BY: SAMANTHA BARTLETT, DVM
Researchers at the University of Montreal in Canada, recently unveiled a new scale for assessing pain in cats. The scale was first unveiled at the AVMA Convention this August. The validation study was also recently published (Steagall PV, Monteiro BP. Acute pain in cats: Recent advances in clinical assessment. J Feline Med Surg 2019;21(1):25-34).
Until now, the assessment of pain in cats was largely based on physical and behavioral parameters wet forth in the Glasgow Composite Measure Pain Scale or the UNESP Botucatu Multidimensional Composite Pain Scale. Although there are other pain scales used, these are the only two that have been validated until now.
The Feline Grimace Scale was developed by the Montreal team of Dr. Paulo Steagall (associate professor of veterinary anesthesia and analgesia) and Dr. Marina Evangelista (a doctoral student). The scale scores from 0-2 on five different facial action units. A total of 4 or greater indicates that analgesia is needed. A zero score indicates absence of the action unit, one is moderate or uncertainty and two is an obvious appearance of the action unit. The facial action units are as follows:
• Ear position: (0) Ears facing forward, (1) ears slightly pulled apart, or (2) ears flattened and rotated outward.
• Orbital tightening: (0) Eyes opened, (1) eyes partially opened, or (2) eyes squinted.
• Muzzle tension: (0) Muzzle relaxed (round),(1) muzzle mildly tense, or (2)muzzle tense (elliptical).
• Whisker position: (0) Whiskers loose and curved, (1) whiskers slightly curved or (2) straight, or whiskers straight and moving forward.
• Head position: (0) Head above the shoulder line, (1) head aligned with the shoulder line, or (2) head below the shoulder line or tilted.
The scale has been validated for veterinarian use, but Steagall and Evangelista are also evaluating its usability by support staff and potentially pet owners. Further research is being done to better determine cutoffs for analgesia as well.
