>Does anyone have a diagnostic definition of rhabdomyolysis.
>2. Does it matter how high the creatine kinase rises?
>3. Is it necessary to detect myoglobinuria, is so, how much?
>Julian Barth.
>___________________________________________________
Working clinical definition of our ICU colleagues is acute destruction of
skeletal muscle, +/- myoglobinuria, +/- hypotension/shock/dehydration.
2. Our ICU criterion of serum CK over 5x uln seems to me rather rigid,
depending on the patient. 2 or 3 samples some hours apart may show CK
rising, (then CK is likely to follow the usual half life while falling).
Other chemical criteria are myoglobinuria, raised K, P, urate, low Ca.
Renal-protective treatment decisions can be taken: eg rehydration,
mannitol, and up to 3 days' alkaline diuresis.
3. In a patient whose aetiology is such one suspects rhabdomyolysis (eg
drugs, crush, hyperthermia, etc), urine Mb is useful confirmation to
continue Rx. However when a patient presents with just renal failure of
unknown origin,it is a valuable pointer to eg Ix of these, and of metabolic
myopathies.
Ep is slow and insensitive but still useful, especially if the urine is
stix + but microscopy -. We find urine Mb immunoassay to be faster,
unaffected by Hb, and quantitative. But if taken to a logical conclusion,
when the patient presents should one use a high serum Mb: Mb clearance
ratio (ref. ** see below) as a pre-Rx criterion?
** http://www.arup-lab.com/myoglob.htm (refers to Wu's Clin Chem paper 40 ,796)
Best wishes, Les Culank
Dr Les Culank,
Consultant Chemical Pathologist.
Dept of Clinical Biochemistry, Addenbrooke's Hospital
Cambridge UK CB2 2QR
Tel: +44 (0)1223.217153 fax: 216862
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