Is waking repeatedly to void robbing your patient of a good night's sleep? An expert discusses causes and treatment options that can banish her daytime fatigue-and lower her risk of nighttime falls.
Clinically defined by World Health Organization criteria as the need to void two or more times per night, nocturia affects 10% of women outside nursing homes. The age-adjusted prevalence increases from 32.9% of women aged 20 to 29 to 88.9% of women 80 years and older.
Quality of life for a woman with nocturia (waking during the night to void) goes increasingly downhill as the number of times her sleep is interrupted goes up. Not surprisingly, the more often she goes back and forth to the bathroom in the middle of the night, the more exhausted she's likely to be the next day. Nocturia is also a risk factor for falls, which can lead to significant complications, especially in the elderly.
Only 2% of men and women report a negative impact on quality of life from waking once during the night, compared with 17% who wake to void three times nightly, and 70% who do so four or more times.1
What's causing the patient's nocturia?
A 24-hour voiding diary is the best tool for diagnosing women with symptoms of nocturia. We recommend asking a patient to complete three 24-hour void-ing diaries to record the timing and amount of fluid intake, urinary frequency, urinary incontinence episodes, and her leaking condition (urge or stress). Three-day diaries are just as likely as 7-day diaries to provide the information you need, and patients are more likely to fill out the shorter forms.3 The 24-hour voiding diary allows you to subclassify a patient's symptoms in an attempt to predict prognosis and initiate treatment.
Polyuria, defined as voiding more than 2.5 L of urine daily, can be diagnosed by totaling the volume voided on the three 24-hour voiding diaries and dividing by three. Polyuria is caused by overproduction of urine both day and night that exceeds a person's bladder capacity. The most common causes of overproduction are diabetes mellitus, diabetes insipidus (from surgery, infection, tumor, or trauma), nephrogenic diabetes insipidus from hypercalcemia, chronic renal failure, lithium therapy, or primary thirst disorders like psychogenic polydipsia, or dipsogenic polydipsia from brain trauma, tumor, surgery or radiation, and drugs such as anticholinergics or psychotropics. When polyuria is diagnosed, refer patients to family practitioners or internists to determine its cause and begin treatment.
Nocturia can be caused by:
Patients diagnosed with nocturnal polyuria produce a greater volume of nocturnal urine than their bladders can hold because of either decreased arginine vasopressin or increased secretion of atrial natriuretic peptide. Arginine vasopressin or antidiuretic hormone (ADH) is produced by the posterior lobe of the pituitary to signal the distal renal tubules to regulate serum osmolarity.