How I approach… Feline idiopathic cystitis

Introduction

The intermittent presence of dysuria, stranguria, hematuria, pollakiuria and/or periuria with no identifiable medical cause in a cat may be consistent with feline idiopathic cystitis, or FIC. This is also the most frequent condition that produces clinical signs related to the lower urinary tract in this species. Feline idiopathic cystitis occurs when a susceptible cat is exposed to internal or external stress, and it is increasingly accepted that FIC is a condition involving the lower urinary tract, rather than a medical condition of the lower urinary tract.

Pathophysiology

Bladder abnormalities

In healthy cats, the urothelium is protected by a layer of glycosaminoglycans (GAGs), but in cats with FIC, the excretion of GAGs in urine is decreased 1. If the GAG layer and/or the urothelium are compromised, there may be contact between substances in the urine and the sensory nerves of the bladder, which could lead to neurogenic inflammation 2. Increased permeability of the bladder is also documented in cats with FIC 3.

Neuroendocrine abnormalities

An increase in the immunoreactivity of tyrosine hydroxylase has been noted in the locus coeruleus and the paraventricular nucleus of the hypothalamus in cats with FIC (Figure 1) 4. Tyrosine hydroxylase is a rate-limiting enzyme in the conversion of tyrosine to catecholamines such as norepinephrine. Cats with FIC therefore produce more catecholamines and have higher circulating catecholamine levels than unaffected cats 5, with a resultant over-activation of the sympathetic branch of the nervous system. Furthermore, chronic stimulation of the alpha-2 receptors of the locus coeruleus leads to their desensitization, adversely affecting their role in inhibiting the release of catecholamines, which contributes to the inflammatory response 2.

As FIC symptoms are often related to exposure to stressors, it is interesting to note that cats with FIC exhibit suboptimal activation of the hypothalamic-pituitary-adrenal (HPA) axis. Indeed, one study reported that administration of exogenous corticotropin-releasing hormone did not cause an increase in ACTH and cortisol in cats with FIC 6. Another study reported that the adrenal glands in cats with FIC were smaller than in normal cats 7.

Risk factors

The identified risk factors for FIC vary from one study to another, but certain elements are highlighted in several sources. Overall, affected cats tend to be middle-aged, overweight males 8. Environmental risk factors, such as living entirely indoors, being a low-activity cat, and residing in a dwelling with multiple cats, have also been identified 8. Conflict with other cats, moving house, or being nervous or scared are also elements recognized as risk factors 8.

Diagnosis

FIC is a diagnosis of exclusion. The main differential diagnoses are urolithiasis, a behavioral problem such as marking or urinating in the house, or a urinary tract infection. Once I have compiled a case history, I move on to basic diagnostic procedures, which include a physical examination, urinalysis and abdominal X-rays. For cases which are recurrent or persistent, ultrasound of the urinary tract should be considered. At the initial consultation, I usually recommend complementing the urinalysis with hematology, biochemistry, and total T4 measurements. If diagnostic procedures do not reveal any abnormality, or simply identify bladder inflammation, a more detailed case history (Table 1) should be obtained to determine if FIC risk factors are present and to identify possible sources of stress in the patient's environment.

Treatment

The treatment plan for FIC may vary from one cat to another, and should involve identifying possible sources of stress for the affected individual and what is required to reduce or eliminate these sources (Table 2). When treating this condition I focus on introducing environmental modifications aimed at reducing stress. One study looked at the occurrence of gastrointestinal, urinary or dermatological diseases and abnormal behavior in cats with FIC and normal cats over a period of 77 weeks 9. Any changes in routine or the environment were noted; these included variations in the care routine, lack of contact with the habitual carer or being cared for by unfamiliar individuals, altered feeding routine, lack of playtime and lack of environmental enrichment in the cage. Exposure to such types of changes significantly increased the relative risk of having partial anorexia, of not toileting for 24 hours, and of defecating and urinating outside the litter box. This was seen equally in cats with FIC and normal cats. In a controlled and enriched environment, it seems to be possible to get FIC-prone cats to have no further episodes of clinical signs or abnormal behavior compared to normal cats 9. This is why it is so important to put a maximum of effort into reducing possible sources of stress for cats with FIC. 

The Indoor Pet Initiative at The Ohio State University is an excellent and free online resource for both owners and animal health professionals to help achieve this goal 10. Stress suffered by or affecting an individual animal is on a continuum, i.e., it is cumulative. The goal is to allow the cat to remain below the reactivity or illness threshold for a given individual. To do so, a multimodal environmental modification(MEMO) approach has been shown to be effective 11. It includes the elements that are addressed below.

Optimal litter box care

When trying to create the "perfect bathroom" for a cat, there are four main categories that I consider: substrate, tray, cleanliness and location (Table 3). Without doubt individual preferences may exist, but most cats will have similar standards.

For the substrate, a clumping, unscented, finely textured litter is recommended. The bottom of the litter box tray should be covered with at least 5 centimeters of litter.

Litter boxes must be large. Most authors suggest that they should be at least 1.5 times the cat’s size, from the tip of the nose to the base of the tail. The cat must be able to fully enter the litter box, turn around and scratch while extending its legs, but most commercial litter boxes do not meet these standards. I often recommend using large storage bins, such as those designed to fit under beds; these provide a sufficiently large surface area, yet the edge is not too high for the cat to step over it. Some owners are more creative and will use other types of containers (Figure 2). If owners choose storage bins with a high edge, I suggest they cut an opening in one side for easy access. Litter boxes must also be changed annually, as plastic is a porous material.

Most authors recommend uncovered litter boxes; however, at least one study has reported that this does not make a real difference to most cats 12. Rather, it seems that the location of the litter box, its cleanliness and the substrate are more important for most cats than the presence or absence of a cover. Nevertheless, I tend to recommend uncovered litter boxes, as it seems that owners generally care for them more when waste is visible or smells are more obvious. Finally, if there is more than one cat, the number of litter boxes should be sufficient so that one individual cannot block access to the litter boxes. This is the reason for the frequent recommendation that the number of litter boxes be equal to the number of cats plus one.

Cleanliness of the litter tray is a key element, and waste must be removed daily. Experience indicates that the element owners most frequently neglect is thoroughly cleaning the litter box. This should be done at least once a month when clumping litter is used and more frequently for non-clumping litter. This involves discarding the litter, cleaning the litter box with warm water and soap, and refilling it with new litter once dry.

Finally, the trays should be both easily accessible and located in areas with little disturbance. In houses with two or more floors, at least one litter box should be placed on each floor. Also, multiple litter boxes in the same room only count as one litter box; as far as access is concerned, there is no real benefit to having more than one litter box in the same room.

Space

Three-dimensional space is important for felines, and cats should be offered plenty of space that enables them to express normal behaviors. It is therefore wise to offer several choices of high places for cats to climb and rest. In households with more than one cat, I believe it is essential that some of these structures should be sized for just one cat; this means that if one cat is already occupying a perch, it is more difficult for another individual to come and dislodge the occupant.

Stable scratching posts, made with a variety of materials and high enough for cats to scratch while stretching, should be accessible near resting areas. Indeed, many cats scratch when getting up after a period of rest.

Cats are predators that hunt small prey in the wild, and numerous attempts at hunting end up in failure. Therefore the time indoor cats spend feeding should reflect this, and food-dispensing toys that encourage cats to work for food and explore their environment are particularly interesting. Preferences vary from one cat to another, and it is wise to rotate the items used to maintain interest and an adequate level of mental stimulation. Some toys involve more movement, while others are more static but require greater use of their paws (Figure 3).

It is important to ensure that each cat can access all resources at all times, especially in multi-cat households. Therefore, several places should be provided for eating, drinking, resting, scratching, etc. Cats that live together should not be forced to cross paths or use the same resource at the same time unless they want to. It is wise to have all these resources on each floor of a house, even in a household with only one cat. As such, if a cat needs to toilet, it does not necessarily need to climb stairs to access the litter tray and meet its needs. The same applies if visitors are present; the cat should be able to stay within its comfort zones if it does not want to interact with strangers.

Predictability and routine

As mentioned above, small alterations in routine can be sufficient to cause changes in appetite and elimination for cats, and can even result in inappropriate toileting. Therefore, having the most stable schedule and environment possible is recommended. If changes must take place, this should be gradual wherever possible. For example, if a dietary change must be made, it is recommended to continue to offer the current diet at the usual feeding place whilst introducing the new diet at the same location. Gradually, owners can give less and less of the usual diet and more and more of the new diet.

Structured and predictable interactions with owners should be prioritized. To achieve this goal, punishment should be avoided; in fact, punishment can increase stress and weaken the human-animal bond. I recommend that my clients identify their cat's favorite interactions with them and set aside periods for such interactions at the same time each day. For example, a brushing session in the morning after breakfast, then a play session with a toy on a stick after work, and petting in the evening before bedtime.

Diet and water consumption

Many diets are designed to help maintain urinary health for cats, but to date studies have not definitively shown that such diets will help in all cases of FIC. When treating such cases I tend to focus more on water intake than dietary composition, although I will always ensure that the cat is being fed a balanced diet. I encourage owners to increase the cat’s water intake, and will often recommend that canned (wet) food is offered wherever possible, as it can result in a lower recurrence of FIC 8 13 14. The use of water fountains is often recommended for cats with FIC, although one study noted that this did not result in a statistically significant increase in water intake with a group of cats; however, clear individual preferences for how the water was offered were noted 15. It therefore seems wise to offer both a water fountain and a water bowl to a cat to discover its preferences.

Medication

Because FIC is self-limiting, pharmacological therapy aims to improve the patient's comfort during an active episode. I consider drugs such as buprenorphine (as it can be administered under the tongue at home by cat owners), or gabapentin can be useful in some cases, as it has an effect on neurogenic pain and anxiety. However, neither drug is licensed for treating FIC. Studies have shown that amitriptyline is not recommended for acute management of FIC 16 17, but is effective in decreasing the clinical signs of recurrent FIC 18.

If intercat aggression has been identified as a source of stress, it must also be addressed, and medication may be required. If a cat with FIC has been the victim of aggression from another cat, the victim is not necessarily the one that should be medicated; in fact if this type of aggression is identified, it is usually the aggressor who is exhibiting the abnormal behavior. It is therefore common for the aggressor to require appropriate pharmacological treatment and behavioral therapy in order to address the problem at source and thereby reduce stress to the victim. However, sometimes the victim will also benefit from concurrent pharmacological therapy to reduce stress or anxiety.

In certain cases, despite optimal litter box care, plentiful surroundings, maintaining a routine, proper diet and addressing aggression, it will be clear that a cat with FIC still shows signs of fear or anxiety. In such cases, the use of psychotropic medication may help to keep the animal's stress level low enough to help decrease the recurrence of FIC, and fluoxetine, a selective serotonin reuptake inhibitor, is one of my top choices for treating anxiety in cats. The fluoxetine dose that I use is 0.5-1.0 mg/kg PO once daily, but I always start at the low end of the dosage range and increase progressively if necessary.

FIC can become a source of frustration for owners, especially if they do not fully understand what is happening. As animal health professionals, we should be clear that, thanks to current knowledge, FIC should no longer be regarded as a urinary tract problem. Owners have far greater power than they realize to decrease the recurrence of FIC: they can, with our support, change the cat’s environment to make this possible. If, despite all their efforts in this regard, their cat cannot cope with the residual sources of stress, a pharmacological treatment may help, but it is far better to address the environmental factors first.