In our hospital most urine myoglobin requests come from patients already in
acute renal failure with a very high CK. Then the question that is being
asked is more often "Is the ARF due to rhabdomyolysis?" rather than "Can we
prevent ARF in this patient with a high CK?"
The extreme hyperkalaemia, hyperphosphataemia and acidosis, out of
proportion to the extent of the ARF, are characteristic of ARF due to
extensive cellular damage, and in my view, (especially) when a very high CK
is accompanied by these features, urine myoglobin is completely unnecessary.
Our nephrologists and intensivists still sometimes ask for it, and get it,
but I suspect it does not alter their management one iota. (This might be
worth auditing..?)
As for myoglobinuria without renal impairment, it can be associated with a
relatively minor degree of muscle injury; thus a qualitative assessment of
the presence of myoglobin in urine is unlikely to be as good a predictor of
renal damage as the peak CK level.
And to add to the metabolic myopathy by-line, I've seen very long chain
acyl-CoA dehydrogenase (VLCAD) deficiency present with rhabdo and ARF in a
40-year-old previously well man who gave a history of dark urine every time
he played football. (Which brings us right back to the
colour-of-urine-in-rhabdomyolysis question....)
Clodagh Loughrey
Chemical Pathologist
Belfast City Hospital
-----Original Message-----
From: TICKNER TREVOR (RM1) Norfolk and Norwich NHS Trust
[mailto:[log in to unmask]]
Sent: 09 April 2002 17:18
To: [log in to unmask]
Subject: Re: Heavy myoglobinuria and urine colour
I am certain that you are right that there is inadequate evidence that
measurement in trauma is beneficial since the evidence of benefit from
diuresis in proven myoglobinuria is very limited.
Unfortunately our starting point is that perceived wisdom has been that
alkaline diuresis protects against renal damage. Thus we need to show that
there is no benefit from this treatment; that this treatment is appropriate
in all cases of trauma (or at least all cases of trauma where the urine is
coloured using a specified standard); or that there is an alternative test
that performs at least as well in the identical patient set.
I simply do not know if one can have significant myoglobinuria in the
absence of a raised CK but one can get a raised CK without significant
myoglobinuria. One might argue that CK can be used as a screen for myoglobin
testing but, until the clinical management is shown to be myoglobin
independent, there persists a case for retention of this test.
Trevor Tickner,
Norwich
> -----Original Message-----
> From: Douglas Thompson [SMTP:[log in to unmask]]
> Sent: 09 April 2002 17:46
> To: TICKNER TREVOR (RM1) Norfolk and Norwich NHS Trust;
> [log in to unmask]
> Cc: [log in to unmask]
> Subject: Re: Heavy myoglobinuria and urine colour
>
> Trevor
> I'm not quite sure what you are saying here. Are you saying that it
> is worthwhile measuring urine myoglobin since CK will not always
> be raised in myoglobinuria? In the abstract you quote the
> myoglobin method is not given but I suspect it to be a non-specific
> and the timing of the samples may also be important.
> I agree with Gerald. There is no evidence that the measurement of
> urine myoglobin is helpful in trauma care.
>
> Douglas Thompson
> Leeds General Infirmary
>
> > There are several questions here.
> >
> > 1) Does raised CK tell you that there is myoglobinuria?
> > 2) Can myoglobinuria exist without raised CK?
> > 3) Does treatment of myoglobinuria benefit the patient?
> >
> > The answer to 1) is no - or at least not in all situations. See, for
> > example http://www.aaos.org/wordhtml/anmeet92/scipro/ppr313.htm I do
> > not know the answer to 2) and would be interested in the evidence. I
> > believe that the evidence for benefit to the patient of active
> > treatment is limited but generally medical wisdom is that diuresis is
> > warranted.
> >
> > Trevor Tickner,
> > Norwich
> >
> > > -----Original Message-----
> > > From: Gerald. Maguire [SMTP:[log in to unmask]]
> > > Sent: 09 April 2002 15:33
> > > To: [log in to unmask]
> > > Subject: Re: Heavy myoglobinuria and urine colour
> > >
> > > What does the measurement of urine myoglobin tell you that the
> > > measurement of serum CK does not? After consultation with the
> > > critical care teams (ITU and neuro), we stopped measuring urine
> > > myoglobin about 18 months ago and nobody misses it.
> > >
> > > Gerald A Maguire
> > > Dept of Clinical Biochemistry and Clinical Immunology
> > > Addenbrooke's Hospital
> > > Cambridge
> > > CB2 2QR
> > > UK
> > > Tel 44 (0) 1223 217159
> > > fax 44 (0) 1223 217794
>
> Dr Douglas Thompson
> Department of Clinical Biochemistry and Immunology
> Leeds Teaching Hospitals NHS Trust
> The General Infirmary
> Leeds, LS1 3EX
> Tel: 0113 3926503
> Fax: 0113 2335672
>
>
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