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- Ankylosing spondylitis has a pretty strict definition,
classification.
Patient should be less than 45 years old when things begin.
They should have decreased spine mobility in two planes.
We do spine measurements to determine that.
And there should be definitive, that means definite,
x-ray changes in the sacroiliac joints
of a certain grade, of a certain level.
And those are pretty strict criteria.
And so because not everybody fulfills those
classification guidelines, that's where
the broader definition of spondyloarthritis comes in,
because not everybody has those x-ray abnormalities.
Now in addition to being younger than 45 years old,
and having abnormal spine measurements in two planes,
and definite x-ray changes of a certain level
at the sacroiliac joints, there should be inflammatory
spine pain, inflammatory back pain.
And that's usually defined as pain
that's worse at night and in the morning.
It's typically better as the day goes on,
or better with activity.
It's a little different than osteoarthritis,
than degenerative arthritis of the back.
Which is the opposite, it's typically
worse with activity, best in the morning.
The pain should be, usually,
better with the use of an anti-inflammatory.
And it may be associated with other pain,
such as buttock pain, which is probably sacroiliac pain.
Gluteal pain.
And, again, pain at the entheses, we call enthesitis,
where the tendons insert.
Such as, Achilles tendonitis, plantar fasciitis,
chest wall or rib pain.
Some patients will have a positive genetic marker
called an HLA-B27.
It is not required for diagnosis,
it certainly will tip the balance if a patient
has a positive HLA-B27, and we're not so quite sure
that the diagnosis fits.
It will certainly make us think twice
that maybe that's what we're dealing with.
But it's not required for diagnosis.
In fact, it ranges all across the board.
Anywhere from 28% or 30%
to 70% in the literature.
And the variation probably has to do with
the genetics amongst different cultures and races.
It's certainly not seen in certain cultures,
and it's definitely present in others,
such as Northern European white men,
HLA-B27 tends to be more positive.
But it's not required for diagnosis.
Most patients will have elevated inflammation tests.
A sed rate, sedimentation rate, and a
CRP, or a C-reactive protein.
It is helpful if those are present,
it's not always present.
So again, there's no one blood test,
no required one blood test for diagnosis.
In ankylosing spondylitis the inflammation tests
generally are elevated
at some point in their disease when it's active.
In the more general spondyloarthritis family,
those who don't have the x-ray abnormalities
on their sacroiliac joints, the HLA-B27
tends to be less positive.
It's been noted, and we don't understand that.
We don't understand if that means a better outcome,
a better prognosis, so this is something time will tell.
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