0:00

Let's turn our attention to the spondyloarthropathies,

0:03

because if we're talking about the sacroiliac joint,

0:06

this is the category of disease that we need to emphasize.

0:11

Spondyloarthropathy abbreviated SPA is a term introduced

0:16

and emphasize over the last few decades the label, a group

0:21

of disorders, the major, one of which shown in the middle

0:24

of this circle being ankylosing spondylitis.

0:28

But you can see in the orange circles a number

0:31

of other disorders that are spondyloarthropathies.

0:35

Now, these disorders classically involve the axial skeleton.

0:40

They involve the spine, they involve the sacroiliac joints,

0:43

they involve both, and they often do so

0:46

at an early stage of the disease.

0:49

We call that sort of involvement, axial spondyloarthropathy,

0:53

I'm gonna abbreviate it a spa.

0:56

But in other cases, the extra axial, uh, problems,

1:01

the things outside of the pelvis, outside

1:04

of the spine may dominate, particularly

1:07

in the initial stages of the disease.

1:09

And those abnormalities include peripheral arthritis,

1:13

bone sclerosis, or osteitis.

1:15

And my favorite one of all, enthesitis.

1:18

An enthesitis is the site of tendon ligament

1:22

or capsular attachment to bone.

1:26

Okay? And enthesopathy is something wrong at that site.

1:29

An enthesitis is an inflammatory process of at that site,

1:33

and they're common.

1:35

That particular finding enthesitis is common in

1:39

the spondyloarthropathies.

1:41

Now, because of the existence of EA spa, extra axial changes

1:46

that may start this particular process,

1:50

we do run into diagnostic problems.

1:53

For example, here's a case.

1:55

This is a 16-year-old male with toe in heel pain.

1:59

I'll let you look at it for a moment.

2:03

You look at this, you can see swelling involving a toe,

2:07

particularly the distal aspect of the toe.

2:10

Withm R imaging. You can see extensive marrow edema

2:14

and soft tissue edema and no, the calcan edema.

2:19

Now, yes, you can diagnoses spondyloarthropathy at this

2:22

stage, but it is a bit of a diagnostic problem for you.

2:27

Here we can see one month later

2:28

that we now have hip synovitis

2:31

and we have erosive changes occurring

2:35

about the synthesis pubis with marrow edema.

2:38

So this disease process began in the periphery

2:41

and now is moving centrally.

2:43

And here we can see another important feature.

2:46

This is enthesitis involving the ischial tuberosity

2:50

where the hamstring tendons attach.

2:53

So you can imagine a case like this presenting initially

2:57

distally and moving

2:59

Toward the central skeleton might produce some

3:03

diagnostic problems.

3:04

So here's another case.

3:06

This is a 19-year-old, uh, male with hip pain.

3:10

And here we can see following intravenous gadolinium

3:13

that there is synovitis within the hip joint

3:16

and a joint effusion.

3:18

But would you be thinking of a spondyloarthropathy?

3:22

Here we can see three months later the classic findings

3:25

of S sacroiliitis.

3:27

So these are diagnostic problems.

3:30

We're much more familiar with

3:31

what happens in the S sacroiliac joint

3:33

and spine, which I'm gonna concentrate in this lecture on.

3:37

But keep in mind

3:38

that things can begin in an atypical fashion.

3:43

Look at this for enthesitis occurring in this case,

3:47

in psoriasis, this is all related to en

3:52

EU problems where tendons and ligaments

3:55

and joint capsules attached leading to bone proliferation.

3:59

We often call this whiskering ill-defined bone proliferation

4:04

leading to marrow edema.

4:06

You can see it here. Here's the marrow edema.

4:08

You can see it on both sides of the patella characteristic.

4:13

Morphologic feature of the spondyloarthropathies,

4:17

which include, by the way, psoriasis, reactive arthritis

4:21

and ankylosing spondylitis.

4:23

So let's, let's go back to the topic.

4:26

The topic is the sacroiliac joint

4:28

and that, let's look at ankylosing spondylitis

4:31

with involvement of the sacroiliac joint.

4:34

Typically bilateral, generally symmetrical,

4:37

but it can be slightly asymmetrical, rarely unilateral

4:42

ileal predominance.

4:43

Every disease process that I know of predominates

4:46

and begins on the ilial aspect of the sacroiliac joint.

4:50

The bone abnormalities, including erosions

4:53

and bone sclerosis, initially, some widening of the joint

4:57

eventually narrowing with fibrous or bony ankylos.

5:01

So this is a relatively early stage. This is the ileum.

5:05

This is the sacrum.

5:06

We can see some early bone bridging,

5:09

but the erosive abnormality on the ilium

5:12

is the dominant feature.

5:14

And then at the late stage, not in every person

5:16

with ankylosing spondylitis,

5:19

but in this particular example,

5:21

widespread intraarticular bone ankylos.