Pain Scales for Cats: FGS, Colorado, and What to Watch

Cats do not limp, cry, or guard the way dogs do, so pain gets missed for months. Two tools fix most of that: the Feline Grimace Scale (FGS), five facial items scored 0 to 2, where 4 out of 10 or more means analgesia is due; and a composite scale such as the Colorado State acute pain scale, which adds posture and response to touch. Used the same way each time, either turns a vague worry into a number you can compare.

Why pain in cats stays invisible

A cat in pain does not perform. It withdraws, sleeps more, jumps less, and eats less, all of which look like temperament or aging. Radiographic studies find degenerative joint disease in roughly 60 to 90 percent of cats over 12 years, yet a small fraction of those cats are on any pain relief, because the owner never sees a limp. Cats also mask pain when watched, which is why scoring works best from a short video or through a quiet observation window rather than by lifting the cat and palpating it.

The Feline Grimace Scale, item by item

Five action units, each scored 0 (absent), 1 (moderate), or 2 (obvious), giving a total from 0 to 10. The cat should be awake, undisturbed, and not being handled; watch for 30 to 60 seconds in the same lighting each time, ideally from a photo or a 10-second clip. A total of 4 or more is the usual cut-off for "give analgesia now", and it has been validated for acute pain such as postoperative, dental, and abdominal pain. One unit moving from 0 to 2 is enough to act on even if the total stays below 4.

Item	0, no pain	2, obvious
Ear position	Ears forward, facing the front	Flattened and rotated outward
Orbital tightening	Eyes open, no squint	Eyes squeezed shut
Muzzle tension	Relaxed, rounded	Tense, drawn back, nose bridge flat
Whisker position	Loose, curved, spread	Stiff, bunched, pointed forward
Head position	Above shoulder line	Dropped below the shoulders

Composite scales: adding posture and touch

The Colorado scale scores behavior, body posture, and the response to palpation of the sore area, each on a 0 to 4 ladder, and adds an overall rating the clinician assigns. It works where the FGS does not: in a hospital cage after surgery, when a nurse can press gently on an incision and watch the cat's ears and pupils. Pair either score with hard numbers, since a cat in acute pain often runs a heart rate above 220 beats per minute, a respiratory rate above 40, dilated pupils, and a rise in blood glucose. A high score with normal vitals usually means fear rather than pain, and the fix is a quiet room, not an opioid.

Scoring after surgery

Score at 20 to 30 minutes after extubation, then every 2 to 4 hours for the first 24 hours, and before and 30 to 45 minutes after every analgesic dose. Write down the time, the total, the drug, and the dose, because the pattern matters more than any single number: a cat that holds a 2 for six hours is doing better than one that dips to 1 and climbs to 5. Common protocols combine an opioid such as buprenorphine at 0.01 to 0.02 mg/kg transmucosally every 6 to 8 hours with an NSAID, and add gabapentin at 5 to 10 mg/kg twice daily for nerve-related or orthopedic pain. Never give human ibuprofen, naproxen, or acetaminophen: 1 regular-strength tablet of ibuprofen is enough to cause kidney injury in a 4 kg cat.

Arthritis and long-term pain

The FGS was built for acute pain and is weak at detecting chronic pain, because a cat with sore hips does not hold a grimace all day. For long-term cases, use an owner mobility questionnaire, a monthly 2-minute video, and simple measurements: the highest shelf the cat still jumps to, how long it takes to climb 10 stairs, whether it uses a ramp you added, and whether it can reach to groom the lower back. Track weight monthly on a kitchen scale, since 300 g lost over 3 months in an older cat often means mouth or joint pain rather than fussiness. Feeding to a target weight rather than free-feeding makes that number readable, and the food calculator gives the daily gram figure.

Six things owners can watch at home

• New hiding, especially in closets or under beds for more than 20 hours a day.
• A hunched loaf posture with the head lowered and front paws tucked, held for long stretches.
• Refusing a jump the cat managed 3 months ago, or hesitating at the edge of the counter.
• Over-grooming one flank or thigh until the hair thins, or the opposite: a greasy, unkempt coat.
• Eating slower, dropping kibble, chewing on one side, or a 5 percent weight loss in 8 weeks.
• Missed litter box visits, straining, or 48 hours without stool, all of which can be pain rather than behavior.

Where pain and other disease overlap

Pain suppresses immunity and raises cortisol, and in a cat carrying latent feline herpes that is enough to trigger sneezing, squinting, and corneal ulcers within days, so a pain plan belongs inside long-term herpes management rather than beside it. Steroids used for chronic pain carry the same trade-off described in toxoplasmosis and cats: immunosuppression can let a dormant infection wake up, and litter changes then need gloves and daily scooping. Dental pain is the most under-scored of all, and a cat that has stopped eating hard food for 2 weeks usually has a mouth problem, not a preference.

Turning a score into an action

1. Score at the same time of day, in the same room, with the cat undisturbed; keep the photos in one album.
2. Book a vet visit when FGS is 4 or higher, or when a single item hits 2.
3. Ask for a dental check and hip and knee palpation at every visit after age 8.
4. Start home modifications at the first hesitation: a ramp to the sofa, a step to the bed, low-entry litter boxes.
5. Recheck the score 30 to 45 minutes after any new analgesic, and again the next day.

Frequently asked