UROLOGY
Urinary Incontinence in Dogs
Medical Management
Mirinda van Schoor
BVSc(Hons); MMedVet(Med)
Bakenkop Animal Hospital,
Centurion
[email protected]
Introduction
The urinary bladder is responsible for storing urine
until it is convenient and appropriate to void urine.
Both urine storage and bladder emptying require
normal functioning and interaction of the autonomic
and somatic nervous systems. In addition, these two
processes also require that the parts of the lower
urinary tract (ureters, bladder, bladder sphincter,
urethra) are intact and functioning normally. For an
animal to consciously and voluntarily initiate voiding,
the cerebrum, brainstem, lumbar and sacral spinal
cord also need to be intact and functioning. When a patient is presented with a complaint of urinary
incontinence it is important to have a systematic
approach during the diagnostic process. Information
that needs to be collected includes the signalment,
complete medical and surgical history, observation of
the voiding process, a complete physical examination,
a detailed neurological examination, palpation of the
bladder, complete urine analysis with urine culture
and antibiogram, haematology and serum chemistry
if indicated, imaging of the urinary tract which may
include radiography, ultrasonography, contrast studies
(cystography and urethrography) and urethroscopy
and cystoscopy.
Urinary incontinence is defined as the loss of voluntary
control over voiding. Rather than intentionally voiding
urine and emptying the bladder, the patient suffers
from intermittent or continuous dribbling of urine.
Most animals are still able to voluntarily empty their
bladder at appropriate times and in appropriate places
but dribbling of urine occurs throughout the day and
night in inappropriate places, especially when the
animal is lying down or sleeping. Many pets are not
aware of the fact that they are dribbling urine. The
prevalence of urinary incontinence varies between
5-20%. When inappropriate urination is reported the clinician
will need to distinguish between loss of voluntary
control versus behavioural causes (submissive
urination), urge incontinence, consciously urinating in
inappropriate places or diseases resulting in polyuria
and polydipsia such as chronic renal failure. The
owner also needs to be questioned about the dog’s
ability to voluntarily initiate a urine stream, the force
of the urine stream, interruptions in the urine stream
during urination, presence of haematuria and any pain
the dog may be experiencing during urination. Perineal
soiling and urine scalding needs to be investigated.
Diagnostic approach Physical examination may reveal an enlarged/
overdistended bladder which is more commonly seen
in cases with neurologic disease or partial urinary
tract obstruction. In cases with non-neurogenic
disease the bladder is usually normal sized or small
at examination. Palpation of a fairly full bladder after
voiding may indicate incomplete voiding and urine
retention. Passing a urinary catheter may determine
the possibility of a partial urinary tract obstruction.
Urinary incontinence can result from a large number
of neurogenic or non-neurogenic causes with non-
neurogenic incontinence being the most common
cause in small animal practice. Of all the non-
neurogenic causes of urinary incontinence, primary
urethral sphincter mechanism incompetence is the
most common urinary storage disorder in dogs.
Issue 02 | MAY 2018 | 25