary emboli block blood flow to the lungs, increasing afterload, leading to right ventricular dysfunction (RVD). RVD is an important prognostic factor and can change management. In this case, bedside echo demonstrated no evidence of right ventricular dysfunction, supporting outpatient management with apixaban and close follow-up; in contrast, evidence of right heart strain may have prompted consideration of more aggressive therapies or inpatient monitoring.

There are several sonographic findings that suggest right heart strain, including RV enlargement (RV:LV ratio), abnormal septal motion such as septal flattening (“D-sign”), and McConnell’s sign (hypokinesis of RV with apical sparing, resembling a flailing sail3). These features reflect acute pressure overload on the RV from a significant pulmonary arterial obstruction. McConnell’s sign is an indication of acute RV strain, rather than chronic changes. Acute RV strain can also be distinguished from chronic overload with the absence of RV hypertrophy.5 It is important to note that the sensitivity of POCUS for detecting right heart strain in PE is limited. For example, McConnell’s sign shows high specificity but low sensitivity for acute PE: one study finding a pool estimate of 22% sensitivity and 97% specificity.4 Additionally, absence of right heart strain on POCUS does not exclude PE, and CT PE remains the gold standard for definitive diagnosis.

In summary, while POCUS did not reveal right heart strain in this patient with confirmed PE, its use provided timely bedside evaluation of cardiac function that contributed to risk stratification and informed clinical management. This case highlights POCUS’s role as a valuable tool in the assessment of suspected PE.

References

  1. Alerhand S, Sundaram T, Gottlieb M. What are the echocardiographic findings of acute right ventricular strain that suggest pulmonary embolism? Anaesth Crit Care Pain Med. 2021 Apr;40(2):100852. doi: 10.1016/j.accpm.2021.100852. Epub 2021 Mar 26. PMID: 33781986.
  2. Daley JI, Dwyer KH, Grunwald Z, Shaw DL, Stone MB, Schick A, Vrablik M, Kennedy Hall M, Hall J, Liteplo AS, Haney RM, Hun N, Liu R, Moore CL. Increased Sensitivity of Focused Cardiac Ultrasound for Pulmonary Embolism in Emergency Department Patients With Abnormal Vital Signs. Acad Emerg Med. 2019 Nov;26(11):1211-1220. doi: 10.1111/acem.13774. Epub 2019 Sep 27. PMID: 31562679.
  3. Day J BA RDCS. Right Heart Evaluation | Point-of-Care Ultrasound Certification Academy [Internet]. Point-of-Care Ultrasound Certification Academy. 2023. Available from: https://www.pocus.org/right-heart-evaluation/
  4. Fields JM, Davis J, Girson L, Au A, Potts J, Morgan CJ, Vetter I, Riesenberg LA. Transthoracic Echocardiography for Diagnosing Pulmonary Embolism: A Systematic Review and Meta-Analysis. J Am Soc Echocardiogr. 2017 Jul;30(7):714-723.e4. doi: 10.1016/j.echo.2017.03.004. Epub 2017 May 9. PMID: 28495379.
  5. Rudski LG, Wyman WL, Afilalo J, Hua L, Handschumacher MD, Chandrasekaran K, Solomon SD, Schiller NB. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography. J Am Soc Echocardio. 2010;23(7):685-713.
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Case 68: Erector Spinae Plane Block for Rib Fracture Pain

Anthony Galvez, Tommy Ngo, Akash Desai

A 62yo male with a history of HIV and hypothyroidism presents to the ED with left-sided chest pain and shortness of breath after a near-syncopal episode followed by a fall 3 days prior. The patient was carrying groceries when he suddenly felt lightheaded and fell to the ground. He denies loss of consciousness or head trauma and reports having not eaten or drinking anything all day. Since the fall, he has had progressively worsening left-sided chest pain and spasming.

Vitals: BP 157/87, HR 70, RR 18, T 98.3F, SpO2 98%

Exam:

  • The patient appeared uncomfortable, splinting with respirations, and was wearing a self-applied weightlifting brace over the left chest wall.
  • Chest wall examination revealed focal tenderness to palpation over the left lateral and posterior ribs without overlying ecchymosis, crepitus, or step-off deformity. There was no flail segment appreciated. Auscultation revealed clear and equal breath sounds bilaterally.
  • Cardiac exam was regular without murmurs.
  • The abdomen was soft and non-tender.
  • Neurologic exam was grossly intact with no focal deficits.

ED Course:

  • Syncope workup showed no significant electrolyte derangements or anemia.
  • Chest x-ray was obtained to evaluate for trauma which showed acute displaced left posterior 4th-7th rib fractures. No pleural effusion or pneumothorax was seen.
  • After administration of ibuprofen, acetaminophen, and oxycodone, the patient’s pain was still reported as 8-9/10. The patient was offered and consented to an erector spinae plane block for multimodal pain control.
  • The block was performed at bedside using ultrasound guidance (Figures 1-2). Half an hour after the block was performed, the patient’s pain had reduced to 4/10. The patient reported increased range of motion and subsequently was able to walk himself to the bathroom.
  • The patient was subsequently cleared by trauma surgery for discharge home with multimodal pain control and follow up with PCP.
Figure 1: With transducer dot caudally, the needle is inserted and aimed at the transverse process. A faint echogenic line represents the needle terminating on the transverse process (TP).
Figure 2: With the needle pressed against the transverse process, the anesthetic is injected just below the erector spinae muscle. An arrow depicts the injectate, which should be seen spreading across the underside of the erector spinae (ES) muscle.

Discussion
Effective pain control in patients with rib fractures is critical to prevent complications such as atelectasis, pneumonia, and respiratory failure.1,2 Traditional management often relies on systemic opioids, which carry known risks including respiratory depression, cough suppression, and delirium.3 The erector spinae plane block (ESPB) is a regional anesthesia technique that provides effective analgesia for thoracic wall pain while reducing opioid requirements.4,5,6 In this case, ESPB resulted in a clinically meaningful reduction in pain and improved range of motion after failure of multimodal oral analgesia and facilitated safe discharge from the emergency department. The ESPB is well suited for the emergency room setting as it can easily be done at bedside using ultrasound guidance and is performed away from the pleura and other critical structures.5,6 Additionally, this technique is more technically straightforward in comparison to paravertebral or epidural blocks, which require greater technical expertise and carry higher risk.7,8 By targeting the fascial plane at the level of the transverse process, there is consistent blockade of the dorsal rami, with variable anterior spread to the ventral rami and intercostal nerves, allowing the ESPB to effectively provide broad unilateral analgesia across multiple rib levels4,5,9,10 (Figures 3-5).

Figure 3. Probe positions and corresponding ultrasound views at three lateral levels: spinous process (midline), transverse process (~3 cm lateral), and rib. The transverse process appears blunted and squared vs. the rounded rib shadow; pleura is visible deep to the rib but obscured behind the TP. (Source: Highland Ultrasound).
Figure 4. Posterior thoracic musculature with the right side partially reflected to expose the spine. The needle (center) is shown targeting the ESP at the level of the transverse process. Both superior and inferior approaches are demonstrated with the ultrasound transducer (blue) positioned in the parasagittal plane. Yellow nerves visible on the left demonstrate the multilevel coverage achieved by cephalocaudal LA spread. (Source: Regional Anesthesiology and Acute Pain Medicine).
Figure 5. Cross-section at T5 showing local anesthetic (dark blue) injected into the erector spinae plane (ESP), with anterior spread (light blue) toward the dorsal ramus (DR), ventral ramus (VR), and intercostal nerves (IC). Needle target is deep to the erector spinae (ES) and rhomboid (Rh), superficial to the transverse process (TP). (Source: Highland Ultrasound)

References:

  1. Hamilton DL, Manickam B. Erector spinae plane block for pain relief in rib fractures. Br J Anaesth. 2017;118(3):474-475. doi:10.1093/bja/aex013
  2. Luftig J, Mantuani D, Herring AA, Dixon B, Clattenburg E, Nagdev A. Successful emergency pain control for posterior rib fractures with ultrasound-guided erector spinae plane block. Am J Emerg Med. 2018;36(8):1391-1396. doi:10.1016/j.ajem.2017.12.060
  3. Peek J, Smeeing DPJ, Hietbrink F, Houwert RM, Marsman M, de Jong MB. Comparison of analgesic interventions for traumatic rib fractures: a systematic review and meta-analysis. Eur J Trauma Emerg Surg. 2019;45(4):597-622. doi:10.1007/s00068-019-01116-w
  4. Forero M, Adhikary SD, Lopez H, Tsui C, Chin KJ. The erector spinae plane block: a novel analgesic technique in thoracic neuropathic pain. Reg Anesth Pain Med. 2016;41(5):621-627. doi:10.1097/AAP.0000000000000451
  5. Kumar G, Kumar Bhoi S, Sinha TP, Paul S. Erector spinae plane block for multiple rib fracture done by an emergency physician: a case series. Australas J Ultrasound Med. 2021;24(3):167-172. doi:10.1002/ajum.12261
  6. Jiang M, Peri V, Ou Yang B, Chang J, Hacking D. Erector spinae plane block as an analgesic intervention in acute rib fractures: a scoping review. Local Reg Anesth. 2023;16:81-90. doi:10.2147/LRA.S414056
  7. Palachick BJ, Carver RA, Byars DV, Martyak MT, Collins JN. Erector spinae plane blocks for traumatic rib fractures performed by nonspecialized emergency physicians: a prospective, interventional study. Am Surg. 2022;88(9):2124-2126. doi:10.1177/00031348221078428
  8. Elawamy A, Morsy MR, Ahmed MAY. Comparison of thoracic erector spinae plane block with thoracic paravertebral block for pain management in patients with unilateral multiple fractured ribs. Pain Physician. 2022;25(6):483-490.
  9. Ivanusic J, Konishi Y, Barrington MJ. A cadaveric study investigating the mechanism of action of erector spinae blockade. Reg Anesth Pain Med. 2018;43(6):567-571. doi:10.1097/AAP.0000000000000789
  10. Chin KJ, El-Boghdadly K. Mechanisms of action of the erector spinae plane (ESP) block: a narrative review. Can J Anaesth. 2021;68(3):387-408. doi:10.1007/s12630-020-01875-2

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Case 67: D-sign in a Post-Cardiac Surgical Patient

Liz Temple, Colleen Campbell

A 51-year-old male patient with past medical history of mitral valve prolapse s/p complex mitral valve repair with left atrial appendage exclusion and repair of atrial septal defect complicated by perioperative pericarditis was directly admitted to the ICU following outpatient echocardiography findings of new right heart strain. Since his open heart surgery, he began to develop progressive dyspnea on exertion and orthopnea accompanied with dizziness and lightheadedness. His exertional capacity has decreased from 3 miles to 100 yards over one week. He otherwise denied fevers,

chills, abdominal pain, or dysuria. He completed an outpatient echo which showed evidence of new severe RV dysfunction which was new compared to his post-operative echo after his complex cardiac surgery which showed preserved RV function. CT PE was completed to rule out PE and did not show evidence of a clinically significant PE as the cause of his new onset RV dysfunction. Bedside cardiac ultrasound was also performed once the patient arrived to the floor.

Vitals: BP 128/75 | Pulse 86 | Temp 97.7 °F (36.5 °C) | Resp 17 | SpO2 98% | BMI 24.4 kg/m²

Physical Exam:

Gen: well appearing, NAD

HEENT: normocephalic, atraumatic, moist mucous membranes, sclera anicteric, EOMI

CV: WWP, RRR, radial pulses 2+, JVP ~9cm

Resp: no increased work of breathing, no accessory muscle use, speaks in full

sentences, breathing comfortably on RA, CTAB

Abd: soft, nontender, nondistended

Ext: no lower extremity edema

Neuro: moves all limbs spontaneously, no facial asymmetry, no dysarthria, EOMI

Labs: Troponin within normal limits

Figure 1. Cardiac POCUS with parasternal long axis showing dilated right ventricle (RV). No evidence of a significant pericardial effusion although there appears to be an echogenic focus on anterior RV free wall.
Figure 2: Parasternal short axis view from formal echocardiogram displaying the “D-sign” of right ventricular strain.
Figure 3: Apical 4-chamber view from formal echocardiogram demonstrating septal bowing into left ventricle most prominently during diastole.

Discussion

The “D-sign” on cardiac POCUS can help to identify right heart strain of varying etiologies, and is often considered a canonical sign for pulmonary embolism. This finding is most clearly visualized using a parasternal short axis view where the left ventricle appears as a D-shaped structure as a result of right ventricular overload which causes the interventricular septum to bow towards the left heart.1,2

While the D-sign has a high specificity (83%), it has a low sensitivity (53%) for pulmonary embolism. Moreover, there are a series of other underlying etiologies of right heart strain that may be associated with this ultrasound signature apart from pulmonary embolism.3

More specifically, right ventricular strain can be stratified by whether it is a result of pressure overload versus volume overload. In a patient with right ventricular pressure overload, elevated pressures on the right side are present both during systole and diastole, and therefore the left ventricular “D-shape” is present throughout the cardiac cycle. Pathologies that correlate with right ventricular pressure overload include pulmonary embolism, pulmonary hypertension, chronic right hear failure with hypertrophy, left-sided heart failure, and ARDS. Conversely, in patients with right ventricular volume overload, the sequelae of volume overload are most apparent during diastolic filling, so the D-sign is most obvious at end diastole while the left ventricle appears more normal and circular shaped during end-systole.4 Conditions that correlate with right ventricular volume overload may include severe tricuspid regurgitation, decompensated heart failure, and excessive volume resuscitation.1

A quantitative tool that is used to distinguish these forms of overload is the Eccentricity Index which utilizes the cross-sectional measurement of the left ventricular cavity in the parasternal short axis view. The index is a proportion between the measurement of length parallel to the septum (D2) and perpendicular to the septum (D1): EI = D2/D1. An EI>1 is suggestive of the D sign. In settings of pressure overload, the EI will be greater than 1 in systole and diastole. In settings of volume overload, the EI is less than 1 in systole and greater than 1 in diastole (Figure 4).5

Figure 4: Eccentricity index calculation to distinguish between right ventricular pressure and volume overload. Source: Pocus 101

In this particular case, it is clear that the interventricular septal bowing is variable throughout the cardiac cycle (Figure 1-3) and the D-sign is most evident at end diastole which would suggest a ‘volume overload’ subset of RV strain. Moreover, the EI follows a pattern consistent with right ventricular volume overload, although this was not measured during the formal echo. The etiology of this volume overload RV strain may have been partly attributed by volume overload as he had an elevated JVD and a plump IVC on formal echo. However, considering the context of his recent open-heart surgery with pericarditis and evidence of RV free wall mobility limitation (Figure 3), there was higher suspicion for external compression or inflammation as the cause of his rapid onset RV dysfunction. A subsequent CT scan suggested evidence of possible pericardial clot resulting in external RV compression. The patient was subsequently scheduled for left and right heart catheterization for further assessment of cardiac pressures as a result of this new onset RV strain on ultrasound before proceeding with further surgical intervention.

This case demonstrates the utility of bedside POCUS and clarity of the D sign as a marker for right ventricular dysfunction, presents the eccentricity index as a tool for distinguishing between pressure and volume overload, and the importance of maintaining a broad differential, beyond pulmonary embolism, for the D-sign on cardiac ultrasound. 

References:

  1. Dinh V. The D Sign - Right Heart Strain from Pressure vs Volume Overload. POCUS 101, https://www.pocus101.com/the-d-sign-right-heart-strain-from-pressure-vs-volume-overload/ (accessed October 17, 2025).
  2. Cativo Calderon EH, Mene-Afejuku TO, Valvani R, et al. D-shaped left ventricle, anatomic, and physiologic implications. Case Rep Cardiol 2017; 2017: 4309165.
  3. Fields JM, Davis J, Girson L, et al. Transthoracic echocardiography for diagnosing pulmonary embolism: A systematic review and meta-analysis. J Am Soc Echocardiogr 2017; 30: 714-723.e4.
  4. Tanaka H, Tei C, Nakao S, et al. Diastolic bulging of the interventricular septum toward the left ventricle. An echocardiographic manifestation of negative interventricular pressure gradient between left and right ventricles during diastole. Circulation 1980; 62: 558–563.
  5. Ryan T, Petrovic O, Dillon JC, et al. An echocardiographic index for separation of right ventricular volume and pressure overload. J Am Coll Cardiol 1985; 5: 918–927.

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Case 66: Rapid Diagnosis of Hemorrhagic Ovarian Cyst in a Reproductive-age Patient

Brigid Larkin, Colleen Campbell

A 20-year-old female with no significant past medical history presented to the emergency department with 5 days of focal right lower quadrant abdominal pain progressively worsening in severity. The pain was constant and non-radiating, accompanied by generalized abdominal discomfort, nausea, and intermittent light-headedness. Her last menstrual period occurred 3 weeks prior. She denied vaginal bleeding, dysuria, hematuria, constipation, diarrhea, or hematochezia. Past surgical history was unremarkable. Family history was notable for uterine fibroids in her mother and maternal grandmother.

Vital signs: BP 118/67 mmHg | Pulse 89 | Temp 99.1 Fº | Resp 16 | SpO2 100%

Physical exam:  The patient was well-appearing but uncomfortable. Her abdomen was soft with mild distention and diffuse tenderness, with voluntary guarding on deep palpation. No CVA tenderness was appreciated.

Labs: Hgb 11.3, WBC 18.7, Negative urine pregnancy test, lactate WNL, Urinalysis negative

Bedside Ultrasound:

  • RUQ/Biliary: no evidence of cholelithiasis or cholecystitis
  • Appendix: no evidence of appendicitis
  • Pelvic/Transvaginal: large adnexal cyst structure (~5cm) with internal echoes suggestive of a hemorrhagic cyst; free fluid visualized in the pelvis. No evidence of intrauterine pregnancy.
Figure 1. Ovary with Adnexal Mass

A CT scan was ordered which showed a hemorrhagic ovarian cyst with mild hemoperitoneum. OBGYN was consulted and recommended no acute surgical intervention. They recommended fluids and outpatient follow-up with repeat ultrasound of right ovarian cyst at 6 weeks.

Discussion:

Acute pelvic pain in reproductive-age women represents a broad differential diagnosis including appendicitis, ectopic pregnancy, ovarian torsion, pelvic inflammatory disease, and ruptured ovarian cyst. Point-of-care ultrasound (POCUS) serves as an essential early diagnostic tool because it is rapid, radiation free, and able to identify adnexal pathology and free intraperitoneal fluid even before CT imaging is obtained.

Hemorrhagic ovarian cysts are typically functional cysts resulting from bleeding into a corpus luteum or follicular cyst. Sonographically, they often demonstrate reticular internal echoes, a lacy or fibrin-strand appearance, or a mixed echogenicity depending on the age of the clot.1,2 Cyst rupture is more likely if the cyst is 5 cm or greater.  Color flow can be used to evaluate for active extravasation.  Symptoms accompanying rupture include sudden severe abdominal pain or near syncope.  Free fluid may be present in the pelvis, with swirling sometimes visible for brisk bleeds. Transvaginal POCUS is highly sensitive for detecting free intraperitoneal fluid of as little as 10cc, making it a valuable adjunct when evaluating patients with suspected hemoperitoneum.3

In this case, the adnexal mass with internal echoes and associated free fluid on POCUS raised concern for a hemorrhagic cyst with rupture, prompting timely gynecologic consultation and confirming findings on CT.

Hemorrhagic cysts frequently mimic appendicitis due to overlapping localization of pain and peritoneal irritation. Studies show that up to 20-30% of reproductive-age women evaluated for appendicitis ultimately have a gynecologic etiology, underscoring the importance of early pelvic imaging.4 The patient’s leukocytosis and focal RLQ tenderness initially broadened the differential, but POCUS rapidly narrowed the diagnosis.

Most hemorrhagic ovarian cysts are self-limited and managed conservatively with pain control and follow-up imaging.5 Indications for intervention include hemodynamic instability, large-volume hemoperitoneum, or concern for ovarian torsion. In this case, the patient remained stable, with moderate hemoperitoneum on CT and no evidence of torsion or persistent bleeding.  Oftentimes with cyst rupture, repeat CBC is indicated to evaluate for ongoing blood loss.

POCUS is a recommended first-line tool in the evaluation of acute pelvic pain in the emergency department. The American College of Emergency Physicians notes the utility of pelvic ultrasound for identifying adnexal masses, cyst rupture, free fluid, and excluding ectopic pregnancy in reproductive-age females.6  While transvaginal ultrasound is the standard of care for evaluation of the ovaries, transabdominal POCUS is highly effective in early triage and in resource-limited or time-sensitive settings.

This case demonstrates the significant diagnostic value of POCUS in identifying adnexal pathology early in the clinical course, guiding appropriate consultation, and avoiding unnecessary CT radiation. Recognition of characteristic sonographic features of hemorrhagic ovarian cysts empowers emergency physicians to differentiate benign from life-threatening causes of pelvic pain.

References:

  1. Jain, K. A. (2002). Sonographic spectrum of hemorrhagic ovarian cysts. Journal of Ultrasound in Medicine: Official Journal of the American Institute of Ultrasound in Medicine, 21(8), 879–886. https://doi.org/10.7863/jum.2002.21.8.879
  2. Talat, H., Tul-Sughra Murrium, S. K., Suleman, T., Tallat, E., Naveed, F., Hussain Shah, S. J., & Hina Zulfiqar, G. E. (2022). Sonographic Findings of a Gynecological Cause of Acute Pelvic Pain – A Systematic Review. Journal of Ultrasonography, 22(90), e183–e190. https://doi.org/10.15557/jou.2022.0030
  3. Kimura, A., & Otsuka, T. (1991). Emergency center ultrasonography in the evaluation of hemoperitoneum: A prospective study. The Journal of Trauma, 31(1), 20–23. https://doi.org/10.1097/00005373-199101000-00004
  4. Andersson, R. E. B. (2004). Meta-analysis of the clinical and laboratory diagnosis of appendicitis. The British Journal of Surgery, 91(1), 28–37. https://doi.org/10.1002/bjs.4464
  5. Bottomley, C., & Bourne, T. (2009). Diagnosis and management of ovarian cyst accidents. Best Practice & Research. Clinical Obstetrics & Gynaecology, 23(5), 711–724. https://doi.org/10.1016/j.bpobgyn.2009.02.001
  6. American College of Emergency Physicians. Emergency Ultrasound Guidelines. ACEP;2016. https://www.acep.org/siteassets/sites/acep/media/ultrasound/pointofcareultrasound-guidelines.pdf
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Case 65: Knee Pain

Colleen Sweeney, Akash Desai

A 55-year-old female with no pertinent past medical or surgical history was brought in by ambulance after a bicycle accident with left knee pain.  She was unhelmeted while riding a bicycle going 10mph when she collided into an e-bike. Her left knee was caught in her handlebars; she denied head trauma and had no LOC.  

Vitals: BP 168/120, HR 70, T 96.0F, RR 22, SpO2 95% on RA, BMI 24.41 

Physical Exam: 
General/Neuro: alert, in acute distress, diaphoretic 
HEENT: normocephalic, atraumatic, EOMI 
CV: normal rate 
Resp: tachypneic 
Abdomen: flat, soft, no tenderness 
MSK: RLE normal 
L knee: +swelling, +deformity. Skin intact, small ecchymosis to left lateral knee. Knee diffusely tender to palpation. Sensation intact to light touch throughout. Palpable popliteal, PT, and DP pulses. Able to wiggle toes. Compartments compressible. Patient unable to tolerate any movement of L knee secondary to pain. 
L lower leg: +swelling from knee distally, no lacerations 
L ankle/foot: normal pulse, sensation intact to light touch throughout 

Radiographs were indicated and initially attempted at bedside, however were unsuccessful as the patient was unable to tolerate the pain. Radiography was delayed until two hours due to pain management and census.  In the interim, a POCUS was performed

Figure 1. Transverse view of infrapatellar lipohemarthrosis. 
Figure 2. Longitudinal view of infrapatellar lipohemarthrosis.  
Figure 3. Longitudinal view of tibia with cortical break (arrow). 

Xray findings: "Acute, comminuted, displaced proximal tibial fracture extending to the lateral and central tibial plateau.  Acute, mildly displaced and impacted fibular neck fracture.  No fracture or malalignment of the left ankle. "

The patient was admitted to the trauma surgery service. The next day, she underwent a left knee spanning external fixator for stabilization of the tibial plateau fracture. One week later, she had an ORIF for long-term fixation of the fracture as well as a hamstring tendon repair. 

Discussion

POCUS is increasingly utilized in acute musculoskeletal trauma. The patient’s gross knee deformity after a traumatic event led to POCUS utilization to provide rapid clinical guidance.  In this patient, ultrasound was complete half an hour prior to the first attempt at radiographs and over 2 hours prior to their completion, thus proving useful in differentiating the severity of a patient’s injury during prolonged wait times and facilitating early orthopedic surgery consultation. 

Ultrasound, though not a primary diagnostic modality for acute fractures, offers sensitivity of 87% and specificity of 70% for proximal tibial fractures specifically in cadaveric models [3]. In Figure 3, the cortical break visible on the left side of the image corresponds to the proximal tibial fracture seen on X-ray. 

Figures 1 and 2 both demonstrate lipohemarthrosis. The presence of hemarthrosis, rather than a simple joint effusion, raises the suspicion for an intra-articular injury or fracture, with ultrasound demonstrating a sensitivity of 90% and specificity of 86% for this finding [2]. When lipohemarthrosis is identified—most clearly visualized in Figure 2 as hypoechoic fat “bubbles” originating from the bone marrow—it is even more indicative of an intra-articular fracture, carrying 97% sensitivity and 100% specificity for such fractures [4]. In its early stage, lipohemarthrosis appears as scattered fat globules, which later settle into the characteristic triple-layer pattern of fat, serum, and blood products [5]. Recognition of hemarthrosis or lipohemarthrosis on ultrasound may help risk-stratify patients for joint aspiration, potentially reducing unnecessary aspirations and associated infection risk. 

The presence of lipohemarthrosis is highly suggestive of a distal femur or proximal tibial fracture. Recognizing these findings early allows clinicians to maintain a high index of suspicion for periarticular fracture prior to radiographic confirmation, enabling prompt immobilization, consultation, and fracture management. This early identification facilitates more efficient triage and throughput in the ED and underscores POCUS as a worthwhile adjunct in knee trauma in addition to traditional imaging such as X-ray, CT, and MRI [6].  

References:  

  1. Stannard JP, Lopez R, Volgas D. Soft tissue injury of the knee after tibial plateau fractures. J Knee Surg. 2010;23(4):187-192. doi:10.1055/s-0030-1268694 
  2. Taljanovic MS, Chang EY, Ha AS, et al. ACR appropriateness criteria® acute trauma to the knee. Journal of the American College of Radiology. 2020;17(5). doi:10.1016/j.jacr.2020.01.041  
  3. Demers G, Migliore S, Bennett DR, et al. Ultrasound evaluation of cranial and long bone fractures in a cadaver model. Mil Med. 2012;177(7):836-839. doi:10.7205/milmed-d-11-00407 
  4. Bonnefoy, O., Diris, B., Moinard, M. et al. Acute knee trauma: role of ultrasound. Eur Radiol 16, 2542–2548 (2006). Doi:10.1007/s00330-006-0319-x 
  5. Levrini G, Reggiani G, Vacondio R, Zompatori M, Nicoli F. Post-traumatic knee lipohemarthrosis: Temporal evolution with progressive separation of the three layers of the joint effusion by ultrasonography and computed tomography. European Journal of Radiology Extra. 2006;60(1):37-41. doi:10.1016/j.ejrex.2006.06.011  
  6. De Maeseneer M, Marcelis S, Boulet C, et al. Ultrasound of the knee with emphasis on the detailed anatomy of anterior, medial, and lateral structures. Skeletal Radiol. 2014;43(8):1025-1039. doi:10.1007/s00256-014-1841-6 

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