Nocturia is getting up at least twice a night to empty the bladder. This disruption of sleep can lead to fatigue, poor concentration, depression and in older people, falls, leading to hip fractures and even head injury.
Although nocturia also seems to increase with age, it can indicate an underlying medical problem, ranging from a bladder dysfunction to diabetes to chronic heart failure. Nocturia can also be a side effect of some medications, such as diuretics used to treat high blood pressure. In men, it could be a sign of a prostate enlargement which is usually benign, but on occasion can also be due to prostate cancer.
Nocturia as a result of excess urine production is another possible cause (called nocturnal polyuria syndrome or NPS). It is attributed to lack of anti-diuretic hormone (ADH). This lack of ADH is often seen in the elderly. NPS is confirmed through bladder charting. The night-time urine output is measured if it is < ⅓ of the total daily urine output, this is considered as excessive.
Another little known cause of nocturia is sleep apnoea.This is when a person stops breathing for several seconds, several times a night. This translates to lighter sleep patterns. Sleep apnoea can be assessed by the ear-nose-throat specialist.
The possible causes of nocturia require investigations. They include
- Bladder chart [Fig 1]
- Blood tests eg. blood sugar level, electrolytes, kidney function
- Ultrasound of bladder
- Uroflowmetry in men to exclude prostate enlargement
- Cystoscopy if microhaematuria is present
It is important not to miss sinister causes, especially bladder and prostate malignancy because medication can mask these diseases.
a) Lifestyle modifications
Since caffeine can cause sleep disruption and nocturia, caffeinated foods and beverages should be avoided for at least 8 hours prior to bedtime. Drinking large amounts of alcohol or fluids should also be avoided for at least 6 hours prior to bedtime.
If evening diuretics eg. frusemide (Lasix) is the cause, then it should be taken earlier, at least 6 hours before bedtime. Other medications to treat nocturia depends on the cause. They include anti-cholinergic drugs eg. solifenacin (Vesicare), tolterodine (Detrusitol) and trospium (Spasmolyt) for overactive bladder. For treatment of NPS, a synthetic version of the hormone, ADH called desmopressin (Minirin) can be given before bedtime to reduce excess urine production at night. In elderly men with enlarged benign prostate (BPH), alpha-blocker drugs like terazosin (Hytrin), alfuzosin (Xatral), tamsulosin (Vesicare) act to reduce the residual urine at night [Fig 2].
Those with weak bladders as a result of ageing or diabetes tend to have high residual urine after voiding. Emptying the bladder before bedtime through catheterization will help avoid the urge to pass urine at night.
Nocturia can indicate an underlying medical condition. Sometimes the cause is easily treated, but at other times, the condition may indicate significant health risks. Nocturia itself causes sleep interruption and lack of sleep is a risk factor for accidents. Hence, it is important to report nocturia to your doctor.