a physical examination alone can sometimes accurately predict
whether the underlying cause of abdominal pain requires surgical
treatment. However, as a result of individual variation, predicting
whether the horse requires immediate referral for surgery is not always
straight forward (Cook and Hassel 2014). Whilst per-rectum palpation
of the abdominal contents can provide further information, the
sensitivity for identifying a ‘surgical colic’ is below that desirable of
a diagnostic test (Klohnen et al. 1996). Peritoneal sample analysis
can be a useful predictor of a strangulating lesion requiring surgical
resection. Access to this diagnostic test is not always readily available
in first opinion practice and waiting for a result may incur significant
time delays in decision making if surgery is required and therefore
result in a poorer prognosis.
Ultrasonographic approach
in Colic Patients
Introduction
The
use of ultrasound in horses with colic
Abdominal pain
(colic)
is a valuable
common
emergency
Transabdominal
ultrasound
can provide
information
in horses
with
abdominal pain.
In many patients
referral hospitals
and
clinics, abdominal
presentation
of equine
to vets,
encompassing
ultrasonography is an integral part of the diagnostic investigation of
a range
of conditions
of which abdominal
the causative
factors, is
horses
referred
with colic. However,
ultrasonography
required underutilised
treatment in the
and
prognosis
vary
hugely with
probably
assessment
of horses
presenting
abdominal
pain et
in al.
first-opinion
practice,
especially
that portable
(Abutarbush
2005). The
probability
of now
a successful
ultrasound machines are increasingly available. Transabdominal
outcome in horses
with identified
pathology
requiring
ultrasonography
accurately
small
intestinal surgical
obstruction
intervention
negatively
with
time of at
onset
to
(Freeman
2002) is
and
was better correlated
than per-rectal
palpation
predicting
small
intestinal
obstruction (Fisher
that was 1997).
subsequently
confirmed
at surgery
surgical
intervention
However,
identifying
(Scharner et al. 2002). Ultrasonography can distinguish between
horses with abdominal
pain caused
by lesions
which and
non-strangulating
and strangulating
small intestinal
pathologies
require help
prompt
treatment,
so-called
‘surgical
therefore
in the surgical
decision-making
process
when a horse
requires
surgical
intervention
(le straightforward.
Jeune and Whitcombe 2014). Intestinal wall
colic’, is
not always
thickness can be measured reliably (Bithell et al. 2010) and large
colon strangulating volvulus can be identified (Abutarbush 2006;
Obtaining
history
a physical
Beccati
et al. a 2011).
It is and
also performing
of value in horses
where examination
small patient size,
temperament,
or advanced accurately
pregnancy does
not whether
allow per-rectum
alone can sometimes
predict
the
examination, and when haematological and biochemical analysis is
underlying
cause
of
abdominal
pain
requires
surgical
not readily available.
5
ultrasonography experience, for the quick detection of major
abdominal abnormalities requiring surgical intervention. Five
inexperienced clinicians were trained to perform the FLASH protocol
in which the abdomen is divided into seven regions. Thirty-six horses
were included in the prospective study and the results of the
FLASH evaluations were compared with serial clinical examination
parameters, surgical versus non-surgical outcomes, and where Im
available, post-mortem findings. The examination took approximately
10 minutes and yielded good to excellent sensitivity (80%), specificity
(96%), positive predictive value (PPV; 89%) and negative predictive
value (NPV; 93%). In an earlier retrospective study by Klohnen et al.
Nephros
(1996) transabdominal ultrasonography performed in horses with small
intestinal strangulation had 100% sensitivity, specificity, PPV and NPV.
in the 17
In the
study, per-rectum
palpation
had colic
only 50% sensitivity fossa)
but a
The
use same
of ultrasound
in horses
with
98% specificity, revealing that ultrasonography is more accurate middle
for
t
Transabdominal
ultrasound
can
provide
valuable
detecting strangulating lesions of the small intestine than per-rectum
The left
information
evaluation. in horses with abdominal pain. In the splee
many
referral hospitals and clinics, abdominal of the l
Equipment
ultrasonography
is an integral
of the
diagnostic
A low frequency (2-5MHz)
curvilinear part
transducer
(probe)
is ideal, it nephrosp
will
allow penetration
of up to 30cm
depth with
and offers
a wide
field of view.
it is reco
investigation
of horses
referred
colic.
However,
A higher frequency and/or linear transducer e.g. a rectal probe per-rectu
will
abdominal
ultrasonography
is probably
underutilised
provide limited
penetration (typically
<12cm) and
a narrower field
in of
the view
assessment
horses important
presenting
with abdominal
but can still of provide
information
and guide the
decision-making
process. practice, especially now that
pain
in first-opinion
Image 6
Patient preparation
portable
ultrasound machines are increasingly available.
The hair coat of the regions to be scanned should be free of dirt
Transabdominal
ultrasonography
identified
(removed by brushing)
and isopropyl accurately
alcohol should
be applied
liberally
so that the
coat is saturated.
Hair 2002)
clipping
is not
small
intestinal
obstruction
(Freeman
and
was usually
required
unless
the hair coat
is especially at thick,
or if the horse
is obese.
better
than
per-rectal
palpation
predicting
small
Acoustic contact gel can be applied to the probe to further improve
intestinal
obstruction
that
was
subsequently
confirmed
contact. Abdominal ultrasound is usually well tolerated.
at Conclusions
surgery (Scharner et al. 2002).
treatment. However, as a result of individual variation,
Ultrasonographic approaches
predicting
whether evaluation
the horse
requires
immediate
A
complete abdominal
involves
systematic
imaging of
referral for surgery is not always straight forward (Cook
and Hassel
Ultrasound
images 2014).
credit: Whilst per-rectum palpation of the
Lucy
Meehan BVSc
MSc CertAVP(VDI)
DipECVDI MRCVS
abdominal
contents
can provide
further information,
References:
the
sensitivity
for
identifying
a
‘surgical
colic’
is below
1.
Abutarbush S.M., Carmalt J.L., Shoemaker R.W.
(2005)
Causes of
colic
in horses in western
Canada: 604 et cases
(1992-2002).
that gastrointestinal
desirable of
a diagnostic
test (Klohnen
al. 1996).
Canadian Veterinary Journal 46: 800-805.
Peritoneal
sample
analysis
be a useful
of a colon
2.
Abutarbush
S.M. (2006)
Use of can
ultrasonography
to predictor
diagnose large
volvulus in horses.
The requiring
Journal of the
American
Medicine Association
strangulating
lesion
surgical
resection.
Access 228:
409-413.
to this
diagnostic
test is R., not
always
readily
available S. in
3.
Beccati
F., Pepe M., Gialletti
Cercone
M., Bazzica
C., Nannarone
(2011)
there a statistical
correlation
between
first Is opinion
practice
and waiting
for ultrasonographic
a result may findings
incur and
definitive diagnosis in horses with acute abdominal pain? Equine Veterinary
significant
time delays
in decision making if surgery is
Journal Supplement
S39: 98-105.
4.
Bithell and
S., Haberson-Butcher
J.L., in Bowen
I.M., prognosis.
Hallowell G.D. (2008)
required
therefore result
a poorer
4
Transcutaneus abdominal ultrasonography is a potentially valuable
tool in the evaluation can
of the equine
acute abdomen
and can
help with
Ultrasonography
distinguish
between
non-
the identification and
of lesions
which require rapid
surgical
intervention.
strangulating
strangulating
small
intestinal
pathologies and therefore help in the decision-making
process
when
horse requires
surgical
intervention
5.
Busoni
V., De a Busscher
V., Lopez D.,
Verwilghen
D., Cassart (le
D. (2011)
of a protocol 2014).
for fast Intestinal
localised abdominal
sonography
of horses
Jeune Evaluation
and Whitcombe
wall thickness
can
(FLASH) admitted for colic. The Veterinary Journal 188: 77-82.
be
measured
reliably
(Bithell
et
al.
2010)
and
large
colon
6.
Cook V.L., Hassel D.M. (2014) Evaluation of the colic in horses: decision for
referral. Veterinary
Clinics can
of North
Equine Practice
30: 383-398.
strangulating
volvulus
be America
identified
(Abutarbush
7.
Fisher A.T. (1997) Advances in diagnostic techniques for horses with colic.
2006; Veterinary
Beccati Clinics
et al.
2011).
It
is
also
of
value
in
horses
of North America Equine Practice13: 203-219.
8.
Freeman
(2002) Ultrasonography
of the equine or
abdomen:
techniques
where
small S. patient
size, temperament,
advanced
and normal findings. In Practice 24: 204-211.
pregnancy
does
not
allow
per-rectum
examination,
and
9.
Klohnen A., Vachon A.M., Fisher A.T. (1996) Use of diagnostic ultrasonography
Im
in horses with signs of acute abdominal pain. Journal of the American
third – move the probe
Veterinary Medical Association 209: 1597-1601.
Im
10. le Jeune S., Whitcomb M.B. (2014) Ultrasound of the Equine Acute Abdomen.
around the middle one third
Veterinary Clinics of North America Equine Practice 20: 353-381.
11. Scharner D., Rotting A., Gerlach K., Rasch K., Freeman D.E. (2002)
Repeatability and reproducibility of transabdominal ultrasonographic
en. Assessment
of measurements
small intestinal
intestinal wall thickness
in thoroughbred horses. Veterinary
Ultrasonography of the abdomen in the horse with colic. Clinical Techniques
Radiology and Ultrasound 49: 282-286.
in Equine Practice 1: 118-124.
Left mid
sence Contact
of gas us
filled
colon
can
be
Image 7
now
systemat
of the ab
s position.
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