CPD ACCREDITED ARTICLE
been reported to cause a syndrome of ataxia and urinary
incontinence, and should be considered in regions where
horses have access to these plants 3 .
Careful questioning may identify iatrogenic causes of uri-
nary incontinence. Epidural administration of alcohol has
been reported in show horses and the author has treated
a horse with urinary incontinence secondary to a misguid-
ed attempt at medicating the sacroiliac joints. There are
also reports of iatrogenic urinary incontinence following
routine theriogenological procedures 4 . Although rare, ab-
errant larval migrans should be considered in any horse
with an inadequate deworming history.
Other aspects of the medical history may also prove use-
ful. A recent history of trauma may allude to spinal cord
injury e.g. cervical or lumbosacral fractures. Sudden onset
ataxia and urinary incontinence and affecting more than
one horse on the property or a history of recent exposure
to EHV-1 infected horses should alert the veterinarian to
the possibility of EHV-1 myeloencephalopathy 1, 2 . A histo-
ry of chronic musculoskeletal pain affecting the back and
hindlimbs may be significant. If a painful musculoskeletal
condition limits a horse's ability to posture to urinate, com-
plete bladder emptying may impossible. This may lead to
the accumulation of large quantities of sabulous urinary
sediment in the bladder, leading to detrusor dysfunction
and eventual bladder paralysis 19 .
Physical examination
In horses with urinary incontinence, the general physical
examination is frequently non-specific and unrewarding,
and there are rarely other clinical signs apart from urinary
incontinence that may point towards to a specific underly-
ing disease process. Fever may indicate an infectious pro-
cess, and in such cases the veterinarian should consider
bacterial cystitis, EHV-1 myeloencephalopathy and spectic
osteomyelitis. Observing the horse urinate may be useful.
Passage of red urine or stranguria in addition to inconti-
nence may indicate the presence of a urolith or cystitis.
Abnormal posturing may indicate musculoskeletal pain.
Pain on palpation of the lumbosacral region or evidence
of hindlimb lameness may also be significant and should
be investigated.
A neurological examination should be performed in all
horses that present with urinary incontinence. In horses
with UMN urinary dysfunction, lesions in the spinal cord
cranial to the lumbosacral intumescence will in most cas-
es be associated with ataxia, paresis and dysmetria affect-
ing the thoracic and pelvic limbs. Severely affected horses
may even be recumbent. In these cases, loss of the inhi-
bition of the mictur ition reflex and pudendal activity leads
to increased urethral resistance despite a full bladder. On
rectal exam, the bladder is turgid, and can be small, nor-
mal or large in size. Manual emptying per rectum difficult.
Urine incontinence in these cases is characterised by short
intermittent bursts of urine passage with incomplete blad-
der emptying, and often occurs secondary to increases
in intra-abdominal pressure (e.g. sudden movement). In
horses with LMN urinary dysfunction, lesions involving the
Figure 5: Flaccid tail paralysis, faecal retention, loss of anal sphincter
tone and loss of sensation to the perineum in a horse with LMN uri-
nary dysfunction. Polyneuritis equi was confirmed at post mortem.
cauda equina results in urinary incontinence in association
with other signs of LMN disease, including flaccid tail pa-
ralysis, faecal retention, loss of anal sphincter tone, loss of
sensation to the perineum (Figure 5) and hindlimb muscle
atrophy and weakness. In geldings and stallions, the penis
may also be paralysed. LMN damage leads to loss of det-
rusor function and overflow incontinence. In these cases
the bladder is full with relaxed urethral sphincters, which
results in urine dribbling because of overflow from the
bladder. On rectal exam the bladder is large and can be
easily expressed using manual pressure. Urine dribbling is
continuous, which helps differentiate it from UMN disease.
Clinical laboratory tests
Blood should be collected and submitted for a complete
hematological profile. Leukocytosis with and hyperfibrino-
genemia indicates an inflammatory or infectious process
and may be associated with septic osteomyelitis or bacte-
rial cystitis.
An urinalysis should be performed and the sediment
should be examined. Remember that crystaluria (primarily
CaCO3) is normal in the horse and cannot be used to di-
agnose urolithiasis. Haematuria may indicate the presence
of a urolith, cystitis, neoplasia or bladder trauma. Pyuria
indicates urinary tract infection and in these cases, a ster-
ile urine sample via urinary catheterisation should be ob-
tained for bacterial culture and sensitivity testing.
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