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. Airway
Bones
Cardiac
Diaphragm
Effusion
Foreign body
Gastric
Hilum

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 diagnosis 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 And Low Prevalence Diseases: Acute Chest Syndrome
In Sickle 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 And Low Prevalence Diseases: Acute Chest Syndrome
In Sickle Cell Disease

28. 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 And Low Prevalence Diseases: Acute Chest Syndrome
In Sickle Cell Disease

29. 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 And Low Prevalence Diseases: Acute Chest Syndrome
In Sickle Cell Disease

30. • 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

31. • 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%
Infection1,2 33%
Pulmonary Infarction 33%
Pulmonary fat emboli 16%
1Pathogens identified using bronchoalveolar lavage
2Chlamydophilia, Mycoplasma pneumoniae & Respiratory Syncytial Virus the most common pathogens
New England Journal of Medicine 2000;342:1855-1865.
National Acute Chest Syndrome Study Group

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

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

34. Medicine 2016 95(7):1-8.
Bedside Lung Ultrasound During Acute Chest Syndrome
In 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.
1K 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.

35. American Journal of Emergency Medicine 2018;36(10):1855-1861.
Bedside Ultrasound As A Predictive Tool For
Acute Chest Syndrome In Sickle Cell Patients
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).

36. 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 And Low Prevalence Diseases: Acute Chest Syndrome
In Sickle Cell Disease

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

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

40. 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:
1. Optimal pain control
2. Empiric broad-spectrum antibiotics
3. Respiratory support
4. Transfusion based on symptom severity, oxygen saturations and hemoglobin

41. References
High Risk And Low Prevalence Diseases: Acute Chest Syndrome In Sickle 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 In Sickle Cell Disease. Medicine
2016;95(7):1-8.
Bedside Ultrasound As A Predictive Tool For Acute Chest Syndrome In Sickle Cell Patients.
American Journal of Emergency Medicine 2018;36(10):1855-1861.

42. See You Next Month!