Heartbroken - anyone veterinary minded help explain what just happened?

[EddieVeddersfoxymop]

On saturday, we had to have our beloved puss put to sleep. She was 14.5 years, and been with us all her life. She was my daughter's best friend.

She'd developed a limp one day, front leg, no injury. She'd done this 2 years ago, vet said onset of arthritis. So we watched her closely but she walked it off within a day, but never seemed totally comfortable on her legs. We noticed a week later that she looked really old and had lost a considerable amount of weight, so took her to the vet.

Vet examined her, nothing found so blood tests were run. Her appetite was great and she was interested in life, so the vet thought her thyroid might be wonky. Full bloods were done, including her thyroid. Thyroid was a little low (when it was expected to come back high) and she was anaemic at 22% although her pallor was normal and didnt suggest an anaemic cat. Everything else within range. No breathing or heart issues either. Urinalysis was done, totally normal.

The vet re ran the bloods, thinking the result didn't reflect the cat but again she was 22%. Blood smears were sent of for analysis. An ultrasound showed a lesion or growth of some sort on her liver but her LFT was totally normal. Loxicom was given in case of inflammation and pain and the cat improved.

She then went flat and listless but still eating so the vet re ran her blood level manually - the pcv was now 24%! Ultrasound was redone and was again no change. She was admitted and put on a drip once we found out that the blood smears showed non regenerative anaemia, but nothing else of note. The drip included b vitamins and steroids. She improved greatly and was sent home on prednisolone.

She was home for 4 days and then went rapidly downhill, hard breathing and total lack of interest in food. She couldn't climb into the litter tray and her eyes were very sunken. We rushed her to the vet and her manual pcv was now 13%, so we decided to let her go and helped her pass away.

We are absolutely heartbroken - she was the most kind, gorgeous cat ever who tolerated being my daughters best bud for 8 years. They were inseperable. We are in shock - how could she have rallied so well and then crashed so quickly? After she passed on, she started to bleed from her nose so the vet wonders if something catastrophic was going on her in her lungs, but nothig was found on exam before she died.

Sorry this is so long, are there any vets/nurses out there who could try and explain what just happened? My own vets were stumped - three vets including 2 senior vets reviewed her and didnt actually find out what was wrong. A sad household this weekend

Low thyroid indicates other disease in cats this is known as euthyroid syndrome.
The initial slight increase in PCV by 2% would be with in the normal variation ie if you ran a hundred tests on the same sample you would expected a range of 2-3% across them all.
You had a non-regenerative anaemia so the body was not making any more red blood cells even though their is low. Anaemia could be due to destruction of red cells, loss through bleeding internally or failure to produce cells in the bone marrow.
From everything you are describing I would guess at failure of production, but reasons for failure to produce vary and a bone marrow sample would be needed to diagnoses. None of the causes of failure of production are good and their are virtually no treatments.
Often anaemic cats do 'crash' quite dramatically.
I hope this helps a little bit.
Sorry you lost your friend

Thank you Lonecat, appreciate the help. Our vet felt that the next step would have indeed been a bone marrow sample but given her age and the rapid decline it just really wasn't an option.

We are just shocked I think, when she came home on the prednisolone she was like a new cat - she was up and down the stairs like a rocket and I took photos in which she looked like a 3/4 year old cat again. It lasted 4 days and then she was gone. I felt terribly guilty afterwards thinking that we should have transfused her and tried for samples, but our vet said that she would never have agreed to that, and I know in my heart that Id have been doing it for totally selfish reasons.

Any thoughts on the nose bleeding about a minute or so after she passed away? My vet thought there might have been something amiss in her airways, perhaps a tumour that had metastasized to her bones, hence the limp that reoccurred about a fortnight before she really started to look thin? Although her breathing was checked by three different vets and was totally normal until the night we rushed her over (when it was heavy and looked hard work rather than rapid).

We miss her so much it's unreal. Feels very unfair to lose her when she was still needed here