| Nocturia | |
|---|---|
| Other names | Nycturia |
| Specialty | Urology |
Nocturia is defined by the International Continence Society (ICS) as “the complaint that the individual has to wake at night one or more times for voiding (i.e. to urinate).”[1] The term is derived from Latin nox, night, and Greek [τα] ούρα, urine. Causes are varied and can be difficult to discern.[2] Although not every patient needs treatment, most people seek treatment for severe nocturia, waking up to void more than 2–3 times per night.
Studies show that 5–15% of people who are 20–50 years old, 20–30% of people who are 50–70 years old, and 10–50% of people 70+ years old, urinate at least twice a night.[3] Nocturia becomes more common with age. More than 50 percent of men and women over the age of 60 have been measured to have nocturia in many communities. Even more over the age of 80 are shown to experience symptoms of nocturia nightly.[4] Nocturia symptoms also often worsen with age. Although nocturia rates are about the same for both genders, data shows that there is a higher prevalence in younger women than younger men and older men than older women.[3][5]
Research suggests that more than 60% of people are negatively affected by nocturia.[3] The resulting insomnia and sleep deprivation can cause exhaustion, changes in mood, sleepiness, impaired productivity, fatigue, increased risk of accidents, and cognitive dysfunction.[6][7][8] 25% of falls that older individuals experience happen during the night, of which 25% occur while waking up to void.[9]
A quality of life test for people who experience nocturia was published in 2004. The pilot study was conducted only on men.[10]
Nocturia diagnosis requires knowing the patient's nocturnal urine volume (NUV). The ICS defines NUV as “the total volume of urine passed between the time the individual goes to bed with the intention of sleeping and the time of waking with the intention of rising.”[11] Thus, NUV excludes the last void before going to bed, but includes the first morning void if the urge to urinate woke the patient. The amount of sleep a patient gets, and the amount they intend to get, are also considered in a diagnosis.[citation needed]
As with any patient, a detailed history of the problem is required to establish what is normal for that patient. The principal diagnostic tool for nocturia is the voiding bladder diary. Based on information recorded in the diary, a physician can classify the patient as having global polyuria, nocturnal polyuria, or bladder storage problems. A voiding bladder diary should record:[citation needed]
Patients should include the first morning void in the NUV. However, the first morning void is not included with the number of nightly voids.[citation needed]
Polyuria is excessive or an abnormally large production or passage of urine. Increased production and passage of urine may also be termed diuresis.[12][13] Polyuria is usually viewed as a symptom or sign of another disorder (not a disease by itself), but it can be classed as a disorder, at least when its underlying causes are not clear.[citation needed]
Global polyuria is the continuous overproduction of urine that is not only limited to sleep hours. Global polyuria occurs in response to increased fluid intake and is defined as urine outputs of greater than 40 mL/kg/24 hours. The common causes of global polyuria are primary thirst disorders such as diabetes mellitus and diabetes insipidus (DI). Urination imbalance may lead to polydipsia or excessive thirst to prevent circulatory collapse. Central diabetes insipidus is caused by low levels of Vasopressin (also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin). ADH is produced in the hypothalamus and stored in and released from the posterior pituitary gland. ADH increases water absorption in the collecting duct systems of kidney nephrons, subsequently decreasing urine production. ADH regulate hydration levels in the body. that helps regulates water levels. In nephrogenic DI, the kidneys do not respond properly to the normal amount of ADH.[14]
Diagnosis of DI can be made by an overnight water deprivation test. This test requires the patient to eliminate fluid intake for a fixed period of time, usually around 8–12 hours. If the first morning void is not highly concentrated, the patient is diagnosed with DI. Central DI usually can be treated with a synthetic replacement of ADH, called desmopressin. Desmopressin is taken to control thirst and frequent urination.[15] Although there is no substitute for nephrogenic DI, it may be treated with careful regulation of fluid intake.[citation needed]
Nocturnal polyuria is defined as an increase in urine production during the night but with a proportional decrease in daytime urine production that results in a normal 24-hour urine volume. With the 24-hour urine production within normal limits, nocturnal polyuria can be translated to having a nocturnal polyuria index (NPi) greater than 35% of the normal 24-hour urine volume. NPi is calculated simply by dividing NUV by the 24-hour urine volume.[16] Similar to the inability of control urination, a disruption of arginine vasopressin (ADH) levels has been proposed for nocturia. Compared with the normal patients, nocturia patients have a nocturnal decrease in ADH level.[citation needed]
Other causes of nocturnal polyuria include diseases such as
Normal human bladder storage capacity varies from person to person and is considered 400 – 600 mL.[18] A bladder storage disorder is any factor that increases the frequency of small volume voids. These factors are usually related to lower urinary tract symptoms that affect the capacity of the bladder. Some patients with nocturia have neither global nor nocturnal polyuria according to the above criteria. Such patients most likely have a bladder storage disorder that impacts their nighttime voiding or a sleep disorder. Nocturnal bladder capacity (NBC) is defined as the largest voided volume during the sleep period.[citation needed]
Decreased NBC can be traced to a decreased maximum voided volume or decreased bladder storage. Decreased NBC can be related to other disorders such as:
A significant number of nocturia cases occur from a combination of causes. Mixed nocturia is more common than many realise and is a combination of nocturnal polyuria and decreased nocturnal bladder capacity. In a study of 194 nocturia patients:[citation needed]
Multifactor caused nocturia is often unrelated to an underlying urological condition. Mixed nocturia is diagnosed through the maintenance and analysis of bladder diaries of the patient. Assessment of cause contributions are done through formulas.
Although there is no cure for nocturia, many actions can manage the symptoms.
If the cause of nocturia is related to benign prostatic hyperplasia or an overactive bladder, surgical actions may be sought out.[citation needed]
