Sunday, July 24, 2011

Notes from July 2011 St. Louis AVMA Conference-Pain and Behavior

These are papers from the July 2011 St. Louis AVMA conference.  I’ve edited them to delete some of the vet only jargon and for space considerations.  If you see (…) that means that information has been deleted due to these considerations.  The ones listed here include HCM, and other heart related papers, treatments, papers on x-rays and echos, thrombosis, kidney disease, idiopathic cystitis, pain management, anesthesia and cardiac disease, supplements and other hazards for pets, and some other basic information I hope is helpful.


Mary P. Klinck, DVM, BSc, DACVB

Faculty of Veterinary Medicine, University of Montreal

Feline pain can be particularly difficult for both cat owners and  veterinarians to assess, and

has historically been under-recognized and  under-treated in veterinary medicine. Clearly,

untreated pain is a direct welfare concern, but it can also have an indirect effect through

alterations in behavior, which have the potential  to affect the human-animal bond and to

increase the risk of pet relinquishment.  Along with increased awareness of pain

management in the profession as a whole has come a growing interest in the problem of

feline pain in particular, resulting in a small but rapidly growing body of research on this


Pain assessment is challenging across species…In nonverbal subjects, a variety of approaches to pain

measurement  have been used, including: a) physiological measures, either absolute or

compared  to base line values, such as heart or respiratory rate, blood pressure,

temperature, pupil dilation, skin electrical conductivity, and hormone levels (e.g., cortisol);

b) behavioral measures such as facial expression, body tension and posture, and

responsiveness to the environment, interactions, or to palpation of the painful area.

Physiological measures often require procedures that are somewhat invasive or disturbing

to the patient, in and of themselves.  Wide “normal” ranges for physiologic values and

variation simply due to the act of measurement itself may also limit the sensitivity and

specificity of these measures.  Behavioral measures can be assessed via observation

combined with limited manipulations, and can be used in contexts where physiological

measures are impractical or costly (e.g., in the pet’s home).  Both physiological and

behavioral criteria for assessment of pain may be affected by other factors, for instance,

stress in the clinic or in the home, or other illnesses. Individual differences can also make

comparison between patients difficult…

Pain can be divided into different categories on the basis of its cause or physiology. The

context of assessment tends to differ in acute vs. chronic pain in cats; veterinarians and

veterinary staff may  have more opportunities for direct monitoring of acute pain in

hospitalized patients (e.g., surgery, trauma, or infection), while cats with chronic causes of

pain may need to be evaluated  less directly, by questioning  the owner in order to 1) detect

the presence of pain, and 2) to monitor it over time.  In a clinical setting, pain can often  be

anticipated on the basis of the disease or procedures…observable symptoms of pain include: 1)

altered demeanor (lack of interest in surroundings, increases or decreases in general

aggression or avoidance behaviors),  2) altered responses to handling (tension, flinching,

withdrawal, growling, hissing, scratching, biting in response to palpation or manipulation);

3) altered or tense body posture (a hunched or rounded back, reluctance to adopt usual

resting postures), 4) changes in weight bearing or lameness, 5) changes in facial

expression (such as squinted eyes), 6) abnormal vocalization, 7) alterations in normal self maintenance

behaviors such as a) grooming… b) toileting (not using the litter box for urine and/or feces or having

“accidents” over the sides, not scratching in the litter), c) eating (decreased appetite or

reluctance to eat certain foods).  As there are individual differences in these behaviors, it

is ideal to assess them at baseline and make comparisons over time, if this is possible.

If there is uncertainty regarding the presence of pain, reassessment after a trial dose of an analgesic may help to clarify whether the apparent abnormality was due to pain.

In the home, owners will usually recognize signs of acute onset or severe pain; however,

chronic or insidious onset pain can produce subtle or gradual changes that may go

unnoticed or wrongly be attributed to “getting old”, or to environmental or other factors (e.g.,

a response to the addition or removal of an animal or family member).  Almost any change

in behavior could be caused  by pain or disease.  Specifically, if there is an unexpected or

unexplained  development of a new or abnormal behavior, or loss of a previous behavior…pain

should be considered as a cause.  Not only undesirable (“problem”) changes indicate pain;

owners may interpret a change as desirable, undesirable or neutral (e.g., a cat that stops

clawing the furniture, vs. a cat that becomes more affectionate, vs. a cat that chooses a

new location for resting), but they may be less likely to report desirable changes to the

veterinarian, unless asked.  Clinicians should be alert to the possibility of pain as a cause of

apparent behavior problems, and should also be prepared to ask about subtle changes in

behavior as a part of the screening process for cats at risk of chronic pain (e.g., animals

with confirmed disease such as neoplasia or inflammatory bowel disease, or animals at risk

for diseases such as osteoarthritis).

Complaints that may be caused by pain but incorrectly attributed  to a primary behavior

Problem  include: over-grooming with hair removal or self-inflicted wounds, hyperesthesia

(manifested  by skin twitching and running  from or attacking  the tail or dorsum), aggression

(in response to petting or handling, or in other contexts), or inappropriate elimination.  It is

important to remember that pain may be the primary cause, but even in cases where it was

not the original cause, it can contribute to maintenance or to progression of the problem,

and therefore require treatment.  Other specific behavior changes due to pain include:

altered activity and sleep/rest habits, changes in appetite, changes in social interactions

with human and animal family members, changes in play or hunting behavior, and changes

in litter box use…

Pain scales using behavioral observation and responses to direct interactions are gaining  in

popularity in feline medicine. Their use may be based on observation alone, or based on

observation and interaction (including palpation of the painful site). There exist several

general types of pain scales, listed below roughly from simplest to most complex:

1) Numerical Rating Scale (NRS)

This consists of a range of numbers (e.g., 0-10, where 0 represents no pain, and 10

represents the worst possible pain); a number within the range is selected based on the

level of pain observed.

2) Visual Analog Scale (VAS)

This consists of a 100 mm  vertical or horizontal line, where one end (0) represents no pain,

and the other end (100) represents the worst possible pain; it is used by placing a mark

along the line to indicate the level of pain observed. The distance from 0 is then measured

with a ruler to obtain the score.

3) Simple Descriptive Scale (SDS)

For this scale, numbers along a range are assigned to verbal descriptions of the level of

pain (e.g., 1 = no pain, 2 = mild pain, 3 = moderate pain, 4 = severe pain), and the observer

determines which description fits best, then assigns the corresponding score.

4) Composite Pain Scale (CPS)

In this type of scale, several criteria are assessed individually (often based using SDS

format) and the scores for all the criteria added together to determine the total pain score.

Prior to clinical use, a pain scale should be demonstrated to be capable of distinguishing

between different levels of pain (= scale responsiveness, or predictive value) in the

intended context, and to yield consistent results between observers and  within observers

over time (= scale reliability). This involves use of the scale to compare subjects with known

differences in intensity of a particular type of pain, to determine if the scale is capable of

distinguishing between levels of pain, or to detect a response to analgesics…It is also important

to consider that a scale that seems to be effective or that has been used for monitoring cat pain after OVH

 will not necessarily be as effective for monitoring pain after declaw or tooth extraction, or in painful

medical conditions such as feline lower urinary tract disease. ..

For chronic feline pain, there has been some preliminary work on the validation of specific

pain scales for use in degenerative joint disease. One such scale is the Client Specific

Outcome Measures scale, which was found to be capable of identifying changes in pain in

response to treatment with meloxicam.  This type of scale uses criteria selected by the cat

owner with the help of the veterinarian/technician, and is therefore specific to the particular

cat.  For instance, criteria might include ability or willingness to jump, use of the litter box,

etc., but will be activities that the owner feels are affected by the cat’s pain.  


a. CSU Acute Pain Scale:,20467/refDownload.pml


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