The most common behavior problem of cats is inappropriate elimination (IE). It is the cause of owners taking drastic measures including banning the cat to the outdoors, abandonment, surrender to a shelter, and euthanasia. It is important that a simple cookbook answer not be used for these cats as is illustrated by the approach that I use.
Most IE is driven by a behavior disorder. However, there is almost always something that initiates the problem. Sometimes IE begins with a stress-producing or insecurity-producing event. Sometimes it begins due to a medical condition. We need to try to find the initiating event and deal with it. If we can do so, treatment for the initiating event is done simultaneously with treatment for the behavioral aspect. However, sometimes the initiating event is resolved, and we only left with the behavioral aspect. But, failing to look for the initiating event can be a disastrous oversight when dealing with this problem.
Underlying medical causes
Although many cats present with behavior-driven IE, this behavior may originate in several physical abnormalities. It is important to address these before proceeding to behavior modification techniques. History is sufficient for some; specific tests are needed for others.
Bladder inflammation, whether sterile or bacterial cystitis, frequently results in inappropriate urination. These cats typically have one or more clinical signs of dysuria, pollakiuria, increased frequency of urination, and hematuria. However, these may be present and missed by owners. Urinalysis usually reveals bacturia, hematuria, and crystalluria although some affected cats will have a normal urinalysis. A urine culture is the most sensitive way of detecting bacturia. Bladder ultrasound can detect chronic cystitis (thickened, irregular bladder walls) as well as uroliths.
Certain types of pain may be manifested when the cat goes to the litter box and positions to urinate or defecate. Most notable is pain from the lumbar spine, lumbosacral junction, hips, and knees. Uroliths in the bladder can also create pain that is manifested when the cat urinates. The discomfort associated with constipation can also be litter box related. These cats' histories may include lameness, reluctance to jump or run, failure to raise the tail when petted, increased sedentary lifestyle, hiding, personality change (especially aggression), reluctance to being picked up, sitting or lying down slowly, a hunched up posture of the back, standing (instead of squatting) in the litter box when urinating or defecating) and protecting a body part. Radiographs of these areas are diagnostic. Litter box-related pain can also be generated by ingrown toenails, especially in older cats, and clumping litter that sticks to the hair on the ventral surface of the feet. These can be detected by examination of the feet. Impacted or infected anal sacs will become painful when the cat defecates, sometimes resulting in a litter-box-pain association. Anal sac palpation or expression is diagnostic.
Polyuria may cause a cat to urinate inappropriately. Common causes of polyuria in cats include diabetes mellitus, renal disease, and hyperthyroidism. Blood panels that include glucose, creatinine, BUN, and total T4 are diagnostic.
The work up
The ideal workup consists of directed history taking, physical examination, a blood chemistry panel including total T4, radiographs of the abdomen, lumbar spine, hips, and knees, bladder ultrasound, urinalysis, urine culture, and anal sac palpation/palpation. When possible, the minimal workup should consist of directed history taking, physical examination, anal sac palpation/expression, radiographs, and urinalysis. Your clinical judgment and the owner's motivation and finances will direct how extensive your workup can be.