Acute water intoxication can cause hyponatraemia over
hours. The relatively hyperosmolal brain cells will
draw water from the hypo-osmolal extracellular
compartment resulting in brain oedema. This is an
osmotic process that can occur through an intact blood
brain barrier as the the movement involves water only.
This is in contrast to inflammatory brain oedema as
seen in menigitis or encephalitis in which the BBB as
well as brain cell membranes are damaged allowing
macromoleclues and inflammatory cell inside the brain
tissue. Osmotic brain oedema can resolve therfore more
quickly than the inflammatory type once the noraml
extracellular osmolality is established.
regards.
--- "R.W. Wulkan" <[log in to unmask]>
wrote: > I would like to comment on this. When
studying the
> blood-brain
> barrier, I have read somewhere- but have forgotten
> of course - that
> injected radioactive sodium appear in CSF only after
> several hours.
>
> Raymond Wulkan
> Rotterdam-NL
>
>
>
>
>
> Date sent: Wed, 18 Oct 2000 06:05:35 -0700
> (PDT)
> Subject: Re: Critical Value for Sodium (age
> specific if set as such)
> From: Mohammad Al-Jubouri
> <[log in to unmask]>
> To: William Marshall
> <[log in to unmask]>,
> "Alter, David N."
> <[log in to unmask]>,
> "'acb mail'"
> <[log in to unmask]>,
> "'medlab list'"
> <[log in to unmask]>
> Send reply to: Mohammad Al-Jubouri
> <[log in to unmask]>
>
> I can't agree more, the figures given are to define
> the biochemical severity not the clinical severity
> or
> consequences of sodium imbalance. Clearly a serum
> sodium dropping rapidly (over hours) from 140 mmol/L
> to 122 mmol/L ( as in acute water intoxication) will
> result in severe clinical effects due to osmotic
> cerebral oedema despite the serum sodium level being
> in the moderate hyponatraemia range. As a general
> rule, acute electrolyte disturbances produce more
> severe clinical sequelae and require urgent
> intervention compared to chronic disturbances.
>
> regards.
>
>
> --- William Marshall <[log in to unmask]>
> wrote: > The time course over which the abnormality
> has
> > developed is arguably as, if
> > not more important, than the absolute value of
> > sodium concentration,
> > certainly in relation to any intervention.
> > WM
> > At 03:42 AM 10/18/00 -0700, Mohammad Al-Jubouri
> > wrote:
> > >I am not sure what do you mean by critical values
> > for
> > >sodium. The reference range for serum or plasma
> > sodium
> > >is 135 - 144 mmol/L (or mEq/L)for all age groups.
> > >Arbitrary values have been used to define
> severity
> > of
> > >hypo or hypernatraemia. For hyponatraemia, mild
> > (126 -
> > >134 mmol/L), moderate (120 - 125 mmol/L) and
> severe
> > (
> > ><120 mmol/L. for hypernatraemia, mild (145 -
> 150),
> > >moderate (151 - 159), severe ( 160 mmol/L and
> > over). I
> > >stress that these are arbitrary values and people
> > may
> > >use different cut off values or even do not use
> > such
> > >defintions depending on their own experience.
> > >
> > >regards.
> > >--- "Alter, David N."
> > ><[log in to unmask]> wrote: >
> Firstly,
> > As
> > >a fresh out of training clinical
> > >> pathologist in the position as
> > >> such, the replies that I have received have
> been
> > >> invaluable in sorting out
> > >> both day to day and longterm issues that I have
> > >> encountered since day one of
> > >> my job.
> > >> So to all those who have replied, Thank you
> very
> > >> much for all of your
> > >> insightful comments and help.
> > >>
> > >> On to the current survey of practice,
> > >> I have reviewed the major references on
> critical
> > >> values but now is a survey
> > >> of current practice.
> > >> What critical values (lower and upper) do
> members
> > >> use for Sodium?
> > >> Apparently, the oft stated lower one of 120
> mEq/L
> > is
> > >> outdated especially for
> > >> children and I was curious how many of us are
> > using
> > >> that value.
> > >>
> > >> Thank you again
> > >> David Alter
> > >> Clinical Pathologist
> > >
> > >
> > >=====
> > >Dr. M A Al-Jubouri
> > >Consultant Chemical Pathologist
> > >Whiston Hospital
> > >Prescot
> > >Merseyside L35 5DR
> > >UK
> > >
> >
> >__________________________________________________
> > >Do You Yahoo!?
> > >Yahoo! Messenger - Talk while you surf! It's
> FREE.
> > >http://im.yahoo.com/
> > >
> >
>
>
> =====
> Dr. M A Al-Jubouri
> Consultant Chemical Pathologist
> Whiston Hospital
> Prescot
> Merseyside L35 5DR
> UK
>
> __________________________________________________
> Do You Yahoo!?
> Yahoo! Messenger - Talk while you surf! It's FREE.
> http://im.yahoo.com/
=====
Dr. M A Al-Jubouri
Consultant Chemical Pathologist
Whiston Hospital
Prescot
Merseyside L35 5DR
UK
__________________________________________________
Do You Yahoo!?
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