Hello, I'm Dr. Kara. I have over 20 years of experience as a veterinarian and I'd like to help with your concerns about Nikita and her diarrhea. Blood in her stool indicates colonic irritation and can be a response to the diarrhea itself.
Diarrhea can be related to something as simple as a quick change in diet or treats or getting into something she should not have like the garbage, a bug, plant material, gastrointestinal parasites or a toxin. More serious causes are a dietary allergy or sensitivity, inflammatory bowel disease, internal organ failure, hyperthyroidism, a partial gastrointestinal obstruction or even infiltrative cancers such as lymphoma.
If your girl seems her self other wise there are a few things that you can try at home.
I recommend with-holding all food for 24 hours to help restore normal gut motility. I know that you have tried this but we need to follow up reintroducing her to food with a bland diet.
During her food fast she can have small amounts of water or low salt chicken broth every couple hours to replace fluids she has lost with her diarrhea.
Today even with the fast you can start Kao-pectate (kaolin pectin formulation) at 1ml per pound or 1 tablespoon per 15 pounds of body weight every 6 to 8 hours. This is quite safe and will coat her irritated gi tract as well as absorbing bacterial toxins. You can use it for several days until her stools look normal. You can find kao-pectate at the drug store.
After her food fast try a bland diet of 2/3 boiled minced white skinless chicken and 1/3 boiled white rice mixed with some low salt chicken broth to make it easy to lap up and swallow. Add 1 tablespoon of canned pumpkin (not pie filling, just pumpkin) to each meal as fiber soothes an irritated colon. If she does well with that feed her that diet in small meals for a few days then slowly reintroduce her normal food by mixing in a little more regular with each meal. It should take 5 days or so to convert her back.
If she continues to have diarrhea even with her food fast, kao pectate and band diet, starts vomiting, refuses to eat after her fast or has a tense painful belly or a fever (more than 103F rectally) she is beyond home care and should see her veterinarian for an examination, some diagnostics, intravenous fluids and supportive care.
I do recommend that you submit a fresh stool sample to her veterinarian for testing as parasites are a common cause of diarrhea.
Even if she improves this time if this is an on and off repeated problem you should have her examined and discuss further diagnotics with your veterinarian to look for an underlying cause. A complete blood count, biochemistry profile and thyroid level as well as a fecal culture would be a good place to start.
Please let me know if you have any further questions.