Pain assessment in cats is one of the greatest challenges in small animal practice. Unlike dogs, cats mask clinical signs of discomfort as a survival mechanism — behavioral heritage that still confuses even experienced teams. The practical result: underdiagnosed and undertreated pain, with direct impact on recovery, behavior and the relationship with the owner.
The good news is that today there are validated scales specifically for cats, with translations into Portuguese and applied research backing them. Using a structured scale, even the simplest, is dramatically better than relying on "he seems fine".
Why assess pain in a structured way
- Reduces observer bias: the same patient assessed by two professionals can receive very different scores — a scale aligns the criteria.
- Documents evolution: numerical record allows comparing time points (before, 2h, 6h, 24h post-surgery).
- Triggers objective intervention: each scale has a specific cutoff that indicates need for rescue analgesia — removes guesswork.
- Educates the team and the owner: shared terms between vet, technician and owner improve home care.
The three most used scales
1. UNESP-Botucatu Multidimensional Pain Scale (UMPS)
Validated for acute post-operative pain in cats, in Portuguese, with a well-established cutoff. Assesses 10 items across 4 subscales:
- Posture (facial expression, general attitude)
- Comfort (reaction to environment, interaction)
- Activity (movements, body posture)
- Mental state (vocalization, reaction to palpation of the surgical site)
Each item scores 0–3, totaling 0–30. Cutoff for rescue analgesia: ≥ 8 points.
Strengths: feline-specific, validated in Portuguese, high inter-observer consistency. Limitation: takes 2–3 minutes to apply and requires initial observation without manipulation.
2. Glasgow Composite Measure Pain Scale — Feline (CMPS-F)
Feline version of the well-known canine Glasgow CMPS. Assesses 7 items, including facial expression, posture and response to wound palpation. Scoring 0–20.
Cutoff for rescue: ≥ 5 points.
Well accepted internationally, with good performance in hospitalization settings. Includes illustrations of facial expressions that help standardize the team.
3. Feline Grimace Scale (FGS)
Developed at the University of Montreal, it is the fastest of the three — takes under 30 seconds. Assesses 5 facial action units:
- Ear position
- Orbital tightening (eyes)
- Muzzle tension
- Whisker position
- Head position
Each item receives 0, 1 or 2 points, totaling 0–10. Cutoff for rescue: ≥ 4/10 (or ≥ 0.4 normalized).
Ideal for quick triage during hospitalization, follow-up visits and assessment during admission without handling the patient. There is a free app ("Feline Grimace Scale") with visual examples that greatly helps standardization.
When to apply (practical protocol)
Suggested key moments in surgical routine:
| Moment | What to assess |
|---|---|
| Pre-anesthetic | Baseline pain (relevant in orthopedics, trauma, chronic pain) |
| Immediate post-extubation | Quick triage (FGS) |
| 30 min post-surgery | Reassessment + rescue if needed |
| 2h, 6h, 12h post-surgery | Following analgesic peak |
| Before discharge | Ensure score is below the cutoff |
| Follow-up visit | Home assessment reported by owner + reassessment in clinic |
Clinical signs often overlooked
Even without a formal scale, always observe:
- Persistent orbital tightening ("squinted" eyes)
- Whiskers tensioned forward (defensive posture)
- Ears low or sideways
- Curled / crouched posture, with abdominal tension
- Isolation or unusual aggression
- Refusal to groom (dull, matted coat)
- Reduced food intake
These signs, isolated or combined, justify applying a formal scale — and often a rescue analgesic.
Owner guidance
Teach the owner to observe at home:
- Appetite and water intake in the first 48 h post-procedure
- Resting posture (painful cats avoid lateral recumbency, prefer tense "sphinx")
- Social interaction (hiding, unusual isolation)
- Unusual vocalization (low growls, long meows)
Offer a direct channel (WhatsApp, phone, app) for the owner to report changes — the sooner you know, the sooner you adjust the analgesic protocol.
The record that makes the difference
Pain assessment only becomes a clinical tool if it is recorded comparably over time. Writing "patient comfortable" does not allow comparison with a 24h follow-up. Writing "FGS 2/10, no rescue" does — and that difference, multiplied by dozens of patients per month, is what separates a mediocre analgesic service from an excellent one.
In cats, pain doesn't shout — it whispers. The professional who listens with method (and records with discipline) delivers the best possible care.
