Keep the atropine within arm’s reach... - Veterinary Practice
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InFocus

Keep the atropine within arm’s reach…

JAYNE LAYCOCK
reports on the ‘pick of the month’ CPD webinar presented by Pip Boydell, BVetMed, CertVOphthal, MRCVS, of Animal Medical Centre Referral Services in Manchester

DEALING with an ocular
emergency in the middle of the
night is stressful enough without
the added pressure of the patient
belonging to your mother-in-law.

Personally, I can’t imagine a worse
case scenario, but this is exactly what
Pip Boydell, co-founder and senior
clinician (neurology and
ophthalmology) at Animal Medical
Centre Referral Services in
Manchester, asked us to assume whilst
presenting a number of
ophthalmology cases at a recent
webinar, entitled Case studies in
ophthalmology
,
organised by
The Webinar
Vet.

The
interactive nature of this
session
allowed the
participating audience, whether in the
UK or further afield, to give their
opinion on diagnostics and treatment
for the various cases he presented.

Cat with corneal perforation

So what would you do with your
mother-in-law’s cat presenting in the
middle of the night with an obvious
corneal perforation?

The majority of attendees
responded by suggesting prioritising
pain relief and, whilst Mr Boydell
agreed this was one important
consideration, he was also keen to
stretch our line of thought and make
us consider the process most likely to
make this cat blind: “uveitis”.

He explained that uveitis would
need to be treated as a priority, and
administering one drop of atropine to
this cat’s eye would not only help to
alleviate its uveitis but would also
relieve pain by relaxing the iris muscle
spasm.

Atropine is a drug we should never
be without under these circumstances
but it can cause, in some cases, quite
alarming hypersalivation, and owners
should always be made aware of this
potential side-effect to prevent any
undue concern.

The use of systemic steroids was
also discussed as they play an important
role in treating uveitis and should be
used as a priority. The use of additional
pain relief in the form of opiates was
advocated by the speaker, but the use of
NSAIDs was not deemed appropriate
in this particular case due to the
concurrent use of steroids.

Now what would you do? Would
you take the cat straight to theatre?
According to Mr Boydell, unless there
is fluid actively leaking from the
anterior chamber or the globe is
collapsed, there is usually no need to consider immediate surgery.

A successful outcome is more likely to be achieved when a full
complement of normal working day
staff are present and, in this particular
case, a conjunctival flap was
performed and the mother-in-law’s cat
made a full recovery.

JRT with the blue eye

The next case involved a JRT which
presented with a “blue eye”. Initially,
mother-in- law described the eye as
sore but over time she felt the eye
became increasingly comfortable again.

The participating audience made a
swift diagnosis of anterior lens
luxation based on the pictures
presented. So now what? Do we
operate to remove the lens straight
away even though it is 2am in the
morning?

Mr Boydell believes the days of
consistently performing lens removal
on these cases are over, and although
some will still need surgery, the
majority can be managed with medical
treatment only. By the lens falling
anterior to the pupil, the drainage of
the aqueous fluid can be obstructed to
cause pupillary block glaucoma.

The main aim of treatment in
these cases is to prevent this glaucoma
from developing and once again
atropine plays an important role. By
dilating the pupil, the lens is given the
opportunity to fall back into position.

Mr Boydell suggested that in some
of these cases the lens will just fall
into its correct position with no
further treatment but in some
situations a mannitol infusion may be
necessary to reduce the volume of the
vitreous body within the eye and
encourage movement of the lens.

Once the lens has
fallen back into its
correct position, the
pupil needs to be
constricted using a
prostaglandin such as
Travoprost. Mr Boydell
was keen to stress that
although he has been
advocating medical
treatment for these cases,
they will still need very
close monitoring over
several hours to ensure
glaucoma does not develop.

Puppy with a scratched eye

Mr Boydell advised to always
encourage patients with ocular
problems to be seen, no matter how
minor they may seem. Compared to
cats, dogs tend to be a lot less tolerant
of uveitis and examples were cited
demonstrating that, if seen promptly,
serious consequences could be
avoided.

A puppy that appears, according to
the owner, to make a full recovery 24
hours after some form of ocular
trauma (often a scratch from the
resident cat), is a typical example. If
veterinary attention isn’t sought early
on in these cases, it is possible that
uveitis could be missed and without
treatment this puppy may present
several days later with a sight-
threatening glaucoma. This is a case
where a simple drop of atropine given
at an appropriate time would have
prevented potentially catastrophic
consequences.

Cat with a melting ulcer

Nobody wants to see a melting ulcer in
a cat, let alone in the middle of the
night with a distressed mother-in-law.
So what would you do?

Members of the audience were
now well-versed with using atropine to
treat pain and potentially sight-
threatening uveitis and to use opiates
for further pain relief.

Topical antibiotics were suggested
as an additional treatment and Mr
Boydell asked for justification of their
use especially when discussions
centred on the class of antibiotic to be
used.

As the ulcer was melting,
pseudomonas was likely to be involved
and a simple scrape should be taken so
cytology could be performed. If, after
cytology, pseudomonas is suspected,
the use of either topical gentamycin or
enrofloxacin could be justified.

The use of a contact lens was
suggested as part of the treatment plan
but Mr Boydell was concerned that
infection could be retained in situ. If the
protective effects of a contact lens were needed, then Mr Boydell
suggested using Hyalan
drops, a component of
joint fluid which has a
viscous consistency
needed to help protect
the eye.

A third eyelid flap
was also suggested but
again Mr Boydell was
concerned that if a
third eyelid flap were
performed we would be
unable to see what was going on and there might be
inappropriate forces applied to the
weakened cornea that could precipitate
perforation.

The administration of plasma
topically was discussed and Mr Boydell
was positive about its use but his
preference is to use acetylcysteine for its
superior anti-collagenase properties. In
the first 2-3 hours he would administer
acetylcysteine drops every 5-10 minutes
in an attempt to remove collagenases
causing the corneal damage.

There was some debate as to
whether steroids were an appropriate
drug of choice under these
circumstances. Mr Boydell pointed out
that he would rarely use topical
steroids in an ulcerated eye but would
almost always use systemic steroids if
a uveitis was present.

In this particular case, he eventually
went on to perform a keratectomy
followed by a large conjunctival graft.

Mr Boydell discussed a number of
other cases including a cat with a
proptosed eye and a dog with a
somewhat surprising diagnosis. To find
out more you will need to log into The
Webinar Vet website and I highly
recommend taking an hour of your
time to listen to all the cases.

There does, however, appear to be
one key message running through a
significant portion of this webinar. If
you do happen to encounter your
mother-in-law in the middle of the
night with an ocular emergency, in a
significant number of cases atropine
should never be more than an arm’s
reach away.

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