Monitoring and assessing behavioral signs is a critical component of every veterinary visit.
Monitoring and assessing behavioral signs is a critical component of every veterinary visit. Virtually any medical condition can present with behavioral signs and behavioral signs may be the first indicators of disease (e.g. irritability, anxiety, aggression, anorexia, depression, decreased response to stimuli, housesoiling, night waking, etc). Behavioral signs can also be used to monitor improvement or response to therapy. Therefore to insure early diagnosis and intervention, owners should be asked about behavior problems at each visit and pet owners should be encouraged to seek guidance as soon as signs arise.
Rather than directly initiating the signs, medical factors may play a contributory role in how a pet might behave in certain situations or respond to specific stimuli which may vary with genetics, previous experience, environment, the stimulus, etc. Signalment is also an important consideration since, for example, the onset of behavior problems in older pets may increase the suspicion of a medical cause.
While it is common to consider the effects of disease on behavior, both acute and chronic stress can have an impact on health as well as behavior, through its effects on the HPA axis and activation of the noradrenergic system. Stress is an altered stated of homeostasis which can be caused by physical or emotional factors. Stress triggers psychological, behavioral, endocrine and immune effects that are designed to handle stress. The first component is the HPA axis, in which the hypothalamus releases corticocotropic releasing hormone (CRH), which stimulates the release of ACTH. The second component is the sympathetic-adrenal-medullary system which releases noradrenaline and adrenaline. Noradrenaline is associated with sensitization and fear conditioning. If stress is persistent or chronic there is continued stimulation of the HPA axis and an increase in cortisol with a depression of the catecholamine system, leading to alterations in the immune system and the possible development of stress related diseases. In humans there may be a correlation between stress and poor health, poor immune function, cardiovascular disease, and cellular aging. In pets, stress has been shown to be a contributing factor to some forms of feline interstitial cystitis (FIC), gastrointestinal diseases, dermatologic conditions and behavioral disorders.
Cats with FIC have altered bladder permeability during stress when compared to cats in an enriched environment. An increase in plasma norepinephrine has been demonstrated in cats with interstitial cystitis. Cats receiving MEMO (multimodal environmental modification) had a significant reduction in FIC, respiratory disease, fearfulness, and nervousness and less inflammatory bowel disease and aggression. In a placebo controlled study there were less bouts of FIC when a Feliway diffuser was installed. Stress and anxiety can alter bacterial flora, inhibit gastric emptying, increase colonic activity, and increase intestinal permeability leading to irritable bowel syndrome, gastrointestinal reflux, stress induced hypersensitivity, and heartburn. In pets, acute fear and anxiety can lead to a decrease in appetite or anorexia such as what might be observed in a pet with separation anxiety that does not eat until the owner returns home. A more chronic form of anxiety may arise with the introduction of a new pet or moving (especially in cats) while the loss of a human or pet in family can cause a "grief" response in some dogs and cats that can affect appetite and health. Stress and anxiety can also lead to diarrhea, vomiting, colitis, picas, polyphagia and polydypsia and may aggravate underlying disease states such as atopic pruritus.
In humans, anxiety might contribute to pruritus in humans, since stress can lead to an increase in cytokines, release of opioids, serotonin and other vasoactive peptides, and a reduction in cortisol especially in atopic individuals. A link has also been found between stress and increased epidermal permeability.10 If this were also the case in dogs, lead a genetically predisposed individual to develop atopic disease. Opioid peptides released during stress may further potentiate pruritus.
Chronic anxiety, stress, conflict and frustration, may lead to behavioral disorders in humans including panic disorders, separation anxiety, social and other phobias, obsessive-compulsive disorders, generalized anxiety disorders, post-traumatic stress disorders, impulse control disorders, and sleep disorders which likely have similar animal correlates. A recent study in dogs identified higher prolactin levels with chronic stress and high anxiety, that was associated with stereotypic and displacement behaviors, fear aggression and autonomic signs. Lower levels of prolactin were associated with fear and phobias. Therefore identifying whether a self-traumatic disorder is behavior, medical or a combination of both is essential for successful control or resolution.
A change in personality or mood, inability to recognize or respond appropriately to stimuli, and loss of previously learned behavior might be indicative of forebrain involvement. Diseases affecting the hypothalamus can also have an effect on behavior. Therefore any disease that directly (intracranial) or indirectly (extracranial) affects the CNS can cause behavioral signs. While there may be identifiable medical signs such as alterations in mental status (stupor, coma), cranial nerve and sensory deficits, seizures, tremors or motor deficits (gait abnormalities, weakness, altered appetite, drinking, and elimination or emesis), this is not always the case. In addition, when pets are presented with behavior changes such as vocalization, unexpected aggression, loss of housetraining, or repetitive disorders, a neurological cause should be suspected if the pet also sleeps more, appears blind or lost, paces constantly, circles to one side, head presses, or has an increase in thirst. Pets should also be monitored over time, since many neurological problems are progressive and new signs may arise. Diseases that affect behavior may be intracranial (e.g. congenital, neoplasia, degenerative) or extracranial (e.g. toxin, hepatic encephalopathy, endocrinopathies, or disease that affect brain oxygenation). Primary behavioral diseases or pathology may also exist such as compulsive or depressive disorders
Endocrine diseases, including hyperthyroidism, hyperadrenocorticism and hypothyroidism can also contribute to both dermatologic signs as well as signs of anxiety. Hypothyroidism may increase 5HT turnover so that behavior changes may be due to alterations in serotonergic activity Since cortisol inhibits TSH release, stress can also diminish thyroid levels. Unless low thyroid levels can be documented, thyroid therapy is not likely indicated. Hyperthyroidism which is relatively common in cats and in some dogs on thyroid supplementation may also increase irritability and may have an effect on skin and coat condition.
Pain can be identified from either behavioral or physical signs. Studies have shown that behavioral measures are an accurate means of measuring pain, and pain assessment scoring systems have been developed both for the veterinary office and for pet owners. Spinal disease, peripheral neuropathies and neuropathic pain can contribute to self-trauma, which can be difficult to differentiate from a behavioral cause. A trial with a product for pain management can help to confirm the diagnosis.
Self traumatic disorders (such as tail mutilation, nail biting, psychogenic alopecia, acral lick dermatitis, face and neck scratching, flank sucking) can have numerous medical causes which lead to pain, pruritus, infections and inflammatory processes. Differentiating medical causes from behavioral is most difficult when there are no primary lesions and the problem is non-seasonal. If diagnostic tests do not reveal a medical cause, response to therapy may be a diagnostic option.
Compulsive disorders can only be diagnosed by excluding those medical problems that might cause the signs. Compulsive disorders may arise out of anxiety, conflict, or frustration. Conflict occurs when the pet is motivated to perform two opposing behaviors. Frustration refers to a situation in which the pet is motivated to perform a behavior but is not able to do so. In these situations the response might be a displacement behavior, where the response is inappropriate or out of context with respect to the stimulus (e.g. tail chasing). Pet owners may further aggravate the problem by reinforcing or punishing (which might increase anxiety and conflict).
Compulsive disorders are those in which the displacement behaviors are exhibited independent of the original context, have no apparent goal and have an element of dyscontrol in either the initiation or termination of the behavior. They may be repetitive, exaggerated, sustained or so intense that they might be difficult to interrupt. Although it has been suggested that stereotypies might be a coping mechanism leading to a reduction in arousal, this is rarely the case. Compulsive disorders are generally associated with stress or anxiety and may affect physical health. There appears to be a genetic predisposition to the development of stereotypic behaviors (e.g. wool sucking in oriental breeds of cats, spinning in Bull Terriers, tail chasing in German Shepherds).
It is possible that there is a common pathophysiology, that neurotransmitters vary between presenting complaints, or that there may be changing involvement as the problem progresses. Beta-endorphins, dopamine, and serotonin have all been implicated.
Self-traumatic disorders including biting, chewing, licking or excessive barbering can lead to skin lesions and alopecia. Medical differentials include diseases that lead to pain or pruritus (e.g. hypersensitivity reactions, neuropathies), infections (e.g. bacterial, fungal, parasitic), endocrinopathies, tumors, or skin disorders associated with systemic diseases (e.g. hepatocutaneous syndrome). When there are no primary lesions, medical and behavioral causes may be particularly difficult to differentiate.
When presented with a cat that has hair loss or licking, the diagnostic workup should begin with an examination, anal gland expression, blood and urine testing and a viral profile. A dermatologic evaluation, including a trichogram, fungal culture, skin scraping and possible biopsy would also be indicated. Assuming no abnormal findings, a therapeutic trial of a parasiticide and a food trial of 8 weeks duration, followed by a steroid response trial might be the only practical way to differentiate pruritus from a behavioral cause. Using this protocol in 21 cases presented for psychogenic alopecia, 76.2% had a medical etiology, 9.5% were compulsive and 14.3% were combined medical and behavioral. A combination of adverse food reaction and atopy (6 cases) was the most common diagnosis. Some cats had atopy, parasitic hypersensitivity or an adverse food reaction alone. Although biopsies indicated an inflammatory response for most medical cases, some cats with histologically normal skin had a medical cause.
For acral lick dermatitis (ALD) in dogs, a physical exam, blood and urine screening and a dermatologic workup, including a skin scraping, fungal culture, cytology and biopsy may all be indicated. When diagnostic tests do not reveal the underlying cause, therapeutic trials with antibiotics, pain medication, anti-inflammatory drugs, parasiticides and / or food trials may be necessary. In some cases complete resolution can be achieved with long term antibiotic therapy alone, indicating that even if the original cause was behavioral, that infection was the maintaining factor. Similarly food trials alone can lead to resolution of signs and recurrence on challenge. Owner supervision and preventive mechanisms such as bandaging or E-collars may also be necessary to allow the lesions to heal. In one of our cases, a mast cell tumor was misdiagnosed as ALD for over 2 years. In a recent publication, 6 dogs presumed to have ALD were diagnosed with lymphoblastic lymphoma, irritation from a Kirschner pin, furunculosis, a mast cell tumor, leishmaniasis and sporotrichosis.
Tail mutilation and hyperesthesia in cats may also be a conflict induced or compulsive disorder requiring a diagnostic workup similar to ALD and psychogenic alopecia. In addition, neurologic disorders (central, spinal) and neuropathic pain are also a consideration. For nail biting, any disease of the nails or nail beds, (immune, inflammatory or infectious including in particular Malassezia) must first be ruled out.
Behavioral management combined with drug therapy is required for the successful control of most compulsive disorders. As a general rule, pets with compulsive disorders, should receive a more structured and stimulating daily routine. Some pets may be particularly sensitive to inconsistency or lack of predictability in their daily schedule or in their interactions with their owners. Therefore the daily routine should include regular sessions of social interaction with people (in the form of training, play and exercise) or with other pets. Owners might be encouraged to focus on play that simulates the normal activities of the species or breed, (e.g. pulling carts, retrieving, mousing). Following social interaction and training, scheduled periods of inattention may help the pet learn to expect and accept spending time alone. At these times it can be useful to have a favored bedding area, and to provide a variety of enrichment toys (feeding, chew and manipulation toys). In fact working for some or all of the daily food is an important component of treatment for most compulsive disorders.
Training should encourage behaviors that are desirable rather than punishing behaviors that are undesirable. Casual and inconsistent owner interactions should be replaced by a program of predictable rewards where the owners insure that all rewards including affection, toys, and food are only given for behaviors other that are incompatible with the compulsive disorder (e.g. resting on a mat, playing with a favored toy). Clicker training can help more immediately reinforce desirable while a leash and head halter for dog or a harness for cats can be used to prompt the desired response as well as to inhibit, disrupt or prevent undesirable behavior.
Clomipramine at 1-2 mg/kg bid for dogs or .5 mg/kg in cats or a selective serotonin reuptake inhibitor (SSRI) such fluoxetine at 1-2 mg/kg once daily for dogs or .5-1 mg/kg per day for cats are usually the first drugs of choice for compulsive disorders in dogs. After 4-6 weeks, if there is insufficient response and no adverse effects, up to double the dose may be needed. Side effects may include gastrointestinal signs include inappetence, lethargy or neurological signs such as tremors or seizures and these drugs should not be used concurrently with MAO inhibitors, other antidepressants or narcotics. SSRI's inhibit P-450 enzyme systems and may reduce clearance of drugs metabolized by these enzymes.
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