Clean urine, symptoms still present, concerned

Hello-

I went to the doctor a week ago with UTI symptoms.  I had frequency, urgency, and a mild burning sensation after urinating, sometimes before.  The doctor did urine test and gave me a script for macrobid(nitrofurantoin), 7 days.  After 4/5 days I was still feeling symptoms, so I called the doctor and yesterday, gave another urine sample.  I spoke to them this morning and they told me my urine was clean.  

I'm a little confused.  I'm still experiencing symptoms(this  morning ill be taking my last antibiotic).  I typically feel pretty normal in the latter afternoon/evening.  Over night and morning though, I still have frequency with the burning sensation.  It may be important to note that for years, I've gotten up at night, sometimes upwards of 5 times to go.  I asked a doc about it once, they didn't seem concerned as I don't have any daytime problems with it.  I normally get up at least twice from sleep, but now when I do I have burning from this UTI.  

What might be the cause of this?  Is is possible to still have the infection but have a clean urine sample?  I was given a script for something else, for the symptoms.  I'm not sure what its called, I haven't received it yet, but its not another antibiotic.  How much time should I deal with continued symptoms and what should be the next course of action?

Any help will be appreciated!

[Arti Sharma, M.D.]

Hello,
You are still experiencing symptoms of urinary tract infection so it is best to get a urine culture done. It will show if there is any bacterial growth and sensitivity of those bacteria to an antibiotic. Apart from urinary tract infection the other causes of increased urine frequency at night are overactive bladder, urinary incontinence, diabetes mellitus, interstitial cystitis and chronic renal failure. You may need to be investigated for above mentioned conditions. Tests like blood sugar, blood urea nitriogen, serum creatinine, creatinine clearance, serum electrolytes, urine concentration and ultrasound KUB may provide more information. I hope it helps.
Best wishes and regards!