Please help me, I am really helpless,

[Piggies&buns]

It is already known that vets who don’t see Guinea pigs often do not know about sterile cystitis.

It is only diagnosed once a course of antibiotics fails, because there are no bacteria found in the urine with sterile interstitial cystitis. Therefore it can take a while to get a diagnosis but it is now more common than bacterial infections.

As long as you now have a diagnosis and can move forward.

 

[dongzheng]

It’s good you now have a definitive diagnosis of sterile IC and ovarian cysts.
You had mentioned the presence of bacteria, sludge and stones many times so it was getting confusing as to what was the actual issue.

I have once again added the guide which explains treatment of sterile cystitis as it is a long term condition.
Glucosamine for cats is frequently used as a treatment for sterile cystitis. It is the one you will find commonly mentioned and used on the forum. There is not one specifically for guinea pigs.
You will need to find what works and is available for you.

Wiebke's Guide to Pees and Stones

And yes Hair loss on the sides is a typical symptom of ovarian cysts. Biting at the sides can be indicative of pain due to the cyst. It’s something to monitor.

I hope she will now be ok with the appropriate treatments

By the way, I saw that this guide says there is no better way to make guinea pig urine acidic, so if that's the case, the first two times I managed to keep his urine at a pH of 6. If the pH is 6, the urine is acidic, so is it good for guinea pigs? I mean, if I use a method to make his urine acidic. Is it good for him?

 

[Piggies&buns]

By the way, I saw that this guide says there is no better way to make guinea pig urine acidic, so if that's the case, the first two times I managed to keep his urine at a pH of 6. If the pH is 6, the urine is acidic, so is it good for guinea pigs? I mean, if I use a method to make his urine acidic. Is it good for him?

They are naturally alkaline. I do not know whether it is healthy to try to force it to become too acidic - you may cause other health issues by doing so. It is not something any owner on this forum would attempt to do without consultation with a very knowledgeable vet.
I do know it is hard to make piggy urine reliably acidic. If it was easy, reliable and safe then it would be something vets would advise to solve all the bladder related issues piggies have. As it isn’t, then I can only surmise it’s probably not possible or a good idea.

 

[dongzheng]

It is already known that vets who don’t see Guinea pigs often do not know about sterile cystitis.

It is only diagnosed once a course of antibiotics fails, because there are no bacteria found in the urine with sterile interstitial cystitis. Therefore it can take a while to get a diagnosis but it is now more common than bacterial infections.

As long as you now have a diagnosis and can move forward.

I'm utterly bewildered by the distinction between bacterial and non-bacterial cystitis, but what's become clearer to me is that after some trial and error, he tolerated this prazosin exceptionally well. Moreover, after the 15-day course of Ciprofloxacin, the white blood cells in his urine have indeed disappeared. As for why cocci were still detected in the urine analysis, it's because when I collected his urine sample, it was mixed with faeces. I'm unsure whether this might have affected the test results. Isn't asymptomatic cystitis only diagnosed when a course of antibiotics proves ineffective? Or are there multiple criteria for diagnosing non-bacterial cystitis? Since his urine now shows no white blood cells, does this prove the 15-day antibiotic course was effective? Does that confirm he had bacterial cystitis initially? I'm getting thoroughly confused. Moreover, new findings show a significant increase in cocci bacteria in his gut. When I asked the doctor who prescribed antibiotics, they said this indicates abundant gut bacteria. I'm unsure what this signifies. I've even noticed he started scratching after the second 7-day course of ivermectin.
Oh, right—does this prove we've just completed the first phase? What should I use to assess his condition next? I'm being driven round the bend.

 

[dongzheng]

I'm utterly bewildered by the distinction between bacterial and non-bacterial cystitis, but what's become clearer to me is that after some trial and error, he tolerated this prazosin exceptionally well. Moreover, after the 15-day course of Ciprofloxacin, the white blood cells in his urine have indeed disappeared. As for why cocci were still detected in the urine analysis, it's because when I collected his urine sample, it was mixed with faeces. I'm unsure whether this might have affected the test results. Isn't asymptomatic cystitis only diagnosed when a course of antibiotics proves ineffective? Or are there multiple criteria for diagnosing non-bacterial cystitis? Since his urine now shows no white blood cells, does this prove the 15-day antibiotic course was effective? Does that confirm he had bacterial cystitis initially? I'm getting thoroughly confused. Moreover, new findings show a significant increase in cocci bacteria in his gut. When I asked the doctor who prescribed antibiotics, they said this indicates abundant gut bacteria. I'm unsure what this signifies. I've even noticed he started scratching after the second 7-day course of ivermectin.
Oh, right—does this prove we've just completed the first phase? What should I use to assess his condition next? I'm being driven round the bend.

Do I only need to remember that if I find blood in his urine at home, it is an aseptic cystitis?

 

[Piggies&buns]

I don’t know why your piggy was taking prozasin- it’s not a medication you have mentioned before?
From what I can see that is a medication to treat hypertension.

Bacterial cystitis = urinary infection symptoms with bacteria present in the urine. Symptoms are resolved with a course of antibiotics.

Sterile cystitis = urinary infection symptoms present (no bacteria detected) but courses of antibiotics fails to stop the symptoms and symptoms persist. This is because there is no bacteria present in the urine for antibiotics to kill.

Porphyrines (a red natural dye common with infections but it is not blood) and blood can be present in infections (or where stones are present).
All seeing this does is tell you something is wrong but it doesn’t tell you what is wrong (ie it could be bacterial, sterile or something else like stones).

White blood cells are the body’s immune response to inflammation and infection. Therefore white blood cells can be present with both bacterial and sterile bladder issues.

If a urine sample was contaminated by anything then it would need to be done again.

Piggies need the right kind of bacteria in their gut for their gut to function and digest food.
If she has the right kinds of bacteria and a good quantity then there is no problem whatsoever.

So:

If your piggy was displaying urinary infection symptoms and had bacteria in her urine; she was given antibiotics and the antibiotics have resolved all the symptoms and no more bacteria is present, then she likely had a bacterial cystitis. This means her treatment has worked and she is no longer unwell. This means the issue is entirely finished and no longer of concern.
This also means that she does not have sterile cystitis.

If courses of antibiotics have not worked and she is still displaying symptoms, and does not have and has never had bacteria in her urine, then this means she may have sterile cystitis.
The treatment is long term glucosamine and painkillers.

If you don’t know what her diagnosis is, then you need to speak to the vet and get them to tell you again.

I’m afraid I am now finding it very hard to follow this thread to actually know what your piggy has or hasnt been tested and treated for and what treatment did or didn’t work.

I didn’t know your piggy was being given ivermectin.
When did she get parasites?

If she has ovarian cysts then that is a separate issue.