CPD ACCREDITED ARTICLE
be removed from the bladder via endoscopic or catheter
lavage (Figure 7) and the bladder should be emptied regu-
larly to prevent continued distension and further damage
to the detrusor 18 . Emptying of the bladder is best achieved
by intermittent passage of a urinary catheter, and in male
horses, passage of a catheter can be facilitated by per-
forming a temporary urethrostomy. Depending on the
dedication of the client, this can be an effective long term
strategy to prevent bladder distention in incontinent hors-
es 18 . Urinary catheters should be used judiciously however,
as they predispose the horse to secondary bacterial cys-
titis, ascending infections of the upper urinary tract and
urethral strictures. Owners should also be instructed to
clean the perineum and hindlegs of the horse daily and
apply petroleum-based creams to the skin to prevent urine
scalding.
Administration of bethanechol chloride (0.25-0.75 mg/g
PO q8-12 h) can also be used to stimulate detrusor muscle
function and encourage bladder emptying. Unfortunately
response to treatment is often disappointing, possibly due
to an inability of the detrusor to contract normally due to
chronic over stretching.
Administration of the α adrenergic blocker phenoxyben-
zamine (0.7 mg/kg PO q6 h) and skeletal muscle relaxants
such as dantrolene or diazepam may help relax the ure-
thral sphincter and encourage bladder emptying in cases
of acute onset UMN urinary dysfunction where the detru-
sor is still able to function normally, but there is little indi-
cation for their use in horses with LMN urinary dysfunction
or chronic end-stage urinary incontinence where the det-
rusor has undergone irreversible damage.
Antimicrobial treatment is usually indicated for horses with
bladder paralysis, particularly if there is evidence of a uri-
nary infection. The choice of antibiotic should be based
upon the results of culture and sensitivity testing, but good
empirical choices are trimethoprim sulphonamides and
penicillin.
VI. Prognosis
The prognosis is largely dependent on the primary cause and
the chronicity of the problem. Horses with incontinence
caused by congenital anomalies, cystoliths, primary bac-
terial cystitis, post-parturient bladder trauma, hypoes-
trogenism, septic osteomyelitis, equine protozoal mye-
loencephalitis, EHV-1 myeloencephalopathy and cervical
spinal cord trauma may all respond favorably following
correction of the primary problem if treated promptly.
In many cases however, the subtle neurological deficits
accompanied by incontinence are not recognized by
owners until months or even years after the initial dam-
age has occurred, during which time irreversible detru-
sor dysfunction has occurred. A successful response to
treatment in these cases is unlikely, regardless of the in-
itiating cause. Conditions that are less likely to respond
to treatment, irrespective of when the diagnosis is made,
include equine degenerative myeloencephalopathy, cer-
vical stenotic myelopathy, polyneuritis equi, sorghum
toxicosis and neoplasia.
VII. References
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Issue 02 | APRIL 2017