Acute Chest Syndrome - EMGuidewire's Radiology Reading Room

The Department of Emergency Medicine at Carolinas Medical Center is passionate about education! Dr. Michael Gibbs is a world-renowned clinician and educator and has helped guide numerous young clinicians on the long path of Mastery of Emergency Medical Care. With his oversight, the EMGuideWire team aim to help augment our understanding of emergent imaging. You can follow along with the EMGuideWire.com team as they post these educational, self-guided radiology slides or you can also use this section to learn more in-depth about specific conditions and diseases. This Radiology Reading Room pertains to Acute Chest Syndrome and is brought to you by Angela Pikus, MD, Mark Baumgarten, MD, Andres Gil Bustamante, and Ahmed Mashal, MD. As always, Michael Gibbs, MD serves as the projects editor.

1. Acute Chest Syndrome Angela Pikus , MD, Mark Baumgarten, MD, Andres Gil Bustamante, MD, Ahmed Mashal, MD Department of Emergency Medicine Carolinas Medical Center & Levine Children’s Hospital Charlotte, North Carolina Michael Gibbs, MD, Faculty Editor CMC Imaging Mastery Project

2. Disclosures This presentation of the CMC Imaging Mastery Project series is proudly sponsored by the Emergency Medicine Residency Programs at Carolinas Medical Center. The goal is to promote widespread mastery of imaging interpretation. There is no personal health information within, and all ages have been changed to protect patient confidentiality.

3. Process Colleagues across CMC share their interesting clinical cases with us. Numerous resident author teams organize cases and add clinically relevant, up-to-date literature. Faculty editors provide peer-review of content for accuracy and impact.

4. Visit our website www.EMGuidewire.com for a complete archive of chest x-ray presentations and much more!

5. A irway B ones C ardiac D iaphragm E ffusion F oreign body G astric H ilum

6. It’s All About The Anatomy!

7. Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 1 Afebrile and vital signs are normal.

8. Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 1 Afebrile and vital signs are normal. Read As “Normal”

9. What Is Your Interpretation? Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 3 Now febrile, dyspneic, tachypneic and tachycardic.

10. Multifocal Infiltrates Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 3 Now febrile, dyspneic, tachypneic and tachycardic.

11. Acute Chest Syndrome Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 3 Now febrile, dyspneic, tachypneic and tachycardic.

12. Acute Chest Syndrome Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 3 Now febrile, dyspneic, tachypneic and tachycardic.

13. Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 5 The patient improved clinically after exchange transfusion. Acute Chest Syndrome

14. Case #1 25-year-old with a history of sickle cell disease presents with severe bilateral leg and lower back pain. Hospital Day 5 The patient improved clinically after exchange transfusion. Side Note: Recall that the patient’s initial chest X-ray appeared normal . This is the case for ≈50% of hospitalized patients who go on to develop ACS. Acute Chest Syndrome

15. Case #2 23-year-old with a history of sickle cell disease referred from urgent care with chest tightness, chest pain, and feeling flushed. Vitals: T 101.5, HR 135, BP 119/84, SPO2 98% room air, RR 25. What Is Your Interpretation?

16. Case #2 23-year-old with a history of sickle cell disease referred from urgent care with chest tightness, chest pain, and feeling flushed. Vitals: T 101.5, HR 135, BP 119/84, SPO2 98% room air, RR 25. Read As “Normal”

17. Case #2 23-year-old with a history of sickle cell disease referred from urgent care with chest tightness, chest pain, and feeling flushed. Vitals: T 101.5, HR 135, BP 119/84, SPO2 98% room air, RR 25. Labs: WBC 41,000, Hgb 7.9 (12.2 4 Days Ago), T. Bilirubin 6.7

18. Case #2 23-year-old with a history of sickle cell disease referred from urgent care with chest tightness, chest pain, and feeling flushed. Vitals: T 101.5, HR 135, BP 119/84, SPO2 98% room air, RR 25. A Chest CT Was Obtained 6 Hours Later

19. Case #2 23-year-old with a history of sickle cell disease referred from urgent care with chest tightness, chest pain, and feeling flushed. Vitals: T 101.5, HR 135, BP 119/84, SPO2 98% room air, RR 25. Acute Chest Syndrome With Multifocal Infiltrates

20. Case #3 31-year-old with a history of sickle cell disease presents with back pain, fever, cough.

21. Case #3 31-year-old with a history of sickle cell disease presents with back pain, fever, cough. What Is Your Interpretation?

22. Case #3 31-year-old with a history of sickle cell disease presents with back pain, fever, cough. Bibasilar Patchy Infiltrates

23. On Presentation 7 Days Prior 1 Year Prior

24. Acute Chest Syndrome With Severe Multifocal Infiltrates Case #3 31-year-old with a history of sickle cell disease presents with back pain, fever, cough.

25. Definition A d iagnosis of acute chest syndrome is made in a patient with a new segmental radiodensity on chest imaging and one of the following: Fever Hypoxemia Tachypnea Cough, chest pain, wheezing American Journal of Emergency Medicine 2022;58:235-244. High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease

26. Pathophysiology Three mechanisms are proposed: Infection Pulmonary intravascular sickling and infarction Embolization of marrow fat American Journal of Emergency Medicine 2022;58:235-244. High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease

27. Epidemiology Vaso-occlusive pain crisis is the leading cause of hospitalization in patients with SCD with 10–20% of these patients developing ACS. Up to 80% with patients who develop ACS experience a vaso -occlusive pain crisis prior to the event. Overall, ACS accounts for approximately 25% of deaths in patients with SCD and is associated with a mortality rate of up to 9% per episode of in adults. American Journal of Emergency Medicine 2022;58:235-244. High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease

28. Triggers Painful vaso -occlusive crises are the most common inciting event of ACS with ACS most commonly occurring 1–3 day after the onset of pain. Infection is estimated to account for up to 25% of ACS cases, with bacterial pneumonia being the primary infectious cause. Alongside infection, asthma is a common trigger for ACS in children, and a history of asthma increases the incidence of ACS. American Journal of Emergency Medicine 2022;58:235-244. High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease

29. 538 patients from 20 centers - the largest published case series Results provide insights into the clinical presentations and outcomes of hospitalized patients with ACS 49% of patients initially presented in pain crisis without clinical or radiographic signs of acute chest syndrome. New England Journal of Medicine 2000;342:1855-1865. National Acute Chest Syndrome Study Group

30. Manifestations: worsening hypoxia, decreased hemoglobin levels, and progressive, multi-lobar pulmonary infiltrates The mean hospital length of stay was 10.5 days [vs. 3 days w/o ACS] 30% required mechanical ventilation and overall mortality was 3% Infection 1,2 33% Pulmonary Infarction 33% Pulmonary fat emboli 16% 1 Pathogens identified using bronchoalveolar lavage 2 Chlamydophilia, Mycoplasma pneumoniae & Respiratory Syncytial Virus the most common pathogens New England Journal of Medicine 2000;342:1855-1865. National Acute Chest Syndrome Study Group

31. American Journal of Emergency Medicine 2022;58:235-244.

32. American Journal of Emergency Medicine 2022;58:235-244.

33. Medicine 2016 95(7):1-8. Bedside Lung Ultrasound During Acute Chest Syndrome I n Sickle Cell Disease Objective To assessed the performance of bedside chest radiograph (CR) and lung ultrasound (LU) during severe acute chest syndrome (ACS), using computed tomography (CT) as the reference standard. Methods Prospective evaluation of 44 ACS episodes admitted to the medical ICU. Three imaging findings were evaluated (consolidation, ground-glass opacities, and pleural effusion). Results Consolidation was the most common pattern and prevailed in the lung bases. The agreement with CT scan patterns was significantly higher for LU than for CR. 1 LU outperformed CR for the diagnosis of consolidations and pleural effusion during ACS. 1 K coefficients of 0.45 vs 0.30 , P < 0.01 for the parenchyma, and 0.73 vs 0.06, P < 0.001 for pleural effusion.

34. American Journal of Emergency Medicine 2018;36(10):1855-1861. Bedside Ultrasound A s A P redictive T ool For A cute C hest S yndrome I n S ickle C ell P atients Objective To investigate the use of bedside lung ultrasound (BLU) in identification of early pulmonary findings associated with ACS in SCD patients. Methods Prospective, observational study of a convenience sample of SCD patients (n=28) presenting to the Emergency Department for a pain crisis. BLU interpretations were made by an emergency physician blinded to the diagnosis of ACS (n=6), and were validated by a second reviewer. Results Five patients in the ACS group had lung consolidations on BLU (83%) compared to 3 patients in the non-ACS group (21%), p = 0.0181, (OR = 12.05, 95% CI 1.24 to 116.73). The ACS group was also more likely to have a pleural effusion and B-lines on BLU than the non-ACS group, p = 0.0175; 0.1657, respectively. BLU identified lung abnormalities sooner than CXR (median 3.6 vs. 31.8 hour).

35. ED Treatment Essentials : Optimal pain control Empiric broad-spectrum antibiotics Respiratory support– supplemental oxygen, bronchodilators, spirometry A transfusion strategy based on goals and severity American Journal of Emergency Medicine 2022;58:235-244. High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease

36. American Journal of Emergency Medicine 2022;58:235-244.

37. American Journal of Emergency Medicine 2022;58:235-244.

38. Key Points ACS is defined as a new pulmonary infiltrate plus: fever and/or respiratory symptoms, ACS is the leading cause of death in patients with sickle cell disease, Proposed causes include infection, intravascular sickling/infarction and fat embolism, Up to 50% of patients who develop ACS during a hospitalization will first present to the Emergency Department in a pain crisis without other symptoms, Admission chest X-rays in patient who go on to develop ACS are often normal; when finding are seen bibasilar infiltrates predominate Bilateral lung ultrasound may be a useful bedside adjunct in the early diagnosis of ACS and chest CT provides definitive imaging, Once the diagnosis of ACS is made, the cornerstones of ED treatment include: Optimal pain control Empiric broad-spectrum antibiotics Respiratory support Transfusion based on symptom severity, oxygen saturations and hemoglobin

39. References High Risk A nd L ow P revalence D iseases: Acute Chest S yndrome I n S ickle Cell Disease. American Journal of Emergency Medicine 2022;58:235-244. Causes And Outcomes Of The Acute Chest Syndrome In Sickle Cell Disease. New England Journal of Medicine 2000;342:1855-1865. Pulmonary Complications of Sickle Cell Disease. New England Journal of Medicine 2008;359:2254-65. Bedside Lung Ultrasound During Acute Chest Syndrome I n Sickle Cell Disease. Medicine 2016;95(7):1-8. Bedside Ultrasound A s A P redictive T ool For A cute C hest S yndrome I n S ickle C ell P atients. American Journal of Emergency Medicine 2018;36(10):1855-1861.

40. See You Next Month!