What could be happening to my mums cat at night?

[CoatHangers5]

My parents cat is an 11 year spayed female. They keep her in every night. In the last year she has stayed out probably a total of 3 night simply because she wouldn’t come back when called. However, the following day of her pulling an ‘all nighter’ she’s always unwell. She struggles to pee, she’s off her food and very reserved. This time round she’s not peeing but when trying it’s blood. This only ever happens when she hasn’t come in at night, hence why they do their very best to get her in. Any idea what she could b doing at night to cause this? Mum thought she could be eating something but I’m wondering could the Toms be getting at her? Thank you.

[Fluffycloudland77]

Do they take her to the vet when it happens?. I’d assume some sort of intermittent illness.

[CoatHangers5]

The last time they ran this past the vet they suggested water infection. I’m just wondering if it’s triggered by something that’s happening while she’s out. She’s such a lovely cat. They are making more of a conscious effort to get her in before it gets too dark now

[missmouse101]

Stress can cause painful cystitis. Have they taken her to the vet?

[HardAsSnails]

Is she locked out all night one those nights or can she get back in through a flap or whatever?

If she's returning late and unable to get in then stress is a possibility.

[HardAsSnails]

^ on those nights

[Fluffycloudland77]

Stress cystitis can he helped by keeping them on cystease all the time but she needs a flap they can set to “in only”.

[viccat]

Maybe the situation is kind of the other way round - when she's unwell, she finds somewhere to hide outdoors?

Peeing blood is a sign of cystitis and should be appropriately treated.

[Infullbloom]

Stress cystitis. She needs to see a vet for treatment. It's very painful for them.