Round pneumonia

Changed by Calum Worsley, 6 Sep 2021

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Round pneumonia is a type of pneumonia usually only seen in paediatric patients. They are well defined, rounded opacities that represent regions of infected consolidation.

Epidemiology

The mean age of patients with round pneumonia is five years and 90% of patients who present with round pneumonia are younger than twelve 5. Round pneumonia is uncommon after the age of eight because collateral airways tend to be well developed by this age 2,5.

Clinical presentation

Patients present with symptoms of chest infection including fever, sweats, and cough. History of infective symptoms is really helpful when excluding other imaging differentials.

Pathology

The proposed theory as to why children develop round pneumonia and adults do not, relates to the development of inter-alveolar communications and collateral airways. These are called pores of Kohn and canals of Lambert, and when they develop, they allow air-drift between the parenchymal subsegments. In adults, these allow lateral dissemination of infection throughout a lobe, leading to lobar pneumonia. In children, where these have not developed, the limited spread of infection results in round pneumonia 2-4

The infective agent in round pneumonia is bacterial. There is no specific bacterium that causes round pneumonia, but since Streptococcus pneumoniae is the most common cause of chest infection, it is little surprise that it is the leading cause of round pneumonia 4. Haemophillus influenza is also a causative organism 6.

Radiographic features

Plain radiograph

Round pneumonias are round-ish and while they are well-circumscribed parenchymal opacities, they tend to have irregular margins. Majority are single lesions, but can be multiple 6.They most commonly occur in superior segments of lower lobes and in the majority of cases (98%), they are solitary 5.

Air-bronchograms bronchograms are often present, and helpful in clinching the diagnosis. Interestingly, they though are only seen in 17% of cases when they occur in adults 2.

Related video

{{youtube:http://youtu.be/taImIMRBLFk}}

Treatment and prognosis

If round pneumonia is confidently diagnosed, it does not require further investigation. With antibiotic therapy and resolution of symptoms, it does not require follow up.

If a follow-up radiograph is performed, 95% of cases will have resolved at 30 days. Only a minority of cases (5%) progress to lobar pneumonia 5.

Differential diagnosis

In children consider

In adults consider

  • -<p><strong>Round pneumonia</strong> is a type of <a href="/articles/pneumonia">pneumonia</a> usually only seen in paediatric patients. They are well defined, rounded opacities that represent regions of infected consolidation.</p><h4>Epidemiology</h4><p>The mean age of patients with round pneumonia is five years and 90% of patients who present with round pneumonia are younger than twelve <sup>5</sup>. Round pneumonia is uncommon after the age of eight because collateral airways tend to be well developed by this age <sup>2,5</sup>.</p><h4>Clinical presentation</h4><p>Patients present with symptoms of chest infection including fever, sweats, and cough. History of infective symptoms is really helpful when excluding other imaging differentials.</p><h4>Pathology</h4><p>The proposed theory as to why children develop round pneumonia and adults do not, relates to the development of inter-alveolar communications and collateral airways. These are called <a href="/articles/pores-of-kohn">pores of Kohn</a> and <a href="/articles/canals-of-lambert">canals of Lambert</a>, and when they develop, they allow air-drift between the parenchymal subsegments. In adults, these allow lateral dissemination of infection throughout a lobe, leading to lobar pneumonia. In children, where these have not developed, the limited spread of infection results in round pneumonia <sup>2-4</sup>. </p><p>The infective agent in round pneumonia is bacterial. There is no specific bacterium that causes round pneumonia, but since <em>Streptococcus pneumoniae</em> is the most common cause of chest infection, it is little surprise that it is the leading cause of round pneumonia <sup>4</sup>. Haemophillus influenza is also a causative organism <sup>6</sup>.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Round pneumonias are round-ish and while they are well-circumscribed parenchymal opacities, they tend to have irregular margins. Majority are single lesions, but can be multiple <sup>6</sup>.<sup> </sup>They most commonly occur in superior segments of lower lobes and in the majority of cases (98%), they are solitary <sup>5</sup>.</p><p><a href="/articles/air-bronchogram">Air-bronchograms</a> are often present, and helpful in clinching the diagnosis. Interestingly, they are only seen in 17% of cases when they occur in adults <sup>2</sup>.</p><h6>Related video</h6><p>{{youtube:http://youtu.be/taImIMRBLFk}}</p><h4>Treatment and prognosis</h4><p>If round pneumonia is confidently diagnosed, it does not require further investigation. With antibiotic therapy and resolution of symptoms, it does not require follow up.</p><p>If a follow-up radiograph is performed, 95% of cases will have resolved at 30 days. Only a minority of cases (5%) progress to <a href="/articles/lobar-pneumonia">lobar pneumonia</a> <sup>5</sup>.</p><h4>Differential diagnosis</h4><p>In children consider</p><ul><li>
  • -<a href="/articles/pulmonary-masses">pulmonary masses</a><ul>
  • +<p><strong>Round pneumonia</strong> is a type of <a href="/articles/pneumonia">pneumonia</a> usually only seen in paediatric patients. They are well defined, rounded opacities that represent regions of infected consolidation.</p><h4>Epidemiology</h4><p>The mean age of patients with round pneumonia is five years and 90% of patients who present with round pneumonia are younger than twelve <sup>5</sup>. Round pneumonia is uncommon after the age of eight because collateral airways tend to be well developed by this age <sup>2,5</sup>.</p><h4>Clinical presentation</h4><p>Patients present with symptoms of chest infection including fever, sweats, and cough. History of infective symptoms is helpful when excluding other imaging differentials.</p><h4>Pathology</h4><p>The proposed theory as to why children develop round pneumonia and adults do not relates to the development of inter-alveolar communications and collateral airways. These are called <a href="/articles/pores-of-kohn">pores of Kohn</a> and <a href="/articles/canals-of-lambert">canals of Lambert</a>, and when they develop, they allow air-drift between the parenchymal subsegments. In adults, these allow lateral dissemination of infection throughout a lobe, leading to lobar pneumonia. In children, where these have not developed, the limited spread of infection results in round pneumonia <sup>2-4</sup>. </p><p>The infective agent in round pneumonia is bacterial. There is no specific bacterium that causes round pneumonia, but since <em>Streptococcus pneumoniae</em> is the most common cause of chest infection, it is little surprise that it is the leading cause of round pneumonia <sup>4</sup>. Haemophillus influenza is also a causative organism <sup>6</sup>.</p><h4>Radiographic features</h4><h5>Plain radiograph</h5><p>Round pneumonias are round-ish and while they are well-circumscribed parenchymal opacities, they tend to have irregular margins.<sup> </sup>They most commonly occur in superior segments of lower lobes and in the majority of cases (98%), they are solitary <sup>5</sup>.</p><p><a href="/articles/air-bronchogram">Air bronchograms</a> are often present though are only seen in 17% of cases when they occur in adults <sup>2</sup>.</p><h6>Related video</h6><p>{{youtube:http://youtu.be/taImIMRBLFk}}</p><h4>Treatment and prognosis</h4><p>If round pneumonia is confidently diagnosed, it does not require further investigation. With antibiotic therapy and resolution of symptoms, it does not require follow up.</p><p>If a follow-up radiograph is performed, 95% of cases will have resolved at 30 days. Only a minority of cases (5%) progress to <a href="/articles/lobar-pneumonia">lobar pneumonia</a> <sup>5</sup>.</p><h4>Differential diagnosis</h4><p>In children consider</p><ul><li>pulmonary masses<ul>
  • -<li><a href="/articles/congenital-cystic-adenomatoid-malformation">type III CCAM</a></li>
  • +<li><a href="/articles/congenital-cystic-adenomatoid-malformation">type III CPAM</a></li>
  • -<li><a href="/articles/pulmonary-fungal-disease">fungal infection</a></li>
  • +<li><a title="Pulmonary fungal infection" href="/articles/pulmonary-fungal-disease">fungal infection</a></li>
  • -<li>
  • -<a href="/articles/pulmonary-masses">pulmonary masses</a><ul>
  • +<li>pulmonary masses<ul>
Images Changes:

Image 3 X-ray (Frontal) ( update )

Caption was changed:
Case 2 :multifocal: multifocal round pneumonia with resolution

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