0:01

So this is an example of a 20-year-old patient

0:04

that presented with a sore throat, difficulty

0:08

swallowing, and pain involving the left tonsil.

0:12

So the issue here is, what is this mass that

0:14

we're seeing in the left side of the neck?

0:18

So when you first look at this, you think that this

0:20

could be an abscess, but this is not an abscess.

0:23

This is a specific disease

0:25

entity referred to as suppurative

0:27

retropharyngeal lymphadenitis.

0:30

So typically, there are a medial and a

0:32

lateral group of retropharyngeal lymph nodes.

0:35

In the early stages, the lymph nodes become

0:39

enlarged and inflamed, and that's adenitis.

0:42

But eventually what happens is that as the

0:44

inflammation continues, the lymph nodes

0:47

become suppurative, and they contain pus.

0:50

So the fact that this fluid

0:51

collection is located paramidline,

0:56

and is in the expected location of the

0:58

lateral retropharyngeal lymph nodes,

1:00

the correct diagnosis is retropharyngeal

1:03

suppurative lymphadenitis.

1:07

Now, when you look at the suppurative lymph

1:08

node here, notice how it's paramidline.

1:10

Now let's take a look at the area

1:13

behind the posterior pharyngeal wall.

1:15

And what we see here is low attenuation in the region

1:19

of the retropharyngeal space that's expanding this.

1:22

Now, the normal anatomy is that there's

1:24

a visceral fascia that's located here.

1:26

There's the prevertebral or paravertebral

1:29

fascia that's located here, and there

1:31

is another fascial layer that's called

1:33

the alar fascia, which is located here.

1:35

The true retropharyngeal space is located

1:38

between the visceral fascia and the alar fascia.

1:43

The space between the alar fascia and the

1:45

prevertebral fascia is called the danger space.

1:48

Now, one can look at this and say,

1:49

well, this looks like an abscess.

1:51

What this is, is retropharyngeal space effusion,

1:55

edema involving the retropharyngeal space, and

1:57

one way that you can confirm this is looking at

2:01

preservation of this vascular structure here.

2:04

So on the sagittal images, if this was an abscess

2:07

that was extending into the retropharyngeal

2:09

space, there should be complete absence because

2:13

an abscess would completely eliminate or erode

2:17

this vascular structure.

2:19

Also, there's the alar fascia here too.

2:21

Occasionally, in effusions involving

2:26

the retropharyngeal space, we can

2:27

actually see that fascial layer.

2:29

But if you have an aggressive retropharyngeal

2:31

space abscess, that alar fascia will be eroded.

2:35

So this is an example of suppurative adenitis

2:39

involving the retropharyngeal lymph node

2:41

associated with retropharyngeal space edema.

2:45

And we can be comfortable.

2:46

It's retropharyngeal space edema because of the

2:49

preservation of this vascular structure that

2:52

approximates the location of the alar fascia.