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and involves two components: (1) the sensory component is nociception, which is the neural processing of noxious stimuli and (2) the affective component is pain perception, which is the unpleasant sensory and emotional experience associated with either actual or potential tissue damage. Pain is the endpoint of nociceptive input and can only occur in a conscious animal; however, there is also involvement of autonomic pathways and deeper centers of the brain involved with emotion and memory. Hence pain is a multi-dimensional experience; it is not just what you feel but also how it makes you feel.3 Acute pain has been defined as pain that exists during the expected time of inflammation and healing after injury (up to 3 mo), and chronic pain is defined as that which exists beyond the expected duration associated with acute pain. Therapy should be focused on the underlying cause of pain, (nociceptive, inflammatory, or pathological) rather than on arbitrary labels based on duration.4 Nociceptive pain occurs when peripheral neural receptors are activated by noxious stimuli (e.g., surgical incisions, trauma, heat, or cold). Inflammatory pain results gradually from activation of the immune system in response to injury or infection, and pathological pain, also called maladaptive pain, occurs when pain is amplified and sustained by molecular, cellular, and microanatomic changes, collectively termed peripheral and central hypersensitization. Pathological pain is characterized by hyperalgesia (exaggerated response to noxious stimulus), allodynia (painful response to nonnoxious stimuli, such as touch or pressure), expansion of the painful field beyond its original boundaries, and pain protracted beyond the expected time of inflammation and healing. Under some conditions, genomic, phenotypic changes occur that create the condition known as neuropathic pain, whereby pain can be considered a disease of the central nervous system. Those changes are not necessarily chronologic. Maladaptive pain, or the risk for it, can occur within a matter of minutes of certain acute pain conditions (e.g., nerve injury, severe tissue trauma, or presence of pre-existing inflammation). A Continuum of Care Appropriate pain management requires a continuum of care based on a well-thought-out plan that includes anticipation, early intervention, and evaluation of response on an individual-patient basis. It should be noted that response to therapy is a legitimate pain assessment tool. Continuous management is required for chronically painful conditions, and for acute conditions until pain is resolved. The acronym PLATTER has been devised to describe the continuum of care loop for managing pain (Figure 1). The components of the PLATTER algorithm for pain management are PLan, Anticipate, TreaT, Evaluate, and Return. It’s Not Just About Drugs Classic veterinary medical education places a strong emphasis on treatment of disease through pharmacology and surgery, the 68 JAAHA | 51:2 Mar/Apr 2015 esoteric skills that are the domain of the trained clinician. Increasingly, evidence-based data and empirical experience justify a strong role for nonpharmacologic modalities for pain management. A number of those should be considered mainstream options and an integral part of a balanced, individualized treatment plan. Examples of nonpharmacologic treatments supported by strong evidence include, but are not limited to, cold compression, weight optimization, and therapeutic exercise. Other treatment options gaining increasing acceptance include acupuncture, physical rehabilitation, myofascial trigger point therapy, therapeutic laser, and other modalities, which are discussed in these guidelines. In addition, nonpharmacologic adjunctive treatment includes an appreciation of improved nursing care, gentle handling, caregiver involvement, improved home environment, and hospice care. Those methods have the critical advantages of increased caregiver-clinician interaction and a strengthening of the humanpet bond. That shared responsibility promotes a team approach and leads to a more complete and rational basis for pain management decisions.5 Recognition and Assessment of Pain The Patient’s Behavior is the Key Because animals are nonverbal and cannot self-report the presence of pain, the burden of pain assumption, recognition, and assessment lies with veterinary professionals. It is now accepted that the most accurate method for evaluating pain in animals is not by physiological parameters but by observations of behavior. Pain assessment, should be a routine component of every physical examination, and a pain score is considered the ‘‘fourth vital sign,’’ after temperature, pulse, and respiration.1,2,6 Obtaining a thorough patient history from the owner can help determine abnormal behavior patterns that may be pain related. Pet owners should be educated in observing any problematic behavioral changes in their pet and to contact their veterinarian in such cases. As shown in Figure 2, pet owners and practitioners should have an awareness of behavior types that are relevant to pain assessment. Those include the animal’s ability to maintain normal behavior, loss of normal behavior, and development of new behaviors that emerge either as an adaption to pain or a response to pain relief. Because behavioral signs of pain are either often overlooked or mistaken for other problems, the healthcare team must be vigilant in recognizing those anomalies in the total patient assessment. Pain Scoring Tools Although there is currently no gold standard for assessing pain in dogs and cats, the guidelines Task Force strongly recommends utilizing pain-scoring tools both for acute and chronic pain. It should be noted that those tools have varying degrees of validation, acute and chronic pain scales are not interchangeable, and canine and feline scales are not interchangeable. The use of pain scoring tools can decrease subjectivity and bias by observers, resulting in more effective pain management, which ultimately leads to better patient care. Acute Pain: Characteristics and Causes Acute pain involves both nociceptive and inflammatory components and