Pediatric Bacterial Pneumonia

Etiology: Bacterial infection of the air space and alveoli
Imaging CXR AP: Look for silhouette sign to locate pulmonary opacity to correct lobe: lingular bacterial pneumonia usually obscures left heart border, right middle lobe bacterial pneumonia usually obscures right heart border, lower lobe bacterial pneumonia usually obscures hemidiaphragm
Imaging CXR Lateral: Look for spine sign of lower lobe bacterial pneumonia: normally lung should get more lucent going from lung apex to lung base, if lung gets more dense going from lung apex to lung base you have lower lobe bacterial pneumonia
Note: A normal CXR AP and lateral effectively rules out bacterial pneumonia
Imaging US: Heterogenous hypoechoic echotexture similar to liver = hepatization of lung
DDX: Pulmonary hemorrhage, pulmonary edema
Complications: Pleural effusion, pleural empyema, lung abscess
Treatment: Antibiotics
Clinical: Bacterial pneumonia in lower lobes can present with abdominal pain due to irritation of the diaphragm and mimic acute appendicitis so look at lungs on AXR and CT

Radiology Cases of Bacterial Pneumonia

Radiology Cases of Silhouette Sign in Bacterial Pneumonia Obscuring the Left Heart Border

CXR of bacterial pneumonia in the lingula — CXR AP (left) shows dense opacity in the lower left lung that is obscuring the left heart border and causes a silhouette sign. CXR lateral (right) shows a dense oval opacity anterior over the heart.

CXR of bacterial pneumonia in the lingula — CXR AP (left) shows dense opacity in the lower left lung that is obscuring the left heart border and causing a silhouette sign. CXR lateral (right) shows a dense triangular opacity anterior over the heart.

CXR of bacterial pneumonia in the lingula — CXR PA (left) shows an opacity in the left mid lung that is obscuring the left heart border while on the CXR lateral (right) the opacity is seen to overlie the heart.

CXR of bacterial pneumonia in the lingula — CXR PA (left) shows an opacity in the lingula that is obscuring the left heart border (silhouette sign) which on the CXR lateral (right) is seen to be projecting over the heart.

Radiology Cases of Silhouette Sign in Bacterial Pneumonia Obscuring the Left Mediastinum and Left Heart Border

CXR of bacterial pneumonia in left upper lobe — CXR PA (above left) shows an opacity in the left lung that obscures the left mediastinum and left heart border which on the CXR lateral (above right) is seen to be located in the upper lung. Coronal (below left) and sagittal (below right) CT without contrast of the chest better localizes the opacities in the left upper lung.

Radiology Cases of Silhouette Sign in Bacterial Pneumonia Obscuring the Left Hemidiaphragm

CXR and CT of bacterial pneumonia in the left lower lobe — CXR PA (above left) shows an opacity in the medial left lower lobe that obscures the medial left hemidiaphragm. CXR lateral (above right) shows a spine sign over the lower thoracic vertebral bodies. Axial CT without contrast of the chest (below left) shows a dense infiltrate in the posterior aspect of the left lower lobe while the sagittal CT (below right) again shows the infiltrate to be located inferiorly and posteriorly in the chest.

CXR of bacterial pneumonia in left lower lobe — CXR PA (left) shows a dense opacity over the heart obscuring the medial aspect of the left hemidiaphragm (silhouette sign) while the CXR lateral (right) shows the opacity is located posteriorly over the lower thoracic spine (spine sign).

Radiology Cases of Silhouette Sign in Bacterial Pneumonia Obscuring the Right Heart Border

CXR of bacterial pneumonia of right middle lobe — CXR PA (left) shows a dense opacity in the middle of the right lung that obscures the right heart border which on the CXR lateral (right) is located over the heart.

CXR of right middle lobe bacterial pneumonia — CXR PA (left) shows dense opacity throughout the right middle lobe which is obscuring the right heart border (silhouette sign). CXR lateral (right) shows the opacity located over the heart.

Radiology Cases of Spine Sign Bacterial Pneumonia

CXR of streptococcus pneumonia — CXR PA (left) shows an opacity medially in the right lower chest which the lateral (right) shows to be located posteriorly resulting in a spine sign.

CXR of spine sign in bacterial pneumonia — CXR AP (above left) shows a hazy opacity projecting over the apex of the heart while the CXR lateral (above right) places the hazy opacity over the last vertebral body that is completely above the diaphragm. Note on the lateral that over the spine, the lung is not getting more lucent going from lung apex to lung base because of this hazy opacity (spine sign). Sagittal CT without contrast of the left hemithorax of the chest (below) shows a dense opacity in the posterior aspect of the left lower lobe.

CXR and CT of bacterial pneumonia in the left lower lobe — CXR PA (above left) shows an opacity in the medial left lower lobe that obscures the medial left hemidiaphragm. CXR lateral (above right) shows a spine sign over the lower thoracic vertebral bodies. Axial CT without contrast of the chest (below left) shows a dense infiltrate in the posterior aspect of the left lower lobe while the sagittal CT (below right) again shows the infiltrate to be located inferiorly and posteriorly in the chest.

CXR of bacterial pneumonia in right upper lobe — CXR PA (left) shows an opacity in the right upper lobe which on the CXR lateral (right) is seen to be located posteriorly causing a spine sign.

CXR of bacterial pneumonia of the left lower lobe — CXR PA (left) shows a retrocardiac opacity which on the CXR lateral (right) is seen to be located over the lower spine resulting in a spine sign.

CXR of bacterial pneumonia in left lower lobe — CXR PA (left) shows a dense opacity over the heart obscuring the medial aspect of the left hemidiaphragm (silhouette sign) while the CXR lateral (right) shows the opacity is located posteriorly over the lower thoracic spine (spine sign).

Radiology Cases of Bacterial Pneumonia in Left Upper Lobe

CXR of bacterial pneumonia in left upper lobe — CXR PA (above left) shows an opacity in the left lung that obscures the left mediastinum and left heart border which on the CXR lateral (above right) is seen to be located in the upper lung. Coronal (below left) and sagittal (below right) CT without contrast of the chest better localizes the opacities in the left upper lung.

Radiology Cases of Bacterial Pneumonia in Lingula

CXR of bacterial pneumonia in the lingula — CXR AP (left) shows dense opacity in the lower left lung that is obscuring the left heart border and causes a silhouette sign. CXR lateral (right) shows a dense oval opacity anterior over the heart.

CXR of bacterial pneumonia in the lingula — CXR AP (left) shows dense opacity in the lower left lung that is obscuring the left heart border and causing a silhouette sign. CXR lateral (right) shows a dense triangular opacity anterior over the heart.

CXR of bacterial pneumonia in the lingula — CXR PA (left) shows an opacity in the left mid lung that is obscuring the left heart border while on the CXR lateral (right) the opacity is seen to overlie the heart.

CXR of bacterial pneumonia in the lingula — CXR PA (left) shows an opacity in the lingula that is obscuring the left heart border (silhouette sign) which on the CXR lateral (right) is seen to be projecting over the heart.

Radiology Cases of Bacterial Pneumonia in Left Lower Lobe

CXR of spine sign in bacterial pneumonia — CXR AP (above left) shows a hazy opacity projecting over the apex of the heart while the CXR lateral (above right) places the hazy opacity over the last vertebral body that is completely above the diaphragm. Note on the lateral that over the spine, the lung is not getting more lucent going from lung apex to lung base because of this hazy opacity (spine sign). Sagittal CT without contrast of the left hemithorax of the chest (below) shows a dense opacity in the posterior aspect of the left lower lobe.

CXR and CT of bacterial pneumonia in the left lower lobe — CXR PA (above left) shows an opacity in the medial left lower lobe that obscures the medial left hemidiaphragm. CXR lateral (above right) shows a spine sign over the lower thoracic vertebral bodies. Axial CT without contrast of the chest (below left) shows a dense infiltrate in the posterior aspect of the left lower lobe while the sagittal CT (below right) again shows the infiltrate to be located inferiorly and posteriorly in the chest.

CXR of bacterial pneumonia of the left lower lobe — CXR PA (left) shows a retrocardiac opacity which on the CXR lateral (right) is seen to be located over the lower spine resulting in a spine sign.

CXR of bacterial pneumonia in left lower lobe — CXR PA (left) shows a dense opacity over the heart obscuring the medial aspect of the left hemidiaphragm (silhouette sign) while the CXR lateral (right) shows the opacity is located posteriorly over the lower thoracic spine (spine sign).

Radiology Cases of Bacterial Pneumonia in Right Upper Lobe

CXR of bacterial pneumonia in right upper lobe — CXR PA (left) shows a triangular dense opacity in the lateral aspect of the right upper lobe that on the CXR lateral (right) is seen to be posterior in location.

CXR of bacterial pneumonia in right upper lobe — CXR PA (left) shows an opacity in the right upper lobe which on the CXR lateral (right) is seen to be located posteriorly causing a spine sign.

CXR of right upper lobe bacterial pneumonia — CXR PA (left) shows a dense opacity in the right upper lobe which is located superiorly on the CXR lateral (right).

Radiology Cases of Bacterial Pneumonia in Right Middle Lobe

CXR of bacterial pneumonia of right middle lobe — CXR PA (left) shows a dense opacity in the middle of the right lung that obscures the right heart border which on the CXR lateral (right) is located over the heart.

CXR of right middle lobe bacterial pneumonia — CXR PA (left) shows dense opacity throughout the right middle lobe which is obscuring the right heart border (silhouette sign). CXR lateral (right) shows the opacity located over the heart.

Radiology Cases of Bacterial Pneumonia in Right Middle Lobe Lateral Segment

CXR of bacterial pneumonia in right middle lobe — CXR PA (left) shows dense opacity in the lateral aspect of the right mid-lung. CXR lateral (right) shows the opacity to be located in the right middle lobe.

Radiology Cases of Bacterial Pneumonia in Right Lower Lobe

CXR of streptococcus pneumonia — CXR PA (left) shows an opacity medially in the right lower chest which the lateral (right) shows to be located posteriorly resulting in a spine sign.