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Cats with feline idiopathic cystitis (FIC) are believed to have an abnormal response to environmental stressors, which may contribute to development of lower urinary tract signs including urinating outside the litter box, frequent attempts to urinate and blood in the urine.
"The signs of stress in cats may be subtle and include hiding from people or other cats, conflict with another cat in the home, exaggerated startle response to sudden or loud noises, and fearful behavior," said S. Dru Forrester, DVM, MS, Dipl. ACVIM, director of Global Scientific Affairs at Hill's Pet Nutrition of Topeka, Kan.
"When a cat perceives environmental stress, it stimulates the brain and activates the stress response system."
This "flight or fight" response enhances a cat's sympathetic nervous input down the spinal cord to the urinary bladder. In normal cats, the adrenal glands release cortisol, which dampens the sympathetic response.
In contrast, cats with FIC have a blunted cortisol response, which fails to adequately restrain sympathetic input to the bladder.
"Increased sympathetic input to the urinary bladder causes neurogenic inflammation and increased permeability of the bladder," Dr. Forrester said. "The end result is increased perception of pain and the typical clinical signs of lower urinary tract disease (pollakiuria, stranguria, accidents outside the litter box), which leads to additional stress."
John M. Kruger DVM, Ph.D., professor at Michigan State University's Department of Small Animal Clinical Sciences, said that clinical experiences and observations by cat owners suggest that chronic stress caused by environmental, psychological, physiologic, or concurrent illnesses may play a role in precipitating or exacerbating signs.
"It's interesting that stressful events such as earthquakes, seasonal weather changes, moves to a new home, major holidays and even food changes have been associated with recurrent episode of lower urinary tract signs," Dr. Kruger said.
"Even minor external events, such as sudden movements, loud noises, unfamiliar places, objects, or people, or changes in regular routine, have been shown to increase the frequency of urination outside the litter box in cats with FIC, as well as healthy cats."
Recent studies have revealed that FIC signs are often the result of complex interactions between the bladder, nervous system and adrenal glands.
"Environmental stress increases stimulus to the brain and activates the stress response system," said Mark Brady, DVM, Dipl. ACVECC, manager of the Veterinary Consultation Service at Hill's Pet Nutrition of Topeka, Kan. "Stress appears to be an important factor in episodes of FIC and often precedes a cat's first episode. Acute signs of stress include crouching, shaking, tail close to the body, dilated eyes, hissing and growling. These signs may be a result of a specific incident or threat."
The pain, suffering and inappropriate urination associated with lower urinary tract signs (LUTS) can cause a great deal of stress for cats and their families. But what can be doubly frustrating is that stress itself can cause the most frequent instance of LUTS.
Brady said stress may be managed by environmental modification, behavior therapy, pharmacologic therapy or pheromone therapy. Often, successful management entails a combination of interventions depending on the specific circumstances of each patient.
Nutrition also plays a key role in successful management of cats with feline idiopathic cystitis. To date, the effectiveness of only one treatment—Hill's Prescription Diet c/d Multicare Urinary Stress—is clinically shown to reduce the recurrence of FIC signs by 89 percent and is formulated with ingredients to help manage stress.
"The nutritional profile of c/d Multicare, which incorporates increased levels of long-chain omega-3 fatty acids and antioxidants, may serve to reduce inflammation associated with idiopathic cystitis and minimize inflammation-induced lower urinary tracts signs and intrinsic stress that may be associated with the condition," Kruger said.
Forrester said Prescription Diet c/d Multicare Urinary Stress contains hydrolyzed casein and L-tryptophan, ingredients known to help manage stress and anxiety in cats.
The Brain-Bladder Connection
The relationship between the brain and bladder is extraordinarily complex and the specific mechanisms by which stress may precipitate lower urinary tract signs in cats are not completely understood.
The easy answer is that acute or chronic stress from any source may increase norepinephrine biosynthesis in the pontine locus coeruleus in the brain, leading to increased sympathetic autonomic outflow.
According to Kruger, this stress-induced activation of the sympathetic nervous system may influence bladder function through activation of the pontine micturition center and increased efferent output to pelvic parasympathetic neurons that regulate bladder contractions; direct alteration of urothelial tight junction integrity, permitting greater contact of urine substances with bladder sensory neurons, resulting in increased afferent signaling and local inflammation; and activation of the immune system and release of proinflammatory cytokines that may induce a variety of sickness behaviors that include lower urinary tracts signs.
Brady notes that the involvement of the central nervous system may explain why therapies directed only at the bladder have a high failure rate.
"Results of studies over the past 20 years indicate that idiopathic cystitis in cats is the result of complex interactions between the bladder, nervous system, adrenal glands, husbandry practices, and the environment in which the cat lives," he said. "FIC has been described as an exaggerated sympathetic nervous system response to stress with a blunted endocrine response."
It's easy to overlook signs of stress or anxiety in cats but it may be more common than you think. In one study of more than 1,000 cats, over half (55 percent) had behavior problems based on observations by owners, and the most common was anxiety (Heidenberger Appl Anim Behav Science 1997; 52:345-364).
Remember that some cats are very good at hiding illness or injury. Consequently, it may be difficult to recognize stress in cats.
If signs of stress are developing, Brady said, then c/d Multicare Urinary Stress could help reduce the rate of recurrent episodes of FIC.
This Education Center article was underwritten by Hill's Pet Nutrition of Topeka, Kan.
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