Rhabdomyolysis: what it is, causes, symptoms and risk group

Imagine that you want to improve your health, reduce some measures and gain more physical disposition.

One of the first things that comes to mind is to start or intensify physical activities, maybe start some gym class, the kind that are being talked about on fitness blogs, like Crossfit or HIIT.

Nowadays, the news in the health and gym area keeps coming. Modalities that mix dance, fight, weight training , aerobic exercises and a lot of physical conditioning have become popular. Especially those of high intensity – in which it takes a lot of breath and conditioning to keep up.

Although regular physical exercise is recommended and highly beneficial, there are some dangers that involve activities and are not always known.

After starting classes, imagine that you have suffered a muscle injury. It may be because you perform the movement incorrectly, you lift more weight than your body can handle (muscle exhaustion) or because a crash has happened (some equipment has fallen on you).

The injuries caused by physical activities can be quite inconvenient, cause prolonged pain, need physiotherapy sessions and even medications.

Even though it is boring, the condition is relatively common in gyms or among practitioners of outdoor activities, such as running or rowing.

Even more serious is when this muscle injury results in rhabdomyolysis, a condition in which the muscle fibers end up releasing the intracellular content into the bloodstream.

Rhabdomyolysis caused by physical activity is still quite rare. Possible causes also include degenerative diseases and accidents, such as landslides, falls and accidents (which result in the crushing of the victim).

However, some studies have pointed to a slight accentuation in cases caused by muscle injury from sports.

What is rhabdomyolysis?

Rhabdomyolysis is a serious syndrome that develops when there is muscle damage followed by the death of skeletal muscle tissue (muscle necrosis), which causes intracellular substances to be released into the blood.

This causes changes in the values ​​of calcium and Adenosine Triphosphate (ATP), responsible for energy storage, causing the muscle to contract in a prolonged and persistent way.

In order to contract, the muscle needs energy, but as the activity is exaggerated, the energy reserves are depleted, causing the production of free radicals that are released into the blood and aggravate muscle damage.

The result is that the tissue begins to necrotize, that is, to die.

But injuries do not necessarily have to be hurt. Although there has been a recent increase in cases seen in practitioners of high intensity activities, the syndrome can be caused by seizures, drug use or infections.

The name of the condition comes from the destruction of the striated musculature. Where rabdo = striated, mio = musculature and lysis = destruction.

When there is a muscle injury and the tissue undergoes necrosis, the contents of the cells are sent to the bloodstream. Among the substances released is myoglobin, which can cause damage to the body, especially the kidneys.

Symptoms can involve muscle weakness, dark urine color, headaches, muscle pain (myalgia) and acute kidney damage (AKI) causing kidney failure.

In some cases, there is no manifestation of representative symptoms. In the most severe cases, rhabdomyolysis can lead to acute renal failure, increased muscle enzymes, the need for hemodialysis and even life-threatening.

Chemical process of rhabdomyolysis

There are 3 types of muscle tissue in the body:

  • Smooth: stomach and intestine muscles, for example;
  • Cardiac: muscle of the heart;
  • Skeletal: muscle that covers the skeleton.

While the first 2 make involuntary movements (that is, they do not depend on our will to perform the contractions), only the skeletal makes voluntary movements.

Skeletal muscles are attached to bones and cover the entire skeleton, comprising most of our musculature. The internal part of the muscle is made up of very thin fibers capable of contracting (called myofibrils).

It is from lesions in the skeletal musculature that rhabdomyolysis occurs.

The chemical processes that occur with rhabdomyolysis are diverse, but in summary, after intense stress there is a marked increase in the concentration of calcium in the injured muscle tissue.

This elevation promotes the manifestation of several events, such as changes in potassium and sodium, which activate degrading enzymes, causing serious damage to the muscle.


The causes of rhabdomyolysis are always caused by muscle damage, and can be of physical or chemical origin (such as crushing or using drugs).

After the muscle is injured, necrosis of the muscle fibers occurs and the internal content of the cells is released into the bloodstream.

Among the substances transferred to the blood are sodium, potassium, calcium and phosphates (electrolytes), muscle proteins (creatine kinase and aspartate aminotransferase) and myoglobins (which transport and store oxygen).

When myoglobin comes into contact with some organs, especially the kidneys, it can cause damage to the body.

The syndrome has an infrequent incidence and studies have pointed out the causes as multifactorial. That is, there are conditions of the organism itself, of the environment or external chemical interferences that can cause the condition.

Physical efforts

Despite being an infrequent cause, it is observed that rhabdomyolysis associated with the practice of physical activities has increased.

The condition may be due to exaggerated physical effort, extreme muscle fatigue , excessive weight lifting or muscle demand above conditioning.

If the activities are practiced on very hot days, in humid, humid environments or under the sun, the risks are high.


Although injuries that occur in the gym, such as muscle strain, are the most remembered muscle traumas, there are more comprehensive situations, such as natural disasters (earthquakes), landslides or car accidents.

These situations have a severe impact on the body and, consequently, generate damage to muscle fibers, which can progress to rhabdomyolysis.

It is still possible that the disease is caused by prolonged muscle immobilization, which compromises blood supply (ischemia).

These are cases in which the person spends long periods in the same position or has some orthopedic pathology that compresses the muscle and decreases blood circulation.

The lack of oxygen and nutrients caused by the reduction of blood flow to the muscle and promotes lesions and tissue necrosis.

High temperatures

Raising or cooling body temperature dramatically can lead to rhabdomyolysis.

When practicing physical activities in extreme climatic conditions (both too cold or too hot) or under the sun, it increases the risk of muscle damage.

Heat stroke also predisposes the patient to the syndrome, as the body temperature is above 40.5º and can trigger rhabdomyolysis. As well as the hypothermia episodes that generate ischemia (decreased blood supply) of the tissues.

Metabolic myopathies

Metabolic myopathies (diseases that affect the muscles) are caused by the deficiency or inability of the muscles to produce or use energy sources correctly.

The conditions develop with intolerance to physical activities, as there is intense fatigue and muscle weakness.

As the muscles are more fragile, even small physical efforts can cause muscle damage.

Infectious diseases

According to surveys by Hospital Professor Doutor Fernando Fonseca, in Portugal, infectious diseases are the main cause of rhabdomyolysis in children.

Generally, there are associated infectious conditions. Being a possible cause to trigger the syndrome.

Among the infections related to rhabdomyolysis are contamination by the respiratory syncytial virus (RSV) , which affects the lungs and bronchi. Usually causing pneumonia and inflammation of the bronchioles.

In addition, pulmonary infections caused by the agent Streptococcus viridans and also by Haemophilus influenzae , can favor rhabdomyolysis. These bacteria cause diseases like meningitis , pneumonia and pharyngitis , for example.

When infectious agents invade the body, they can cause the destruction of muscle tissue, the production of toxic substances that attack the body or a change in immune responses, leading to muscle necrosis.

However, some researchers point out, in articles published in Acta Médica Portuguesa (scientific magazine of the Portuguese Medical Association) that the relationship between infections and rhabdomyolysis is still not completely clarified.

Metabolic diseases

The diseases that can be associated and provide greater risks to rhabdomyolysis are:

  • Hereditary disorders of carbohydrate metabolism;
  • Deficiencies of mitochondrial respiratory chain enzymes;
  • Disorders of fatty acid oxidation (VLCAD deficiency);
  • Carnitine-palmitoil deficiency.

Abuse of alcohol and drugs and other substances

In the case of drugs, there are two conditions that favor rhabdomyolysis, one being direct and the other indirect.

Directly, drugs (including licit or illicit ones, such as alcohol, medication, LSD and cocaine) can act directly on muscle fibers, impairing cell function and increasing the risks of necrosis and release of myoglobin into the bloodstream.

Among the listed substances capable of triggering the disease are:

  • Alcohol;
  • Methanol (used in cosmetics, perfumes, medicines, for example);
  • Ethylene glycol and isopropanol (generally used as fuel and automotive solvents);
  • Heroin and methadone (a substance similar to heroin, but with less effect);
  • Cocaine, barbiturates, amphetamines, MDMA (Ecstasy), LSD;
  • Carbon monoxide;
  • Toluene (used in glues and paints, as well as being a raw material for enamels, dyes, medicines and cleaning products).

In addition, there are intoxications that are related as well:

  • Coturnismo (poisoning caused by the consumption of quail birds);
  • Buffalo fish poisoning (Haff’s disease);
  • Attack or bites of snakes, black widow spider and bees.

Indirectly, overuse of drugs can cause loss of balance, fainting and beats that promote muscle damage.

For example, cases are reported in which rhabdomyolysis is caused by fainting due to excessive alcohol consumption. Fainting, in these cases, compressed the blood supply to the muscle and started the injury.


According to a study in the area of ​​nephrology at the Central Hospital of Funchal, in Portugal, several substances can assist in the onset of rhabdomyolysis.

Statins, like Simvastatin , Atorvastatin and Rosuvastatin , are drugs used by a significant portion of the population in order to reduce cholesterol. However, it is also the substance that causes the most rhabdomyolysis among cases related to the use of chemical substances.

Mostly, there is muscle weakness and pain along with the increase in creatinine- phosphokinase rates (an enzyme present in several tissues, but mainly in muscle, with the function of storing creatine phosphate and producing ATP).

Hypotheses are raised about how statins cause muscle damage. Although many authors and doctors admit the relationship between the use of some drugs and the induction of rhabdomyolysis, the causes are still debated and remain inconclusive.

It is estimated that fatal cases of rhabdomyolysis caused by statins are up to 3 cases per 1 million diagnoses.

Other substances capable of triggering the disease are:

  • HMG CoA reductase inhibitors : generally used to lower cholesterol;
  • Fibrates : usually used to control triglycerides;
  • Antihistamines : antiallergics;
  • Salicylates : normally used for pain, fever and inflammation;
  • Caffeine ;
  • Neuroleptics : tranquilizers usually used in cases of schizophrenia and mania;
  • Anesthetics : if the patient is predisposed to malignant hyperthermia (sensitivity to the use of anesthetics and muscle relaxants);
  • Amphotericin B : antibiotic;
  • Corticosteroids ;
  • Theophylline : antiasthmatic used in respiratory diseases;
  • Tricyclic antidepressants ;
  • Aminocaproic acid : used in surgical powders or hemorrhagic cases.

Electrolytic changes

Deregulations of potassium, phosphate and sodium in the body can cause or trigger rhabdomyolysis.

When phosphate levels in the body are below normal, the condition is called hypophosphatemia , which can be triggered by vitamin D deficiency and kidney problems, for example.

In general, the withdrawal of the substance is more associated with rhabdomyolysis if the patient frequently consumes alcohol or has an external muscle injury (for example, a fall or an exaggerated effort capable of hurting the muscle).

Already hypokalemia refers to the reduction of potassium in the blood. The condition is usually caused by vomiting, diarrhea or excessive elimination of potassium from the urine.

The first signs of potassium deficiency are manifested through muscle weakness, cramps and altered heart rhythm.

The symptom of muscle weakness is caused by a lack of oxygen in the tissue. With little oxygen supply, the chances of injuries occurring during physical activity are increased.

In addition, imbalanced sodium also poses a risk to rhabdomyolysis. The condition is called hyponatremia and is characterized when the body retains too much fluid and reduces blood sodium levels.

These changes cause blood dysregulation and affect the supply of nutrients and oxygen to the muscles, favoring injuries and providing rhabdomyolysis.

Infection in rhabdomyolysis

The diagnoses made in children are more associated with infections, which can be prevented by viruses, bacteria, fungi or other parasites. But the incidence in adults is also high.

By April 2018, Brazil had registered 286 cases of influenza and 41 deaths. But what does the flu virus have to do with rhabdomyolysis?

The influenza A and B viruses, in addition to being responsible for major pandemics, including a recent one, in 2009, are also one of the most frequent causes of infectious rhabdomyolysis.

This is because the virus infects muscle tissue and can form myotoxins in it, causing muscle destruction. There is then the release of intracellular content into the bloodstream.

Infections caused by bacteria, on the other hand, can act in two ways: directly affecting the muscles (by the action of the bacteria, or causing responses in the body (for example, promoting the production of toxins that affect the muscles).

The most common bacterial infections to rhabdomyolysis are:

  • Legionella Pneumophila is a bacteria that causes Legionnaires’ Disease , a serious respiratory infection that can lead to death.
  • The Streptococcus bacterium has several species and can cause various diseases, including pharyngitis, meningitis, sinusitis, adrenal diseases and pneumonia, for example.
  • The salmonella is more associated with eggs, but may be present in chicken as well. Associated symptoms are diarrhea, vomiting and nausea.

There is also the bacterium Francisella tularensis , which causes tularemia, popularly called rabbit fever . Transmission occurs through ticks and can cause sore throat , abdominal pain, diarrhea, vomiting, coughing and breathing difficulties.

Groups of risk

Although rhabdomyolysis is not common, studies have shown an increase in recent rhabdomyolysis cases.

This increase can be attributed, among other factors, to the popularization of high intensity physical activities, especially in gym classes.

Students are not always conditioned to demand so much from their muscles. Without a moderate start and a gradual increase in exercise, injuries are favored, which can lead to rhabdomyolysis.

Some aspects that can favor the disease are:

  • Athletes who perform activities under the sun;
  • Practitioners of physical activities that consume alcohol and other drugs;
  • Workers exposed to the sun;
  • Beginners in physical activities;
  • People who demand too much of the body without proper professional monitoring;
  • Athletes or sportsmen who maintain poor nutrition and hydration;
  • People and athletes who suffer a muscle injury and do not respect the recovery time.


The most frequent signs and symptoms of rhabdomyolysis are muscle pain (myalgia), reduction or loss of muscle strength (asthenia) and the dark color of the urine (caused by the presence of myoglobin in the urine).

Muscle pain is not always present, but it usually affects the thighs, shoulders and buttock muscles.

In general, muscle weakness and fatigue, nausea, tachycardia and mental confusion can appear when muscle damage gets worse.

How is the diagnosis made?

Clinical symptoms, such as pain in the muscles and darkened urine, are factors indicative of rhabdomyolysis.

In cases where there is trauma, muscle injuries or bruises, the doctor can perform a physical test to assess the sensitivity of the region. However, the diagnosis is confirmed through laboratory tests.

The medical professionals most suitable for diagnosis and treatment are the general practitioner, general surgeon and orthopedist , in addition to specialists in traumatology and physiotherapists.


Although clinical observation involves some well-marked symptoms, such as the dark color of urine and muscle pain, it is necessary to confirm the diagnosis with laboratory tests.

Serum creatine phosphokinase (CK)

The test takes a blood sample and analyzes the concentrations of creatine phosphokinase, which is an enzyme used in muscle functions.

The test is very specific to diagnose muscle injuries, because after any type of damage to the muscles occurs, the levels of creatine kinase are high in the blood.

CK rates rise between 12 and 24 hours after an injury to muscle tissue occurs. In general, peak levels of the substance usually occur until the third day.

Aldolase and carbonic anhydrase

When the creatine phosphokinase test is very high, aldolase and carbonic anhydrase help to compose the interpretation of the results. If the results are high, there are strong indications of muscle breakdown or injury.

Serum and urinary myoglobin

The measurement of myoglobin can be done on blood (serum) or urine samples, using traditional collections.

However, the urine test may not specify myoglobin, hemoglobin or erythrocytes in the blood, which makes the test less specific for rhabdomyolysis.

If the test takes a few days to complete, myoglobin may have established itself again, because if the kidneys are not compromised, there is usually a rapid filtering of the blood and elimination of the substance in the urine.

Other complementary exams

Toxicological tests may also be ordered by the doctor to detect the consumption of drugs or medications that favor rhabdomyolysis, muscle biopsy, potassium, calcium and sodium levels, in addition to tests that analyze renal and cardiac sufficiency.

Is there a cure?

-Yeah . The condition, in most cases, develops well and does not result in complications.

Cases that put the patient’s life at risk are uncommon and are usually associated with other aggravating behaviors, such as the use of drugs or infectious conditions.


In general, the condition is treated in order to stabilize the patient through hospitalization.

Therapeutic intervention depends on the patient’s condition. But intravenous serums are usually given to hydrate the body.

If it is not of apparent cause (such as muscle injuries), it is necessary to investigate the cause of rhabdomyolysis, as it may involve unknown orthopedic disorders that compress the blood circulation.

Treatment follows with:

Hydration and fluid replacement

Hydration is the most immediate measure of treatment, followed by the verification and correction of electrolyte disturbances, such as potassium, calcium and sodium.

If the patient has a reduction in urine production, hydration should be intensified, up to 1.5 liters of serum per hour may be applied.

The serum assists in the work of renal filtration, making the organ to eliminate irregular substances from the blood more quickly, such as myoglobin.

As there is a tendency for the patient to be accumulating fluid, the use of diuretics may be necessary.


Complications involving kidney involvement are more serious and may require more intensive therapy, using hemodialysis treatment.

Therapy is to cleanse the blood and stabilize the body’s rates. For this, the patient’s blood is sent to a machine that acts as an external kidney. When you do the blood filtration, immediately, the blood returns to the body.

In general, therapy is temporary, but it may be necessary to prolong sessions due to injuries and kidney failure.


Serum to intensely hydrate the body is the main medication used. Some cases require medicines based on sodium bicarbonate and diuretics.

When uric acid production is high, allopurinol can be administered in order to stabilize the condition.

If urine is reduced, it may be necessary to induce diuresis using mannitol , a medicine that stimulates urine production.

There are debates about the efficacy of the use of mannitol-type diuretics as therapy, and, before, the substance was widely used as a diuretic when poisoning occurred. Currently, it is suggested that the intervention can reduce the cases of chronic insufficiency in some cases of rhabdomyolysis, benefiting the patient.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Living together

In general, rhabdomyolysis progresses well if it is diagnosed and treated quickly.

As the syndrome may be the result of an injury, the patient may proceed with pain and movement difficulties. Therefore, doing physiotherapy and rehabilitation sessions help to reduce pain and bring more well-being.

The measure only aims to recover muscle tissue, without impacting the complications of the disease.

When the kidneys are compromised, changes in diet can reduce the impacts on the body. Consultation with the nutritionist is indicated in order to establish an adequate eating plan and indications about the consumption of liquids.

The adoption of less impacting physical activities can also be effective after rhabdomyolysis. Among them, stretching, yoga, pilates and relaxation classes .


If there are no complications, rhabdomyolysis is quickly eased. In a few days or weeks the symptoms and organ dysfunctions reduce and disappear.

Renal functions are reestablished in most patients who have had some level of kidney failure or injury. Even when hemodialysis sessions are prescribed, therapy can usually be stopped in a few weeks.


In April 2015, the Brazilian Army recorded the death of an 18-year-old recruit in the state of Ceará.

The suspicion that the young man died of rhabdomyolysis was confirmed and generated a debate about the physical demands of the soldiers, who are often not prepared for such intensive training.

The reports pointed out that the recruit was ill, had extreme fatigue and even then he was forced to continue the exercises, which would have aggravated the condition and generated rhabdomyolysis.

When he was seen, the patient already had internal bleeding and kidney failure, causing his death after a few days.

Therefore, the syndrome when left untreated can progress to severe kidney damage and cause death.

Complications can involve:

Renal injury and failure (ARI)

Acute Renal Insufficiency (AKI) is the most serious complication, occurring in about 15% of patients. It is usually the main cause associated with mortality.

Kidney complications occur due to the concentration of myoglobin in the organ, more specifically in the renal tubules. The incidence of death is 20% in patients who have AKI and already have antecedent or associated diseases, such as immunological diseases.

Complementary studies pointed out that, in order to have some kidney damage, in addition to the high concentration of myoglobins, it is necessary that the body is dehydrated and there is an increase in potassium, creatinine or phosphate in the blood.

Cardiac arrest

High concentrations of potassium and calcium can result in various damage to cells. In the heart, changing substances can cause arrhythmias and even lead to cardiac arrest.

Intravascular coagulation

Rhabdomyolysis can cause changes in the behavior of the substances responsible for coagulation, causing the formation of small clots in any part of the body.

These clots end up interfering with blood flow and reduce the supply of oxygen to the tissues.

If the affected organ is vital, such as the heart, intravascular coagulation can be life-threatening.

Compartment syndrome

The cases are more associated with direct muscle injuries caused by trauma or intense effort. In this case, the risks to life are high after 6 hours after rhabdomyolysis begins.

The compartment syndrome occurs when there is an increase in the pressure exerted inside the muscle, which causes the worsening of muscle damage.

Then there is a situation of cyclical cause and effect, where the pressure causes the death of the muscle tissue, which tends to accumulate more fluids and to increase the pressure.

The condition is alleviated or resolved with surgery to decompress the region. However, the risks of infection are high and the cases must be analyzed by the doctor.

How to prevent?

The causes of rhabdomyolysis are diverse and generally associated with multiple factors. That is, the condition needs conditions that favor its triggering. Which can make prevention more difficult.

But, in general, it is possible to reduce the risks with the adoption of measures. Check out:

  • Hydrate yourself correctly, especially during physical exercises;
  • Avoid practicing physical activities in very hot or very cold places, including activities in the sun;
  • Eat properly, avoiding nutritional deficiencies;
  • Reduce the consumption of alcohol and other drugs;
  • Increase the exercises or change the modalities gradually;
  • Respect the body’s signals, avoiding extreme fatigue;
  • Take breaks for your muscles to recover properly.

In addition, it is necessary that all physical activity is indicated and evaluated by a physical education professional  who will determine the intensity and exercise routine according to your ability.

Rabdomiólise e Crossfit

Although it occurs infrequently, Crossfit can cause rhabdomyolysis, just like any other high-intensity sport or activity.

There is no way to separate the risks of muscle injury from sports, even if they are practiced with the accompaniment of sports professionals. The greatest example are athletes and players, who have the support of coaches, physiotherapists and orthopedists, and can still suffer injuries throughout their sports careers.

It is important to note that the monitoring of a qualified professional will reduce the risk of injury and that, in general, there are other associated factors that favor the damage to the musculature.

One of the great factors that associate rhabdomyolysis with crossfit is that, in the first years when the sport started to spread, there was little knowledge about the correct ways to be practiced, which occasionally caused injuries to some practitioners.

Currently, the correct professional monitoring during physical activity, with the practitioner respecting the physical limitations of his body, makes the risks of crossfit the same as other intensity activities.

Common questions

Why can dehydration cause rhabdomyolysis?

When performing physical activities in hot and humid environments, the body tends to sweat more to maintain body temperature. However, this sweat favors an electrolyte imbalance (potassium, calcium and sodium), favoring muscle damage.

Are older sportspeople more at risk?

Age is not a direct factor in the occurrence of rhabdomyolysis. However, if the person uses drugs, such as statins, the risks are high. That is, it is the use of medications that aggravates the chances of the disease.

Why does the urine get dark?

Myoglobin is considered a pigment, being responsible for the reddish color of the muscles.

When rhabdomyolysis occurs, there is a high release of myoglobin in the blood.

The kidneys filter the blood and eliminate the substances through the urine. Therefore, the coloring tends to become more accentuated.


Rhabdomyolysis in horses

The syndrome is quite common in horses. The condition is also called Monday’s disease.

The animals most affected are those of breed and high commercial value or that exercise less frequently.

Thus, in the same way that humans are injured because they are not conditioned to the activities and physical efforts required in the activity, the affected horses usually do not have frequent rhythms of exercises and training.

So, when they are subjected to the most intense activities, usually in specific competitions or weekends, the marked effort causes muscle damage.

The process develops in the same way as in humans, with the release of hemoglobin into the bloodstream, usually affecting the kidneys.

Historical reference

The syndrome is quite old and has been reported for years. In the Bible there is reference to rhabdomyolysis, when the Hebrew people were affected by a plague.

According to the analyzes, the condition was caused because the people consumed the quail bird. The bird feeds on hemlock, a plant that does no harm to the animal, but to humans it is highly toxic.

In addition, reports from the First World War point to the possible occurrence of rhabdomyolysis. The soldiers, who suffered crushing and physical trauma, had kidney failure and usually died after 1 week.

With the recent growth in classes and high-intensity exercise modalities, studies on rhabdomyolysis associated with sport have also grown.

Physical activities are essential to maintain health and assist in the proper functioning of the body. But it is necessary that they are planned and monitored by physical education professionals or physiotherapists, in order to avoid injuries.

Although there are other triggering factors, the correct performance and progressive evolution of activities can prevent damage to muscles of any intensity, also reducing the possibility of rhabdomyolysis.

To learn more about health and organic functioning, keep an eye on the Healthy Minute!