Stereotypic and compulsive disorders in pet animals

               

Compulsive disorders often arise from situations of conflict or anxiety. If the source of the conflict can be identified in the initial stages, it may be possible to resolve the problem without drugs. This might be accomplished by finding all situations where the problem occurs and either avoiding the situation entirely or teaching the pet to display a different, more acceptable behavior.

Medical problems might actually be the underlying reason that a pet exhibits a particular behavior. Therefore, before diagnosing a compulsive disorder, all possible medical problems must be considered. In addition, once a medical problem causes a pet to begin exhibiting a behavior (e.g. licking, chewing) it can become compulsive.

Over time, the constant repetition of the problem and your response to the dog may lead to a change in neurotransmitters in the brain so that the behavior may begin to appear more frequently or in more situations than before. Sometimes it becomes exaggerated or so intense that it may be hard to interrupt. At this point, the behavior may have become compulsive and may require a combination of behavior management, changes to the household, and drugs to improve or control the problem. In addition, if the initial conflict and anxiety are not identified and controlled, the problem will not be entirely resolved.

Determine whether your response may in any way be contributing to the problem. If you are trying to stop your pet either by patting or offering a treat, then this serves to reward the behavior. Similarly, punishment may merely serve as a form of attention. If you raise the level of punishment or show any anxiety or upset in your response to the dog, then you will likely add to your pet’s anxiety and conflict.

If you observe the pet displaying the undesirable behavior, be calm, interrupt it without saying anything or looking at it, and redirect its behavior to another activity (play, exercise, toys stuffed with food). Your goal is to train the dog to exhibit an acceptable alternative response while remaining calm and consistent and then reward! This can be accomplished by:

Using a physical control device such as a leash and head halter or an interruption device such as a water spray, shake can, ultrasonic device, or remote citronella spray to stop the undesirable behavior. Then reward the desirable response.

 Training the pet to perform an acceptable response through command training (e.g., settle, down). Use the command as soon as the behavior starts (or can be anticipated) and then reward the desired response.

Walking away or ignoring the pet. Once the behavior stops, look for a desirable behavior to reinforce.

Environmental changes can cause some pets to become more anxious. Returning to a more acceptable environment for the pet may improve the problem. Increasing the pet’s interest in exploring and playing may reduce the level of anxiety and the performance of the undesirable behaviors.

Cats: Give your cat some new places to perch, some new areas to climb or scratch, or some bags or boxes to explore. Sometimes cats will show interest in the TV or a video. Toys that hang, dangle, or can be batted are attractive to many cats. There are now toys where food can be stuffed inside, that the cat manipulates by scratching, chewing, rolling to get the food out. Some cats are attracted to kitty herb gardens.

Dogs: Most dogs are attracted to toys that contain food and those that can be chewed. A variety of chew and play toys for dogs have been developed that can be coated, filled, or stuffed with food to attract and distract the dog for long periods of time. Freezing food and treats after inserting them in the toys can increase the duration of time spent chewing. Dogs that enjoy investigating and exploring may be better distracted by games where they have to search to find new toys and treats. Videos designed for dogs to view may be of interest to some dogs.

Interactive play provides social contact, attention, and more physical activity for the pet. Exercises, play, and working sessions for dogs might include walks, jogging, swimming, agility, fetch, flyball, or other chase-related games (soccer, football, Frisbee, hockey). Cats are more likely to be stimulated by toys that can be batted, chased, or pounced upon. Toys that can be dangled in front of the cat to chase or can be rolled across the floor often work best. Games with food as a reward may also help maintain interest. Training sessions can be an effective form of attention, mental stimulation, and positive social interaction for both dogs and cats. Sometimes obtaining another pet, or providing play sessions with other pets, can help reduce the time spent engaging in compulsive disorders.

The goal of training, exercise, play, exploration, feeding, and social interactions is to help calm the pet so that it is either relaxed, settled and sleeping, or displaying appropriate acceptable behaviors (rather than displaying compulsive behaviors). Helping your pet develop a comfortable resting area and setting up some cues and situations that help to relax the dog can further reduce compulsive displays. A favored blanket, a TV or CD, or a special odor might be associated with these relaxation sessions and times. A settle down command for dogs (see settle handout) can be particularly useful. A diet change or natural supplement may help to calm the pet or reduce anxiety.

 It may be necessary to temporarily block the performance of the behavior (e.g., Elizabethan collar, bandaging, sedative, leash control) so that repetition of the behavior does not cause further injury or damage.

Medical drug therapy: if there is a medical component to the problem, then drugs to resolve infection, pain, or inflammation may be needed.

Behavioral drug therapy: drugs that help return the serotonin system back to a more normal state of function is usually needed for compulsive disorders. Sometimes drugs that reduce anxiety can be useful as well.

Reference: Landsberg G, Hunthausen W, Ackerman L 2003 Handbook of Behavior Problems of the Dog and Cat. Saunders, Edinburgh

Mechanism of pain

Pain sensation is a dynamic process with highly organized neural and chemical circuits. Sensory information is transmitted to the central nervous system from afferent neurons, a process termed ‘nociception’. These incoming pain signals are processed within the dorsal horn of the spinal cord and result in reflexive actions, such as withdrawal from the source of injury. Reflexive actions facilitate a rapid response, while, concurrently, pain signals are transmitted to the brain to produce an emotional response and memory. The motivational responses to pain, which provoke a goal-directed action of avoidance, results from activity within the hypothalamus, periaqueductal grey area and thalamus, whereas the anterior cingulate cortex evaluates the hedonistic value of pleasure and of pain. Within the midbrain, the pain system interacts closely with the fear system at several locations, such as within the amygdala and periaqueductal grey, facilitating consolidation of memories that will be important for recognising potentially dangerous stimuli in the future and developing flexible responses of avoidance.

Pain signals are suppressed or amplified by coordinated neural connections between the brain and spinal cord. During sympathetic nervous system activation or the fight–flight–freeze response when animals may be scared, pain sensations are suppressed – a phenomenon referred to as ‘stress-induced analgesia’. Conversely, conditioned safety signals can increase pain sensation, through the release of peptides, such as cholecystokinin, in the cerebrospinal fluid, which can suppress pain control mechanisms, including opioid analgesic drugs, acupuncture and placebo effects. The regulation of pain sensation is discussed further below.

During the fight–flight–freeze response, suppression of pain serves an adaptive function, allowing the animal to escape from or resolve the conflict. The ‘gate control theory’ suggests that sensory inputs of pain are modulated through ascending and descending pathways in the central nervous system. Descending neural pathways potentiate or attenuate pain signals influencing the amount of neurotransmitter released by the incoming neurons or by changing the sensitivity of the ascending nerves in the spinal cord to these neurotransmitters. Analgesia is not just a response to pain but can also be classically conditioned to avoid painful sensation. When stimuli are perceived that are predictive of pain from past experience, descending signals may be sent to inhibit pain sensation (anti-nociception).

Conversely, safety signals can result in the release of peptides such as cholecystokinin in the cerebrospinal fluid surrounding the spinal cord, which suppress pain-controlling mechanisms (anti-analgesia). Thus administering painful physiotherapeutic interventions to an animal in the presence of a safety signal (most often the owner) may actually exacerbate the pain of the procedure. Hyperalgesia refers to exaggerated pain states with increased responsiveness to signals within the spinal cord. The pain threshold is lowered, and sensory nerve fibers release large quantities of neurotransmitter in the spinal cord in response to afferent signals. It may arise for many reasons, but chronic compression of pain fibers within the spinal cord due to a back lesion are a common cause in animals. In these cases the pain may be sensed as arising from the point of compression or the area served by the nerve. Neuropathic pain refers to a pain that arises as a result of nerve damage and can be extremely painful.

Causalgia is a particular form of hyperalgesia associated with nerve damage (neuropathy) particularly stretching. It is sensed as a burning pain following trauma local to the nerve. It is therefore an important differential in cases presenting with attempts at self-mutilation. A history of trauma to the region and exacerbation by warmth with remission in response to cooling of the affected area may help identify the problem, which often resolves within a year. Infection may also result in hyperalgesia, both with and without neuropathy. For example, it has been suggested that herpes virus infection of the trigeminal nerve in horses may be a cause of headshaking, a severe, involuntary tossing of the head by the ridden horse. It is also known that two types of glial cells, astrocytes and microglial cells, that act as immune cells within the central nervous system, specifically recognise and bind to bacteria and viruses, and when activated they release nitric oxide, prostaglandins, and proinflammatory cytokines, such as interleukin-1 and tumor necrosis factor. These chemicals excite neurons and are key mediators within the spinal cord of exaggerated pain states.

Phantom-limb pain is a common sequel to limb amputation in humans and usually develops several days following surgery. It is reportedly more common in individuals who experienced pain in the limb before amputation. An animal experiencing phantom limb pain might be expected to present with self-mutilation of the wound site and this must be differentiated from direct wound site problems such as irritation from sutures; alternatively, the animal may show a more general pain response. Pain sensation may be suppressed by competing motivational systems. For example, in poultry it has been found that expression of feeding and of pre-laying behaviour produces a degree of analgesia. While there are no scientific reports known to the authors of this being tested experimentally in a physiotherapeutic context, this is often applied in practice by feeding or distracting an animal during examination. It would also be interesting to examine the effects of enriched environments on rehabilitation, especially in horses that often undergo box rest in very barren environments. The processing of pain is also affected by background mood. For example, pain reports are lower in human subjects when stimuli are paired with positive or pleasant odours. Therapeutically, the creation of a relaxing environment for treatment is therefore to be advised for many reasons. Suppression of pain also occurs during and following intense aerobic activity, and is likely mediated by endogenous opioids. This may be one of the benefits of hydrotherapy.

However, not all interventions producing analgesia are necessarily positive and it is important to be aware that when an animal is faced with inescapable aversion, as might occur as a result of intense restraint during painful manipulation, learned helplessness may result. This results in emotional biasing of behaviour towards passivity, active inhibition of skeletal muscles and opioid-mediated analgesia. Thus, if an animal initially struggles and is then overzealously restrained, it may be harder to identify the source of pain.

Reference: Animal Physiotherapy: Assessment, Treatment and Rehabilitation of Animals

Edited by Catherine M. McGowan, Lesley Goff, Narelle Stubbs.

An overview of pain

The International Association for the Study of Pain defines pain as ‘an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage’. Pain is a potent negative affective state that focuses an animal’s attention and biases its behavior.

One of the problems with assessing pain in animals is that pain can only be measured indirectly; while humans can self-assess their levels of pain and verbally report pain scores, the subjective experiences of animals are particularly difficult to assess. An animal in pain will withdraw from the source of the insult if it can be identified, protect the area affected both through immobilization and active defensive aggression and may communicate the pain to others through changes in facial expression, body postures and vocalizations.

By contrast, health and happiness are identifiable by an open and relaxed posture, facial expressions of contentment and production of chemicals that are associated with pleasure, such as endorphins. The ability to recognize and to respond to painful stimuli has evolved to protect individuals against tissue damage and provides information to safeguard against dangerous or threatening stimuli in the future. Pain may be associated with suffering at many different levels, depending on both the circumstance and the cognitive ability of the animal concerned. At its simplest it may be a temporary negative state, which guides the animal’s withdrawal from a noxious stimulus.

A variety of animals may be able to anticipate pain and generate feelings of anxiety when faced with a predictably painful stimulus and will take avoidance action as appropriate. This will cause the activation of the hypothalamic–pituitary axis and behaviorally might include threatening behavior or attempts at escape (fight or flight response). The intensity of the response is usually directly related to the intensity of the perceived threat. It is important to realize that the perceived threat arises from a combination of factors (e.g. previous experience, sensitivity to pain, emotional state) without a single cause; and as a result of the accumulation of several risk factors within the three levels of behavior assessment discussed in the previous section. Therefore, simply approaching the animal may not seem threatening from the person’s perspective, but very threatening from the animal’s perspective. It is also thought by some that certain species such as horses and dogs may be capable of a pain phobia; this involves the generation of an ungraded and extreme reaction in response to even the most low grade sign of any pain.

While pain phobias may exist, they should be distinguished from extreme responses that have been conditioned and allodynia. This is an exaggerated pain response to normally innocuous stimuli, and although mechanisms are unknown, allodynia probably arises in the structures of the limbic system of the brain, such as the amygdala and periaqueductal grey, which are associated with the processing of emotions.

Animals showing an extreme response for whatever reason are potentially very dangerous and require specialist intervention in consultation with a veterinary behaviorist. An even higher cognitive level of response to pain is pain empathy, i.e. responding to the pain of others and many owners may report that their pets are capable of this, although it remains to be demonstrated scientifically.

Pain is also often classified according to its temporal pattern and this is associated with different psychological impacts and behavioural tendencies, which might be apparent in a range of species. In humans, individual painful episodes may be referred to as per-acute pain episodes and are behaviorally characterized by vocalization and withdrawal of the painful area. Acute pain refers to episodes that last up to about 3 weeks and are associated with fear and anxiety, reduced activity and care-soliciting behaviour. Subacute pain lasts for between 3 and 12 weeks and is characterized by oscillating bouts of activity and inactivity, signs of frustration (including irritability) and the development of coping strategies associated with longer term adaptation to the pain. Early signs of depression may also become apparent at this time.

Beyond this, the pain may be considered chronic and depression, together with other passive coping strategies, is more likely. Often subacute episodes may occur against a background of chronic pain in individuals with longstanding musculoskeletal lesions, and in the horse this may present as periodic bucking set against a ‘loss of spirit’. While the changes over time may partly reflect natural adaptive developmental changes to an unresolved lesion, it is important to recognise that learning will also occur as a consequence of the responses made over time and affect the response that is shown.

Reference: Animal Physiotherapy: Assessment, Treatment and Rehabilitation of Animals

                        Edited by Catherine M. McGowan, Lesley Goff, Narelle Stubbs

Skin grafting in a dog

History: The dog brought with history of vesicant burn in the leg which was not taken care and leads to infection and necrosis of the skin of lateral aspect of the thigh region of the right leg. See image above.

Treatment: I advice the owner to bring the dog for debridement of the wound to make it fresh. Then fixed the surgery.

Discussion:  A skin graft is a piece of skin that has been totally removed from the body and placed on a wound. Blood vessels in the wound bed will quickly grow into the underside of the skin graft, thus bringing it back to life. If the blood vessels cannot grow quickly enough into the the underside of the skin graft, the graft will die. For this reason the wound must be adequate to nutritionally support the graft and the surgeon must very carefully prepare the skin graft so that vessels will be able to grow into the graft.

Indication:

• Skin grafts are used for wounds that are caused by
  • traumatic accidents
  • oncological surgery (tumor removal)
  • thermal burns
  • chemical burns
  • vesicant burns - injected medications such as chemotherapeutic medications or some injectable anesthetics
• The procedure has the advantage of requiring only one surgery once the wound bed is adequately prepared for grafting.

Types of skin grafts that are used to repair the wounds:

• Full-thickness skin grafts are most commonly used in dogs and cats. This involves removing the a piece of skin and removing the fat from the underside of the skin. The donor site must have enough surrounding loose skin so that the incision can be closed. The survival ("take") of a full-thickness skin graft is the same as a partial-thickness skin graft.
• Partial-thickness skin grafts skin grafts involve shaving a very thin layer of skin off the donor site. No hair will grow from this skin graft because the hair follicles are in the deeper layers of the skin. The donor site will heal on its own and does not involve closure of an incision. This type of graft donor site can be more painful, as the raw donor site will have many exposed nerve endings that need to heal over with time. The indication for partial thickness skin grafting is for cases in which a dog has massive skin loss (especially a burn victim) and there is limited normal skin that is available to be used for skin grafting.

Care at home after surgery:

•  Limit activity for 3 weeks after surgery
•  Keep the bandage dry
• Check the toes for swelling and coldness if the graft site is on a limb (while the bandage is on)
•  Return to veterinarian at the scheduled times for bandage changes
• After the bandage is no longer needed, cover the graft site with a soak (if the graft site is on a limb) for a period of 3 to 4 weeks to prevent your pet from licking and chewing at the site. If needed, an Elizabethan collar may be recommended to prevent self-mutilation.

Reference: http://www.vetsurgerycentral.com/skin_grafts.html