Figuring Out Urinary Problems

Cindi sent this to me...

This is a crystal question.  Cindy has a puppy, Hottie, but we're now calling her Hot Pants. 
We believe that HP is suffering from bladder crystals of some sort.  All of the tests that her vet has done have shown nothing.
Are there any home remedies that we can try to help this little girl?
This is only one lab result, there are many more, but all with the same negative conclusion.
Anti-biotics helped when administered, but when stopped, the symptoms returned.

Let's start at the beginning and look at the cause of urinary problems and how we diagnose them.  The first symptoms that are reported are normally an increase in drinking and/or urinating, straining to urinate, or abnormal appearance of urine.  The first test we run is a basic urinalysis.  This test analyzes various chemical parameters of urine, such as pH, protein levels, glucose, and other things.  We also look at a urine sample under the microscope to view any red and white blood cells, bacteria, and crystals.  If we see crystals, we can usually identify which kind they are, which helps determine the best form of treatment.

Now in many cases it's not as simple as finding crystals or not.  Some bladder disorders never produce crystals.  In other cases stones can form without releasing any noticeable crystals in the urine.  So just because crystals aren't seen by the vet doesn't mean that there isn't a stone.

My first question is why do you think there is a urinary problem?  If the urinalyses were completely normal, this pretty much rules out an infection.  In an infection you'll see abnormal cells, bacteria, and so on.  If there is a suspicion of stones in the bladder, there are two ways to easily find them.  The first is abdominal x-rays, which can clearly show the most common types of stones.  However, there are some stones that x-rays pass through and therefore cannot be seen with this form of imaging.  There are various contrast studies that can be performed, but it's often easier to have abdominal ultrasound performed. With ultrasound you can see any stone, sediment, or sludge in the bladder as well masses, thickness of the bladder walls, and so on.  Blood tests won't detect a bladder abnormality but will determine if there are problems with the kidneys (the beginning of the urinary tract).  And all of this leads to my second question...what tests were run?  You mentioned that many were run, but none showed crystals.  Did they show other problems?

To summarize, here is my normal order of testing for urinary tract disorders:
1.  Urinalysis with sediment analysis.  Some vets will also do a urinary culture as part of the initial diagnostics.
2.  If this doesn't give the answers or if the problem doesn't resolve with initial therapy, do abdominal x-rays.
3.  If there still isn't a resolution of the problem and the specific cause hasn't been identified yet, do abdominal ultrasound.
4.  If there are no signs of bladder abnormalities, stones, etc., yet symptoms still persist, I will certainly do a urine culture.  In some cases I may do this step earlier (such as if we find rod-shaped bacteria).

Also, difficult urinary infections may require 4-8 weeks of continual antibiotics.  Treating for 1-2 weeks and then stopping may not be sufficient.  I normally treat for a minimum of 2 weeks, and if this doesn't work I'd look at possibly doing a urinary culture.

Cindi, I hope this helps.  Obviously there is more information that is needed before finally figuring out what is going on with HP.