Rhabdomyolysis

Rhabdomyolysis is a breakdown of muscle fibers. It can be caused by muscle contusions and extreme physical activity, infections or taking certain medication, for example.

The muscle breakdown can manifest itself in the form of muscle pain or go unnoticed. In some people, however, it can lead to serious complications such as acute kidney failure and requires urgent hospital treatment – sometimes even in an intensive care unit.

Milder cases of rhabdomyolysis can go unnoticed. If not, the typical symptoms include:

• muscle pain
• muscle weakness
• reddish-brown urine

The pain is usually noticeable in the muscle groups located near the torso, for example in the shoulders, upper thighs and lower back. The muscles can also cramp.

Other symptoms – especially with more serious cases – include:

• general feeling of being unwell
• high temperature (fever)
• rapid heart rate
• stomach ache
• nausea and vomiting

Rhabdomyolysis has a number of different causes. Examples of frequent triggers include:

• muscle contusions as a result of an accident or impact
• prolonged periods lying in the same position (immobility)
• surgery
• extreme sport that overexerts the body – such as running a marathon without prior training
• alcohol and drug consumption
• taking certain medication, including cholesterol-lowering drugs: especially the combination of fibrates and statins
• infections, especially in children
• improperly regulated sodium levels (electrolyte imbalance)
• overheating of the body (hyperthermia), e.g. due to heat stroke
• side effect of the treatment of mental disorders with neuroleptics, for example
• side effect of treatment with anesthetics
• a compartment syndrome (when fluid becomes retained in the muscle tissue as a result of an injury, causing severe pain)

Several factors often coincide with rhabdomyolysis.

Anyone can develop rhabdomyolysis. However, it is more common in children under the age of 10 and people over the age of 60. People who are overweight and men also tend to be more prone to rhabdomyolysis.

Regardless of the specific trigger, with rhabdomyolysis, cell fragments are released into the bloodstream. In the case of very mild muscle fiber breakdown, this causes few problems. In more severe cases, however, life-threatening complications can sometimes ensue.

One comparatively common complication is acute kidney failure: it is presumed that the released muscle protein myoglobin blocks the renal tubules and damages the kidney cells. The blood supply to the kidneys is also impaired. This reduces or even halts the production of urine.

The typical consequences of rhabdomyolysis can also include a lack or excess of certain salts (electrolytes) in the blood. For example, muscles may cramp if there is too little calcium in the blood (hypocalcemia). Conversely, the potassium level in the blood can often become elevated (hyperkalemia), increasing the risk of cardiac arrhythmia.

On rarer occasions, the released substances can cause the blood to clot throughout the vascular system. In extreme cases, multiple organ failure occurs, even affecting the lungs and liver.

In most people, the complications of rhabdomyolysis can be controlled through intensive in-hospital monitoring and treatment. In such cases, the original muscle damage also usually heals without consequence.

A detailed patient consultation is used to obtain the first important indications of possible muscle breakdown. If rhabdomyolysis is suspected, this is confirmed through laboratory tests.

Doctors usually regard a diagnosis as confirmed if the amount of the protein creatine kinase in the blood is far higher than normal. Creatine kinase enters the bloodstream from the deteriorating muscle cells and is a sign of the condition’s severity.

A urine test strip can also be used to quickly determine whether the muscle protein myoglobin is being released in the urine and the patient is suffering from myoglobinuria.

The standard diagnosis methods for rhabdomyolysis also include an electrocardiogram (ECG) as the muscle breakdown can also regularly lead to cardiac arrhythmia.

Doctors generally start by trying to eliminate the cause of rhabdomyolysis. This means that medication that could trigger muscle breakdown is usually stopped. If the breakdown is due to physical exertion during sport, giving the body a few days to recover and drinking plenty of fluids can suffice to resolve mild cases. However, the doctor needs to assess this.

If there is a risk of complications, hospitalization is required. A thin plastic tube is used to inject fluid into a large vein (venous catheter) to help flush out harmful substances and avoid kidney failure.

In serious cases, temporary renal replacement therapy (dialysis) and treatment in an intensive care unit may be necessary – especially if the potassium levels can no longer be regulated as this can cause life-threatening cardiac arrhythmias.

If a compartment syndrome is suspected to have caused the muscle breakdown, surgeons are involved in the treatment.