What's causing my cat's anemia?

If you’re following the Venting thread over on Off Topic, you know one of my barn cats, Sonic, went missing for two weeks. He came back Saturday, disappeared again, then came back Monday morning. He was starving, and ate everything I put in front of him, but the eye membranes were white, so I immediately rushed him to the vet for a checkup. Checkup showed that he was anemic (red blood cell count is 30; anemic is considered 28 or lower, per vet). No parasites in the stool. Nothing showed on a tox screen or in the regular blood work. Kidneys, liver, etc. all normal. He had lost 2lbs while he was missing, but his appetite is quite good. The vet did an ultrasound as well, and found nothing.

He’s also simply not himself. This is an outgoing cat who is quite confident; he’s not like that anymore. The neighbor across the road mowed his pasture Monday morning, while Sonic was in the large crate in the barn (ready to get to the vet) - he freaked out. This is a sound he’s heard all his life, and for some reason he was totally flipped out about it. He cries and cries in his crate. At the vet, he buried himself under the mats and newspapers in the cage. All of this is highly unusual for him.

I’m at a loss. I’m used to dealing with anemia as part of FIV or FeLV, but he’s been vaccinated for FeLV and tests negative for FIV. Any ideas on what we could look at, if he doesn’t start to get better soon? The vet gave him Convenia and a dewormer (Pyrantel) just in case, but I’ve got a feeling it’s something else, something we’re missing.

Renal insufficiency or failure is the number one cause of anemia. That would be my first guess. A simple blood test that looks at creatinine will give you an answer. Sub Q fluids for a few weeks may cause acute renal failure to resolve.

1 Like

Thanks. I’m pretty sure the vet looked at his creatinine levels, but I will double-check, to be on the safe side.

Regenerative? Non-regenerative? Macrocytic, microcytic? Just “anemia” gives little info. He could be recovering from internal bleeding due to being hit by a car or grabbed by a predator. He could have mycoplasma or neoplasia. You need more work-up.

The RBC is 30? That’s unlikely to result in clinical signs unless loss was rapid and very recent. If that’s the only clinical abnormality you may be looking at a stressed cat who experienced something two weeks ago that’s left him with a major behavioral change. Cats can experience the equivalent of PTSD. We had a very confident cat that never went outside again after some unknown event. We assume something chased her up a tree where she was trapped for three days before we found her.


I gave as much information as I have. He’s borderline anemic. We don’t know what’s causing it. That’s the question: what should we be looking at/for? I’ve looked at autoimmune hemolytic anemia, but the symptoms don’t all fit with his, so looking at other options to put to the vet as well as that.

I plan on taking him back, probably Friday if I can get away from work long enough, for a checkup.

I had wondered about the stress myself, as we don’t know where he was for those two weeks. He has no wounds, and the vet did an ultrasound, but found nothing.

Can you post all of the labs they have drawn?

1 Like

I don’t have them, but I can get them tomorrow.

Poor Sonic! I have no advice just hugs and best wishes for him. I hope it is something simple.

As far as the personality change I had an outside cat that disappeared for several days. Could not find him anywhere and then on day he crawled out of the back of my “garage.” He had been holed up there the whole time and had apparently been completely terrified/terrorized. I had come home on the day he vanished and the door to that building had been shut and tied shut, too. I never left it that way so someone had done this. As near as I could figure out and this is just guesswork on my part, the guy who rented the warehouse on the property had his two dogs out - one of who was a known cat killer - and I think the dog chased him into the garage. Poor cat was never the same. He had previously been the terror of the neighborhood but after that never left the property and would hide during the day and flinched at every noise. He got over it but not completely and even then it was some months. I blame this incident for the rapid acceleration of his impending CRF. I hope Sonic recovers and goes back to his old self.



Jingles for Sonic !

1 Like

Maybe severe stress can cause temporary anemia? The body can do some weird things when it’s under stress. Since the vet can’t find a cause and it doesn’t sound like it’s severe, hopefully it will resolve itself.

Regarding his behavior, I have a cat that loves to be outside during warm weather. This past spring, he was outside and a dog came onto my property and chased him up a tree. He stayed up there for a while. When he came down and came inside, he had no interest in going outside which was very unusual for him. It was understandable, after what had happened. He gradually returned to normal but it took at least a month.

Hugs to you and Sonic! I hope he feels better soon.


If this is (so far) just borderline anemia and a behavioral change, I would give him time in a quiet place and a high quality, extra wet food multiple times a day. Two pounds in two weeks is a lot for a cat to lose so you may be looking at the beginning stages of renal failure.

I hope he gets better and chills out soon.


I’m thinking that could be part of it - w/o knowing where he was for those 2 weeks, there’s no way to know what he went through. We don’t have any dogs in the area that would chase him (not anymore, anyway . . .), but maybe if he went too far, a coyote may have spotted and chased him.

He actually seemed a bit better this morning - he was washing himself when I went to feed them, and seemed content to be held. Feels as though he might have gained a bit of weight, too. Still not about to let him out, though!


Tick infestation during his walkabout?

The vet and I both looked him over closely - didn’t find tick or flea on him. Outside cats are also treated in the summer, so I doubt that was it.

Did you ever get a copy of the labs?

Not yet - it’s been crazy with the first week of classes, but I will call and get them.

Fleas? I found a feral cat in my bushes almost dead. She had fleas so bad and was so anemic that she almost died. I couldn’t afford $20K for blood transfusions, so I had to syringe feed her every two hours for a month before she she was out of the woods.


That would be an easy solution, but he’s treated every month and had no fleas at the vet. Oddly, though, that’s how I found him - he’d collapsed in the full sun, covered in fleas. He almost needed a transfusion, but we squeaked by without one.

How is dear SONIC ?

Jingles & AO !

But isn’t that the reason for the anemia? Blood loss from fleas?

Anemia feels pretty terrible. Until his counts are back up, isn’t not unreasonable that he feels crummy :frowning: It takes quite a bit of time to build red cells.

1 Like