A 5-year-old boy is brought to the office by his parents due to bed-wetting. The patient has stayed dry during the day since age 3 but has continued to wet the bed 4 or 5 nights a week. He urinates approximately 5 times during the day; the urinary stream is continuous and strong. Bowel movements occur daily and are soft. The patient is otherwise healthy and takes no daily medications. Height and weight are tracking along the 75th percentile. Vital signs and examination are normal. Urinalysis is unremarkable. This patient's bed-wetting is most likely caused by which of the following?

Question

A 5-year-old boy is brought to the office by his parents due to bed-wetting.  The patient has stayed dry during the day since age 3 but has continued to wet the bed 4 or 5 nights a week.  He urinates approximately 5 times during the day; the urinary stream is continuous and strong.  Bowel movements occur daily and are soft.  The patient is otherwise healthy and takes no daily medications.  Height and weight are tracking along the 75th percentile.  Vital signs and examination are normal.  Urinalysis is unremarkable.  This patient's bed-wetting is most likely caused by which of the following?

Quizplus · Accepted Answer

11ec160b_3cf1_49ca_9249_4d5d8e790eec_MD0001_00 This patient has primary nocturnal enuresis, defined as bed-wetting in a child age ≥5 who has never achieved a prolonged period of nighttime urinary continence. The pathogenesis primarily involves a maturational delay in the development of bladder control. As neural pathways in the brain evolve over the first few years of life, voiding normally progresses from a primitive reflex to a purposeful action. This process of developing bladder control involves the following: This process, and therefore toilet training, is typically complete by age 4 in most children. However, nighttime bladder control may be delayed until school age in others, leading to primary nocturnal enuresis. Patients with a family history of nocturnal enuresis are at increased risk of delayed maturation. In addition to delayed bladder control, the pathogenesis may also involve increased overnight urine output due to decreased antidiuretic hormone activity and/or excessive fluid consumption in the evenings. Reduced bladder capacity can also contribute (Choice C). (Choice A) Bladder flaccidity can occur in patients with impaired spinal cord signaling (eg, spina bifida causing neurogenic bladder). The sensation of bladder fullness is lost, which leads to both daytime and nighttime incontinence, incomplete emptying, and a weak urinary stream (eg, dribbling). In addition, other neurologic findings (eg, leg weakness) are usually expected with spinal cord lesions. (Choice D) Osmotic diuresis is characterized by urinary excretion of excessive solute, such as glucose with diabetes mellitus. In addition to nocturnal enuresis, children with diabetes mellitus typically also have daytime polyuria and poor growth, which are not seen in this patient. Furthermore, glucosuria would be expected on urinalysis. (Choice E) Posterior urethral valves are an anatomic abnormality that can cause nocturnal enuresis. However, patients also typically have daytime incontinence, obstructive symptoms (eg, weak stream), and recurrent urinary tract infections, none of which are seen in this child. Educational objective: Primary nocturnal enuresis (ie, bed-wetting at age ≥5 without prior nighttime urinary continence) is caused primarily by a brain maturational delay in the development of bladder control.

A 5-Year-Old Boy Is Brought to the Office by His