WVC 2017: Distinguishing Mental and Physical Disease in Cats

At the Western Veterinary Conference, Valerie Tynes, DVM, DAVB, discussed the interactions between physical and mental health in cats, including the difficulties in discerning behavioral issues from physiologic diseases.

Cats are exceptional at hiding signs of illness. Stress can also cause cats to display behaviors that may be mistaken for signs of disease. For example, decreases in appetite, activity, or grooming can all be indicative of either physical disease or mental stress.

Stress, said Dr. Tynes, can be defined as “any physical, chemical, or emotional force that disturbs homeostasis and the accompanying response that attempts to restore homeostasis.” Fear may be defined as a response to a threat, whereas anxiety is the response to a perceived threat, or the emotional response to a threat. Both chronic fear and chronic anxiety can result in stress, a disturbance in the cat’s homeostasis.

Appropriate stress is meant to be adaptive and to help an animal deal with a change in its environment. Chronic stress, on the other hand, may be maladaptive and may cause disease states on its own. Chronic stress may lead to damage to the cardiovascular, reproductive, digestive, and immune systems. Additionally, said Dr. Tynes, “permanent structural and functional changes are possible” in the brain; memory capabilities may be enhanced temporarily in cases of stress.

This damage is due to the overstimulation of two physiologic systems. The sympathetico-adrenomedullary system is activated, causing release of epinephrine and norepinephrine. This release is designed to conserve oxygen and redirect it to muscles allowing for escape. Additionally, the hypothalamic—pituitary axis is stimulated, whereby corticotropin-releasing hormones cause release of cortisol. Cortisol release causes an increase in heart rate and respiratory rate, while the reproductive and gastrointestinal systems are suppressed.

These two systems are stimulated in cases of both mental and physiologic stress. Physiologic stress may be induced by hunger, thirst, pain, chronic illness, sleep deprivation, and exposure to extreme temperatures. Mental or psychological stress may be induced by exposure to novelty, unpredictable environments, and situations that lead to frustration or fear. Social conflict between cats is also a common source of psychological stress, but the signs may be subtle, such as blocking behavior or cats staring. When cats are well socialized and comfortable with each other, they often will groom each other and sleep touching one another. Cats not displaying these behaviors may be in conflict.

When a clinician is assessing whether a disease is behavioral or mental, it is important to tease out various aspects of the history and signs. Dr. Tynes recommends a thorough baseline physical examination and behavior assessment, as well as asking key historic questions of the client. For example, it is important to note how many cats are in the home as well as the physical health of those cats. Any household changes should be documented. It is also vital to note the presence of resources such as litterboxes, food, water, and stimuli such as cat trees or vertical jumping locations. All of these are required for the mental and physical health of each cat, and any cat that is cut off from these resources may feel significant stress.

Stress can have a direct impact on a number of disease states. One example is urogenital disorders, specifically feline idiopathic cystitis (FIC), which is known to cause inappropriate elimination. As reported in scientific studies, cats suffering from FIC are known to have an inappropriate response to stress, resulting in increased permeability of the urinary bladder. Although not all causes of FIC are known, stress definitely plays a role.

Veterinarians can help support their patients by recommending enrichment, such as adequate vertical space, as well as appropriate pain control. It is important to decrease stress, and treatment options include synthetic pheromones, neutraceuticals, or anxiolytic medications.

Amanda Landis-Hanna, DVM, graduated from Auburn University in 2002. Since then, she has practiced small animal, exotic, shelter, and relief medicine. She was a VCA medical director for 7 years in California and Virginia, and she served as director of veterinary medicine for Voyce from 2013 to 2016. Dr. Landis-Hanna resides in Virginia with her family and rescue Labrador, Sophie.