Submitted by Dr. Jay Motola on Dec. 31, 2014
If you are woman over the age of 40, there is a good chance that you need to wake up at night in order to urinate. This entity is known as nocturia, usually refers to waking up at least twice nightly and needing to urinate. A recent study from the San Francisco VA Medical Center has identified that over one-third of women over 40 experience this symptom. For every 5 years of aging, the risk associated rose by 21%.
Nocturia can be a very troubling problem to many. Waking up once nightly usually is not very problematic as most people can fall back to sleep. However, waking up multiple times becomes far more troubling for the patient. Interrupting the sleep cycle repeatedly results in the inability to enter the deep phases of sleep which are required in order to feel well rested the following morning.
Most people will produce 300-600cc (10-13 ounces) of urine overnight. An average bladder capacity is about 300 cc. Therefore, most people will wake up on average 0-2 times per night. Conditions such as hypertension, diabetes and obesity can make this worse. Sleep apnea can also worsen the condition.
In elder women, further complicating the potential development of nocturia is menopause. The hot-flashes that patients experience can result in poor sleep patterns, and subsequent awakening to void. The likelihood of having undergone a hysterectomy increases with advancing age, and this is another risk factor for developing nocturia. Use of melatonin has been shown to help better maintain the sleep cycle
The handling of body fluids and the production of urine is a very complex process that depends on both our kidneys and heart. There is a constant monitoring of the level of salt in the circulation, as well as the body’s fluid volume. High salt intake or dehydration can alter urine production. There is maintenance of our body fluids, almost like a thermostat, that allows for increase urine production when we have too much body fluid, and conservation or a decreased urine output, when our body needs fluids. Helping to control this mechanism are two substances, Vasopressin, which is produced by the brain, and Atrial Natriuretic Factor (ANF) which is produced by the heart in response to the detection of increased blood volume.
Several behavioral modifications can be made to help control nocturia. Limiting fluid intake in the evening hours is likely to be beneficial. Alcohol and its diuretic effect will result in the increased production of urine and limiting its intake should help. Caffeine, a direct bladder stimulant should also be limited. Urinating frequently in response to excessive fluid intake is your body’s normal response to the fluid.
Nocturia is a very complex entity. During the daytime hours, when we are usually in the upright position, especially in elder patients, body fluids tend to accumulate in gravity dependent position, such as the legs and the feet, which may commonly be seen as a swelling in the legs at the end of the day, recognizable by the lines that may form at the edge of sock lines. At night, however, when we are recumbent, these fluids get redistributed to the circulation. The excessive fluid stimulates our kidneys to produce urine and possibly result in increased production of urine in the overnight hours in some groups of patients.
A condition known as Primary Nocturia exists and these patients produce large volumes of nighttime urine. Daytime voiding for these patients tends to be unaffected. Management of this problem is fairly difficult. Some patients may benefit from using DDAVP (synthetic vasopressin), however, those using this medication must be monitored by a physician as dangerously low levels of sodium may develop that could result in confusion, seizures and even death in extreme cases. Fluid restriction in the afternoon and evening hours should be adhered to.
Certain other medical conditions exist that are associated with fluid overload that can also result in nocturia. These conditions include congestive heart failure, venous stasis disease, lymphedema ,the nephrotic syndrome and liver failure. The treatment of these underlying conditions will often help improve nocturia. Some of these conditions are associated with an increased production of may cause a distension of part of the heart, called the atrium, resulting in the release ANF. Stroke may also result in abnormalities resulting in nocturia, as can the use of the medication lithium which is used for the treatment of bipolar disease. Tailoring diuretic usage to the daytime hours may be helpful. Blood pressure needs to be well controlled and congestive heart failure needs to be treated to maximize cardiac function. Low potassium also needs to be avoided and potassium supplementation may be required.
The need to wake up at night to urinate can be very debilitating for some patients, and is a very common condition. Behavioral modification, the detection of underlying conditions, and the treatment of these entities can help make this a much more manageable condition. Efforts at developing safe medications have not been very successful. Some patients may benefit from the use of anticholinergic medications. An evaluation with your physician should help with the management of this problem.