You didn't mention if your vet tested for parasites...if not, that's the place to start. Some worms you can see in the stool, but most you can't. Giardia and coccidia are also very common causes of diarrhea and she could have picked them up almost anywhere. If her fecal test is clear...here are some suggestions.
After LOTS of trial and error with our Cavalier who had diarrhea for months (lots of vet work, tested negative for pancreatitis, EPI, parasites etc.)...here's what worked for us (don't try it all at once...make gradual changes):
-Raw diet: This is just what works for him, I know this is not feasible for many people, and that's okay. But, I would try a dry food that is chicken free at least...Fromm and Nutrisource are good ones, with many flavor options. My opinion would be to steer clear of Blue Buffalo and Hill's due to many recalls. Also cut out the wet food for now, but it wouldn't be a bad idea to add warm water to her food...if she's having lots of diarrhea, she is probably at least mildly dehydrated.
-A really good, multi-strain probiotic: Fortiflora by Purina is only one strain, and while it might be helpful in mild cases, its probably not enough to restore the gut balance. We have been using this one: Gut Guard: For Dogs With Irritated, Leaky Guts with good results, but there are many formulated for dogs with multiple strains of beneficial bacteria.
-Slippery Elm: an herb that comes in powder (capsule) form, protects and heals the digestive tract. You can find this at a health-food store, or online...maybe even a grocery store's vitamin/supplement section. I really think this has been the biggest help in healing our dog...we give a half capsule for each meal on his food, but for a big dog you can give a whole one.
-Canned, plain pumpkin: about a tablespoon with each meal. This can help form the stool by adding a bit of fiber.
-If at all possible, try to avoid any more antibiotics. Metronidazole can help in the short term, but almost always the diarrhea comes back, usually worse. It upsets the balance of bacteria that keep digestion running smoothly. Our dog got pneumonia, so we had to use antibiotics, and that is what started his diarrhea too.
Once you settle on a routine, try to not change anything for at least a few weeks to let her system calm down...I know it's tempting to keep trying things to stop the runs, but that can just irritate her gut more. One more thought...check the amount you are feeding her. Some dogs can only handle a certain amount of food per meal, and even a little too much gives them the runs. If she's thin and you have upped her food to try and compensate, that could cause diarrhea. I have 50lb and 65lb dogs who eat 1 cup each per meal, and that is enough to keep them at a healthy weight. Some dogs need more, but most moderately active house pets need less than you think, especially if they're eating a good quality food. I'd not worry too much about her gaining weight yet (unless she's literally emaciated) and focus on getting her tummy on the right track. Once that is under control, you can very gradually increase her portions and the weight will come.
I know how you feel...it is frustrating to feel helpless when your dog is not well and you don't know what's wrong. But, there is hope!! Our little guy has had very consistent, firm stools for about 3-4 months now, and he's finally starting to gain weight! This is after about 6 months of mucousy, sometimes bloody, watery stools...accidents at night in the house, and many, many butt baths (he has long hair 😫), and no firm diagnosis from the vet. Good luck with your girl!
After LOTS of trial and error with our Cavalier who had diarrhea for months (lots of vet work, tested negative for pancreatitis, EPI, parasites etc.)...here's what worked for us (don't try it all at once...make gradual changes):
-Raw diet: This is just what works for him, I know this is not feasible for many people, and that's okay. But, I would try a dry food that is chicken free at least...Fromm and Nutrisource are good ones, with many flavor options. My opinion would be to steer clear of Blue Buffalo and Hill's due to many recalls. Also cut out the wet food for now, but it wouldn't be a bad idea to add warm water to her food...if she's having lots of diarrhea, she is probably at least mildly dehydrated.
-A really good, multi-strain probiotic: Fortiflora by Purina is only one strain, and while it might be helpful in mild cases, its probably not enough to restore the gut balance. We have been using this one: Gut Guard: For Dogs With Irritated, Leaky Guts with good results, but there are many formulated for dogs with multiple strains of beneficial bacteria.
-Slippery Elm: an herb that comes in powder (capsule) form, protects and heals the digestive tract. You can find this at a health-food store, or online...maybe even a grocery store's vitamin/supplement section. I really think this has been the biggest help in healing our dog...we give a half capsule for each meal on his food, but for a big dog you can give a whole one.
-Canned, plain pumpkin: about a tablespoon with each meal. This can help form the stool by adding a bit of fiber.
-If at all possible, try to avoid any more antibiotics. Metronidazole can help in the short term, but almost always the diarrhea comes back, usually worse. It upsets the balance of bacteria that keep digestion running smoothly. Our dog got pneumonia, so we had to use antibiotics, and that is what started his diarrhea too.
Once you settle on a routine, try to not change anything for at least a few weeks to let her system calm down...I know it's tempting to keep trying things to stop the runs, but that can just irritate her gut more. One more thought...check the amount you are feeding her. Some dogs can only handle a certain amount of food per meal, and even a little too much gives them the runs. If she's thin and you have upped her food to try and compensate, that could cause diarrhea. I have 50lb and 65lb dogs who eat 1 cup each per meal, and that is enough to keep them at a healthy weight. Some dogs need more, but most moderately active house pets need less than you think, especially if they're eating a good quality food. I'd not worry too much about her gaining weight yet (unless she's literally emaciated) and focus on getting her tummy on the right track. Once that is under control, you can very gradually increase her portions and the weight will come.
I know how you feel...it is frustrating to feel helpless when your dog is not well and you don't know what's wrong. But, there is hope!! Our little guy has had very consistent, firm stools for about 3-4 months now, and he's finally starting to gain weight! This is after about 6 months of mucousy, sometimes bloody, watery stools...accidents at night in the house, and many, many butt baths (he has long hair 😫), and no firm diagnosis from the vet. Good luck with your girl!