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Taking Miralax for constipation. Does not pee for long time. Dehydrated?

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3-year old granddaughter has been on Miralax over a year for chronic constipation. Sometimes she goes for days (5-6-7) without a BM. Often when she hasn't pooped for several days (especially in hot weather), she then nearly stops urinating. Like she wakes up in morning after 10 hrs. of sleep and doesn't need to pee. Last time, went until about 2:00 pm before peeing (foul smelling, dark pee). Does constipation cause someone to stop peeing? Is she dehydrated? Could they be giving her too much Miralax (they put it in her all of her milk and water bottles - which is her primary source of liquids.) Help! Is there something about being extremely constipated which causes you not to be able to pee? Last time this happened (no BM for 5 days following a suppository which allowed her to poop), I gave her all the liquid I could (fruit smoothies, etc. without the Miralax.) by 8:00 pm, after sitting in warm bath, she pooped - it was first a round ball, then about 18 inches of poop - roughly half of which was very dark brown and dried up, the other half looked more normal. Why does she stop peeing? Isn't this dangerous? Is she just dehydrated???
Posted Sat, 1 Jun 2013 in General Health
Answered by Dr. Luchuo Engelbert Bain 4 hours later
Hi and thanks for the query,
Chronic constipation in a child could arise from very simple causes to more complex organic causes. It would be important to get a few questions answered first to facilitate the clinical reasoning here. At what age was she put on a milk formula? When did she stop being breast fed? When she was being breast fed, was she presenting with similar symptoms? Is this the first milk formula she has ever used before? If no, how did she respond with the very first milk formula? For how long has she actually been constipated? How is her appetite and growth curves? both physical and intellectual? Who actually does the preparation of her formula? Has she consulted a pediatrician before for this problem, and if yes, what was done and how was the response under the prescribed therapy?

Errors in preparing the milk formula on its own could cause constipation. It might get to concentrated or the child might naturally react to this as such. Secondly, common diseases that could cause complication in child could be a retracted size of the anus (anorectal malformations) which could require simple enlargement or correction process. Rare diseases associated with abnormal contractions of the rectum called Hirshprung's disease should be also thought of. Hypothyroidism, gluten enteropathy and a spinal cord abnormality could also be implicated in the process.

Impaction of feces in the rectum could cause some pressure on the bladder, which is located just in front of it and actually block flow of urine. Accumulation of this urine in a chronic fashion could predispose to urinary tract infections, dilation of the urinary tubules above the bladder and chronic kidney disease.

I strongly suggest you book an appointment with a pediatrician for a proper clinical assessment and management.

Thanks for the query and do not hesitate asking further questions if need be.

best regards,
Luchuo, MD.
Above answer was peer-reviewed by
Follow-up: Taking Miralax for constipation. Does not pee for long time. Dehydrated? 16 hours later
Miralax is a powdered (polyethylene glycol 3350)stool softener purchased over the counter in the US, at the recommendation of the girl's pediatrician. She has been on it for a couple years now. It is put in her milk (cow's milk purchased at the super market) and in her water. Thus, the dosage she is getting on a daily basis varies, depending on how much milk and water she drinks that day. When she was an infant, she was breast fed for about the first 8 months; even then she did not have daily bowel movements, but she was urinating normally, I believe. She sometimes would go several days (up to 4) without a BM. But we did not notice any problems related to the infrequent bowel movements until she started eating baby food and drinking formula. That is when she was put on Miralax on a daily basis. But when she was bottle fed, the Miralax was put into her morning bottle only; she drank this at one setting and bowel movements were acceptable. When she went off the bottle, the Miralax was put into all of the milk and water she drank, but this was there is no way of telling how telling exactly how much she gets daily - and it must vary day to day. I will see a pediatrician about this, even if the child's mom does not participate. Do you think the constipation could be from becoming too dependent on Miralax. Why is the problem worse in the summer when the weather is hot? Could the constipation and failure to urinate be due to dehydration?
Answered by Dr. Luchuo Engelbert Bain 26 minutes later
Hi and thanks for the specifications once more,

Continuous use of Miralax could actually contribute to chronic constipation. It acts by drawing blood from the intestines into the intestinal lumen and could dehydrate the child. In severe cases, it could dehydrate the child and explain why the child might not urinate very frequently. It could be very appropriate to make the child to drink so much.

However, you will need to consult the pediatrician to evaluate replacement of Miralax, or introduce another product. Secondly, a proper clinical evaluation is required to rule out a serious organic disease as previously mentioned.

I totally agree with you that it’s very important to get a consultation with the pediatrician.

Thanks and best regards,
Dr Luchuo, MD.
Above answer was peer-reviewed by
Follow-up: Taking Miralax for constipation. Does not pee for long time. Dehydrated? 5 hours later
Please rephrase your sentence: "It could be very appropriate to make the child to drink so much." Do you mean, "It's appropriate to make the child drink a lot" or "It may not be appropriate to make the child drink so much Miralax?" Could you explain your statement????
Answered by Dr. Luchuo Engelbert Bain 14 minutes later
Hi and thanks for the request for the precision.

I am sorry that I was not clear in what I said earlier.
To replace the fluid lost, it is advisable to give a lot of water and fluids to the child to drink (make the child drink as much water and fluids as possible) to somewhat compensate for this fluid loss (gap).
This however remains a temporary measure as you wait to get a complete review from the pediatrician.
Thanks so much for your patience and best regards,
Luchuo, MD.
Above answer was peer-reviewed by
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