Differentiating Pulmonary Edema, Pneumonia, Copd/Asthma, Bronchiolitis, Ards, Pulmonary Embolism



Differentiating Pulmonary Edema, Pneumonia, Copd/Asthma, Bronchiolitis, Ards, Pulmonary Embolism


Kevin M. Swiatek

Sammy Pedram





1. A 56-year-old man develops acute respiratory failure and is mechanically ventilated. Point-of-care ultrasound is used to evaluate the etiology of his respiratory failure. His anterior chest shows the pattern with lung ultrasound in Figure 56.1.






Which of the following most accurately describes this pattern?


A. A horizontal reverberation artifact that represents air-pleura interface


B. Horizontal artifacts that repeat the distance from the probe to the nearest blood vessels


C. A vertical reverberation artifact that represents fully inflated lung


D. Vertical artifacts indicating an underlying interstitial syndrome

View Answer

1. Correct Answer: A. A horizontal reverberation artifact that represents air-pleura interface

Rationale: A-lines are horizontal reverberation artifacts that represent a strong reflection from the air-pleura interface. The presence of A-lines is not itself pathologic. The distance between A-lines is equal to the distance from the probe to the air-pleura interface.

Selected References

1. Doerschug KC, Schmidt GA. Intensive care ultrasound: III. Lung and pleural ultrasound for the intensivist. Ann Am Thorac Soc. 2013;10(6):708-712. doi:10.1513/annalsats.201308-288ot.

2. Lichtenstein DA. BLUE-protocol and FALLS-protocol. Chest. 2015;147(6):1659-1670. doi:10.1378/chest.14-1313.



2. Based on the case presented in Question 1 and Figure 56.1, which of the following is most true regarding this pattern of lung ultrasound findings?


A. This pattern is commonly seen in patients with edematous interlobular septae.


B. This pattern is commonly seen in patients with dry interlobular septae.


C. This pattern excludes pneumothorax at this location.


D. This pattern suggests an interstitial syndrome as the cause of respiratory failure.

View Answer

2. Correct Answer: B. This pattern is commonly seen in patients with dry interlobular septae

Rationale: An A-line predominant pattern, as shown in Figure 56.1, indicates that the interlobular septae are characteristically dry. The A-line reverberation artifact is an apparent “second” pleural reflection, deep to the pleura, twice the distance of the original pleural reflection. It represents a strong reflection from the aeration just below the pleural line, which is consistent with aerated lung, but can also be present with pneumothorax. The presence of B-lines would suggest an interstitial syndrome or edematous interlobular septae (pulmonary edema), which are not seen here. Additionally, in an ICU population of mechanically ventilated patients, an A-line pattern has a 93% specificity, 50% sensitivity, and 97% positive predictive value for a pulmonary artery occlusion pressure (PAOP) ≤18 mm Hg. However, in a later study, lung ultrasound was shown to be of limited usefulness for predicting PAOP.

Selected References

1. Lichtenstein DA. BLUE-protocol and FALLS-protocol. Chest. 2015;147(6):1659-1670. doi:10.1378/chest.14-1313.

2. Lichtenstein DA, Mezière GA, Lagoueyte J-F, Biderman P, Goldstein I, Gepner A. A-lines and B-lines: lung ultrasound as a bedside tool for predicting pulmonary artery occlusion pressure in the critically ill. Chest. 2009;136(4):1014-1020, ISSN 0012-3692, doi:10.1378/chest.09-0001.

3. Volpicelli G, Skurzak S, Boero E, et al. Lung ultrasound predicts well extravascular lung water but is of limited usefulness in the prediction of wedge pressure. Anesthesiology. 2014;121(2):320-327.




3. Based on the case presented in Question 1 and Figure 56.1, which of the following techniques can help better visualize this pattern on lung ultrasound?


A. Low gain, probe at an oblique axis to the surface of the skin


B. Low gain, probe at a perpendicular axis to the surface of the skin


C. High gain, probe at an oblique axis to the surface of the skin


D. High gain, probe at a perpendicular axis to the surface of the skin

View Answer

3. Correct Answer: B. Low gain, probe at a perpendicular axis to the surface of the skin

Rationale: A-lines and lung sliding are best visualized with the linear or phased array transducers, but the phased array probe may be needed to achieve the depth adequate to visualize A-lines. The linear transducer allows for high-frequency detailed visualization of the pleural line. Proper positioning of the probe perpendicular to the skin with a low gain setting will optimize these artifacts.

Selected Reference

1. Doerschug KC, Schmidt GA. Intensive care ultrasound: III. Lung and pleural ultrasound for the intensivist. Ann Am Thorac Soc. 2013;10(6):708-712. doi:10.1513/annalsats.201308-288ot.



4. A 76-year-old man with a history of coronary artery disease presents complaining of shortness of breath and wheezing. He notes a 7 lb weight gain over the past 2 weeks. He has orthopnea and dyspnea on exertion, as well as lower extremity edema. Chest ultrasound is used to evaluate his complaint and reveals Figure 56.2 and image Video 56.1.






Which of the following best describes the characteristics seen in Figure 56.2 and image Video 56.1?


A. Profuse B-lines are present and consistent with an interstitial syndrome.


B. An A-line predominant pattern is present and consistent with pneumonia.


C. Few B-lines are present, consistent with dry interlobular septa.


D. A C-profile pattern is seen, consistent with heart failure.

View Answer

4. Correct Answer: A. Profuse B-lines are present and consistent with an interstitial syndrome.

Rationale: B-lines are vertical reverberation artifacts commonly seen in patients with interstitial syndromes. In this case, the patient appears to have signs and symptoms consistent with heart failure. On ultrasound, an occasional B-line may be a normal finding between rib spaces, but this patients has many B-lines (more than three) in a single image, which is abnormal. A thin pleural line and profuse B-lines in a symmetric distribution are highly suggestive of an interstitial syndrome (e.g., pulmonary edema). Evidence also suggests that if many B-lines are detected in a bilateral, symmetric distribution in all lung zones, this is associated with increased left ventricular filling pressure.

Selected References

1. Hubert A, Girerd N, Breton HL, et al. Diagnostic accuracy of lung ultrasound for identification of elevated left ventricular filling pressure. Arch Cardiovasc Dis. 2019;11(1):53. doi:10.1016/j.acvdsp.2018.10.115.

2. Lichtenstein DA. BLUE-protocol and FALLS-protocol. Chest. 2015;147(6):1659-1670. doi:10.1378/chest.14-1313.

3. Muniz RT, Mesquita ET, Souza Junior CV, Martins WA. Pulmonary ultrasound in patients with heart failure—systematic review. Arq Bras Cardiol. 2018;110(6):577-584. doi:10.5935/abc.20180097.



5. Based on the case presented in Question 4, Figure 56.2, and image Video 56.1, which of the following are mandatory characteristics of this finding?

I. Comet-tail artifact

II. Makes A-lines more prominent

III. Arises from the pleural line

IV. Moves in concert with lung sliding


A. I, II, and III


B. I, II, and IV


C. II, III, and IV


D. I, III, and IV

View Answer

5. Correct Answer: D. I, III, and IV

Rationale: Lichtenstein describes three mandatory criteria used to identify B-lines: a comet-tail (reverberation) artifact, arising from the pleural line, which moves in concert with lung sliding when present. Four other criteria are often seen with B-lines: extend from pleural line to the distal edge of the image, well-defined, erases A-lines, hyperechoic. These criteria help to distinguish B-lines from other comet-tail artifacts.

Selected References

1. Lichtenstein D. Novel approaches to ultrasonography of the lung and pleural space: where are we now? Breathe. 2017;13(2):100-111. doi:10.1183/20734735.004717.

2. Miller A. Practical approach to lung ultrasound. BJA Educ. 2016;16(2):39-45. doi:10.1093/bjaceaccp/mkv012.



6. On auscultation, the patient from Question 4 is found to have a blowing systolic murmur and bilateral rales. Point-of-care cardiac ultrasound demonstrates the finding seen in image Video 56.2. Putting all of these findings together, which of the following is the most likely diagnosis?


A. Pneumonia


B. Pulmonary embolism


C. Heart failure exacerbation


D. Pneumothorax

View Answer

6. Correct Answer: C. Heart failure exacerbation

Rationale: Pulmonary edema can develop rapidly in patients with mitral regurgitation from a myocardial infarction or acute heart failure. In this instance, B-lines help to confirm the diagnosis of pulmonary edema as the cause for impending respiratory failure. A systematic review and meta-analysis of ED patients with acute heart failure suggests that point-of-care lung ultrasound can be used accurately and reliably as an adjunct to other diagnostic modalities.

Selected References

1. Lichtenstein DA. BLUE-protocol and FALLS-protocol. Chest. 2015;147(6):1659-1670. doi:10.1378/chest.14-1313.

2. Mcgivery K, Atkinson P, Lewis D, et al. Emergency department ultrasound for the detection of B-lines in the early diagnosis of acute decompensated heart failure: a systematic review and meta-analysis. CJEM. 2018;20(3):343-352. doi:10.1017/cem.2018.27.




7. A 74-year-old man presents to the Emergency Department (ED) with a 1-day history of shortness of breath and cough productive of purulent sputum. His temperature is 38.5°C, BP 115/60 mm Hg, HR 110 bpm, RR 20/min, and SpO2 90% on room air. His chest is examined with lung ultrasound, which reveals Figure 56.3.






Which of the following patterns is most consistent with the ultrasound findings?


A. Diffuse B-lines


B. A-lines


C. A/B pattern


D. Consolidation

View Answer

7. Correct Answer: C. A/B Pattern

Rationale: In this scenario, the patient presents with the clinical syndrome of pneumonia associated with focal B-lines on lung ultrasound. Figure 56.3A demonstrates B-lines and the pleura appears somewhat irregular, which is consistent with an inflammatory interstitial syndrome. In contrast, Figure 56.3B demonstrates normal pleura with an A-line pattern. An A/B pattern describes an A-profile (normal appearance) in one hemithorax and a B-profile (B-lines) in the other. This suggests a heterogeneous distribution of the inflammatory process, as may be seen with pneumonia, in contrast to a diffuse pattern, which would be expected with cardiogenic pulmonary edema.

Selected References

1. Bhatt H, Patel C, Parikh S, Jhaveri B, Puranik J. Bedside lung ultrasound in emergency protocol as a diagnostic tool in patients of acute respiratory distress presenting to emergency department. J Emerg Trauma Shock. 2018;11(2):125. doi:10.4103/jets.jets_21_17.

2. Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure*: the BLUE protocol. Chest. 2008;134(1):117-125. doi:10.1378/chest.07-2800.



8. Additional images of the right hemithorax are obtained of the patient in the case presented in Question 7. Which of the following signs is seen in Figure 56.4?







A. Shred sign


B. Sinusoid sign


C. Stratosphere sign


D. Bat sign

View Answer

8. Correct Answer: A. Shred sign

Rationale: Figure 56.4 demonstrates a shred sign. The shred sign artifact is seen when there is subpleural consolidation of lung tissue, in which a portion of consolidated lung is visualized adjacent to the reflection from a deeper, aerated portion of lung. The irregular interface between the consolidated and aerated lung tissues gives a “shredded” appearance. The shred sign is nonspecific, but can help to define lung pathology in a clinical context. For example, in the case presented in Questions 7 and 8, this likely represents ultrasound evidence of pneumonia. It should be noted that the shred sign can also be seen with pulmonary infarct, subpleural lung abscess, and lung cancer.

Selected References

1. Biswas A, Lascano JE, Mehta HJ, Faruqi I. The utility of the “shred sign” in the diagnosis of acute respiratory distress syndrome resulting from multifocal pneumonia. Am J Respir Crit Care Med, 2017;195(2). doi:10.1164/rccm.201608-1671im.

2. Mojoli F, Bouhemad B, Mongodi S, Lichtenstein D. Lung ultrasound for critically ill patients. Am J Respir Crit Care Med. 2019;199(6):701-714. doi:10.1164/rccm.201802-0236ci.

3. Rinaldi L, Milione S, Fascione MC, et al. Relevance of lung ultrasound in the diagnostic algorithm of respiratory diseases in a real-life setting: a multicentre prospective study. Respirology. 2019. doi:10.1111/resp.13659.




9. The patient’s symptoms (Questions 7 and 8) and ultrasound findings (Figures 56.3 and 56.4) are most consistent with which clinical diagnosis?


A. Community-acquired pneumonia


B. Acute respiratory distress syndrome (ARDS)


C. Congestive heart failure exacerbation


D. Chronic obstructive pulmonary disease (COPD) exacerbation

View Answer

9. Correct Answer: A. Community-acquired pneumonia

Rationale/Critique: The case presented in Questions 7, 8, and 9 and chest ultrasound findings (Figures 56.3 and 56.4) suggest a focal inflammatory or infectious process, such as community-acquired pneumonia. ARDS would demonstrate a patchy pattern of B-lines with hypoxia, which would be bilateral. Hydrostatic pulmonary edema from a heart failure exacerbation would show a thickened pleural line with many B-lines bilaterally. Chest ultrasound examination of those with COPD and asthma can be normal (A-line pattern) and would also be expected to appear symmetric.

Selected Reference

1. Lichtenstein DA. BLUE-protocol and FALLS-protocol. Chest. 2015;147(6):1659-1670. doi:10.1378/chest.14-1313.



10. A patient is mechanically ventilated for acute respiratory failure. Lung ultrasound is performed as shown in Figure 56.5 and image Videos 56.3A and B. Lung sliding is present, but reduced in a scattered distribution.






What is the most likely diagnosis?


A. Acute respiratory distress syndrome


B. Pulmonary edema


C. Pulmonary embolism with infarct


D. Asthma exacerbation

View Answer

10. Correct Answer: A. Acute respiratory distress syndrome

Rationale: Figure 56.5 and image Videos 56.3A and B demonstrate a bilateral heterogeneous distribution of B-lines. In the figure, the left upper lobe is spared. The left lower lobe, right upper lobe, and right lower lobe with B-lines are shown. The right posterolateral aspect has a pleural effusion and left appears normal. This distribution is consistent with ARDS. Pulmonary edema is a profuse pattern of B-lines with intact lung sliding. Pulmonary embolism with infarct would demonstrate A-line pattern, with or without shred sign, and pleural effusion. Asthma exacerbation would also demonstrate an A-line predominant pattern.

Selected References

1. Copetti R, Soldati G, Copetti P. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovasc Ultrasound. 2008;6(1). doi:10.1186/1476-7120-6-16.

2. Doerschug KC, Schmidt GA. Intensive care ultrasound: III. Lung and pleural ultrasound for the intensivist. Ann Am Thorac Soc. 2013;10(6):708-712. doi:10.1513/annalsats.201308-288ot.



11. Over the next 6 hours, the patient from Question 10 develops hemodynamic decline. The physician performs reassessment with lung ultrasound and notes the same findings as before. Which of the following is most true regarding this patient’s lung ultrasound findings?


A. The presence of B-lines rules out pneumothorax.


B. An A-line predominant pattern is consistent with ARDS.


C. The number of B-lines does not predict mortality in ARDS.


D. The patient should receive diuretics for pulmonary edema.

View Answer

11. Correct Answer: A. The presence of B-lines rules out pneumothorax.

Rationale: ARDS is a heterogeneous disease process that can produce a B-line predominant pattern in a heterogeneous distribution. With high-pressure ventilation, pneumothorax can develop. However, the presence of B-lines rules out pneumothorax with 100% sensitivity and 100% negative predictive value, because two opposing layers of pleura must be present to create this artifact. In addition, the number of B-lines may have a prognostic impact on ARDS mortality and the likelihood of successfully weaning from a ventilator. The asymmetric heterogeneous B-line pattern argues against cardiogenic pulmonary edema.

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Jun 9, 2022 | Posted by in CARDIOLOGY | Comments Off on Differentiating Pulmonary Edema, Pneumonia, Copd/Asthma, Bronchiolitis, Ards, Pulmonary Embolism
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