Video urodynamics is the investigation of choice for your symptoms. Your problem can be Overactive bladder (OAB), which is a condition caused by sudden involuntary contraction (overactivity) of the bladder detrusor muscles. OAB is characterized by any of the following symptoms; urinary urgency, with or without urge incontinence, increased frequency and night time urination (nocturia), in the absence of any causative infection or any bladder pathological conditions.
The cardinal symptoms of OAB are considered to be urgency, frequency, and nocturia. The investigations to establish the cause are;
1) urine culture for mycobacterium; this will need special culture medium
2) cystoscopy; which has been done for your and is basically to rule out any bladder tumor, diverticulum etc.
3) vaginal ultrasound; to rule out fibroid, which can cause pressure on bladder and cause increased frequency.
4) frequency / volume charts
5) urine cytology
7) postvoid residual volume assessment using urethral catheterization or ultrasonography
8) cystometry: This is a simple method for testing the bladder's storage function and provides information on bladder capacity, the extent of accommodation or compliance, the ability to sense bladder filling and temperature, and the presence of an appropriate detrusor muscle contraction.
9) urodynamics: This is used to measure bladder pressure during micturition.
10) uroflometry; The urine flow rates are assessed based on the detrusor pressure and urethral resistance. One voids in a commode connected to a computer which measures peak urine flow rate, etc.
Treatment of overactive bladder is by following;
1) Anticholinergic medications like Oxybutynin and tolterodine.
2) Capsaicin: bladder (intravesical) administration in OAB.
3) Other medications; Gabapentin, hydroxyzine, montelukast
4) Physical therapy; Pelvic floor physical therapy (PT) may be recommended to decrease tightness in these muscles. Physical therapist works on the patient's body to manually "release" the tightness, tender points, trigger points, and restricted movement of the connective tissues and muscles.
5) Exercises; Many patients feel that gentle stretching exercises help relieve symptoms.
6) Electrical stimulation; sacral nerve stimulation.
7) Behavioral therapies; Behavioral therapies for urinary frequency work to slowly increase the time interval between voids, which increases the amount of urine the bladder can comfortably hold; this is called timed voiding.
8) Diet; alcohol, tomatoes, spices, chocolate, caffeinated and citrus beverages, and high-acid foods may contribute to bladder irritation and inflammation. Artificial sweeteners may aggravate the symptoms.
Please read this resource for the overactive bladder syndrome;
Please feel free for your follow up questions.