The Chartreux plan starts at the knee, not the heart, because a luxating patella is the finding you can get on a 2-minute hands-on exam at 6 months, years before an echo shows anything. Order of work: knees at every visit, kidney ultrasound at 10 months and 2 years, echo from 12 months, and a weigh-in every 30 days for a breed that gains weight on a 10% portion error.
1. Knees: grade 1 to 4, and what each grade changes
Medial patellar luxation is graded by hand, not by machine. Grade 1: the kneecap can be pushed out of its groove but snaps back on its own. Grade 2: it pops out when the stifle flexes and stays out until someone straightens the leg. Grade 3: it sits out permanently and can be pushed back in. Grade 4: it is out and cannot be replaced at all. Grades 1 and 2 are what a screening exam looks for: they are silent, and a grade 2 knee at 12 months is a lame cat at 6 years.
Screen by palpation at 6 to 8 months and at every annual visit after that; add radiographs of both stifles at 12 months if any grade is felt, 2 views per leg, at 120 to 250 dollars. Grade 1 gets a recheck at 6 months and a note in the record. Grade 2 with any lameness, or grade 3 and above, goes to a surgical opinion: a tibial tuberosity transposition with a trochlear groove deepening runs roughly 1,200 to 3,000 dollars per knee, and recovery is 6 to 8 weeks of restricted jumping.
The owner controls load: a 6 kg cat carrying 1 kg extra puts about 20% more force through a joint that already tracks wrong, so weight is part of the orthopedic plan.
2. Kidneys: 2 scans, 14 months apart
Polycystic kidney disease (PKD) is inherited as a dominant trait in this family of breeds, which means one affected parent is enough and roughly half the litter can carry it. Cysts of 1 to 2 mm are visible on ultrasound but are rarely present before 6 months, so the first useful scan is at 10 to 12 months and the second at 24 months; a cat clear on both stops PKD scanning.
Write 4 numbers on the report: kidney length in mm (35 to 45 mm is the usual adult range), number and size of cysts, a urinalysis with specific gravity (below 1.035 means concentrating ability is going), and creatinine with the laboratory's own reference interval. SDMA above 14 µg/dL flags filtration loss before creatinine moves, and a systolic blood pressure of 160 mmHg or more on 2 visits needs treatment. A PKD1 DNA swab is available and cheap, but a negative swab does not replace the scan in a breed where the test's validation is less settled; use it as a second opinion, not a discharge.
3. Heart: the echo from 12 months
Hypertrophic cardiomyopathy (HCM) is the reason the echo repeats every 12 months rather than once. Three values change the plan. Maximal diastolic wall thickness: under 5.0 mm normal, 5.0 to 5.9 mm a recheck in 6 months, 6.0 mm or more the usual echocardiographic definition. LA/Ao: 1.5 or below normal, 1.5 to 1.7 equivocal, above 1.7 means the atrium is dilating. SAM, yes or no. A murmur at grade 1 to 2 buys an echo within 4 weeks; grade 3 or a gallop, within 7 days. No DNA test replaces this scan, because the validated feline MYBPC3 tests cover the Maine Coon and Ragdoll variants only.
4. Weight: the 10% portion error
Score body condition 1 to 9 monthly and log the weight on a weight trend chart; 5 is the target and 7 is where the plan changes. A 10% portion error on a 6 kg cat is 25 g of dry food a day, which is under one small handful, and it adds about 400 g in 3 months. Two triggers: a 10% gain in 90 days means re-measuring the cup, and a 5% loss in 30 days means a vet visit within 72 hours, because in this breed loss is more often disease than diet.
Feed to resting energy requirement, roughly 70 × weight in kg to the power 0.75, which is about 250 kcal a day at 6 kg, and start any loss plan at 80% of the target weight figure. Split it into 3 meals and stop free-feeding, because a bowl that is never empty removes your only measurement.
5. The annual schedule
| Age | Knee palpation per year | Kidney scan per year | Echo per year | Weigh-ins per month | Blood panel |
|---|---|---|---|---|---|
| 6 to 8 months | 1 (first grade) | 0 | 0 | 1 | 0 |
| 10 to 12 months | 1 | 1 (first) | 1 (baseline) | 1 | 1 |
| 24 months | 1 | 1 (second) | 1 | 1 | 1 |
| 3 to 6 years | 1 | 0, or 1 if cysts | 1 | 1 | 1 every 12 months |
| 7 years and up | 1 | 1 | 1 | 2 | 2 |
6. Four signals you can see at home
- The 3-legged skip. A cat that hops for 3 to 10 seconds after a jump and then walks normally is describing a grade 2 kneecap; count the episodes per week.
- Sleeping respiratory rate. 30 seconds, twice a week, 30 per minute as the ceiling; 40 once or 30 three times means a call, not a wait.
- Water and clumps. Above 45 mL/kg a day, or litter clumps that doubled in 2 weeks, points at the kidneys before any blood test does.
- The rib line. Run a flat hand along the ribs every 2 weeks: ribs you cannot feel under a 5 mm fat layer mean the portion has drifted, whatever the scale says.
7. Hour-level thresholds
| What you see | Number | Act within |
|---|---|---|
| Open-mouth breathing at rest | any | 0 to 1 hour |
| Sleeping respiratory rate | 40+ once, 30+ x3 | 2 hours, else 24 hours |
| Sudden hind-limb paralysis, cold pads | 1 or 2 legs | 30 minutes |
| Cannot bear weight on a hind leg | more than 12 hours | 12 hours |
| No urine in 24 hours | 24 hours | 2 hours |
| Not eating, overweight cat | 24 hours | 4 to 6 hours |
| Weight down 5% in 30 days | 5% | 72 hours |
| Limping that lasts | 3 days | 7 days |
8. The bill
| Item | USD | CNY |
|---|---|---|
| Orthopedic exam | 50 to 90 | 100 to 250 |
| Stifle radiographs, 2 views per leg | 120 to 250 | 300 to 700 |
| Kidney ultrasound | 120 to 250 | 300 to 700 |
| Echocardiogram | 220 to 450 | 600 to 1,200 |
| Patellar surgery, one knee | 1,200 to 3,000 | 3,000 to 8,000 |
| Year one total, no surgery | 400 to 800 | 1,000 to 2,200 |
9. Five steps for the next 30 days
- Ask for a knee grade in writing at the next visit; grade 1 to 4 is a number, not an opinion.
- Book the 10 to 12 month kidney scan and the baseline echo on one morning.
- Weigh monthly and log it; 10% in 90 days is the portion, 5% in 30 days is the vet.
- Measure the daily ration with a scale for 7 days, then decide whether the cup was honest.
- Diarise the 24 month kidney scan now, because the second scan is what ends the PKD question.
None of this diagnoses a cat: a luxation is graded by hand and film, PKD on ultrasound, HCM on echo. The plan's only claim is timing, that a grade 1 knee and a 4 mm cyst are both cheaper at 12 months than at 8 years.
Terms mentioned in this article
Frequently asked
At what age can a luxating patella be graded?
From 6 to 8 months, by hand. The grade runs 1 to 4 and needs no sedation, which is why it belongs in every kitten visit. Radiographs at 12 months are for the cats where a grade was felt, not for every cat.
Is one normal kidney scan enough?
No. The first scan at 10 to 12 months can be clear while cysts appear in the following year, which is why the second look at 24 months exists. Two clear scans end PKD screening; one clear scan only buys time.
What does patellar surgery cost, and when is it indicated?
Roughly 1,200 to 3,000 dollars per knee, or 3,000 to 8,000 CNY, for a tibial tuberosity transposition with groove deepening. It is indicated at grade 3 and 4, and at grade 2 that already causes lameness; grade 1 is monitored.