TABLE 78.1 DIFFERENTIAL DIAGNOSIS OF URINARY FREQUENCY Intraurinary system Extraurinary system Renal Renal parenchymal disease Sickle cell disease Nephrogenic diabetes insipidus Ureter Ectopic ureter Nephrolithiasis Bladder Urinary tract infection/bacterial cystitis Viral cystitis Chemical cystitis Posterior urethral valves Urethra/Penis/Vagina Urethritis Vulvovaginitis (infectious, foreign body, trauma) Balanitis Meatal ulceration Urethral syndrome Pinworms Neurologic Neurogenic bladder (spinal cord lesion, spina bifida) Central diabetes insipidus (head injury, brain tumor, septo-optic dysplasia) Uninhibited/unstable bladder Abdominal Abdominal/pelvic mass Ovarian torsion/cyst Appendicitis Pregnancy Constipation Endocrine/Metabolic Hyperglycemia/diabetes mellitus Hypercalciuria Salt-losing congenital adrenal hyperplasia Drugs/Toxins Caffeine Ethanol Lithium Diuretics Vitamin D Psychogenic Behavioral Psychogenic polydipsia Munchausen-by-proxy Urethra, Penis, Vagina, and Anus Frequency is a presenting symptom of urethritis, more specific to the adolescent population The most common etiologies of urethritis are Chlamydia trachomatis and Neisseria gonorrhoeae Balanitis and balanoposthitis in young males,