Feline lumbar intervertebral foraminal disc extrusion and a Spotlight on medical control of reproduction in toms

Show Notes

This month Dr Sam Taylor sits down with Dr Daniel Ryan to talk about feline spinal disease. We're also featuring our monthly JFMS clinical spotlight interview in which Nathalie Dowgray discusses medical control of reproduction in toms, alongside other reproductive issues, with Professor Stefano Romagnoli.

To begin our episode, Dr Sam Taylor is joined by Dr Daniel Ryan who was the winner of the 2022 JFMS Open Reports Best Practitioner Paper. They discuss the different types of disc extrusion, the ways in which they can present in our patients and his tips for diagnosis.

Nathalie then sits down with Professor Stefano Romagnoli to discuss his JFMS clinical spotlight article Reversible control of reproduction in tom cats: medical options for manipulating libido and fertility as well as a wider discussion on the JFMS Reproduction special issues that Professor Romagnoli was the guest editor of.

For further reading material please visit:

https://journals.sagepub.com/doi/epdf/10.1177/20551169221112068?fbclid=IwAR3rYVvwsUuuXLinBGoTxDILqLRgV1ByNj2xN7SiTKvfSTGox18F1KqQQ1w

https://journals.sagepub.com/doi/epub/10.1177/1098612X231171406

Tune in next month for a very special episode and more clinical spotlight interviews.

Host:

Nathalie Dowgray, BVSc, MANZCVS, PgDip, MRCVS, PhD, Head of ISFM, International Society of Feline Medicine, International Cat Care, Tisbury, Wiltshire, UK 

Speakers:

Dr Samantha Taylor, BVetMed(Hons) CertSAM DipECVIM-CA MANZCVS FRCVS, Feline Medicine Specialist and ISFM Academy Lead

Dr Daniel Ryan, BVM BVS BVMedSci AFHEA MRCVS, ECVN Resident in Neurology and Neurosurgery at Royal Veterinary College and winner of the 2022 JFMS Open Reports Best Practitioner Paper

Dr Stefano Romagnoli, DVM, MS, PhD, Dipl ECAR, Professor In Small Animal Reproduction and published JFMS Author

For ISFM members, the full recording of this discussion is available for you to listen to at portal.icatcare.org. To become an ISFM member, or find out more about our Cat Friendly schemes, visit icatcare.org

Creators & Guests

Host

Nathalie Dowgray

What is Chattering With ISFM?

Welcome to Chattering With ISFM, the official monthly podcast of the International Society of Feline Medicine, hosted by Nathalie Dowgray (Head of ISFM). Each month, we chatter about cats and cat-friendly practices with industry experts and contributors to The Journal of Feline Medicine and Surgery. Each episode contains highlights from our longer discussions and interviews, which are accessible to ISFM members at portal.icatcare.org. If you would like access to our full episodes, would like to become an ISFM member, or find out more about our Cat-Friendly schemes, visit icatcare.org.

Nathalie Dowgray: Hello, welcome
to the May 2023 episode of

Chattering with ISFM. I’m
Nathalie Dowgray, Head of ISFM

and host of this months podcast.
This month Sam Taylor interviews

the 2022 winner of the JFMS Open
Reports Best Practitioner Paper,

Dr Daniel Ryan, and they'll be
talking about feline spinal

disease. We are also featuring
our monthly clinical spotlight

interview. This month I’m
speaking to Professor Stefano

Romagnoli on his clinical
spotlight article, medical

control of reproduction in toms
as well as having a wider

discussion on the JFMS
Reproduction special issues that

Professor Romagnoli was the
guest editor of. We hope you

enjoy this episode.

Sam Taylor: Okay, and can you
tell us a little bit more about

the different types of disc
extrusion? Because I know

particularly your study was
special because it described a

particular type of extrusion.
But for people like me who are

more medics than neurologists,
can you tell us generally about

the different types and then
particularly about your study?

Daniel Ryan: We can divide
intervertebral disc disease as a

category into several different
ones. We split it up a little

bit further in dogs, because we
tend to see more different

presentations of those. But the
three main ones that I guess I

would consider in cats would be
something like an intervertebral

disc extrusion. So that's the
ones you may have heard of was

like hansen type I. So that's
what you'd picture a dachshund

as having. So that's where
you've got herniation or

slippage, basically, of the
pulpy middle, so that nucleus

pulposus through the top bit of
the disk, and that goes into the

vertebral canal and can cause a
number of different signs. We've

then got an intervertebral disc
protrusion. So that's that

hansen type II. So the one that
you tend to think of as maybe a

slower chronic progressive type
disease. And that's where you've

got bulging of that top bit of
the discs of annulus fibrosis

into the vertebral canal,
causing that spinal cord

compression. And then we've also
got another type that's

relatively important in cats as
well, where we kind of have the

acronyms, some of the many
acronyms that appear in

neurology, and that's an acute
nucleus pulposus extrusion or an

ANMPE. And that's where we've
got this sort of pulpy bit in

the middle, this nucleus
pulposus explodes outwards, sort

of hits the spinal cord and
causes concussive injuries, so

more like a bruise with there
being very residual, very

minimal residual compression,
but it's more of a contusive

damage to the spinal cord itself
that that causes the problem. I

guess when we think of the
different types that are most

common in cats, we tend to think
of either an extrusion or an

ANMPE being the most common.

Sam Taylor: You mentioned there
can also be some sinister

presentations of spinal disease
in cats and can I just pick you

up on that for a moment.
Obviously, we're talking about

disc extrusion, but what type of
other causes of spinal disease

might you also see in in cats?

Daniel Ryan: I think one of the
top things that we always have

to have on our list with the cat
whose presenting with a

myelopathy, so a problem with
the back legs and spinal cord

problem, we would quite often
when we've got a cat who's got a

progressive disease have
something like a neoplasia on

the list. So quite up there, one
of the most common causes that

are being diagnosed, probably
similar to your internal

medicine, would be lymphoma. So
I guess that doesn't typically

discriminate in age, they can be
at any age, and that would be

with a progressive sign of a
spinal cord disease. We can also

see other types of tumours as
well, so some of the peripheral

nerve sheath tumours or
meningiomas as well, but we can

also have a number of other sort
of non neoplastic diseases. So

we can see a vertebral canal
stenosis, so that happens in

some british short hairs, we've
got a narrowing of the vertebral

canal itself, which pinches the
spinal cord, as well as

sometimes things like FIP, as
well, can present just having a

spinal cord component, but less
commonly.

Sam Taylor: Yeah, that's
interesting actually, I recently

done a bit of work on FIP, and
we did have the odd case with

the spinal presentation. So
that's a good point, a good

differential, to consider. In
general, how to cats with disc

disease present? Do we expect
the neurological deficits that

we might in dogs? Or what's your
experience of cats that are

coming in with disc disease?

Daniel Ryan: We tend to try and
have this five finger rule.

That's where we try and describe
and summarise an animals

clinical presentation using five
different variables. And that

can really help with our
clinical reasoning. So those

five things that we consider
covers the onset. So is it acute

or chronic? The progression? Is
it getting worse, staying the

same or getting better? Is it
painful? Or is it not painful?

Is it lateralized, so affecting
one leg more than the other, but

also its localization? Finally,
so is it for example, T3L3, or

is it more L4S3? Then if we
consider those three main types

of disk disease that we just
talked about, an intervertebral

disk extrusion, that typically
tends to be acute, so over a few

days to sub acute, or just more
than a few days, it tends to be

progressive, and they're often
painful as well. However, I do

find it really hard to judge
pain in cats, I think they can

be so difficult to read and some
cats will be overtly painful,

but others with what you think
is a painful condition, what you

diagnosed as a painful condition
really don't show it outwards to

you. So I think it's kind of the
most nonspecific of all of that

part of the five finger rule.
When the clinical signs with an

extrusion can be really
variable. Sometimes it can be

just a pain, and they can
progress through to show signs

of paresis or ataxia or
paraplegia. So sometimes there's

signs of a myelopathy there but
not always. Other sorts of

presentations. For other types
of discs, when we've got a

protrusion, that's typically a
chronic, progressive and non

painful condition. Although in
some small cases it can be

painful. Typically, you would
see an ataxia or paraparesis

there, maybe in an older cat,
but it's not particularly

painful. And then finally, we
have the ANMPE, so that acute

non-compressive nucleus pulposus
extrusion, the most

characteristic finding of this
condition is the upper acute

onset, so really, really sudden.
So for example, the cat has been

absolutely fine. And then it has
come back like this or it has

been absolutely fine, you've
turned away and then the cat's

been found like this. And quite
typically with an ANMPE, there

is a suspected trauma, sort of
60 70% of those cases will have

a suspected or known trauma. In
that case, we may see a

lateralization of a side, so one
leg much more markedly affected

than another one.

Nathalie Dowgray: And now over
to Professor Romagnoli to talk

about feline reproduction.
Your article really talks

exceedingly well about some of
the concerns that historically

we've had with using
progesterone's in cats, and the

sort of higher dose regimes that
may have led to a lot of those

side effects. So the articles
sort of really advocated I think

the sort of lower dose daily
treatment, do they still need to

be given once a day? Is that the
safest way to do it rather than

maybe a weekly higher dose
protocol?

Stefano Romagnoli: The only
studies that we have on the

weekly protocols were done with
a slightly higher dosage. So the

very low dosage that we're
currently using on a daily

basis, it's never been tried on
a weekly basis. That's actually

an interesting question. But I
think that with the current

formulation, with the current
oral drops formulation, I think

it would be unlikely that it
work on a weekly basis. The one

that was working well with a
weekly administration was the

pill. But now that pill in
countries where it is still

marketed, it's a 2.5 mg pill,
and 2.5 mg per week is not as

low as we would like it to be.
And that dosage, I think, has

been demonstrated to be safe for
up to a maximum of 30 weeks. We

should probably try and decrease
the dosage by half, or maybe by

25%. And fine. If it works. But
we need to do some research on

that.

Nathalie Dowgray: Yeah. And I
was thinking, I guess,

especially for ease of owner
administration, once a day,

compared to once a week is
obviously a little bit easier.

So it'll interesting to see, I
think, there's obviously still a

lot to learn on these drugs and
historical knowledge is very

helpful, but also with the
variation and dosages, I guess

they're,

Stefano Romagnoli: but you know,
from a practical standpoint, if

you're using a daily treatment,
I think if you miss a day,

nothing happens.

Nathalie Dowgray: Yeah, it's
true. You miss a week, something

might go wrong. In terms of male
cats with the implants, how

would you monitor them? If let's
say there's a reason why

surgical neutering is not going
to be an option, but the owners

want to have sort of continued
suppression of some of those

more Tom cat type signs, how do
you monitor them to determine

maybe when a an implant needs to
be replaced?

Stefano Romagnoli: Well, the
easiest thing would be to take a

calliper such as this, and
measure their testicles. You

know, because tom cats testicles
decreased by about 50% during

treatment, and then they start
growing back as soon as the

implant effect starts to wane.
So, you know, using this, even

owners can do this, but
sometimes cats don't like to be

handled by the owner to do those
types of things. So, I mean, the

veterinarian can easily do that.
And as soon as you see that the

testicle starts growing again.
That means that, you know, that

cat very soon is going to start
roaming and mounting and

fighting again.

Nathalie Dowgray: Okay, no, that
makes sense. Would you recommend

measuring them on say, a monthly
basis? Or?

Stefano Romagnoli: Yeah, not
more often otherwise, you start,

you risk missing, you know,
minor changes.

Nathalie Dowgray: And we've sort
of talked about or touched on it

earlier around, maybe not
delaying puberty and cats

intended for breeding, male cats
intended for breeding. But if

say it's a male cat not intended
for breeding, but maybe there's

a medical reason why surgical
castration is not an option,

what age would you feel
comfortable using a GnRH implant

in those cats?

Stefano Romagnoli: While
certainly a GnRH agonist can be

used pre puberty. So you can
start basically whenever you

want, if that cat is not
intended for breeding and, and

his or her reproductive system
does not need to be working at

any time, you can start whenever
you want, even three, three or

four months of age.

Nathalie Dowgray: Okay, so you
can go quite young. If lets say

you have a queen that you really
want to prolong oestrus

suppression with, so maybe
she's not intended for breeding

but for health reasons we can't
neuter her, what would be your

preferred method for doing that?

Stefano Romagnoli: If it's
reproductive control that needs

to be done for life, I would
certainly go with GnRH agonist.

There are data already that they
can be used sequentially, two to

three times in cats, you know,
so like, two to three years, is

probably safe. And actually,
we've just started a study

dealing with chronic deslorelin
treatment in cats. So we're

looking at health of both toms
and queens treated for prolonged

periods of time with deslorelin,
and I do think that that's the

way to go. I mean, that's the
safest option. Certainly.

Nathalie Dowgray: If you are an
ISFM member you can hear more

from Stenfano with his full
interview being available on the

ISFM members podcast, to access
this please visit

portal.icatcare.org. As well as
the podcast ISFM veterinary

members can also access all the
other ISFM member benefit

including our 2020, 2021 and
2022 congress recordings,

monthly webinars and clinical
clubs, the discussion forum and

much much more. If you're
looking for more CPD in June, we

have several open access
webinars. The first is from

IDEXX, 'Diagnostic approach to
chronic feline enteropathy', and

the second is from Bova, 'Feline
compliant? How to help clients

medicate their cats’. Keep on
eye on ISFM social media for

more details. And don't forget,
JFMS is now an open access

journal so if you wish to read
Professor Romagnoli’s clinical

spotlight article or any of the
articles in the reproduction

special issue, please do follow
the link in the show notes.

We'll be back again next month
with a special episode from the

team at iCatCare on Cat Friendly
Principles for veterinary

professionals. If you don’t
want to miss it make sure you

sign up to Chattering with ISFM
on you preferred podcast

platform. We'll see you again
next month.