TL;DR: Involuntary bed wetting in older female dogs is often caused by spay incontinence and is generally not an emergency unless accompanied by blood, pain, or straining.
What causes involuntary bed wetting in older female dogs?
In older female dogs, bed wetting is frequently a sign of urethral sphincter mechanism incompetence (USMI), commonly referred to as spay incontinence. This condition occurs when the muscles that hold the bladder closed lose their strength over time, often due to aging and hormonal changes. It is important to understand that your dog is likely unaware she is leaking; it usually happens while she is asleep or completely relaxed, and she is not doing it intentionally.
Is my dog's involuntary bed wetting a medical emergency?
- Low Urgency: For a senior dog that is otherwise happy, active, and eating well, bed wetting is typically not a life-threatening emergency.
- When to Seek Prompt Care: If you notice your dog straining to urinate, blood in the urine, or signs of pain, schedule a veterinary visit more urgently.
- Rule Out Other Issues: A vet appointment is necessary to check for underlying conditions like urinary tract infections or bladder stones.
How does taking a photo help the veterinary triage process?
- Document Urine Characteristics: A photo of the urine spot on bedding helps the vet evaluate the volume of leakage and the color of the urine.
- Assess Skin Health: Clear photos of the genital area allow the vet to check for redness or 'urine scald.'
- Determine Severity: Visual evidence helps the veterinarian understand how long moisture has been sitting against the skin and if secondary infections are developing.
Clinical Context (Merck Veterinary Manual)
In senior female dogs, urinary incontinence commonly results from hormonal-responsive urethral incompetence due to deficiency of sex hormones following neutering, or idiopathic urethral sphincter incompetence. Affected animals may dribble urine, leave pools of urine, and exhibit perivulvar dermatitis from urine scalding. Urge incontinence, associated with detrusor irritability, can also cause inappropriate leakage. Treatment options include estrogenic compounds such as diethylstilbestrol, although availability may be limited, or alpha-adrenergic agonists such as phenylpropanolamine at 2-4 mg/kg/day in divided doses, adjusting the dosage to the minimum required to maintain continence. Anticholinergic drugs like oxybutynin chloride (0.5 mg/kg/day, PO) or propantheline (dogs <20 kg, 7.5 mg/day; dogs >20 kg, 15 mg/day) are used to treat urge incontinence.
Chapter: Urology
Source: The Merck Veterinary Manual, 11th Edition (Page 1524)