of antidiuretic hormone (also known as arginine vasopressin or AVP). This hormone burst reduces the kidney's urine output well into the night so that the bladder does not get full until morning. This hormone cycle is not present at birth. Many children develop it between the ages of two and six years old, others between six and the end of puberty, and some not at all. The second ability that helps people stay dry is waking when the bladder is full. This ability develops in the same age range as the vasopressin hormone, but is separate from that hormone cycle. The typical development process begins with one- and two-year-old children developing larger bladders and beginning to sense bladder fullness. Two- and three-year-old children begin to stay dry during the day. Four- and five-year-olds develop an adult pattern of urinary control and begin to stay dry at night. Diagnosis Thorough history regarding frequency of bedwetting, any period of dryness in between, associated daytime symptoms, constipation, and encopresis should be sought. Voiding diary People are asked to observe, record and measure when and how much their child voids and drinks, as well as associated symptoms. A voiding diary in the form of a frequency volume chart records voided volume along with the time of each micturition for at least 24 hours. The frequency volume chart is enough for patients with complaints of nocturia and frequency only. If other symptoms are also present then a detailed bladder diary must be maintained. In a bladder diary, times of micturition and voided volume, incontinence episodes, pad usage, and other information such as fluid intake, the degree of urgency, and the degree of incontinence are recorded. Physical examination Each child should be examined physically at least once at the beginning of treatment. A full pediatric and neurological exam is recommended. Measurement of blood pressure is important to rule out any renal pathology. External genitalia and lumbosacral spine should be examined thoroughly. A spinal defect, such as a dimple, hair tuft, or skin discoloration, might be visible in approximately 50% of patients with an intraspinal lesion. Thorough neurologic examination of the lower extremities, including gait, muscle power, tone, sensation, reflexes, and plantar responses should be done during first visit. Classification Nocturnal urinary continence is dependent on 3 factors: 1) nocturnal urine production, 2) nocturnal bladder function and 3) sleep and arousal mechanisms. Any child will experience nocturnal