WHY DOES A CYSTINOTIC CHILD DRINK SO MUCH?

Crystals deposit in various organs of the body. In the kidney, they deposit in tubular cells. One of those functions is to control water excretion (how much one urinates).

The kidney works by filtering about 50 gallons of water per day (in the adult) and then reabsorbing 49 gallons of water back, as it passes the tubular cells. One can, therefore, imagine that if the tubular cells are damaged even just a little bit, one can lose a lot of extra water. Children with cystinosis, therefore, cannot conserve water. When we drink a lot we "pee" a lot, and when we don't drink so much, we don't "pee" so much. Cystinotics "pee" a lot no matter how much they drink, although they will urinate somewhat more, given more fluids. Cystinotics, therefore, need almost unlimited access to fluids and should rarely, if ever be restricted from water ( and then only under a doctor's strict supervision). One cannot punish or reward these children using fluids: it is too dangerous. Parents often relate to me how young children will drink out of toilet bowls or lick water off windows, especially in the winter. This is a sign they need water they can get to and easily, especially at night.

Cystinotics will usually drink so much that they won't eat, and this is a real problem in getting adequate calories for growth. I try and substitute high calorie drinks for as much water as possible, i.e.. milk, milkshakes, root beer floats, etc. Milk is a super source of good amounts of calories, proteins and fat.

Another problem is that drinking so much really puts the bladder to work. Usually cystinotics will not be toilet trained for urine, especially at night, until late, sometimes not until ages four to seven. School peer pressure usually helps, but can be a problem if the child is made fun of when he has poor control of urine during the day. Remember they don't have good control and that should be understood. Parents need to walk a fine line between understanding and not being manipulated.

If anyone has trouble dealing with this (most parents do) or any related problems, it is necessary to discuss it openly with your physician.

Your child is an individual and individual medical problems should be discussed with your physician.


Sheldon Orloff, MD Sub-Chief of Renal Medicine/Kaiser Hospitals

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