0:00

Next, let's discuss bacterial pneumonia

0:03

and what it can look like on imaging.

0:06

Here we have a child that underwent a radiograph

0:09

and we can see, unlike in our viral pneumonia cases,

0:13

we see a more focal opacity in the left mid lung here.

0:17

If we look at the lateral, we can see that it corresponds

0:20

to an area of consolidation in the superior segment

0:24

of the left lower lobe,

0:26

and this is a typical appearance when paired

0:29

with the right clinical symptoms for a bacterial pneumonia

0:33

or a community acquired pneumonia.

0:34

In this case, it's segmental in the superior segment

0:37

of the left lower lobe.

0:40

Compare this to another patient here

0:42

who in another location has what looks like consolidation

0:48

in the right mid to lower lung.

0:50

We can confirm on the lateral

0:52

that this is in the right middle lobe.

0:54

We can see this very clear triangular density bounded

0:58

by the minor fissure

1:00

and the anterior aspect of the major fissure.

1:03

What's important to note here is that the fissures seem

1:07

to be retracted towards each other.

1:10

Normally, the minor fissure should extend out

1:13

more horizontally like this,

1:15

and the major fisure will go down

1:17

a little bit lower like this.

1:19

So the fact that we have complete opacification of

1:21

that right middle lobe with retraction

1:24

of the fissures tells us, tells us

1:26

that this is in fact atelectasis

1:28

and this is atelectasis of the entire right middle lobe.

1:32

Now, atelectasis can occur in conjunction with a pneumonia.

1:36

It can either be the underlying cause

1:39

or it can be superimposed.

1:41

So you are going to have

1:43

to rely on the patient's clinical symptoms

1:44

to know whether this is simply atelectasis

1:46

for some other reason versus elects

1:49

associated with an infection.

1:51

In this particular case, this patient did not have fever

1:54

or a white count or other infective symptoms,

1:58

and so this was actually just right middle lobe atelectasis

2:01

know, however, that atelectasis

2:03

and pneumonia can sometimes look quite similar

2:05

to each other, particularly if it's in smaller areas,

2:09

so a segmental or subsegmental region.

2:11

And so clinical history is gonna be

2:13

really important in those cases.

2:16

This is a different patient

2:18

who underwent a chest radiograph,

2:20

and we can see here

2:21

that there's a focal rounded opacity in the peripheral

2:26

right lower lung.

2:28

Again, we don't see those features

2:30

of a viral inflammatory syndrome in the hila.

2:35

When we look on the lateral radiograph,

2:39

it might be a little bit difficult to appreciate,

2:42

but that seems to be hiding back here posterior

2:45

to the heart, and this turned out

2:47

to be what's called a round pneumonia.

2:49

So the patient had clinical symptoms typical of pneumonia,

2:53

but this particular pneumonia has a more rounded appearance

2:56

and this is still a bacterial pneumonia,

2:59

But it's somewhat unique

3:00

to pediatric patients in this type of imaging appearance.

3:04

And this is related to the fact

3:06

that younger children under the age of about eight

3:09

don't have fully developed collateral airflow

3:11

or air circulation.

3:13

Those are perhaps you might remember from med school,

3:15

the channels of Lambert and the pores of cone.

3:19

And so as a result, bacterial spread can be hindered

3:23

and thus the pneumonia remains contained

3:26

within a rounded region.

3:28

If you have a patient with a finding like this

3:31

and they're under the age of eight,

3:33

they do not require further workup

3:35

for a mass lesion if they have corroborating symptoms.

3:39

If there's any clinical concern, you could go on

3:42

to get a CT scan or perhaps follow up radiographs

3:45

after their antibiotic treatment is complete.

3:48

But otherwise, this is a typical appearance

3:51

for a round ammonia in a lung in a young child,

3:54

there's also an entity called round atelectasis

3:58

that can have a very similar appearance.

4:00

However, this is more common in adults.

4:02

It's typically subpleural in location,

4:04

and I'm not going to be showing a case of it here.

4:07

The last case I'll show you is a CT scan

4:10

of a slightly older child.

4:12

We have an axial contrast enhanced soft tissue series,

4:16

and I'm going to change the windowing a little bit

4:19

so we can focus on the lungs more.

4:21

And we can see immediately that in the posterior aspect

4:24

of the superior segment, right lower lobe,

4:26

that there is a cavitary lesion posteriorly.

4:29

As we scroll, we can see

4:31

that there's a thick soft tissue rind,

4:35

and that is the main finding with a few additional small

4:38

patchy and tree and but opacities, this turned out

4:41

to be a bacterial pneumonia with cavitation.

4:45

It's important to know

4:46

that infective cavitary lesions are not limited

4:49

to bacterial pneumonias,

4:50

and in fact are more classic in other types of pneumonias

4:54

that we'll discuss later.

4:56

But it is important to know that they can happen,

4:58

and so it should still be on your differential depending on

5:02

the patient's clinical status

5:04

and their immune competency status.