What is urinary incontinence?
Incontinence is the involuntary loss of urine — the dog does not choose to urinate, they simply lose control of the bladder. It is important to distinguish it from marking, excitement urination or incomplete toilet training (all of which are voluntary behaviours).
Common causes
Urethral Sphincter Mechanism Incompetence (USMI)
The most common cause, particularly in medium to large spayed bitches. Oestrogen normally maintains urethral sphincter tone — after spaying, oestrogen drops and the sphincter weakens. The dog loses urine passively, typically while sleeping or resting.
Neurological causes
- Disc herniation or spinal cord injury affecting bladder control.
- Wobbler syndrome.
- Spinal tumours.
Anatomical
- Ectopic ureter: the ureter inserts below the sphincter rather than at the bladder neck. Typically presents in young females who have never been continent.
Urinary tract infection
Cystitis can cause urgency incontinence — such strong urge to void that the dog cannot reach the outdoors in time. Usually accompanied by other signs: genital licking, blood in urine, frequent small urinations.
Polyuria from various causes
Diabetes mellitus, renal failure, Cushing's syndrome — produce urine in such volume that the dog cannot hold the bladder.
Diagnosis
- Urinalysis and urine culture → rule out infection.
- Bloodwork → rule out systemic disease.
- Abdominal ultrasound → evaluate bladder, ureters and kidneys.
- IV urography or CT → if ectopic ureter is suspected.
- Neurological exam → if neurological signs are present.
Treatment
- USMI: phenylpropanolamine (PPA) — first-line treatment. Increases urethral sphincter tone. Oestriol or DES as alternative in bitches.
- UTI: appropriate antibiotic based on culture and sensitivity.
- Ectopic ureter: surgical correction or laser cystoscopic correction.
- Neurological: dependent on underlying cause.
- Palliative management: dog nappies, skin barrier creams, frequent hygiene to prevent urine scald.