Feline Inappropriate Elimination (IE) disorders include behaviors such as urination outside of the litter box, defecation outside of the litter box, urine marking and spraying, or any of these behaviors in combination.  IE is the most commonly reported behavioral problem amongst cats and has been estimated to be present in 59% to 79% of feline behavioral consults seen by veterinarians.  It is also the highest reported reason for feline relinquishment to shelters 1 .  IE can be devastating to the owner, creates a burden on shelters, and contributes to the incidence of feline euthanasia.  It is important that both owners and members of the veterinary profession have an understanding of this disorder.  The aim of this paper is to discuss normal feline elimination behavior, address causes of behavioral and non-behavioral IE disorders, and explore potential actions that owners and veterinarians may utilize to resolve IE disorders.

Normal Feline Elimination Behavior

Urination and defecation in the feline patient consists of three normal phases: digging in the litter box, active elimination, and some degree of covering their elimination product.  Normal urination is fairly consistent amongst sexes and consists of squatting in the litter box or other horizontal surface.  This is in contrast to spraying, which generally consists of producing small amounts of urine on a vertical surface, such as a wall or chair.  Spraying is considered to be a means of social communication by scent, rather than an effective means of voiding urine 2 .

The tendency for cats to cover their urine and feces after voiding is considered to be an innate behavior, as cats in the wild consistently display these behaviors 1 .  Furthermore, kittens in a domestic setting show a natural tendency to dig in sand prior to displaying elimination behaviors.  However, this does not mean that the use of litter and the litter box design is an innate behavior for cats.  In the wild, cats have their choice of where to eliminate based on location, available substrate, previous social interactions occurring at that site, and whether they have previously used that site for elimination purposes in the past.

Behavioral Causes of Inappropriate Elimination

Behavioral causes of inappropriate urination and defecation generally fall into two broad categories termed "aversions" and "preferences".  Aversions refer to any circumstance in which the cat develops an objection to the use of their litter box, leading to elimination behaviors in inappropriate places such as carpet, bedding, floor mats, etc.  Cats may develop an aversion to either the location of the litter box or the litter itself, thus the two types of aversions are generally classified as either substrate or location aversion.

Aversions to location may arise when the cat learns to associate the location of the litter box with a negative quality or event.  Some causes for aversions to the location of the litter box may include aversion to the scent of another cat near the litter box, previous negative experiences with people or other animals near the litter box, avoidance of objects near the litter box (for example the cat may not like to urinate near a mirror), or any previous experiences that have lead to anxiety with regards to the location of the litter box 3 .  Other examples may include having a litter box in an area of the house that is unpredictable or noisy.  Additionally, owners often place litter boxes in areas of the house that are not used by the cat.  Previous studies have indicated that cats may have a preference for eliminating in areas where they spend the majority of their time; this is especially true for kittens and geriatrics who may not venture into other areas of the house often 4 .

Substrate aversions occur when a cat develops an aversion to the type of litter and/or box that is being used.  Three common causes for developing substrate aversions include aversions to tactile sensation, aversions to scent of the litter, and previous negative experiences that the cat has learned to associate with the litter.  A cat may be innately averse to certain qualities that influence the tactile sensation of a given litter; for example, some cats may not like large granular litter or litter with high moisture content.  Some cats may dislike the smell of certain litters and develop an aversion to the litter and litter box.  Further, a cat may learn to associate negative experiences with the type of substrate/litter that he/she is being offered.  An example of this may be a recently declawed cat that has gotten litter in his/her surgical site and has learned to associate the litter type with pain.  Finally, the cat may develop an aversion to the type of litter box that is being offered.  Some cats may not like boxes that are enclosed at the top or may have difficulty with very deep sided litter boxes.  The latter is often true for geriatric or arthritic cats as it may be painful for them to get in and out of the box 4 .

Along with aversions to location and substrate, preferences may also occur to either location or substrate.  Often preferences occur secondarily to aversions.  For example a cat may develop an aversion to the litter box location/substrate and consequently find that it actually prefers the tactile stimulation of carpet or bedding over its litter.  However, primary aversions may develop in isolation, as well.  Cats often develop primary substrate preferences for soft litters, such as finely granulated clumping litters and when a litter type is switched to a different kind they may seek out a softer place to eliminate that mimics their preference for the former litter.  Cats also develop location preferences.  Examples of this might include shy cats that prefer to eliminate in quiet and more predictable areas of the house.  Another example may be a cat that prefers a given site in the house because of a certain smell or view 4 .

Feline spraying or marking, in contrast to inappropriate urination and defecation, is more commonly associated with social dynamics, and is a normal behavior in cats.  Cats use spraying as a means to communicate and/or mark their territory.  It is more commonly associated with male behavior, and neutering of male cats has proven to be a successful treatment option for many spraying problems in tomcats.  Females are less likely to spray; however, it is not uncommon for this problem to occur in households with female-only cats.

With regards to social communication, spraying may occur in either a dominant or non-dominant cat.  A dominant cat may use spraying to mark his territory or display aggressiveness toward another feline in the household.  A less dominant or subordinate cat may spray in response to feeling threatened, fearful, or contested by another cat.  If a cat is spraying, social dynamics should be thoroughly investigated by the owner to determine who/what may be causing the marking behavior.  If the spraying behavior is occurring in a single cat household, one should investigate whether outside cats may be contributing to the situation.  Other causes for spraying may include competition with human counterparts or a recent relocation to a new home 5 .

Risk factors have been identified that appear to be associated with an increased incidence of behavioral IE disorders.  Some statistically significant risk factors include reduced digging before and after elimination and the use of a scented litter.  Other risk factors that may contribute to IE include improper litter box cleaning, an inadequate number of boxes in the household (at least one for each cat in the household), multiple cat households, and any disruption of the cat's normal routine.  Further, any medical problem causing a diseased state of the urinary tract significantly puts the cat at increased risk for developing an IE disorder.  Medical causes for IE are discussed below 6 .

Non-Behavioral Causes of Inappropriate Elimination

Every cat that presents with an IE disorder should have a complete diagnostic work up to rule out non-behavioral causes for elimination disorders.  Any form of urinary tract disease in cats can cause inappropriate elimination disorders.  These cats will also often present with blood in their urine, painful urination, difficulty urinating, urinating more frequently, or producing a greater or lesser volume of urine; however, these signs are not consistent and the absence of additional signs beyond IE cannot be used to rule out urinary tract disease.  Feline lower urinary tract disease (FLUTD) is a common syndrome that occurs in cats and includes any disease or disorder that affects the lower urinary tract.  Examples of such diseases include cystitis and urolithiasis.  Cystitis is inflammation of the bladder wall and may be caused by both infectious and non-infectious causes.  Urolithiasis refers to a disease state in which there is a precipitation of minerals that causes stone formation in the urinary tract.  The feline patient often exhibits signs that may manifest as a behavioral IE disorder and FLUTD can be overlooked if a complete diagnostic work up is not performed 5 .

Finally, there are many other medical conditions which may cause inappropriate elimination in the feline patient.  Kidney disease is a common disorder affecting the geriatric population.  Cats with kidney disease often have increased urgency and frequency of urination and may not make it to the box in time.  Other disease states which may contribute include endocrine diseases such as diabetes and hyperthyroidism, as well as gastrointestinal diseases.  Furthermore, arthritic cats may have a difficult time maneuvering themselves in and out of the litter box which can contribute to the progression of IE.  Geriatric patients may be at an increased risk for developing these diseases 4 .  Therefore it is imperative to perform a complete diagnostic workup on all aged feline patients showing signs of IE disorder.

Management of IE in Cats

According to the feline behavior guidelines published by the American Association of Feline Practitioners, the appropriate management of any feline behavioral problem is to first rule out any non-behavioral or medical causes, modify the cat's environment in a positive way, and intervene with the cat's behavior in such a way that creates a positive learning experience.  Medication should only be used as a last resort, and should be used in conjunction with behavioral modification techniques 2 .

The first steps that should be taken to modify the cat's environment are to interfere with the olfactory component of house soiling and make the IE sites more unattractive to the cat.  All locations in which the cat is inappropriately eliminating should be thoroughly cleaned; the owner should use enzymatic cleaners to eliminate the odor, if possible.  Depending on the area of the house in which the cat is eliminating, it may be warranted to confine the cat from that area until the owner is confident that the IE behavior has resolved.  Techniques should also be utilized that create aversion to the IE site.  One may place materials such as plastic, aluminum foil, double-sided tape, or bubble wrap over the site, place threatening objects such as a mirror or vacuum cleaner near the site, and/or invest in an ultrasonic device to deter the cat from going near the site.

Next, the owner should modify the cat's litter box environment to determine why the cat is having IE, as well as to correct the problem.  To determine if location aversion is causing the IE, the owner should move the litter boxes to other locations throughout the house.  If the current placement of the litter box is in the laundry room, for example, they could move it to a location that is more likely to be utilized by the cat, such as the family room.  This is especially true for geriatrics and kittens, who often spend their time in one or two preferred locations throughout the house.  Further, it may be advisable for the owner to add additional litter boxes to the home and distribute them throughout the house.  If moving the litter box helps to stop the IE, one might reasonably expect that the IE was due to a previous location aversion.  If, however, the cat appears to prefer the IE site due to the location in the house, and not because it is averse to other locations in the house, the owner may elect to place a large litter box over the IE site to promote appropriate use of the litter box.

In order to detect and/or treat substance aversions and preferences, the owner may also concurrently offer what is termed a "litter box cafeteria" to the cat.  The owner can experiment with various types of litter such as very fine clumping litter, pellets, pine shavings, crystal litter, or even newspaper.  By analyzing the material upon which the cat has chosen to eliminate, it may give the owner a better idea of which litters to experiment with first.  For example, if the cat is urinating on bedding or laundry, he/she may prefer soft substrates; the owner could experiment first with a soft litter variety such as finely granulated clumpable or pine shavings.  If the cat was an outdoor cat at one point, a substrate similar to dirt may be advisable.

Other modifications to the litter box include committing to cleaning the litter box at least one to two times daily, as cats often become averse to litter and litter boxes due to cleanliness issues.  Further, changing the type of litter box may also be helpful; for example an arthritic cat may not be able to get into a deep-sided box and a shy cat may prefer a litter box with a lid 6 .

If these methods do not prove to be helpful in eradicating the problem, the owner should scrutinize the social interactions occurring between the cat and other animals of the household; especially if the cat is spraying.  While social conflict can be difficult to resolve between cats, there are steps that can be taken to help alleviate social conflict.  The cats may need to be separated for a period of time while other environmental adjustments are made.  If there is obvious feline aggression occurring, this should be brought to the attention of the veterinarian.  Some modifications that may be suggested may include placing bells on the cats' collars, changing feeding habits/environments, altering play/social time, etc 4 .

Creating positive learning experiences should be a top priority for any owner battling feline IE.  One should be aware that punishment such as rubbing the cats face in the soiled spot, swatting the cat, or any other form of physical punishment are not productive means of creating learning in cats.  They should understand that these actions can actually contribute to creating a greater degree of elimination anxiety in the cat.  The AAFP states that the most effective way to intervene is to disrupt the unwanted behavior every time that it happens.  While this may not always be possible, the owner should be advised to disrupt the behavior as soon as it occurs, preferably within 30 to 60 seconds of onset, for the greatest effectiveness.  A common and suggested approach is to startle the cat with a loud, unpleasant sound.

If behavioral modification strategies do not work to resolve the IE behavior, pharmacological intervention may be utilized at the discretion of the veterinarian.  Pharmacological intervention alone typically does not resolve IE behaviors, and should be used in conjunction with behavior modification strategies.  Three classes of drugs that are commonly used include benzodiazapenes, tricyclic antidepressants (TCAs), and specific serotonin reuptake inhibitors (SSRIs).  These drugs work to reduce anxiety that may be associated with or contributing to IE behaviors.  Typically these drugs are administered over a course of several weeks and are tapered off as the behavior resolves, however, some cats may need to be on these drugs more long term.  As with all drugs, unwanted effects often occur and the veterinarian and owner should discuss the potential risks and benefits before beginning a trial therapy 4 .

Treatment for medical causes of inappropriate elimination will vary based on the disease or disorder that is diagnosed.  A variety of treatments exist for patients exhibiting FLUTD, some of which include antibiotic administration, anti-inflammatory administration, nutritional management, and surgical intervention.  Patients with kidney disease will often be treated with fluids, nutrition management, and various medications.  Diabetic patients may be placed on insulin and hyperthyroid patients will likely be treated with thyroid medication.  Arthritic patients may be administered medications to help alleviate pain and supplementation to help support healthy joints.  These treatment regimes will be determined by the veterinarian following a complete and thorough examination and diagnostic work-up.

Outcomes

Management of feline IE disorders is often difficult for owners, as behavioral modification can be stressful to both the owner and the cat.  However, owners should be advised that the "prognosis" for feline IE is quite good if caught early and appropriate behavior modification and/or pharmacological intervention is employed.  In fact, one study reported an 83% to 100% rate of success or significant improvement in IE behavior if treatment was sought within 6 months of the start of the problem 6 .  If a medical disorder is diagnosed, the prognosis or outcome will be dependent upon the disease diagnosed.  If the condition is able to be resolved, however, IE behaviors will likely resolve, as well.  Having a greater understanding of normal feline elimination and knowledge of some of the underlying causes of feline IE can help owners and veterinarians to identify IE disorders early, which increases the chances of successful outcomes for the owner and their cat.

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