Chronic Pain Assessment

Chronic Pain Assessment

Chronic pain assessment is currently accomplished by using a combination of caregiver and veterinarian assessments, as well as physical examination. The use of validated pain assessment tools and checklists are strongly recommended. A validated metrology tool reliably measures what it is intended to measure (pain, mobility, etc.), and is able to pick up clinically significant changes for which it is being used. These instruments are detailed below and identify the impact of chronic pain on various domains such as activity, activities of daily living, and quality of life (QOL).

In general, chronic pain assessment is achieved with the central involvement of the cat caregiver because our profession has moved to an understanding that caregivers know their pets best. However, cats with chronic pain may demonstrate subtle or gradual changes in behavior, which can be overlooked or go undetected by caregivers. Therefore education should be provided, for example during routine checkups for young adult cats, so the caregiver learns to recognize and identify these changes.

It is important to remember that the caregiver questionnaires that have been developed to assess chronic pain have been developed for specific conditions (e.g., musculoskeletal pain), and they may not be appropriate for other conditions.

In the clinical setting, the participation of veterinary technicians and nurses in pain assessment is extremely valuable as part of client education, particularly in a busy practice and/or when providing telemedicine service.

Early Screening

Screening tools can detect chronic pain in its early stages, allowing for early intervention. Early detection will minimize suffering and promote appropriate treatment (pharmacologic, nonpharmacologic, and environmental changes) and may be more successful in the early stages of disease before tissue, joint, or organ damage is advanced and central sensitization has become the main driver of pain.

Clinical Metrology Instruments

Clinical Metrology Instruments (CMIs) or Client Reported Outcome Measures (CROMs) (Table 1 below) are questionnaire-based measurement tools to quantify chronic pain.

• They are based on the observations of the caregiver over time and include differing assessments (depending on the tool) of the cat’s daily living activities, function, and, in some cases, QOL.
• These tools should be used and tracked over time to assess the efficacy of treatment interventions.
• Selection of a CMI should be based on the patient’s condition(s) and needs, as well as the caregiver’s willingness/ability to utilize the instrument regularly. The appropriateness of a CMI depends on the condition it was developed to measure (e.g., one developed for musculoskeletal pain is probably not appropriate for oral pain). If there are several CMIs for a given condition, the same CMI should be used for that patient for each condition during reassessment, both for validity and ease of comparison.
• Essential attributes of an assessment tool include reliability, sensitivity, utility, construct validity, and content validity (See box below). More information can be found here.

• Feline tools that have been developed to assess acute pain in cats (e.g., the Feline Grimace Scale) should not be used for chronic pain, just as tools for one species should not be used in another. The ideal use of a tool is for the pain condition it was developed to measure, however future clinical research may define wider applicability of given tools.

PLATTER Approach

The acronym PLATTER has been used to describe the continuum of care loop for managing pain. The components of PLATTER are PLan, Anticipate, TreaT, Evaluate, and Return (see Figure 1 below).

   Reprinted with permission from the AAFP. Epstein M, et al. 2015 AAHA/AAFP Pain Management Guidelines for Dogs and Cats. Journal of Feline Medicine and Surgery.
   Available at catvets.com/pain-management.

Quality of Life (QOL)

• Chronic diseases and many related treatments can have a negative impact on QOL.

• Cats live in the moment, therefore, unlike humans, cannot know that “tomorrow may be better” while experiencing pain and going through unpleasant treatments. Our patients do not make choices for themselves - that falls on the caregiver - and we must partner with them to make good, well-informed patient-centric decisions.

• Long before end of life decisions are made, assessment and evaluation of QOL is as important as assessing the impact of diseases, and assessing the benefit or negative effects of individual or combined treatments.

• Despite wide usage, the term QOL with respect to animals does not have a universally consistent or accepted definition.

• One definition of QOL is “an individual’s satisfaction with its physical and psychological health, its physical and social environment, and its ability to interact with that environment"

• QOL and Health Related Quality of Life (HRQOL) are different. QOL is a broad term and considers all aspects of a pet’s life which include physical and mental health. HRQOL refers to the specific impact of a medical condition on an individual’s health

• An HRQOL instrument should be able to detect disease (be discriminative) and measure health changes over time (be evaluative)

• One tool is a 20-item instrument that is completed online by caregivers and can reliably differentiate sick from healthy cats and shows promise for tracking QOL associated with chronic feline diseases. Currently, this instrument (Vetmetrica) is only available by subscription through NewMetrica (newmetrica.com)

• The veterinary team should discuss internally among themselves what they mean by QOL or HRQOL so that everyone is on the same page when communicating with clients