My baby was recently very dehydrated and had to be medically treated
for this. I am concerned that the treatment did not happen quickly
enough and I want to know if there are any long term side effects
known as a result of this.

Hi jonishii, I came across this article at
http://www.weitzlux.com/settlementverdict/injury/medicalmalpractice_509.html
which stated:

"Instead, Weitz & Luxenberg attorney Marc J. Bern argued, failure to
hospitalize the baby led to severe dehydration which caused a seizure,
then hypoxia, leaving the child with a seizure disorder, a mental
disability."

More details of the case fcan be found on that URL.

Best regards and good luck,
PoliticalOyster

I think a really good place to find your answer is located at:

http://www.wrongdiagnosis.com/news/baby_circumcision_mix_up.htm or 

Medical News Summary: Baby dies unnecessarily due to poor treatment of dehydration 

About: Baby dies unnecessarily due to poor treatment of dehydration 
Date: 19 Feb 2004 
Source: BBC News UK Edition 
Medical News Summary (summary of medical news story as reported by BBC
News UK Edition): A 17 month old baby was admitted to hospital after
suffering dehydration from gastroenteritis. Doctors gave her the wrong
type and amount of fluid to treat her dehydration. This resulted in
swelling of her brain and death.
URL: http://news.bbc.co.uk/1/hi/northern_ireland/3503187.stm 
Related Disease Topics: Gastroenteritis, Dehydration 
Related Treatment Topics: Fluid replacement 

Holly
www.ajlounyinjurylaw.com

While the mentioned legal cases below could certaily occur in a
setting of untreated dehydration, they are far and away the exception.
 Seizures in the setting of dehydration are usually due to alterations
in the sodium level in the blood.  The other case, involving cerebral
edema, likely was also due to using an inappropriate fluid in the
setting of a low or high sodium level.
These are really only concerns during the most severe state of
dehydration.  Once the baby is rehydrated, if they haven't happened
already, they aren't going to happen.  The only things I could think
to look for would be end organ damage, specifically kidneys and brain,
due to prolonged hypovolemic shock (i.e. decreased oxygen delivery due
to low blood volume).  But if your baby is acting normally (eating
well, alert, moving his/her arms & legs, meeting normal developmental
milestones, etc) and not retaining fluids (swelling of the arms or
legs, difficulty breathing) then these are extremely unlikely.
Hope this helps out.