Skip to content Skip to sidebar Skip to footer
Home / How to Know You Have a Chest Infection

How to Know You Have a Chest Infection

Post a Comment
  1. Education
  2. The role of chest...
  3. The role of breast radiography in confirming covid-nineteen pneumonia

Exercise Practise Pointer

The role of chest radiography in confirming covid-nineteen pneumonia

BMJ 2020; 370 doi: https://doi.org/10.1136/bmj.m2426 (Published 16 July 2020) Cite this as: BMJ 2020;370:m2426

Read our latest coverage of the coronavirus pandemic

Loading

  1. Joanne Cleverley , consultant radiologist1,
  2. James Piper , senior clinical teaching fellow (acute medicine)two 3,
  3. Melvyn M Jones , general practitioner and clinical associate professoriv 5
  1. iDepartment of Radiology, Royal Free Infirmary NHS Trust, London, Uk
  2. 2Royal Free Infirmary NHS Trust, London, UK
  3. 3UCL Medical School, Royal Complimentary Campus, London, United kingdom
  4. 4Research Department of Primary Intendance & Population Health, UCL, Royal Gratuitous Campus, London, UK
  5. vInstitute of Biomedical Instruction, St George's University of London, London, UK
  1. Correspondence to M Jones melvyn.jones{at}ucl.air conditioning.britain

What you need to know

  • A normal breast radiograph does not exclude covid-xix pneumonia

  • No single feature of covid-19 pneumonia on a chest radiograph is specific or diagnostic, but a combination of multifocal peripheral lung changes of ground glass opacity and/or consolidation, which are most normally bilateral, may exist nowadays

  • Diagnosis might be complicated as covid-19 pneumonia may or may not be visible on breast radiograph; consider other causes for patients' respiratory symptoms

Covid-19 is likely to remain an important differential diagnosis for the foreseeable future in anyone presenting to hospital with a flu-like disease, lymphopenia on full blood count, and/or a change in normal sense of smell (anosmia) or taste.12

Most people with covid-19 infection do not develop pneumonia3; however, chest radiography of people who are seriously sick with respiratory symptoms when they present to hospital tin aid to identify those with covid-19 pneumonia.

In this article we offer advice to non-radiologists on how to expect for changes on breast radiograph that may be suggestive of covid-xix pneumonia, as prompt review and report from an onsite or remote radiologist is not ever available.

The recommendations in this article are based on a combination of emerging evidence, current guidelines, and our clinical feel.

For the radiograph examples used in this article, we cannot confirm whether each patient tested positive for covid-nineteen considering nosotros did non have admission or ethical approval to access these patients' clinical records; yet, they were all diagnosed with covid-19 pneumonia as they had supportive radiographical features during the covid-xix pandemic.

What is covid-xix pneumonia?

No fixed definition of covid-nineteen pneumonia exists; in this article the term is used when describing patients with clinical features of covid-xix infection who have either clinical or radiological prove of pneumonia,45 or astute respiratory distress.1

Like other pneumonias, covid-19 pneumonia causes the density of the lungs to increase. This may exist seen as whiteness in the lungs on radiography which, depending on the severity of the pneumonia, obscures the lung markings that are normally seen; notwithstanding, this may be delayed in appearing or absent.

• When lung markings are partially obscured past the increased whiteness, a footing glass pattern (ground glass opacity, fig 1) occurs. This tin be subtle and might demand confirmation with a radiologist.

Fig 1

Fig 1

Ground glass opacity. Posterior-anterior breast radiograph of patient A, a man in his 50s with covid-nineteen pneumonia. Features include ground glass opacity in both mid and lower zones of the lungs, which is predominantly peripheral (white arrows) with preservation of lung mark. Linear opacity can be seen in the periphery of the left mid zone (black arrow)

  • Download figure
  • Open in new tab
  • Download powerpoint

• Peripheral, coarse, horizontal white lines, bands, or reticular changes which tin be described, as linear opacities may besides be seen in association with ground glass opacity (fig 1).

• When lung markings are completely lost due to the whiteness, it is known as consolidation (this is usually seen in severe illness) (fig two, 3c).6 A small case series in Korea found that, in polymerase chain reaction (PCR) confirmed covid-19 infection, in those with radiological abnormalities, lxx% of the radiographical opacities (number of lesions, not patients) were consolidation.seven

Fig 2

Fig two

Consolidation. Inductive-posterior (AP) chest radiograph of patient B, a man in his 50s, with severe covid-nineteen pneumonia, showing bilateral dense peripheral consolidation and loss of lung markings in the mid and lower zones (outlined arrows)

  • Download effigy
  • Open in new tab
  • Download powerpoint

Fig 3

Fig three

Serial radiological progression seen with covid-19 pneumonia. (a) Normal posterior-inductive chest radiograph of patient C, a human in his 50s (taken up to 12 months before access, included here for comparison). (b) AP chest radiograph of patient C when he adult covid-19 pneumonia—taken in the emergency department (twenty-four hour period 0 of access), showing ground glass opacities in the periphery (outer third of the lung) of both lungs in the mid and lower zones (white arrows), preservation of lung marking, and linear opacity in the periphery of the left mid zone (blackness pointer). (c) AP chest radiograph of patient C on day 10 of admission, showing progression to severe covid-19 pneumonia: patient intubated with endotracheal tube, cardinal lines, and nasogastric tube in situ. Dense consolidation with loss of lung markings is at present seen behind the heart in the left lower zone (outlined arrow). Extension of the peripheral footing glass changes seen in (b) tin can be seen in the periphery of the right mid and lower zones and the left mid zone (white arrows)

  • Download figure
  • Open in new tab
  • Download powerpoint

Covid-19 pneumonia tin be classed every bit an atypical pneumonia because of the radiographic appearances of multifocal basis glass opacity, linear opacities, and consolidation. These changes are as well seen in other singular pneumonias, including other coronavirus infections (severe acute respiratory arrangement, SARS, and Middle East respiratory syndrome, MERS).eight

What do you look for on chest radiography?

Review the radiograph systematically, looking for abnormalities of the eye, mediastinum, lungs, diaphragm, and ribs,9 and remembering that radiographic changes of covid-xix pneumonia tin be subtle or absent.

Compare with previous chest radiographs when bachelor.

Look for evidence of ground drinking glass opacity, peripheral linear opacities, or consolidation in the lung.

Which parts of the lungs are unremarkably affected?

A quantitative meta-analysis roofing 2847 patients in Cathay and Australia, and a multinational descriptive analysis of 39 case written report articles summarising 127 patients, found that covid-nineteen pneumonia changes are by and large bilateral on chest radiographs (72.9%, 95% conviction interval 58.6 to 87.1) and accept footing drinking glass opacity in 68.v% of cases (95% CI 51.8 to 85.2) (fig i, fig 3b); all the same, these information are pooled and then information technology is non possible to link the radiographic findings to the duration of disease or severity.10

A retrospective example series of 64 patients hospitalised with covid-nineteen infection in Hong Kong found that chest radiograph changes are oft peripheral (41%) and lower zone (50%) in distribution11; these findings are supported by a pictorial review from the US describing common manifestations and patterns of lung abnormality seen on portable chest radiography in covid-19 patients12; it does not, however, describe a formal methodology, the geographical location of the patients, or the numbers of patients included.

This pictorial review also suggests that the coarse linear opacities associated with covid-19 on chest radiography typically appear in the lung peripheries (fig ane, fig 3b).12

A small case series in Korea showed that 80% of radiographical changes (again this relates to the number of radiological lesions seen, not patients) were found peripherally.seven

Summary of potential breast radiograph findings in covid-nineteen pneumonia

  • Most patients with covid-xix infection have a mild illness and practice non develop pneumonia3

  • The breast radiograph may be normal in upward to 63% of people with covid-19 pneumonia, particularly in the early stages7111625 (just there is uncertainty around this estimate, ranging from 0% to 63%)

  • Changes include ground drinking glass (68.5%),ten coarse horizontal linear opacities, and consolidation.12 These are more probable to be peripheral and in the lower zones, but the whole lung can be involved711

  • Ground glass advent is common in earlier presentations and may precede the appearance of consolidation1112

  • Bilateral lung involvement is most common (72.9%) (just tin can be unilateral in 25%).ten

  • Signs suggestive of potential comorbidities on chest radiography might be obscured by signs of covid-19 pneumonia

  • The appearance of nodules, pneumothorax, or pleural effusion (i-three%) might be incidental, acquired by covid-19 or past comorbidities

What else might exist visible?

Consider covid-xix infection in patients with nodular lung lesions, pneumothorax, and pleural effusion as these accept been reported in case serial of patients with covid-19 infection in China and Korea7111314; yet, the evidence within these reports is not strong, making it difficult to be certain when these are incidental findings, a sign of dual pathology, or unusual manifestations of covid-19. The pictorial review mentioned above also reports this range of radiological abnormalities but cites similar studies.12

Look for cardiac outline abnormalities on chest radiography as cardiac complications are reported with covid-19 (which tin can exist seen on echo15); however, no reports of cardiac abnormalities seen on chest radiographs have been published.

It is adept practice to look for radiograph features that might indicate comorbidities such as tumours, emphysema, customs acquired pneumonia, and bone fracture. Look for misplaced tubes (eg, endotracheal, nasogastric, pleural drains) and lines (eg, key venous lines), and testify of heart disease including sternotomy wires, which could betoken previous cardiac surgery. Not all of these comorbidities have been reported in relation to covid-19 chest radiographs10161718; however, in some cases, covid-19 pneumonia changes might exist and so widespread that features suggestive of comorbidities are obscured.

What are the differential diagnoses?

Ground glass advent, consolidation, and linear opacities can besides be caused by

  • Other atypical pneumonias and the early stages of community acquired pneumonias

  • Pulmonary aspiration

  • Pulmonary oedema

  • Lung cancer

  • Inflammatory lung disease, such every bit pulmonary eosinophilia

  • Vasculitides, eg Wegener'south (granulomatosis with polyangiitis)

  • Bleeding.

Causes of other singular pneumonias include SARS and MERS, mycoplasma infection, Coxiella burnetti, and legionella19 (not an exclusive list).

Causes of bacterial community acquired pneumonias include Streptococcus pneumoniae, Haemophilus influenzae, and Klebsiella20 (non an exclusive list). Breast radiograph changes from community acquired pneumonias are typically unilateral affecting only one part of the lung. Customs acquired pneumonias are predominantly associated with consolidation on breast radiography, not ground glass opacity or linear opacities.xx

Recent reports suggest that vaping causes radiological abnormalities,21 and these appearances have been described as being similar to covid-xix.

How reliable is chest radiography?

Avoid relying solely on imaging findings; use them in conjunction with clinical findings to class an overall clinical assessment, because

  • No single characteristic on chest radiography is diagnostic of covid-19 pneumonia

  • Initial chest radiography may be normal but patients may after develop clinical or radiological signs of covid-19 pneumonia—ie, early on radiographs may be negative (see patient D, fig 4)112223

    • A retrospective example series of 64 patients hospitalised with covid-xix infection in Hong Kong establish that 31% (20 patients) had normal chest radiographs on admission. Of these patients, 35% (northward=vii) developed radiographical changes on follow-up radiography.1122 This study likewise suggested that pinnacle radiological severity on chest radiography is seen at days 10-12 of symptom onset.11 (see patient C, fig iii)

    • On the footing of this study, the multinational consensus statement from the Fleischner Society for thoracic radiology stated that breast radiography tin can be insensitive in mild or early on covid-19 infection.2224

    • In a series of 1099 hospitalised patients with laboratory confirmed covid-19 from across China, of the 274 patients who had chest radiography on admission 162 (59.1%) showed abnormalities, most usually "bilateral patchy shadowing" (n=100, 36.five%). Of 1099 patients 975 had computed tomography just it is unclear how many of the chest radiographs were false negatives for covid pneumonia.

    • The introduction of a systematic review of case series and case reports covering 919 patients in Cathay and Korea suggests that while chest radiography is of picayune diagnostic value in the early stages, in intermediate and avant-garde stages, features suggestive of covid-19 infection may be seen.23 All the same, information technology is unclear in the review how the conclusions regarding chest radiography were reached.

Fig 4

Fig 4

Serial radiological progression seen with covid 19 pneumonia . (a) A normal AP chest radiograph of patient D, a adult female in her 70s who is in hospital with covid-19 infection (day 0 of access). (b) An AP chest radiograph of patient D on day 8, showing ground drinking glass opacification at present nowadays at both lung bases (white arrows). Consolidation is also seen in the periphery of the left upper and mid zones (outlined arrows). Increased density (whiteness) is also present in the periphery of the right upper zone; this is non as dumbo or white equally that seen in the left lung, showing progression of lung change of ground-glass opacification to consolidation (outlined arrows)

  • Download figure
  • Open up in new tab
  • Download powerpoint

A case series of 799 patients from Wuhan China with confirmed covid-19 looked at a subset of those who died (n=113) or were discharged (north=161) and reported that all patients had abnormalities on chest radiograph on admission.16

  • Chest radiographs can be normal in some patients with clinically diagnosed covid-19 pneumonia, or who accept been diagnosed with covid-xix pneumonia past computed tomography—ie, there may be false negative radiographs.71125

    • In the Hong Kong retrospective case serial described above, four patients never developed abnormalities on radiography; yet ane of these patients (25%) had ground drinking glass opacities on chest computed tomography (performed within 48 hours of chest radiography).eleven

    • A case series of nine patients with PCR confirmed covid-19 infection in Korea reported that three had abnormal baseline radiographs but eight had changes on baseline computed tomography, suggesting five of eight baseline radiographs (63%) were false negatives.7

    • A case series in China reported that a subset of two of 5 (40%) patients had normal chest radiographs, but computed tomography washed on the same day confirmed covid-nineteen pneumonia.25

Features and limitations of chest radiographs in covid-19

Normal

  • Fundamental mediastinum and centre appear normal

  • Lungs predominantly contain air (appearing black)

  • Lung markings are present, representing claret vessels extending from the hilum to the lung periphery (these branch and decrease in calibre, such that few vessels are seen at the lung periphery)

  • The diaphragm is curvilinear in outline with sharp costophrenic margins

Ground glass opacity

  • The initial abnormalities suggesting covid-nineteen pneumonia on a breast radiograph are loss of the normal blackness appearance in the lung

  • This is seen as increased whiteness, (because of increased density), but not enough to totally obscure lung markings; giving a basis drinking glass appearance

  • Ground glass opacities can be difficult to discover; radiologist confirmation is recommended

  • Horizontal linear opacities may exist seen with basis-glass change9 (fig 1, fig 3b)

  • Location: normally bilateral but can be unilateral.seven More often reported in a peripheral lung8 adjacent to the chest wall and diaphragm and usually with a distribution in the mid and lower zones8911Fig 4b shows footing glass opacities in the right upper zone, as will exist the case in approximately 20% of patients with covid-19 pneumonia

Consolidation

  • Ground-glass opacities go denser (whiter) and progress to consolidation with complete loss of lung markings

  • Location: The areas of consolidation are likely to have progressed from sites of ground glass opacities (fig 2, fig 3c)

Limitations

AP images from portable machines produce a poorer quality epitome when compared with a PA chest radiograph done in a defended radiography facility, therefore tin can be more than difficult to interpret. Limitations of AP chest radiograph include reduced inspiratory effort because of the patient'southward positioning (potentially exacerbated by their illness), resulting in sub-optimal imaging; lung changes may therefore appear more than marked or localised infection may exist missed; the center can also appear magnified.

Under-exposure of a chest radiograph can occur with operator factors such inappropriate radiation dose, rotation of the patient, patient factors such high body mass index, chest wall abnormalities (or breast prostheses), and inappropriate processing of the paradigm. In an under-exposed epitome, the whole radiograph appears whiter. In comparison with a site with pathology or abnormality, the affected site or expanse will be of increased density (whiter) compared with normal areas (fig 1)

When and how is chest radiography requested?

The British Lodge of Thoracic Imaging (BSTI) suggests that all seriously sick patients (oxygen saturation <94%, National Early Warning Score, NEWS >326) initially have a chest radiograph and that those who do not meet those criteria should accept a chest radiograph if "clinically required" (fig 5).27

Fig 5

Fig 5

Decision tool for radiological management of patients with suspected covid-nineteen. Adapted from BSTI27

*94% unless known COPD, in which example <90%
**Unsuspected/unexpected cases may exist incidentally discovered on chest radiography/computed tomography at this phase; should exist reviewed in the context of clinical suspicion every bit to likelihood of covid-19
***Archetype and indeterminate computed tomography tin be scored by the reporting radiologist for severity of findings as either "mild" or "moderate/severe"

  • Download figure
  • Open in new tab
  • Download powerpoint

Guidelines from the Fleischner Club for thoracic radiology recommend considering chest radiography and covid-19 testing (dependent on local availability) when inpatients have marked respiratory symptoms, which they define as "hypoxaemia, moderate-to-astringent dyspnoea," after considering advisable differential diagnoses.2228

At our centre, in line with National Institute for Health and Care Excellence (NICE) guidance,29 all patients with marked respiratory symptoms caused by suspected covid-19 infection have a breast radiograph as a office of their initial assessment. Our local guidance involves seeing patients in one case referred30 with a threshold for investigating of any combination of fever >37.viii°C; shortness of breath, especially at rest; persistent cough; new wheezing; respiratory rate >20 breaths/min; heart rate >100 beats/min; new defoliation; haemoptysis; the appearance of cyanosis and oxygen saturations <92%.29

Make a note of known comorbidities and smoking history on paperwork requesting investigations; this volition help radiologists to consider other pathologies that may be causing patients' symptoms.

Asking posterior-anterior chest radiograph views whenever possible, every bit it produces a improve image than an inductive-posterior epitome, although you lot may be guided by the patient's condition and local guidelines.

There is currently no role for requesting imaging for suspected covid-19 in Britain primary care.

When might other radiological investigations be required?

If the patient is breathless, with oxygen saturation of less than 94%, and the breast radiograph is normal or uncertain for covid-nineteen, BSTI guidelines advise chest computed tomography31 (fig 5).

Consider pulmonary emboli as a crusade of respiratory symptoms equally evidence suggests a high prevalence of thrombotic complications in covid-19 patients in intensive care. In a Dutch case series, of 184 patients in intensive care with covid-nineteen pneumonia, 31% experienced thrombotic complication (blended outcome of symptomatic acute pulmonary embolism, deep vein thrombosis, ischaemic stroke, myocardial infarction, or systemic arterial embolism).32 Consider computed tomography pulmonary angiogram and relevant biochemical tests if pulmonary embolism is suspected.

How does practice vary internationally?

The BSTI31 states that there is "no role for computed tomography imaging in the diagnosis of covid-19 unless the patient is seriously ill (NEWS score >3) OR if PCR is unavailable" and the American Society of Thoracic Radiology (STR)33 says "routine screening computed tomography for the identification of covid-19 pneumonia is currently non recommended by virtually radiology societies." The Fleischner Lodge for thoracic radiology endorses this approach.22

In Mainland china, computed tomography has been preferred over chest radiography because patients were encouraged to present to infirmary early for diagnosis as a public health measure, and computed tomography in the early stages of covid-19 infection is more likely to be diagnostic than early on breast radiograph.22

In the Usa and UK, still, patients with early on disease are encouraged to stay at abode and to present to infirmary only if symptoms progress; at this after stage the hazard of detecting covid-nineteen changes on chest radiography is likely to exist higher.22

Other countries, including Italy and Espana, have not reported their approach to covid-xix imaging beyond occasional example series and reports.343536

In low resource settings, chest radiography may be more readily available than computed tomography.37

How can cross infection risk be minimised?

Minimise the adventure of cross infection by considering whether imaging is necessary, and if so, which type of imaging is most appropriate.22 For case, with ventilated patients, a portable chest radiograph at the bedside has a lower adventure of cross infection than computed tomography because ventilated patients are more likely to generate aerosol and volition require additional support during imaging. To minimise cross infection risk from moving patients, some centres insist that only inductive-posterior chest radiographs (usually bedside) are performed.22

• Designate imaging areas as "not-covid-19" and "covid-19" areas with designated machines and decontamination procedures for patients with suspected covid-19.3839

• Utilize appropriate personal protective equipment.

Which patients need follow-up radiography?

Guidance from the British Thoracic Society (BTS) recommends follow-up for patients with a clinico-radiological diagnosis of covid-19 pneumonia, as follows:

• Patients who required intensive care or high dependency unit admission or were cared for on the ward with severe pneumonia:

  • Virtually assess at 4-vi weeks later hospital discharge, and go along to face-to-confront clinical assessment if indicated and a face up-to-face review with chest radiography for all at approximately 12 weeks.

• Patients with a balmy to moderate clinico-radiological diagnosis of covid-19 pneumonia who did not crave intensive care or loftier dependency unit care—typically cared for on the ward or in the community:

  • Request a routine follow-up chest radiograph at 12 weeks subsequently discharge with unlike treatment pathways depending on radiographic resolution or not

The guidance recognises the clinical dubiety most covid-19 pneumonia prognosis. We recommend that clinicians involved in such care read the total guidance.40

Instruction into practice

  • How might the stage of a patient'southward affliction bear on chest radiograph estimation?

  • What differential diagnoses will y'all consider if consolidation is visible on breast radiography?

  • What pathways are in identify to ensure people who have had covid-nineteen pneumonia get the necessary follow-upwards?

How patients were involved in the creation of this commodity

Two patients reviewed this article. As a result of their input we have fabricated several changes to the manuscript, including adding a clearer explanation of the differing approaches to imaging in the US, United kingdom, and China, and including a reference to emerging information on cardiac complications of covid-19. They also helped place acronyms and abbreviations that were very UK focused.

Search strategy

We searched PUBMED on the 26 March 2020 using the search terms "COVID-xix," and "chest radiography." Nosotros identified 20 articles. We excluded articles nigh computed tomography or that were not related to imaging. Only in one article on screening did the title relate to chest radiographs.7

How this article was made

We searched Medline (come across search strategy) and identified 2 relevant systematic reviews. Nosotros also used evolving local clinical guidance, Google scholar, and the NHS 111 website to collect current information on covid-xix. JC used her expertise as a chest radiologist, seeing approximately 200 images of suspected covid-19 to inform this commodity. JP is an acute doctor involved in the management of covid-19 patients. About of the published research relates to China so we have supplemented this with local guidance where bachelor.

Footnotes

  • Competing interests The BMJ has judged that there are no disqualifying financial ties to commercial companies. The authors declare the post-obit other interests: none.

  • Further details of The BMJ policy on financial interests are hither: https://www.bmj.com/about-bmj/resources-authors/forms-policies-and-checklists/declaration-competing-interests

  • Contributorship and guarantor: MJ conceptualised this article, undertook the literature search and is guarantor. JC used her cognition of breast radiology to inform the content of the commodity and sourced the images. JP used his knowledge of assessment and management of covid-19 patients to inform the article. MJ, JC, and JP drafted and checked the final article.

  • Patient consent: We considered seeking individual consent to apply radiological images. However, as patients with covid-19 are ill and an infectious risk, obtaining consent was not possible. We approached the infirmary ethics committee chair, Trust R&D, and Information Protection atomic number 82 for permission to use anonymised radiological images without specific consent. They agreed this was adequate.

  • Provenance and peer review: commissioned; externally peer reviewed.

This article is made freely available for use in accordance with BMJ's website terms and atmospheric condition for the duration of the covid-19 pandemic or until otherwise adamant by BMJ. Yous may use, download and print the article for any lawful, non-commercial purpose (including text and information mining) provided that all copyright notices and trade marks are retained.

https://bmj.com/coronavirus/usage

References

  1. ↵
  2. ↵
  3. ↵
  4. ↵
  5. ↵
  6. ↵
  7. ↵
  8. ↵
  9. ↵
  10. ↵
  11. ↵
  12. ↵
  13. ↵
  14. ↵
  15. ↵

    Zeng J-HY, Liu Y, Yuan J, et al. Clinical characteristics and cardiac injury clarification of 419 cases of COVID-19 in Shenzhen, Cathay. SSRN 3556659 [Preprint] 2020. https://ssrn.com/abstract=3556659

  16. ↵
  17. ↵
  18. ↵
  19. ↵
  20. ↵
  21. ↵
  22. ↵
  23. ↵
  24. ↵
  25. ↵
  26. ↵
  27. ↵
  28. ↵
  29. ↵
  30. ↵
  31. ↵
  32. ↵
  33. ↵
  34. ↵
  35. ↵
  36. ↵
  37. ↵
  38. ↵
  39. ↵
  40. ↵

View Abstruse

olsonmdlisives.blogspot.com

Source: https://www.bmj.com/content/370/bmj.m2426

Post a Comment for "How to Know You Have a Chest Infection"