Extraordinary urinary frequency sometimes develops in children without any other urologic signs or symptoms and there is rarely a physical basis for this condition. The patient is usually a previously toilet trained child (in the 3-7 year age group, characteristically, and male) with sudden onset of urinary frequency as often as every five minutes. The syndrome of excessive isolated daytime urinary voiding is a benign self-limiting condition of unknown etiology that may last from months to years. Dietary factors, alkaline urine, food allergies, behavioral problems, stress or abuse are not factors in this disorder.
The average frequency of micturition for a normal 3 to 4-year-old child is 9 times in 24 hours, but by the age of 12 years the number of voidings decreases to 4-6 times per day.
The evaluation of children with isolated daytime urinary frequency still requires careful history taking, physical examination and urinalysis. The initial complaints with most of these children are some urgency and excessive daytime urinary frequency with small volumes. Nocturia is usually absent, but if it occurs it is disproportionate to the extraordinary daytime frequency. Straining to void is unusual. Urinary incontinence, hesitancy, stranguria, dysuria, hematuria and bowel problems are characteristically absent. Similarly, polyuria is absent and fluid intake is usually normal.
Excessive urinary frequency can be a sign of genitourinary or endocrinologic disease. Frequent voiding must be differentiated from polyuria related to diabetes insipidus or diabetes mellitus.
Complete urinalysis with dipstick measurement of pH, protein, glucose, leukocyte esterase, nitrite and specific gravity is important. Normal urinary concentrating ability is confirmed by specific gravity of greater than 1.020. The first morning urine, after restricting evening and nighttime intake, will usually achieve this degree of concentration. The child’s fluid intake should not be restricted if the history is compatible with polydipsia and polyuria because hypernatremia will be the result in children with diabetes insipidus. Microscopic examination of the spun urinary sediment and urine culture is also important.
Uroradiological investigation is usually not required, but a renal and pelvic sonogram can be reassuring in those children with extraordinary urinary frequency that is slow to resolve.
The treatment of isolated urinary frequency needs a lot of reassurance, as other treatments are unnecessary and unproductive. Antibiotics are not helpful. Anticholinergics are rarely helpful.