Valarie V. Tynes, Colleen S. Koch, and Leslie Sinn Behavior can change as a result of medical problems or physiological changes. If shelter operations, behavior, and/or medical staff identify behaviors that may have an underlying medical cause, they can be addressed immediately, relieving suffering and increasing the adoptability of the animal. Conversely, if medical conditions that cause or exacerbate problematic behaviors are missed, time may be wasted on training or attempted behavior modification, thus prolonging suffering and time spent in the shelter. At the same time, a complex relationship can exist between physical conditions or disease and behavior, so careful attention must be given to how the two systems (mind and body) affect each other. To provide optimal medical care for any animal, it is imperative that we first move beyond the paradigm where we attempt to separate “medical” conditions from “behavioral” conditions. All medical conditions will result in some behavioral change (American Psychiatric Association 2013). Many of these are the most basic of signs and symptoms that all veterinarians are taught to look for, such as the lethargy and anorexia associated with many illnesses. In addition, every behavior is a result of neurochemical action at the molecular level in the nervous system and thus cannot ever be completely separated from the physiological (see Figure 4.1). While some behavioral changes can be associated with organic diseases, such as space‐occupying masses in the central nervous system or the changes that occur as a result of infection and/or inflammation, other behaviors can result from dysregulation at the neurophysiological or neurochemical level—problems that we still have much to learn about. It is hoped that with advancing technology, our understanding of the neurophysiologic basis of behavior will continue to improve. Using a medical model approach to problem behaviors can improve communications between caregivers, shelter staff, and the rest of the health care team. This approach broadly categorizes behavior problems using terminology similar to that used in human mental health. However, these categories are purely descriptive and often attempt to assign a motivation to the unwanted behavior. This terminology does not necessarily reflect a knowledge of the cause, mechanism, or neurobiology underlying the behavior (American Psychiatric Association 2013). Some behaviors may reflect a dysregulation or disruption of the neurological system and may thus be considered truly malfunctional, as the medical model suggests. Other behaviors may represent an animal’s attempt to adapt to an environment to which adaption is not completely possible and should be considered maladaptive (Mills 2003). Having a thorough understanding of normal species‐typical behaviors for the animal in question is critical to developing a management and/or treatment plan for the individual exhibiting maladaptive or malfunctional behaviors. A third category that will not be covered in this chapter is the normal adaptive behaviors of animals that are simply inconvenient or problematic for their caretakers. See Chapters 12 and 18 for more information on training and behavior modification. Figure 4.1 This diagram depicts how genetics, the environment, and medical conditions/disease processes all contribute to behavior. The relationship and interconnectedness of all of these components will be reflected in the overall health and welfare of the individual. A variety of different disease processes can cause and/or contribute to the worsening of both maladaptive and malfunctional behaviors. Many individuals will simply differ in how readily they react to stimuli, the degree to which they respond, and how long they stay emotionally aroused. These differences often represent normal individual variations in temperament and are also affected by an individual’s experience during development. It is well understood that dogs and cats continue to express many of the behavioral patterns expressed by their wild ancestors. The behaviors typical of sick animals represent a highly adaptive behavioral strategy, so it is not surprising that many of these behaviors have been retained in spite of domestication. Initially, most sick animals will display varying degrees of lethargy and anorexia. In many cases, this occurs due to the development of a febrile response. These behaviors, often viewed by caretakers as abnormal, are in fact normal and serve a beneficial purpose for the affected animal (see Box 4.1). Fever has the effect of assisting the animal to combat infectious disease by potentiating numerous immunologic responses (Hart 2010; Hart 2011). It also produces a body temperature that is inappropriate for the growth of most pathogenic organisms. The same physiologic response that produces the fever results in anorexia, and the animal, with no desire to move about in search of food or water, will save energy needed to make up for the increased metabolic cost of the fever. Due to the fact that febrile animals feel cold, they are likely to lie curled up. This reduces the body surface area and decreases heat loss by convection and radiation. Piloerection is also likely in sick animals, as it provides some increased insulating ability (Hart 2010). The lethargic, ill animal will spend less time grooming, so a coat that appears dirtier or oilier than normal may be an indication of illness. Grooming requires movement and thus expenditure of energy, and oral grooming can lead to a significant amount of water loss, especially critical to a febrile animal attempting to conserve water, energy, and body heat. There will be some variation in how rapidly these behavioral changes set in and in the degree to which they appear, depending upon the pathogen involved. Some diseases will cause a rapid and severe onset of lethargy and anorexia, while others may develop more slowly, and the behavioral signs may be less obvious. The status of each individual’s immune system may also affect the degree of illness experienced and thus the degree of behavioral change. An animal’s coat can provide important clues regarding its health status. Grooming behavior has evolved in mammals to serve a variety of purposes, depending upon the species. These behaviors may spread natural body oils throughout the coat, contributing to coat health and thermoregulation, as well as effectively decreasing ectoparasite loads (Hart 2011). Saliva contains a variety of antibacterial and wound‐healing substances, so that the predisposition for animals to lick body parts and wounds is likely an evolved behavioral tool for decreasing the incidence of infection (Hart 2011). When animals fail to practice normal self‐grooming behavior, it should serve as a warning sign that something is wrong. Some dogs can be adept at hiding their illnesses, but cats are even better at it. This may be due to the cat’s unusual position of being both predator and prey, depending upon the environment. Anorexia is often the first sign noted by caretakers of sick cats. The fastidious nature of the cat contributes to the ability to mask signs of disease. For example, if cats have diarrhea, they are likely to clean themselves, removing all signs of the mess, until they become too ill to do so. The more sedentary and nocturnal nature of the cat may also cause caretakers to overlook inactivity due to illness until it becomes severe. Unkempt hair coat in a cat should be immediately noted and a possible cause investigated because the cat must be either ill, injured, or otherwise impaired in its movement in order for it to stop grooming itself. A variety of different studies have suggested that monitoring sickness behaviors in the cat may be an excellent means of evaluating feline welfare and that cats’ behavior is a more reliable indicator of their level of stress than their physiological responses (Stella et al. 2013). One study demonstrated that the presence of unusual external events is enough to increase the risk of sickness behaviors in cats (Stella et al. 2011). When cats are exposed to multiple unpredictable stressors, including exposure to unfamiliar caretakers, an inconsistent husbandry schedule, and discontinuation of play time, socialization, food treats, and auditory enrichment, they demonstrate a higher incidence of sickness behaviors (Stella et al. 2013). These behaviors include increased vomiting (Stella et al. 2013), decreased food intake, avoidance of elimination for 24 hours, and elimination outside the litterbox (Stella et al. 2011). Nowhere else is the interplay between behavioral and physical health more apparent than when looking at the impact that stress plays on every aspect of health. Increasingly, science is uncovering the myriad of different ways in which stress affects living organisms at every stage of development. Much controversy exists about how to define stress, so for the purpose of this chapter, stress (or stressors) is defined as anything that disturbs or threatens homeostasis. These stressful forces may be physical, chemical, or emotional and typically result in physiological or behavioral responses as the organism attempts to restore homeostasis. The physiological events that occur during an acutely stressful event are intended to be adaptive, and, in most cases, they do succeed in helping an organism maintain homeostasis by adapting to the stressor. When stress is chronic and unremitting, or the individual cannot successfully act in such a way as to decrease the stressors, a variety of physiological events can conspire to damage the overall health and well‐being of the organism. Thus, in the long term, the stress response can be maladaptive. There are two primary components of the stress response, involving two different endocrine systems. The first is the sympathetic nervous system response. Within seconds of perceiving a stressor, the sympathetic nervous system begins secreting norepinephrine, and the adrenal medullae begin secreting epinephrine. This begins to prepare the body for “fight or flight.” The second system is the hypothalamic‐pituitary‐adrenal (HPA) axis, generally believed to be the body’s primary stress‐responsive physiological system (Hennessy 2013). When the HPA axis is triggered, the hypothalamus releases corticotrophin‐releasing factor that triggers the release of adrenocorticotropic hormone from the pituitary gland. This hormone then stimulates the release of glucocorticoids from the adrenal cortex. Several other hormones, including prolactin, glucagon, thyroid hormones, and vasopressin, are secreted from various other endocrine organs. The overall effect of these circulating hormones is to increase the immediate availability of energy, increase oxygen intake, decrease blood flow to areas not critical for movement, and inhibit digestion, growth, immune function, reproduction, and pain perception. In addition, memory and sensory functions are enhanced. Essentially, the goals of all of this physiological activity are to make more energy available for immediate use and to put on hold any and all processes that are not involved in immediate survival. Acute stress has been shown to enhance the memory of an event that is threatening (McEwen 2000). This is clearly adaptive if it allows the organism to form strong associations, enabling it to avoid dangerous things in the future. Knowing this should increase animal handlers’ awareness of the important and lasting impact that their behavior and actions can have on an animal. An unpleasant handling experience may have long‐term, negative effects on the animal’s behavior, ultimately making that animal less adoptable. If the stress response continues, for whatever reason, cardiovascular, metabolic, reproductive, digestive, immune, and anabolic processes can all be pathologically affected. The results can include myopathy, fatigue, hypertension, decreased growth rates, gastrointestinal distress, and suppressed immune functioning with subsequent impaired disease resistance. Chronic stress can even lead to structural and functional changes in the brain, and when extreme conditions persist, permanent damage can result (McEwen 2000). It is believed that when dealing with chronic stress, the HPA axis becomes dysregulated, and the various components of the system may no longer respond in the predicted fashion. For example, in some cases, chronic stress results in adrenal hypertrophy and elevated levels of glucocorticoids, while adrenocortical‐stimulating hormone (ACTH) levels remain unchanged. At this point, the dysregulation results in an HPA axis that is no longer able to respond appropriately to future stressful events, and measurements of glucocorticoid levels may become less meaningful (Hennessy 2013). Stress can arise from a variety of different sources, both physiological and psychological. Physical stress can be caused by hunger, thirst, pain, exposure to extreme temperatures, disease, illness, and sleep deprivation. Psychological stress can result from exposure to novelty, unpredictable environments, social conflict, and constant exposure to fear‐ or anxiety‐provoking stimuli as well as any other situation that leads to chronic frustration or conflict. A lack or loss of control is another important psychological stressor. In fact, novelty, withholding of reward, and the anticipation of punishment (not the punishment itself) have been found to be the most potent of all psychological stressors (McEwen 2000). A variety of different means have been used in an attempt to measure physiological stress, including but not limited to measuring glucocorticoids and their metabolites in hair, urine, feces, blood, and saliva. Glucocorticoids in blood and saliva do appear to measure the condition of the animal at that moment, whereas glucocorticoids in urine, feces, and hair reflect the condition of the animal over a longer time frame (Hennessy 2013). ACTH and luteinizing hormone‐releasing hormone stimulation tests have also been used to measure adrenal and pituitary sensitivities, respectively, and one study demonstrated increased HPA responsiveness and reduced pituitary sensitivity occurring in the face of chronic stress (Carlstead et al. 1993). The altered responsiveness was suggestive of HPA dysfunction. A decrease in peripheral lymphocyte numbers and an increase in neutrophil numbers, along with an increased neutrophil:lymphocyte ratio, is another well‐documented response to glucocorticoid release and has been proposed as another reliable method for evaluating the stress an animal may be experiencing (Davis et al. 2008). Studies have shown that the average shelter dog does have higher levels of circulating cortisol than pet dogs that were sampled in their homes (Hennessy et al. 1997). Some studies of shelter dogs have found that circulating levels of cortisol return to normal within days to weeks, but others have found that HPA axis dysregulation develops in some dogs (Hennessy 2013). Any single individual’s response to stress will vary as a result of several different factors such as genetics, temperament, experience, environment, and learning. For example, cats not socialized to people have been shown to be more likely to experience high levels of stress when exposed to people in a shelter setting (Kessler and Turner 1999a). Experiences during the first weeks of life have been shown to have profound effects on an animal’s ultimate ability to cope with stress (Foyer et al. 2013). The importance of the role of maternal stress on the developing offspring during the prenatal period is receiving an increasing amount of attention (Jensen 2014). Research in numerous species has demonstrated that when the gestating mother experiences stress, it can alter her behavior and affect the behavioral development of her young (Braastad et al. 1998; Chapillon et al. 2002; Champagne et al. 2006). Subsequently, her offspring often show a decreased ability to deal with stress: they may have some learning impairment and they may be more susceptible to the conditioning of fearful responses, especially to auditory stimuli (Ross et al. 2017). The individual’s perception of stress, which will also vary based on experience, is ultimately the most important factor that influences the effect of stress. Many potential stressors exist for the sheltered dog and cat. Table 4.1 provides a summary of common shelter stressors and behavioral signs of stress. Several studies have evaluated the stressors impacting shelter and laboratory cats. Shelter cats exhibiting higher stress scores are at higher risk of developing upper respiratory tract infections (Tanaka et al. 2012). One study reported that feigned sleep may be a coping mechanism seen in stressed shelter cats (Dinnage 2006). An increased need for restorative sleep has been demonstrated in both humans and animals exposed to physiological or biological stress (Rampin et al. 1991; Rushen 2000). These data suggest that while cats may appear to be the most relaxed of animals, they may, in fact, suffer the highest levels of stress. The stress level of most kenneled cats will decrease over the first few days to weeks. One study demonstrated that two‐thirds of cats will adjust well within the first two weeks (Kessler and Turner 1997). The same study demonstrated that about 4% of cats maintained a high level of stress for the entire study period, suggesting that for a small segment of the feline population, housing in the shelter for any extended period may not be in the best interest of that individual (Kessler and Turner 1997). Table 4.1 Common Stressors and Behavioral Signs of Stress in Shelter Dogs and Cats (Jones and Josephs 2006; Horváth et al. 2008; Beerda et al. 1998, 1999; Carlstead et al. 1993; Kessler and Turner 1999b; Tanaka et al. 2012; Kessler and Turner 1997; Dinnage 2006). Recognizing the behavioral signs of pain in non‐verbal species is challenging. Because animals can’t tell us when they experience pain, it is critical to train shelter staff to recognize their non‐verbal signs if we are to ensure good welfare. A number of problem behaviors can occur in dogs and cats in response to pain. These can include irritability (increased sensitivity and reactivity to stimuli), aggressiveness, restlessness, excessive vocalization, changes in activity level, and an increase in anxiety‐related behaviors. In an animal that was previously behaviorally stable, any abrupt changes in behavior can signal pain, but they are especially noteworthy when occurring in a middle‐aged or geriatric animal. Pain in the shelter animal may be even more difficult to identify since caretakers may not be familiar enough with an individual to determine what is normal or abnormal for that animal. To further complicate matters, physiologic responses to pain and stress can be similar, and because animals entering a shelter are likely to experience stress, this may make differentiating the two very difficult. In addition, it is normal for most animals to try to mask their pain, and they may be even more likely to do this when placed in a stressful situation. The objective signs of medical problems that typically result in pain cannot always be identified with a physical exam, radiographs, laboratory work, and so forth. Therefore, it is generally accepted that behavioral rather than physiological signs are the most important parameters we should attend to when evaluating pain in animals (Epstein et al. 2015). We should also always keep in mind that if a procedure, injury, or illness causes pain in humans, then it would be wise to assume that it causes pain in dogs and cats as well. Different animals will manifest pain differently, and there is no single behavior that can be considered pathognomonic for pain. Neither does the absence of certain behaviors always indicate the absence of pain. Many behaviors considered to be indicative of pain can also occur due to anxiety or fear in both dogs and cats. In addition, the presence of other diseases can change the appearance of pain behaviors. Several studies have found that subjective behavioral measures can be used successfully to identify pain in animals and subsequently evaluate the efficacy of treatment (Holton et al. 1998; Cloutier et al. 2005; Bennett and Morton 2009). However, more research is needed to refine and validate some of the current methods. Because some diagnostic capabilities may be limited in a shelter situation, anecdotal information suggests that when in doubt, a course of treatment with analgesics and/or anti‐inflammatories may be warranted if a painful condition is suspected. Failure to recognize pain is a significant welfare concern. Training shelter staff is a crucial task for shelter management to ensure that staff can reliably and consistently recognize even the most subtle signs of pain in animals. Table 4.2 provides a summary of behavioral signs of pain in dogs and cats. Improving our ability to identify pain in cats is important for many reasons. Degenerative joint disease (DJD) is more common in cats than previously believed (Perry 2014). Although some cats will appear pain free and still have joint abnormalities visible on radiographs (Monteiro and Steagall 2019), several studies have shown that signs of pain and discomfort associated with DJD commonly occur prior to the appearance of radiographic signs (Hardie et al. 2002; Clarke and Bennett 2006). Overt lameness is much less common in cats than dogs (Clarke and Bennett 2006). In addition, while palpation may be effective at determining when and where dogs experience pain, cats often resist palpation under normal circumstances; therefore, response to palpation is unlikely to be diagnostic for pain or discomfort. Osteoarthritis is not the only cause of chronic pain in the cat; pain secondary to cancer and dental disease (e.g., feline orofacial pain syndrome [FOPS]) should also be of concern. When evaluating dogs and cats for pain, it is also important to be aware that there are different kinds of pain and altered sensation. Neuropathic pain has been defined as “pain arising as a direct consequence of a lesion or disease affecting the somatosensory system” (Shilo and Pascoe 2014). It is considered a chronic pain state that results from peripheral or central nerve injury and can be due to acute events such as amputation or systemic disease such as diabetes. As opposed to functional pain, neuropathic pain is believed to serve no purpose. Nociceptors are not involved, and the mechanisms underlying the syndrome are unclear. The relief of neuropathic pain is generally considered extremely challenging. The possibility of phantom limb pain, where the patient perceives pain in a limb that is no longer present, should also be considered as a possible outcome of amputation (Shilo and Pascoe 2014). Since animals cannot report what they are experiencing verbally, and limited diagnostic capabilities may prevent us from being able to clearly recognize these conditions in animals, it will be even more incumbent upon the caretaker to be extremely observant for signs of pain in animals. Table 4.2 Behavioral signs of pain in dogs and cats (Mills et al. 2020; Bacon et al. 2019; Godfrey 2005; Bennett and Morton 2009; Slingerland et al. 2011). Anxiety is the emotional response that occurs when there is the anticipation of future danger. What is critical for animal caretakers to be aware of is that the danger does not have to be real; it may be unknown or imagined. Equally important is that when animals perceive something to be dangerous or threatening, that is what they will respond to emotionally. The physiological responses to feelings of anxiety are similar to the responses that are seen with fear (see Box 4.2). Many of these behaviors can also be seen associated with particular medical conditions, further complicating some diagnoses. In addition, it appears that some individuals have behavioral dysfunction due to pathological anxiety, and this results in maladaptive behavior. A definition for pathological anxiety has been proposed: “Pathological anxiety is a persistent, uncontrollable, excessive, inappropriate and generalized dysfunctional and aversive emotion, triggering physiological and behavioural responses lacking adaptive value. Pathological anxiety‐related behaviour is a response to the exaggerated anticipation or perception of threats, which is incommensurate with the actual situation” (Ohl et al. 2008). Differentiating pathological anxiety from the situational anxiety that might be expected in an animal that has recently been introduced into a shelter situation will not be easy as the line between normal and abnormal is often vague. However, caretakers should remain aware that some animals will not adapt well to the shelter environment due to preexisting behavioral pathology. In addition, the behavioral pathology may predispose these animals to illness and poor welfare due to the chronic stimulation of the HPA axis and the animal’s inability to adapt to the changing environment. Lastly, anxiety can occur as a result of any disease process, pain, or discomfort, especially if it remains unidentified by caretakers and thus untreated. A variety of different neurological disorders have the capability of affecting behavior in a variety of different ways. While many neurological disorders are steadily progressive and, thus, will eventually present additional non‐behavioral signs, in many cases, behavioral changes will precede the appearance of other more severe neurological signs by weeks or even months. Storage diseases, neoplasia, inflammatory conditions, degenerative conditions, toxicosis, malformations, ischemia, and infections can all lead to changes in behavior. The location of a brain lesion will dictate the associated behavior changes. The limbic system, whose structures lie deep within the brain, functions to control memory, emotions, and basic drives such as sexual activity, anxiety, and feelings of pleasure. Damage to the limbic system can result in personality changes, including increases in fearfulness and aggressive behavior. In other cases, seizures may result. The forebrain, including the prefrontal area, is the part of the brain associated with cognitive behavior, motor planning, thought, and perception. Forebrain lesions can lead to changes in temperament, loss of previously learned behaviors, and failure to recognize or respond appropriately to environmental stimuli. Lesions of the brain stem or forebrain may lead to changes in awareness or consciousness and mentation. Animals with brain stem lesions may demonstrate altered responses to stimuli, dullness, and stupor and may become comatose (Lorenz et al. 2011). Intracranial neoplasia can be either primary or secondary, and, depending on the location within the brain and the character of the tumor, brain neoplasia can result in several different behavioral changes. Primary brain tumors originate from cells within the brain and meninges and are more likely to result in insidious, slowly progressive effects, whereas secondary tumors resulting from metastatic disease will usually result in acute changes. Seizures, while the most recognizable, are not always the most common sign of a brain tumor. Other early behavioral and clinical signs of a brain tumor such as changes in behavior and mentation, visual deficits, circling, ataxia, head tilt, and cervical spinal hyperesthesia are often not appreciated. Reluctance to climb stairs, pacing, standing in corners, stumbling over objects, housesoiling, and agitation may also be seen. Primary brain tumors in the dog may include meningioma, astrocytoma, neuroblastoma, oligodendroglioma, and ependymoma, to name a few. Dogs with brain tumors are usually presented with concurrent neurologic deficits, but one study found that when brain tumors developed in the rostral cerebrum, behavioral changes commonly occurred prior to the appearance of other neurologic deficits (Foster et al. 1998). These changes were described as dementia, aggression, and alteration in established habits. Many of the dogs in the study, but not all, also had seizures, but 72% of them had no neurological deficits on presentation. Neurological deficits eventually appeared in all cases, with some taking up to three months to appear (Foster et al. 1998). Meningiomas, the most common primary brain tumor in dogs, usually occur in dogs more than seven years of age but have been seen in dogs as young as 11 weeks. Behavioral signs may include increases in aggression, head pressing, circling, housesoiling, pacing and panting (common signs of agitation), vocalizations, seizures, and changes in mentation. While neoplasia in dogs younger than six months occurs less often, the brain is the second most common site for it to develop, so age alone cannot always rule out the possibility of a brain tumor. However, brain tumors occur most often in dogs more than five years of age. Meningiomas are also the most common tumor of the feline brain and have been documented in cats as young as one year of age. Geriatric cats with meningioma have been presented to their veterinarian with the owner complaint of “just not being themselves” (Sessums and Mariani 2009). Clinical signs that have been reported include reluctance to play, episodic lethargy, and aggression. One owner reported apparent pain when she touched her cat’s head, three months prior to presentation with other clinical signs (Karli et al. 2013). Generalized seizures in dogs and cats are characterized by the animal falling into a laterally recumbent position with limbs rigid and paddling. They may or may not evacuate their bladder or bowels, they may vocalize, and they will usually fail to respond if spoken to or touched. Focal seizures, however, are involuntary movements that may be localized to a single limb or part of the face. The animal experiencing a focal seizure may be somewhat responsive to other stimuli, but an aura and pre‐ and postictal phases may be present. These types of seizures can result in unusual behavioral presentations and can be difficult to diagnose. Focal seizures may be divided into motor and sensory‐type seizures. While motor seizures involve involuntary movement of one part of the body, sensory focal seizures may result in abnormal sensations such as tingling, pain, or visual hallucinations. Fly‐biting or fly‐snapping behaviors in some dogs may occur as a result of focal seizures with visual hallucinations. However, evidence linking these and similar behaviors to gastrointestinal distress confirms the possibility of multiple etiologies that can be associated with this non‐specific behavioral sign (Frank 2012; Mills et al. 2020). Complex focal seizures (formerly known as psychomotor seizures) are focal seizures with alterations in awareness. Affected dogs may exhibit repetitive motor activities such as head pressing, vocalizing, or aimless walking or running (Berendt and Gram 1999). In some cases, complex focal seizures manifest as impaired consciousness and bizarre behavior, such as unprovoked aggression or extreme, irrational fear (Dodman et al. 1992, 1996). Seizures are just one type of involuntary movement disorder in dogs and cats. Other forms of involuntary movements can occur and will need to be differentiated from seizures and primary behavioral disorders. Movements seen during periods of inactivity can be confirmed as movement disorders rather than behavioral disorders. However, involuntary movement disorders such as those associated with cerebellar diseases will occur during periods of activity. Some metabolic diseases and peripheral nervous system and musculoskeletal disorders may also result in involuntary movements. Involuntary movements limited to facial or head movements are likely to be caused by a seizure disorder. Cats with acute onset of partial seizure involving orofacial movements, such as salivation, facial twitching, lip smacking, chewing, licking, or swallowing, along with other behavioral changes, such as sitting and staring while motionless and/or acting confused, have been diagnosed with a form of hippocampal necrosis (Pakozdy et al. 2011). The majority of these cats exhibited other neurological abnormalities on their first presentation. Seizures in cats may also be associated with metabolic disease such as diabetes mellitus, hepatic encephalopathy, neoplasia, or meningoencephalitis (Barnes et al. 2004). Toxins may lead to personality changes in animals. Animals that have been intoxicated may present with central nervous system signs such as ataxia, stupor, seizures, or death. When signs are acute, a history of exposure is usually present. Shelter staff will be unlikely to encounter these scenarios since once the animal is in the shelter, opportunities to access toxic substances will be limited. Most degenerative conditions of the neurologic system are heritable and will appear within the first few weeks to months of life. They include such conditions as cerebellar abiotrophy and lysosomal storage diseases. Cerebellar abiotrophy can be minimal to rapidly progressive and varies to some degree by the breed affected. The condition has been reported in many breeds, including the Kerry blue terrier, rough‐coated collie, beagle, Samoyed, Irish setter, Gordon setter, Airedale, Finnish harrier, Bernese mountain dog, Labrador and golden retriever, cocker spaniel, cairn terrier, and Great Dane. Most puppies will be normal at birth. At two to nine weeks of age, they begin to show signs of cerebellar damage, including ataxia, intention tremors, swaying, hypermetria, a head tilt, and a broad‐based stance. At the extreme, pups may demonstrate opisthotonos with extensor rigidity of the forelimbs and flexed hindlimbs, the typical decerebellate posture. While the age of onset is prior to four months in most cases, some animals may not show signs of disease until two to two‐and‐a‐half years of age. In some cases where the disease progression is minimal or very slow, some animals can learn to compensate for their disabilities. Cerebellar abiotrophy can develop in the cat but has been less well documented. A single case report has described adult‐onset cerebellar cortical abiotrophy with retinal degeneration in a domestic shorthaired cat (Joseph 2011). If observed and examined carefully, the clinical signs associated with cerebellar degeneration should be readily differentiated from primary behavioral problems. Lysosomal storage diseases are relatively rare genetic defects that are characterized by progressive neuronal degeneration. They are most likely to occur in purebred animals with a history of inbreeding in the affected line. Animals born with lysosomal storage diseases are normal at birth, with clinical signs usually developing during the first year of life. Neuronal ceroid lipofuscinosis is one of the storage diseases that can appear in adult animals. Case reports of dachshunds with this condition have reported dogs developing the signs at three, five, and seven years of age (Cummings and de LaHunta 1977; Vandevelde and Fatzer 1980). Early signs may include ataxia, disorientation, weakness, and behavioral changes, but, with time, affected individuals will suffer vision loss, progressive motor and cognitive decline, and seizures. Clinical signs will vary with the site of the brain inflammation and may be acute or chronic. A progressive, acute disease process is most typical. Neurological deficits seen with inflammation may be diffuse, focal, or multifocal. Encephalitis or parenchymal central nervous inflammation may present with depression, stupor, coma, or other types of altered consciousness. Blindness, ataxia, seizures, and other behavioral changes may also be seen. Box 4.3 lists some of the more common infectious and parasitic causes of central nervous system signs in dogs and cats. Inappropriate elimination is a common behavioral complaint for pet owners, but it is also often a primary sign of a medical condition. Distinguishing the two and/or recognizing when a medical condition exists at the same time as learned behavior (or a failure of house training) can be challenging but will be critical to solving the problem. Box 4.4 lists some of the more common reasons for dogs and cats to soil the house with urine. Regardless of the species, the first challenge is to observe the animal and attempt to determine if it has voluntary control over urination some of the time, all of the time, or none of the time, as this will help narrow down the list of differential diagnoses. Incontinence is the failure of voluntary control of micturition (urination), with either a constant or intermittent, unconscious passage of urine. Several different medical conditions can result in urinary incontinence. Disorders of micturition are generally divided into two types: neurogenic and non‐neurogenic. Some animals can experience urinary incontinence some of the time and still have voluntary control of urination at other times. This is most likely to occur with non‐neurogenic conditions. Behaviorally, incontinence can appear differently, ranging from constant dribbling, leaking during activities with abdominal push (getting up from lying down, jumping up, stretching, changing positions), leaking only when sleeping, intermittent dribbling while maintaining the ability to signal and void, and/or sometimes appearing to be under conscious control. Diagnosis may require a complete history, comprehensive physical examination including palpation of the distended and empty urinary bladder, a digital rectal examination, a neurologic examination, and a urinalysis. Obtaining a complete history in the shelter setting can be difficult or impossible, especially if the relinquishing owner is not forthcoming about the pet not being house trained or litterbox trained, fearing that the information may prevent adoption and/or result in euthanasia. Observation of the pet for postural changes during urination can be helpful in identifying the etiology of the problem. If an animal assumes the postures associated with elimination (squatting, lowering of pelvic limbs, tail position, ear position, etc.) then one can assume that the elimination is conscious. It is important to remember that these elimination processes do not always occur alone, and there may be several etiologies underlying a problem behavior. There may be neurological, infectious, anatomical, and/or behavioral components contributing to the incontinence. When this is the case, treating only one etiology is not likely to result in a discontinuation of the incontinence. Each will need to be addressed separately for the best results. One of the most common non‐neurogenic disorders seen in dogs is hormone‐responsive incontinence. Older studies have suggested that this condition may affect more than 20% of gonadectomized female dogs (Arnold 1992; Thrusfield et al. 1998). However, more recent studies have not found incidence rates that high. Specifically, the condition appears to occur secondary to urethral sphincter mechanism incompetence (USMI) and results in incontinence most often when the animal is relaxed or asleep. Neutering appears to increase the risk of urethral incompetence in large dogs (>20 kg), and neutering prior to three months of age may increase the risk of urinary incontinence in female dogs (Spain et al. 2004), but additional studies have not consistently supported this finding (see Section 4.8.4). Other conditions that can lead to USMI and the occasional dribbling of urine are urinary tract infection (UTI), inflammation, prostatic disease, or a history of prostate surgery. Animals with these problems should still have voluntary control of urination some of the time, but at other times the urethral incompetence allows urine to dribble out, and the animal cannot voluntarily stop the flow. Urinary bladder storage dysfunction can also result in frequent leakage of small amounts of urine. This can occur due to detrusor muscle instability, UTIs, chronic inflammatory disorders, infiltrative neoplastic lesions, external compression, and chronic partial outlet obstruction. These animals, too, will have voluntary control over urination some of the time. Continuous dribbling of urine with the ability to urinate voluntarily can also occur in cases of ectopic ureters. Ectopic ureters are a congenital anomaly of the urinary system and are most commonly seen in juvenile female dogs. Some dog breeds, including golden retrievers, Labrador retrievers, Siberian huskies, Newfoundlands, miniature and toy poodles, and some terriers appear to be predisposed (Berent 2011). However, there appear to be regional differences in breed prevalence. The condition occurs infrequently in cats. Affected dogs will display urinary incontinence from birth and may have problems with chronic UTIs. Diagnosing the condition will require imaging such as cystoscopy, ultrasonography, contrast urography, or cystourethrovaginoscopy. Surgery is required to correct the condition. Dogs may also urinate due to excitement, fear, or conflict. This is an involuntary action that can occur due to fear‐inducing or social stimuli. It typically occurs as the dog lowers its pelvic limbs, with the ears held back and tail tucked. The tail may be stiff, and the tip may be wagged rapidly if the dog is more conflicted rather than fearful. The dog may also roll over and then urinate while demonstrating the same ear and tail posture. It is critical that the dog not be punished for this behavior. Even acting upset or frustrated with the dog may increase their fear, anxiety, and conflict and, thus, make the problem worse. The problem is more likely to occur in young dogs and may be exacerbated by the presence of a full bladder during exciting or fear‐inducing events. Young female puppies may be particularly prone to this problem due to poor sphincter control. Ideally, these dogs should be greeted only after first being allowed outside to eliminate to ensure that they have an empty bladder. People should avoid leaning over these dogs when greeting. If all people who interact with the dog greet the dog in a calm, non‐threatening manner, the problem will usually improve with age. When an animal is experiencing continuous dribbling of urine, without the ability to voluntarily control urination, it is most likely a result of a neurogenic disorder such as lower motor neuron bladder. However, the presence of uroliths often have a similar presentation. These conditions occur as a result of a lesion in the spinal cord and have a guarded to poor prognosis, depending on the cause of the lesion (e.g., trauma, neoplasia, intervertebral disc disease). Lesions of the cerebellum or cerebral micturition center can also result in frequent, involuntary urination or leakage of small amounts of urine. When faced with a dog that is urinating inappropriately and the urination appears to be conscious rather than unconscious, consider that the dog may have been incompletely house trained or may have a medical condition resulting in polyuria and polydipsia or an inflammatory disease leading to an increased urgency and frequency of urination. Dogs with cognitive decline may begin housesoiling simply due to a loss of previously learned behaviors. Canine cognitive decline is an irreversible, neurodegenerative condition of aging dogs (and cats) and is a diagnosis of exclusion. In addition to housesoiling, pets with cognitive decline may also act disoriented, seem less interested in social interactions, have altered sleep‐wake cycles, and appear anxious or apathetic. Aged dogs may need a more complete medical workup to rule out the large number of conditions that could be contributing to the behavior. For example, anything leading to musculoskeletal pain or weakness can result in incomplete elimination, where a dog postures to eliminate but cannot maintain the posture until she has completely voided the bladder or bowels. The dog may then return indoors and need to eliminate shortly thereafter, resulting in housesoiling. Good observation skills are necessary to recognize this problem in a case where the cause may not be readily identified with radiographs. Urine marking is another potential cause for housesoiling in the dog. Urine‐marking behavior is a normal form of communication. Intact male dogs urine mark more than castrated or female dogs but all dogs may urine mark. When neutered animals mark indoors, it is often due to situations involving conflict, frustration, or anxiety. However, this may also simply reflect incomplete house training. Regardless of the posture used for urination, medical conditions will need to be ruled out. There are a variety of medical causes that may contribute to housesoiling in the cat, and housesoiling is likely one of the more common reasons for cats to be relinquished to shelters. If cats are placed in a cage in a shelter, they are likely to begin using the litterbox due to the lack of other preferable surfaces. However, some cats develop preferences for soft, absorbent substrates, so they may choose to eliminate on any bedding that is placed in their cages. If the cat has an aversion to the litterbox or the substrate offered in the box, it may eliminate on newspaper or other surfaces in the cage. Cats housed in groups in rooms within the shelter may be more likely to eliminate outside the litterbox, and due to the presence of multiple cats, it may be challenging to determine which cat is not using the box. Fear or stress associated with interactions with unfamiliar cats may lead to urine‐marking behavior and possibly even feline interstitial cystitis, also known as feline idiopathic cystitis (FIC). If other cats block access to boxes (either overtly or covertly), or a cat is simply too afraid to approach a box out of fear that it may be ambushed by another cat, elimination outside the box may occur. However, any elimination outside the box should prompt exploration for an underlying medical condition first, before making the determination that it is purely a behavioral problem. Any medical condition resulting in polyuria, polydipsia, incontinence, constipation, diarrhea, pain associated with elimination, increased frequency and/or urgency to eliminate, orthopedic disease making it difficult or painful to climb into a box, and declining sensory capabilities making it difficult to locate the box can all lead to elimination outside the box. Caretakers should also be aware that an aversion to the litterbox may still exist long after the medical condition that promoted it is treated and eliminated. Feline lower urinary tract disease (FLUTD) is a relatively common syndrome in the cat and often leads to the deposition of urine outside the box. FLUTD refers to disorders affecting the urethra and/or urinary bladder. Stranguria, dysuria, pollakiuria, hematuria, and urination outside the box are all signs that are consistent with FLUTD, but numerous underlying etiologies are possible. Common etiologies include UTI, uroliths, urethral plugs, idiopathic cystitis, bladder neoplasia, malformations, trauma, and urinary incontinence. UTIs should first be ruled out with a urinalysis, preferably using urine collected by cystocentesis. One study demonstrated that clinical signs are, in fact, a poor predictor of UTI in cats and recommended urine culture as the best method for confirming the presence or absence of bacterial infections (Martinez‐Rustafa et al. 2012). The same study found that the best predictive factor for the presence of UTI was urinary incontinence (Martinez‐ Rustafa et al. 2012). UTIs are often associated with other underlying medical conditions and are rarely a primary disorder in cats. Good antibiotic stewardship requires that we avoid treating cats presumptively with antibiotics since the likelihood of infection in young cats is small. FIC has been shown to be the most common cause of signs of FLUTD in the cat (Lekcharoensuk et al. 2001; Gerber et al. 2005; Saevik et al. 2011). However, FIC is a diagnosis of exclusion. FIC describes recurring cystitis when no underlying cause for signs can be identified; a variety of different causative factors are suspected. Cats with FIC appear to have altered bladder permeability, and several studies have documented its association with stress (Buffington et al. 2002; Westropp et al. 2006; Stella et al. 2013). Cats with FIC appear to have increased sympathetic activity (Buffington and Pacak 2001; Buffington et al. 2002), to be more sensitive to environmental stress, and to have a decreased ability to cope with changes in their environment. Research continues to support the hypothesis that stress is associated with the development of FIC. One study, published by Cameron et al. (2004), found that cats with FIC were more likely to live in multi‐cat households and to experience conflict with another cat in the household. Clearly, a shelter environment has the potential to negatively affect the welfare of cats that are prone to FIC, and appropriate treatment will involve the treatment of symptoms as well as an attempt to identify and reduce the stressors that may be affecting the cat. Several different treatments for FIC have been investigated, and no single medication has been found to be consistently effective at treating the signs. Since FIC is likely a condition with a multifactorial etiology, it is likely that treatment will be multifactorial as well. One study that evaluated multi‐modal environmental modification (MEMO) in the management of cats with interstitial cystitis found that with MEMO there was a significant reduction in lower urinary tract signs, fearfulness, and nervousness (Buffington et al. 2006). MEMO was defined as changing the cat’s environment to decrease stress. Examples of these changes included avoidance of punishment, diet changes, techniques for increasing water consumption, changing to unscented clumping litter, improved litterbox management, provision of more structures for climbing and perches for resting and viewing, scratching posts, audio and visual stimuli when the owner was absent, increased client interactions with the cat, and identification and resolution of inter‐cat conflict in the household. See Chapters 16 and 17 for more information on feline housing and enrichment. The nervous system of the gastrointestinal (GI) tract and the central nervous system are linked in a bidirectional manner by the sympathetic and parasympathetic pathways, resulting in what is referred to as the brain–gut axis. Due to this interrelationship, chronic stress can have profound effects on the enteric nervous system (ENS). Severe life stressors have been associated with several GI tract conditions in humans (Bhatia and Tandon 2005), and the effects in animals are just now being explored. Chronic stress has been demonstrated to decrease gastric emptying, increase intestinal contractility, increase gut permeability, reduce water absorption in the gut, disrupt normal electrolyte absorption, and increase the colonic inflammatory response (Bhatia and Tandon 2005). Many gastrointestinal conditions such as chronic diarrhea and vomiting may be closely associated with stress. However, when presented with an animal with GI signs, the possibility of internal parasites and infectious organisms must also be ruled out. Newer polymerase chain reaction (PCR) tests can be helpful in ruling out some of these conditions. It is important to always keep in mind that nothing precludes an animal from having GI distress from multiple etiologies; therefore, both infectious causes and stress may need to be addressed. Disruptions in the microbiome have been shown to play a role in anxiety and depression in many species (Foster and Neufeld 2013). In addition, studies in laboratory animals have shown that when young developing animals do not have normal gut microbiomes, they develop an exaggerated stress response and a dysregulated HPA axis (Sudo et al. 2004). Minimal work has been done on the role of the gut microbiome on behavior in dogs, but some limited research suggests that dogs demonstrating aggressive behavior may have distinctly different populations of gut bacteria compared to dogs that do not show aggression (Kirchoff et al. 2019; Mondo et al. 2020). More research is needed to identify what constitutes a healthy gut microbiome and how to adjust an “unhealthy” gut before we can apply what we have learned to companion animal care. Once again, the impact of stress on normal development and general health is clear and reminds us that it must not be overlooked. Behavioral signs that may be associated with gastrointestinal disease include polyphagia, hyperphagia, polydipsia, coprophagia, and grass and plant eating. Oral behaviors such as frequent licking of surfaces (not self‐licking), sucking, pica, gulping, and lip‐smacking behaviors may all be associated with gastrointestinal disorders. However, some partial motor seizures may also be associated with similar behaviors. Many gastrointestinal disorders can manifest with unusual behavioral signs. In one recent study where 19 dogs were examined due to frequent surface‐licking behaviors, 14 of the dogs were determined to have some form of gastrointestinal disease (Bécuwe‐Bonnet et al. 2012). These included conditions such as delayed gastric emptying, irritable bowel syndrome, gastric foreign body, pancreatitis, and giardiasis, to name a few. The unusual behavior of fly biting, considered by some to be a compulsive disorder, has even been found to be associated with gastrointestinal conditions such as gastroesophageal reflux (Frank et al. 2012). Pica is the consumption of non‐nutritive items such as fabric, paper, and plastic. There is little research available involving companion animals and pica. However, a literature search for pica as a clinical sign links it to a variety of disease processes, including portal caval shunts, iron‐deficiency anemia, pyruvate kinase deficiency, ehrlichiosis, gastrointestinal disorders, neurologic damage, feline infectious peritonitis (FIP), and other medical conditions (Thomas et al. 1976; Black 1994; Goldman et al. 1998; Marioni‐Henry et al. 2004; Kohn et al. 2006; Kohn and Fumi 2008; Bécuwe‐Bonnet et al. 2012; Berset‐Istratescu et al. 2014). Both cats and dogs can be affected. Pica has also been described in horses, cattle, sheep, and other domestic species (Houpt 2011). In rats and mice, pica has been associated with gastrointestinal disturbances and may be an adaptive mechanism used to cope with gastrointestinal upset (Takeda et al. 1993; Yamamoto et al. 2002). In a recent case report, a 5.5‐year‐old dog with a 4.5‐year history of pica (eating rocks) resolved when diagnosed and treated for mild hip dysplasia (Mills et al. 2020). There is some indication in the literature that oriental cat breeds (Burmese and Siamese) may be represented in numbers higher than the general hospital population, suggesting the possibility of an underlying genetic predisposition for pica (Blackshaw 1991; Bradshaw et al. 1997; Overall and Dunham 2002; Bamberger and Houpt 2006). To date, the evidence for a genetic basis is purely correlative. Underlying medical causes for pica should always be investigated and ruled out through appropriate diagnostics. A behavioral diagnosis of an abnormal repetitive disorder is made by excluding all possible medical conditions. If financial constraints limit testing, a clinical trial with appropriate gastrointestinal protectant drugs is indicated prior to using any kind of psychoactive substance. Behavioral enrichment is indicated, and behavior modification can be attempted (Blackshaw 1991). There is a single documented case study that successfully used behavior modification to diminish the occurrence of pica in a cat (Mongillo et al. 2012). In humans, the relationship between skin disease and mental health has received much attention in the past decade. The skin and the central nervous system are both derived from the embryonic ectoderm, and they share many of the same hormones, neuropeptides, and receptors. Many of these substances are involved in neurogenic inflammation, pruritus, and pain sensation, and stress can alter their release. A substantial number of chronic dermatoses in humans are heavily influenced by stress. It has been estimated that in as many as one‐third of the humans with skin disease, the condition is complicated by significant psychosocial and psychiatric morbidity. Patients with atopic skin disorders also have a higher prevalence of anxiety, depression, excitability, and suicidal ideation and a decreased ability to cope with stress. While many of these emotions may be impossible to confirm in our non‐verbal patients, it is logical to assume that stress has the potential to cause similar pathophysiologic responses that perpetuate the itch‐scratch cycle. Cases of dogs with pyoderma and pruritic skin disease associated with psychogenic factors have been reported (Nagata et al. 2002; Nagata and Shibata 2004). Newer research supports the likelihood that chronic skin disease, especially that which causes pruritis, can lead to stress and subsequent behavior change (Harvey et al. 2019; Yeom et al. 2020; McAuliffe et al. accepted for publication). Harvey et al. (2019) found that dogs with chronic atopic dermatitis demonstrated problematic behaviors such as mounting, chewing, hyperactivity, coprophagia, begging for and stealing food, attention seeking, excitability, excessive grooming, and reduced trainability. The frequency of unwanted behaviors increased when the degree of pruritis was more severe. In another study (data not yet published), dogs with higher levels of pruritis were found to have significantly higher levels of aggression, fear, separation‐related problems, attention‐seeking behaviors, excitability, and sensitivity to touch (McAuliffe et al. accepted for publication). While the exact relationship between these problem behaviors and atopy have not yet been determined, chronic atopy and pruritis is known to result in reduced quality of life; therefore, the potential for chronic anxiety and stress is clear. For that reason, the clinician should remain aware of two important things. First, many skin conditions may be exacerbated in the stressed shelter animal. Second, animals with chronic skin conditions may be more likely to exhibit problem behaviors—and these behaviors might be reduced by treatment that improves their skin condition. When placed in situations of frustration or conflict, some animals will show displacement behaviors, and grooming is commonly seen as a displacement behavior in many species. Psychogenic alopecia is a term often used to refer to a skin condition of cats in which irregular patches of hair are removed, presumably by licking and chewing. Some have suggested that oriental cat breeds (Siamese, Burmese, Abyssinian) may be at higher risk of developing this problem (Sawyer et al. 1999). Hair may be missing over the flanks, abdomen, front legs, or virtually anywhere on the body. This condition may occur secondary to anxiety or environmental stress but is a diagnosis of exclusion because many pathophysiological conditions can contribute to feline overgrooming. One case series that examined cats with a presumptive diagnosis of psychogenic alopecia found that 76% of the cats had medical conditions causing pruritus (Waisglass et al. 2006). A painful sensation may cause cats to overgroom as well, so radiographs may be helpful in some cases. Regrowth of hair and resolution of the overgrooming, after treatment with pain medication, is suggestive of pain as an underlying cause for the behavior. While less common, dogs can also overgroom areas of their body due to environmental stress or anxiety, although, as is the case with cats, painful sensations may also lead to overgrooming in the dog. When overgrooming behavior occurs primarily as a response to anxiety or conflict, it has the potential to develop into a repetitive disorder, generalize, and eventually occur even in the absence of the original stressors. Some have referred to this as a compulsive disorder. Regardless of the terminology applied, if the animal is believed to be overgrooming due to stress or anxiety, the primary treatment approach must be aimed at relieving the anxiety through a combination of environmental management, behavioral modification, and anxiety‐relieving medications. Acral lick dermatitis (ALD), also sometimes referred to as acral lick granuloma, is primarily a dermatological syndrome that is a result of self‐trauma. While some individuals may begin licking a leg to excess due to anxiety, frustration, or conflict, studies have found that many other underlying causes for these lesions are possible (Denerolle et al. 2007). Pruritus due to allergies, orthopedic pain, trauma, neoplasia, bacterial pyoderma, and fungal infections are just a few possibilities. Once a dog begins to lick and causes an open lesion, the dog will continue to lick it, no matter the original cause. When presented with a patient with ALD, a complete medical workup aimed at identifying the underlying cause is ideal. Long‐term treatment with appropriate antibiotics will almost always be required. Treatment may also include ancillary medications to break the itch‐scratch cycle (e.g., glucocorticoids, antihistamines). Physically preventing the dog from licking the lesion may be necessary to ensure resolution. This may be accomplished with the use of e‐collars, bandages, socks, body suits, or leggings, depending on what the individual patient tolerates. Once the lesion is completely healed, attention will need to be paid to the patient to determine if they continue to lick at the legs. In the experience of these authors, ALD is rarely a primary behavioral problem. If that is suspected, then the patient needs to be fully evaluated for other signs of fears or anxieties, such as noise sensitivities or phobias, barrier frustration, or separation anxiety, as it is unlikely that ALD would exist as a primary behavioral problem without one of these comorbid conditions. Grooming is a common displacement behavior, and the dog who is anxious about the strange sights, sounds, and smells of the shelter, as well as the sudden change in its living arrangement and separation from familiar people, may be inclined to exhibit displacement grooming to the extent that it develops or worsens an existing ALD. Feline hyperesthesia is a poorly understood syndrome, known by a variety of different names, including rolling skin syndrome, twitchy skin syndrome, and feline neurodermatitis, to name a few. It is characterized by short episodes of thoracolumbar skin rolling or rippling, and, in some cases, epaxial muscle spasms. Cats may appear anxious or agitated and demonstrate exaggerated tail movements, running, vocalizations, or self‐directed aggression. The self‐directed aggression may be the extreme end of a spectrum that includes excessive licking, plucking, biting, and/or chewing directed at the tail, lumbar, flank, or anal area. In some cases, the increased motor activity, exaggerated rolling, crouching, and elevation of the perineal area may be confused with the behavior typically shown by an estrus female. Feline hyperesthesia is referred to as idiopathic in most textbooks because no single causal factor has been elucidated. It has been hypothesized that the behaviors are a result of focal seizures, sensory neuropathies, and dermatologic disease resulting in pruritus. As is the case with other skin conditions, it is likely that environmental and social stressors play a role in this condition. Systemic diseases such as toxoplasmosis and hyperthyroidism should be ruled out, as well as painful spinal or skin conditions, severe pruritus, FLUTD, anal sacculitis, and myositis, as they may all contribute to the behavior. Any disease condition that affects the central nervous system or alters reactivity to stimuli will need to be ruled out if the clinician is presented with a cat showing signs similar to feline hyperesthesia (Ciribassi 2009). After ruling out and treating any underlying medical problems causing pain or pruritus, feline hyperesthesia may be treated empirically as a partial seizure disorder. Both phenobarbital and primidone have been used to treat the condition (Aronson 1998), as well as clomipramine and fluoxetine (Overall 1998). Ultimately, treatment of every individual animal will need to reflect the putative etiological basis of that particular case. Attention will need to be paid to identifying and, if possible, removing the environmental stressors that may be contributing to the problem. Pathologic self‐mutilation has been studied much more in humans and non‐human primates than in domestic animals. In non‐human primates, it is believed by many to be a maladaptive coping mechanism. Rearing in a suboptimal environment, and specifically social isolation, is considered a risk factor (Dellinger‐Ness and Handler 2006). Stressors such as relocation have also been known to lead to self‐injurious behavior (SIB) in some primates (Davenport et al. 2008). SIB in dogs and cats is often but not always associated with tail chasing, circling, and subsequent tail tip mutilation. Self‐mutilation is most likely to be associated with pain, dysesthesia, or paresthesia. One case has been documented of a 30‐month‐old Labrador retriever that presented with acute onset tail mutilation (Zulch et al. 2012). Radiographs of the tail revealed some soft‐tissue swelling and a mineralized ossicle in one intervertebral space that may have caused discomfort. Administration of analgesics led to complete resolution of the behavior. Self‐mutilation has been documented in several other species secondary to nerve injury, pain, and altered sensation, so self‐mutilation behaviors should always lead to a thorough physical exam and imaging, if possible, to rule out underlying medical causes. Empirical treatment with analgesics or anti‐inflammatories may be warranted in some patients before determining that self‐mutilation is a primary behavioral problem. Box 4.5 lists some of the most important medical rule‐outs for common repetitive behaviors (often referred to as compulsive disorders) in dogs and cats. Endocrine imbalances have the potential to change many aspects of an animal’s behavior because they usually result in altered motivation for meeting particular bodily needs (see Table 4.3). For example, an animal with diabetes mellitus will demonstrate increased thirst and hunger. The subsequent drive to acquire more food or water can lead to unusual behaviors such as attempting to drink water left on the floor during cleaning procedures. Hypothyroidism is one of the endocrinopathies most often mentioned as being associated with behavioral changes in dogs. However, there are minimal data supporting any causal association between hypothyroidism and aggression. One study compared the analytes commonly used to evaluate thyroid function between dogs with and without aggression toward people and found no difference between the two groups (Radosta et al. 2012). A double‐blind placebo‐controlled trial evaluated the effect of six weeks of thyroid replacement on owner‐directed aggression in 29 normal dogs with borderline low thyroid values and found no difference between the treatment and control groups (Dodman et al. 2013). In another study of 20 hypothyroid dogs without diagnosed behavior problems, treatment with levothyroxine resulted in no behavioral change other than increased activity levels (Hrovat et al. 2018). Serotonin and prolactin levels were also measured prior to, at six weeks, and six months after the initiation of levothyroxine therapy, and no significant changes in levels were noted (Hrovat et al. 2018). Thus, at this time, there are no data to support the proposal that thyroid supplementation may benefit behavioral therapy in dogs. Hypothyroidism rarely occurs naturally in cats but is a common sequela to treatment for hyperthyroidism. Clinical signs are similar to those seen in dogs with hypothyroidism. Congenital hypothyroidism, while also rare, has been well documented in cats, as it is the most common cause of disproportional dwarfism (Jones et al. 1992). While the physical changes associated with congenital hypothyroidism are numerous, mental dullness and lethargy are the most commonly mentioned behavioral changes.
4
The Relationship between Physiology and Behavior in Dogs and Cats
4.1 Introduction
4.2 General Concepts of the Relationship between Medical and Behavioral Issues
4.3 Recognizing the Behavior of the Sick Animal
4.3.1 Cats
4.4 The Role of Stress
4.4.1 Cats
Common stressors
Behavioral signs of stress
Dogs
Separation from familiar social figures
Loud noises
Restraint and unpredictable handling
Confinement
Elimination on unfamiliar surfaces and/or in living space
Sounds and odors associated with the stress and aggressive behavior of other dogs
Altered routines
Immersion in novel environment, surrounded by novel stimuli
Trembling
Crouching
Oral behaviors (e.g., snout licking, swallowing, smacking)
Yawning
Restlessness
Lowered body posture
Increased autogrooming
Paw lifting
Vocalizing
Repetitive behavior
Coprophagy
Cats
Unpredictable handling and husbandry routines
Increased density of group‐housing
Inability to hide
Decreased food intake and weight loss
Less play and active exploratory behaviors
More time awake and alert
Attempting to hide
Behavioral apathy
Vocalization
Escape behaviors
Aggressive behavior
Feigned sleep
4.5 The Behavior of Pain
4.5.1 Cats
4.5.2 Neuropathic Pain
Dogs
Cats
More common
General signs
Anorexia
Avoidance behaviors
Hiding
Aggression
Hunched body posture
Whining or howling
Decreased social interactions
Changes in activity level
Changes in temperament or mood
Reluctance to move or change position when recumbent or
Increased restlessness and frequent changes in position
Tense facial muscles with ears pulled back from the face and a grimace
May attempt to bite at or lick a painful area
May rub painful areas against walls, doors, or other objects
Increased heart rate, respiratory rate, and/or blood pressure
Avoidance or flight behavior
Restlessness or agitation
Hunched posture
Squinting eyes
Reluctance to move
Vocalization (including purring)
Gait changes
Decreased appetite
Changes in grooming behavior
Tail flicking
Changes in interactions with people
Decreased tolerance to handling
Aggression when certain body parts are manipulated
Aggression when attempting to move or lift
Less common
Signs of pain associated with degenerative joint disease
Pica
Housesoiling
Noise sensitivity
Clinginess
Excessive licking
Decreased walking, running, jumping, or climbing
Increased sleep
Decreased play
Stiff movement or a shuffling gait
Appearance of weakness
Difficulty jumping
Altered temperament
Inappropriate elimination
4.6 Common Medical Conditions Resulting in Behavioral Signs
4.6.1 Anxiety Disorders
4.6.2 Neurological Disorders
4.6.2.1 Neoplasia
4.6.2.1.1 Dogs
4.6.2.1.2 Cats
4.6.2.2 Seizures
4.6.2.2.1 Cats
4.6.2.3 Toxicosis
4.6.2.4 Degenerative Conditions
4.6.2.5 Inflammatory Conditions
4.6.3 Urogenital Disorders
4.6.3.1 Urinary Incontinence
4.6.3.3.1 Dogs
4.6.3.2 Cats
4.6.4 Gastrointestinal Disorders
4.6.4.1 Pica
4.6.5 Dermatological Disease
4.6.5.1 Overgrooming
4.6.5.2 Acral Lick Dermatitis
4.6.5.3 Feline Hyperesthesia
4.6.5.4 Self‐Injurious Behaviors
4.6.6 Endocrine Disease
4.6.6.1 Dogs
4.6.6.2 Cats
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