18.JPG

 

 

The term myolysis is sometimes used to refer to muscle lysis (destruction), more commonly called rhabdomyolysis.

 

In medicine, rhabdomyolysis refers to a situation in which skeletal muscle cells rapidly degrade and release their contents into the bloodstream.

This corresponds to the destruction of the muscle cells making up the striated muscles (voluntary muscles, as opposed to smooth muscles which are automatic muscles).

Rhabdomyolysis, from Greek:

  • "rhabdo":   striped

  • "myo":       muscle

  • "lysis":       destruction

 

This is associated with a release of myoglobin (muscle protein) which passes into the blood and urine, causing myoglobinuria.
There is also an increase in certain enzymes in the blood....

CAUSES

This muscular damage can be caused by physical factors (crushing injury, or intense exercise), medication, drugs...

 

There are also infectious, viral or microbial causes, as well as metabolic factors (decrease of potassium, phosphate, ...).

 

Some people have a hereditary muscle disease that increases the risk of rhabdomyolysis: iIndeed, some muscle diseases (myopathies) facilitate the occurrence of rhabdomyolysis and should be sought in case of atypical circumstances (non-extreme effort) or recurrent episodes (following an infection ...)
Some people may be predisposed to rhabdomyolysis, probably because of a latent metabolic disorder linked to a genetic disease.

DIAGNOSTIC

The diagnosis is usually made with blood and urine tests.

The release of muscle enzymes in the blood, in particular creatine kinase (or CK, also called CPK) and myoglobin, confirms rhabdomyolysis.

A creatine kinase level higher than 5000 U/L is a sign of massive rhabdomyolysis. The normal CK level is between 25 and 190 U/L.

 

During the destruction of a muscle, the release of myoglobin will be filtered by the kidneys. This myoglobin is toxic to the renal tubules.

 

The passage of myoglobin in the urine gives it a reddish-brown color, hence the name "port" or "tea-colored" urine.


SYMPTOMES

  • Muscle contractures.

  • Muscle pain.

  • Painful muscle hardening and swelling, either localized or generalized.

  • Decreased muscle strength.

  • Cramps.

  • Hyperthermia (elevated temperature).

  • Shock (failure of vital organs to function).

 


The diagnosis can be confused (differential diagnosis) with abdominal pain or respiratory system damage, due to the weakness of the muscles of this system that can cause lung malfunction.


The release of muscle cell components into the bloodstream leads to electrolyte disturbances, which may result in nausea, vomiting, confusion, coma or heart rhythm abnormalities.

 

COMPLICATIONS


 

Massive cell destruction releases potassium into the bloodstream; this hyperkalemia can lead to heart rhythm disturbances or even cardiac arrest if the kalemia is really high. It also releases toxins that can lead to death in the short term.


The release of myoglobin into the bloodstream can cause acute renal failure. The renal damage is increased by relative dehydration due to muscle oedema resulting in fluid sequestration within the muscle.


We also note hyperphosphatemia (elevation of phosphorus levels in the blood) as well as hypocalcaemia (decrease in calcium levels in the blood).


 


 

TREATMENT


 

There is no treatment as such, rhabdomyolysis acts like a crisis that cannot be stopped...

Its prevention is based on an important hydration with a control of the inputs (perfusion) and outputs (urine) and intensive care.

The correction of ionic disorders is imperative, hence the need for monitoring in an appropriate department.

Renal insufficiency, if significant, or a cardiac rhythm disorder, may necessitate recourse to transient haemodialysis.


 


 

In some cases, such as in hereditary genetic diseases, where rhabdomyolysis can be massive, the patient may be placed in an artificial coma.

This state of sedation and analgesia ensures the physical and psychological comfort of the patient and facilitates the care techniques.

The body in an artificial coma allows the vital functions to be put to rest by preventing them from drawing too much from their reserves, from consuming energy by demanding oxygen and thus avoiding an overly aggressive response from the body against the trauma suffered, or cardiovascular dysfunctions.

 

In case of severe rhabdomyolysis, the prognosis is vital.

After acute rhabdomyolysis, the muscle generally recovers within a few days or weeks.


 

   Webinar on rhabdomyolysis by Pr Pascale de Lonlay, chief animator of G2M filiale.

MYOLYSIS