4yr old CAH male with frequent urination

[Judy__0__0]

  I have a 4yr old son who also has congenital adrenal hyperplasia.  
  My question is is regarding his frequent urination to the point that
  anyone who spends time with  him comments on how frequent it is.  He is
  fully trained during the day however still requires a diaper at night.
  I know this is not uncommon for a boy this age however, 50% of the week he wets
  through his diaper, sometimes to the point where  his hair requires washing.
  He does drink a fair amount due to the cah and his need for salt however not much
  more than my 6yr old daughter.  He has been known to have his last drink at 5 fall asleep
  at 6, wake to take his meds at 7:30 with very small amount of water,
  wake at 4 with a very full diaper.  Have nothing to drink at 4am and urinate very much at 4,
  5 and 6am(still with nothing to drink).  How is this possible to urinate so much
  not having drank since 5pm the night before?  He has been tested for an infection
  and sugar which were both okay.  Please help, this mom is very concerned
  about her son and can't help but feel there is something wrong.

[hfhs M.D.-AK]

_

Dear Judy,
To begin with, your child is only four years old.  It is not uncommon for a child to have accidents particularly at night at this age.  Fifteen percent of 5 year olds still wet the bed at night.  Voiding problems, or dysfunctional voiding, are  also common in children.  Dysfunctional voiding can range from very mild problems to, rarely, severe problems which cause damage to the kidneys.  Difficulties with urination may range from frequency, burning, daytime and night time leakage.
An Unstable bladder is a frequent problem that can start anytime during childhood.  The bladder is hyperactive and tries to empty frequently, often without warning.  The child with this problem may run to the bathroom frequently or even have accidents.  You state that the child doesn’t have accidents during the day but only at night.  It is hard to comment at this early age  on whether or not this child has an unstable bladder.  I would give the child more time to develop before you conclude something is wrong.
The question regarding the mobilization of fluid and large amounts of urine passed between 4 am. and 6 am. is explained by changes in the patients hormonal status or possibly his medications.  Typically fluid mobilization occurs when the body is overloaded.  The body regulates fluid absorption with aldosterone and ADH(anti-diuretic hormone).  The concentration of these hormones at different times allows for the increases or decreases of urine flow.  There are also specific medications alter this balance.   Some medications help the body eliminate more fluid (diuretics) just as there are medications to help the body retain fluids often used to help prevent children from wetting the bed at night(DDAVP).
This information is provided for general medical educational purposes only.  Please consult your physician for diagnostic and treatment options pertaining to your specific medical condition.  More individualized care is available at the Henry Ford Hospital and its satellites (1 800 653-6568).
Sincerely,
HFHS M.D.-AK
*keyword:Urinary Frequency