Statement of the Problem

A cat was evaluated because of a 2-year history of daily urination on horizontal surfaces in the home; the problem started shortly after moving to a new home. Possible medical causes were ruled out by the primary care veterinarian prior to referral.

Signalment

The patient was a 4.5-year-old spayed female domestic shorthair cat.

History

The cat had been acquired at 8 weeks of age from an animal shelter. History prior to adoption was unremarkable. The cat lived in a second-floor apartment for 2 years following adoption with its owner, a roommate, and 2 other cats. During this period, all cats used the litter box reliably. When it was 2.5 years old, the cat moved with its owner to a single-family home. The home was located in a residential neighborhood within the flight path of a metropolitan airport; no other people or animals lived in the new home. The cat was provided with supervised outdoor access several times per week but did not have contact with other animals. The cat had unrestricted access to a single litter box (22 × 15 × 6 inches) with scented clumping litter in the unfinished basement. The owner worked from home and was able to observe the cat's daily behavior patterns consistently. The litter box, litter cleaning frequency, and household schedule remained the same as in the previous home.

The cat started urinating daily on horizontal surfaces near the exterior walls in the basement approximately 1 month after the move. Urine was deposited on varied substrates, including area rugs, wall-to-wall carpeting, concrete, and wood flooring. The owner added a second litter box in the basement and a litter box on the main level, increased the frequency that waste was scooped out of the litter to daily, changed to an unscented litter, and removed the rugs and carpet from the basement. These interventions did not reduce the frequency of periuria. The cat started urinating on the main floor of the home over the next few months, which prompted the owner to pursue behavior consultation.

At the time of consultation, the cat was urinating approximately 3 to 4 times daily in the litter box and once daily elsewhere. Urine locations were consistently near air vents, windows, exterior doors, or walls, and urine was deposited on various substrates. The owner tried placing potted plants and decorative items to block access to soiled areas, but the cat would physically move those items to urinate in the air vent. The owner indicated that the cat had dilated pupils, twitched its tail, had a tense posture, and adopted a crouched stance consistent with normal feline urination posture when urinating outside the litter box. The owner did not observe scratching or attempts to cover prior to or after elimination. Periuria often occurred after a plane flew over the house or after the cat saw a person outside the home, but was not limited to these events.

The owner described the cat as hypervigilant and reported that the cat actively looked out through the home windows with an intense, forward posture for extended periods of time. The cat frequently growled at passersby but was socially interactive with visitors inside the home when they initiated an interaction with it or when the window blinds were closed. The cat reacted aggressively if it saw a neighborhood cat outdoors, although this situation was witnessed less frequently than once per month.

The cat maintained a vigilant focus on the windows for most of the in-home consultation and did not initiate social interaction or engage in grooming or sleeping. It was distractible with social interaction but immediately returned to the window when the interaction ended.

Physical Examination Findings and Laboratory Results

The cat weighed 4.2 kg (9.3 lb) and had a body condition score of 6 on a scale from 1 to 9. No abnormalities were detected during a general physical examination or during orthopedic and neurologic examinations.

The cat had been examined by the referring veterinarian 6 months after the onset of periuria. Results of a complete physical examination and analysis of a urine sample obtained by means of cystocentesis were unremarkable. Analysis of a urine sample obtained by means of cystocentesis 3 months later revealed moderate microscopic hematuria. Results of survey radiography of the thorax, abdomen, and musculoskeletal system were unremarkable; no uroliths were seen. Survey radiography and analysis of a urine sample obtained by means of cystocentesis were repeated 4 months later, and results were again unremarkable. A CBC and serum biochemical profile were performed at this time, and results were within reference limits, except that the Hct and hemoglobin concentration were high and the RBC distribution width was low. Serum thyroxine concentration was within reference limits.

Diagnosis

Differential diagnoses for periuria were considered including medical causes, marking behavior, and feline inappropriate elimination.¹ Results of repeated physical examinations and survey radiography were negative for neurologic and orthopedic conditions that may have affected the cat's mentation or its ability to access the litter box. Results of clinicopathologic testing ruled out most common conditions, such as diabetes mellitus, renal disease, and hyperthyroidism, that could cause polyuria. Results of analysis of 3 urine samples obtained within a 7-month period were normal with the exception of moderate hematuria in 1 sample, which may have been iatrogenic. This reduced the likelihood that the periuria was related to lower urinary tract disease or feline idiopathic cystitis, although these conditions can be difficult to rule out. Bacteriologic culture of a urine sample was not performed, so an occult infection may have been present, even though bacterial cystitis would be unexpected in an adult cat with otherwise normal clinical findings. Results of radiography were negative for radiopaque calculi, and the cat did not have a history of pollakiuria. It was not possible to rule out radiolucent calculi without ultrasonography or contrast radiography; these options were recommended but declined because of the cost. Low RBC distribution width is considered clinically unimportant when other cell volume parameters are within reference limits. High Hct and hemoglobin concentration can be associated with blood collection artifact or hemoconcentration and mild dehydration; these values were not considered clinically relevant.

Inappropriate elimination problems occur when a cat evacuates its bowel or bladder for normal elimination purposes in a location other than the litter box. Common causes include preferences for a substrate other than litter, aversions to the litter box or litter, inappropriate location or type of litter box, or limited access to the litter box because of social interactions or physical restrictions. This cat eliminated on a variety of surfaces, which made a substrate preference unlikely. Although the cat consistently returned to previously soiled locations to eliminate, the consistency between the soiled areas was more closely related to social or environmental factors than a specific location preference. The cat's elimination patterns did not change in response to appropriate litter box maintenance, which decreased the likelihood of litter box aversion secondary to poor litter box hygiene. There was no history of social restriction on litter box access, and litter box placement was adequate to ensure easy physical access at all times.

Feline urine marking is a method of communication that allows for social and spatial organization within a social group or environment and is mainly territorial or anxiety based.² Although urine marking occurs more commonly on vertical surfaces, it can include or be limited to horizontal deposition of urine. A primary diagnosis of urine marking was suggested by the apparent association between the cat's periuria episodes and response to stressors (hypervigilance and reaction to passersby and planes), the social and environmental importance of soiled locations, the apparent lack of distinct elimination preferences or aversions, and the lack of response to previous treatment for inappropriate elimination by the referring veterinarian.

Treatment

A synthetic feline facial pheromone^a diffuser was plugged into an electrical outlet in the living room, and a second diffuser was plugged into an outlet in the basement. This synthetic feline facial pheromone has been shown to reduce the frequency of feline urine marking³ and decrease overall stress as measured by an increase in grooming, food interest, and food intake.⁴ Several scratching posts were placed in the living room to change the social context of previously soiled locations and to encourage scratching as a form of communication preferable to urine marking.

Environmental management consisted of application of opaque window coverings and playing a heterogeneous mixture of sound waves extending over a wide frequency range to decrease exposure to visual and acoustic arousal triggers. The owner was instructed to engage the cat with several structured play sessions each day as a way to replace vigilant behaviors with more appropriate interactions. A litter box was added near the front door to provide an appropriate elimination location on the main level of the home. Although litter box rejection was not suspected, systematic preference testing was prescribed and confirmed that the cat preferred a large uncovered litter box, a litter depth of 1.5 inches, and unscented litter. The owner was instructed to keep a journal of all periuria events and to clean soiled areas with an enzymatic cleaner.

These changes eliminated all urine marking for > 6 months, but urine marking recurred if the window coverings or the main-floor litter box was removed. Treatment was initiated with fluoxetine (4 mg [0.95 mg/kg {0.432 mg/lb}], PO, q 24 h) for its effect on serotonin concentrations and urine-marking frequency.⁵ Extra-label medication use was discussed with and approved by the owner; the owner was advised of possible adverse effects, such as anorexia, sedation, gastrointestinal upset, and increased agitation.

The cat's vigilance and reactivity were substantially improved, as rated by the owner, within 2 to 3 weeks after treatment with fluoxetine was started, and the cat maintained normal levels of activity, play, and social behavior. Window coverings were removed approximately 4 weeks after treatment was started, and the main-floor litter box was gradually moved to the opposite side of the room without any recurrence of urine marking. A follow-up conversation 18 months after initiation of treatment revealed ongoing resolution of urine marking with continued medication use; results of clinicopathologic testing performed every 6 to 12 months were unremarkable. Medication tapering was discussed but declined by the owner.