Editing Functional: Nocturia (section)

== Decreased Bladder Capacity ==

=== Definitions ===
*'''<span style="color:#ff0000">Nocturnal urine volume exceeds nocturnal bladder capacity and the patient awakens because of the need to void</span>'''
**'''<span style="color:#ff0000">Can result from either a (2)</span>'''
**#'''<span style="color:#ff0000">Global decrease in bladder capacity, as expressed by a low maximum voided volume (MVV)</span>''' 
**#*'''Maximum voided volume (MVV): the largest single voided volume in a 24-hr period'''
**#'''<span style="color:#ff0000">Simply a decrease in nocturnal bladder capacity i.e. small nocturnal bladder capacity, as expressed by a nocturnal bladder capacity index (NBCi) > 0</span>'''
* '''Nocturnal bladder capacity index (NBCi)'''
**'''Useful means to examine the relationship between the patient’s own bladder capacity and nocturnal voided volumes during a 24-hour period.'''
** '''NBCi = Actual number of nightly voids (ANV) − Predicted number of nightly voids (PNV)'''
*** '''Actual number of nightly voids (ANV) or nighttime frequency: number of voids recorded from the time the individual goes to bed with the intention of sleeping, to the time the individual wakes with the intention of rising'''
*** '''Predicted number of nightly voids (PNV) = (Nocturia Index (NI) − 1)'''
**** '''Nocturia index (Ni) = Nocturnal urine volume (NUV)/Maximum voided volume (MVV)'''
*****'''Nocturnal urine volume (NUV): Total volume of urine passed during the night, including the first morning void'''
*****'''If Ni > 1, nocturia or enuresis occurs because functional bladder capacity (MVV) is exceeded'''
** '''If NBCi > 0, nocturia occurs at volumes less than MVV i.e. small nocturnal bladder capacity'''
** Example: a patient who voids 8 times per night (ANV = 8), who voids a total of 800 mL during the intended hours of sleep (NUV = 800 mL), and who has an MVV of 200 mL would have an Ni of 4 (Ni = NUV/MVV = 800 mL/200 mL = 4). This patient’s PNV = Ni − 1 = 4 − 1 = 3. Therefore this patient’s NBCi = ANV − PNV = 8 − 3 = 5. An NBCi of 5 indicates a substantially diminished nocturnal bladder capacity

=== Causes (11): ===
# '''Ureteral calculi'''
# '''Bladder calculi'''
# '''Cystitis''' (bacterial, interstitial, tuberculous, radiation)
# '''Cancer''' of the bladder, prostate, or urethra
# '''Bladder outlet obstruction'''
# '''Neurogenic bladder'''
# '''Low bladder compliance'''
# '''Medications''' '''such as xanthines (caffeine, theophylline) and β-blockers'''
# '''Idiopathic nocturnal detrusor overactivity'''
# '''Anxiety disorders'''
# '''Learned voiding dysfunction'''

=== Management ===

*'''Directed at underlying cause'''
** '''Phytotherapies'''
*** '''Pygeum africanum and cernilton are associated with improvement in nocturia'''
** '''Medical therapy'''
*** α-blockers, 5-ARIs, antimuscarinics, and antimuscarinics plus α-blockers have occasionally been found to have a statistically significant reduction in nocturia episodes, but clinical significance appears to be minimal.
*** '''When 5-ARIs and α-blockers are used in combination, they have the same degree of success as α-blockers alone'''
*** '''The optimal patients to treat with medications that target the bladder and the prostate appear to be those who have a large number of nocturia episodes (mostly resulting from severe urgency)'''
** '''Surgery'''
*** Patients with '''high-pressure urinary retention''' causing nocturnal enuresis are treated by initial catheterization to relieve the pressure, followed by appropriate assessment with a view to using endoscopic surgery to resect, vaporize, or enucleate the prostate, or open removal of the prostate
**** '''Treating bladder outlet obstruction is thought to improve nocturia''' by:
***** Lowering postvoid residual volume
***** Increasing functional bladder capacity
***** Reducing urinary frequency
**** '''TURP appears to be superior to tamsulosin for treatment of BPH-related nocturia'''