What Is Rhabdomyolysis?
Picture of muscle injury with rhabdomyolysis
Rhabdomyolysis is a condition that may occur when muscle tissue is damaged due to an injury in which muscle in the body is damaged (rhabdomyo=skeletal muscle + lysis= rapid breakdown).
There are three types of muscle in the body, including:
- skeletal muscles that move the body;
- cardiac muscle located in the heart; and
- smooth muscle that lines blood vessels, gastrointestinal tract, bronchi in the lung, and the bladder and uterus. This type of muscle is not under conscious control.
Rhabdomyolysis occurs when there is damage to the skeletal muscle.
- The injured muscle cell leaks myoglobin (a protein) into the bloodstream. Myoglobin can be directly toxic to kidney cells, and it can impair and clog the filtration system of the kidney. Both mechanisms can lead to kidney failure (the major complication of rhabdomyolysis).
- Significant muscle injury can cause fluid and electrolyte shifts from the bloodstream into the damaged muscle cells, and in the other direction (from the damaged muscle cells into the bloodstream). As a result, dehydration may occur. Elevated levels of potassium in the bloodstream (hyperkalemia) may be associated with heart rhythm disturbances and sudden cardiac death due to ventricular tachycardia and ventricular fibrillation.
Complications of rhabdomyolysis also include disseminated intravascular coagulation, a condition that occurs when small blood clots begin forming in the body's blood vessels. These clots consume all the clotting factors and platelets in the body, and bleeding begins to occur spontaneously.
- When muscles are damaged, especially due to a crush injury, swelling within the muscle can occur, causing compartment syndrome. If this occurs in an area where the muscle is bound by fascia (a tough fibrous tissue membrane), the pressure inside the muscle compartment can increase to the point at which blood supply to the muscle is compromised and muscle cells begin to die.
- Rhabdomyolysis was first appreciated as a significant complication from crush and blast injuries sustained in a volcano eruption in Italy, in 1908. Victims of the blast injuries during the first and second World Wars help further understand the relationship between massive muscle damage and kidney failure.
The most common symptoms of rhabdomyolysis include:
- muscle weakness;
- muscle aches; and
- dark urine.
The muscle damage causes inflammation leading to tenderness, swelling, and weakness of the affected muscles. The dark urine color is due to myoglobin being excreted in the urine. Some affected individuals describe this as blood in the urine, but when it is examined under a microscope, no red blood cells are seen.
Symptoms related to the expected complications of rhabdomyolysis include:
- symptoms of kidney failure, which may include swelling of the hands and feet;
- decreased urine production;
- shortness of breath as excess fluid builds up in the lungs;
- symptoms of hyperkalemia (weakness,nausea,lightheadedness, andpalpitations due to heart rhythm disturbances); and
- disseminated intravascular coagulation may present as unexplained bleeding (as previously discussed).
In children, renal failure and disseminated intravascular coagulation are less common. The symptoms are primarily muscle aches and weakness.
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How Does Rhabdomyolysis Occur?
Some common causes of the muscle damage due to rhabdomyolysis include:
- Major blunt trauma and crush injury
- Lightening strikes
- Major burns
- Prolonged immobilization (for example, patients who have been lying in one position for a prolonged period of time due to a debilitatingstroke, alcohol ordrug overdose, or those who have remained unconscious for a prolonged period of time for other reasons). The weight of the body is enough to crush the muscles that are pushed up against a hard surface such as the floor.
- Excessive exercise, for example, running a marathon or excessive weight lifting
- Patients in status epilepticus, in which the seizure lasts for a prolonged period of time and muscles involuntarily contract
- Dystonic reactions cause muscles to spasm, and if left untreated can damage muscle
- Cholesterol lowering medications [for example, statins prescribed to treat high cholesterol (particularly when combined with other cholesterol lowering medications such as fibrates)]
- Antidepressant medications [for example selective serotonin reuptake inhibitors (SSRIs) antidepressants may cause a serotonin syndrome characterized by agitation,fever, and muscle spasm]
- Some anesthetics can cause malignant hyperthermia syndrome with high fever and muscle rigidity
- A variety of drugs of abuse [for example, cocaine, heroin, phencyclidine (PCP), and amphetamines]
- Hyperthermia and hypothermia (high and low body temperature, respectively)
- Complications from a variety of infections caused by bacteria, viruses, and fungi
- Association with other diseases such assickle cell disease, polymyositis, and dermatomyositis
- Complications from the venom from snake bites and black widow spider bites.
When Should I Call the Doctor about Rhabdomyolosis?
Rhabdomyolysis is often seen as a complication of a major medical event such as trauma or other illness. It is usually recognized by the health care practitioner during evaluation and treatment of the patient.
- For example, a patient who suffers electrocution is expected to develop rhabdomyolysis, and care will be taken to monitor and potentially minimize the complications of muscle breakdown. Similarly, a patient who has been immobile on the floor for many hours after sustaining a stroke is at risk for rhabdomyolysis, and diagnostic tests for this potential complication are often performed.
- In some situations, it is important for the individual to seek medical care if symptoms of muscle weakness and dark urine occur. These symptoms may occur due to prolonged exercise such as running a marathon or excessive weight lifting.
- Patients taking medications such as statins and fibrates for cholesterol control should be aware that unexplained spontaneous muscle pain or dark urine, both symptoms of rhabdomyolysis, should be a signal that medical care should be accessed.
How Do You Test for Rhabdomyolysis?
The evaluation of rhabdomyolysis begins with the history and physical examination of the patient. The health care practitioner will assess the underlying potential causes for muscle breakdown. Sometimes it is obvious; the patient is a trauma victim. Sometimes it will require detailed information gathering about the patient such as any underlying medical conditions and medication history.
- The physical examination will not only focus on muscle injury but also on the potential complications of kidney failure and hyperkalemia with associatedheart rhythm disturbances.
- Blood tests may include a complete blood count and clotting profile, electrolytes, kidney function (BUN and creatinine), and creatine phosphokinase (CPK), a chemical found in muscle that is also released into the blood stream with muscle damage. Markedly elevated levels of CPK in the appropriate clinical setting confirms the diagnosis.
- Urinalysis may be helpful. Myoglobin can be presumed to be present in the urine if the chemical test for blood in the urine is positive but no red blood cells are seen on microscopic examination.
How Can I Treat Rhabdomyolysis at Home?
If rhabdomyolysis is suspected, early medical evaluation is required. It is important for the patient, their family, or caregivers, to recognize the potential that the disease exists, and seek urgent medical care.
If the case is mild, home treatment may include rest and adequate hydration, along with rehydrating by plenty of drinking fluids.
What Is the Medical Treatment Rhabdomyolysis?
- Rhabdomyolysis may result in life-threatening complications, and all of the potential complications need to be considered during medical care.
- For many patients, treatment for muscle breakdown begins in the pre-hospital situation where an emergency medical technician or paramedic recognizes the potential for muscle injury. Intravenous infusion of large amounts of saline fluid helps increase the glomerular filtration rate, or the amount of fluid that is being pushed through the filters located in the kidney. The goal of increased fluid flow is to dilute toxins, such as myoglobin, that may clog and damage the filtering system of the kidney.
- In addition, the pre-hospital personnel will consider heart monitoring to evaluate for evidence of hyperkalemia, which can lead to heart rhythm disturbances and sudden cardiac death.
- Treatment in the emergency department will continue the pre-hospital care. There is also a need to be concerned about evaluating and caring for the underlying problems that caused the rhabdomyolysis to occur.
- Prevention of kidney failure is one of the primary focuses of acute care. Fluid, medication, and potentially dialysis may required to help support kidney function while the circulating myoglobin proteins are cleared from the body.
- Hyperkalemia therapy includes monitoring the patient's electrocardiogram (EKG), exploring any abnormalities that may predict potentially fatal heart rhythms such as ventricular tachycardia and ventricular fibrillation. Medications may be used to shift potassium out of the bloodstream and eventually out of the body through the urine.
- Disseminated intravascular coagulation is another complication of rhabdomyolysis and may require transfusion of blood clotting products. These may include fresh frozen plasma, cryoprecipitate, and platelets.
- Patients who develop complications of rhabdomyolysis often require hospitalization and monitoring. Specialist consultations are considered based upon the patient's status. A nephrologist (kidney specialist) may be needed to advise in regard to the need for dialysis. An orthopedic surgeon may be asked to help if the diagnosis of compartment syndrome is a possibility.
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What Are the Medications for Rhabdomyolysis?
The goal of treatment to prevent kidney damage is to maximize the amount of fluid flowing through the nephrons and glomeruli in the kidney, in effect, trying to wash out the myoglobin fibers that can clog the filters of the kidney. The effect is to increase urine output, which can be measured and monitored.
- Diuretic medications, such as furosemide (Lasix) may be given intravenously to promote urine output. This may be used even if the patient is somewhat dehydrated, but close observation of the patient's vital signs, including blood pressure and pulse rate, is necessary.
- If the vital signs are stable, mannitol may also be injected intravenously to increase blood flow to the kidney and increase urine output.
- Sodium bicarbonate may be added to the intravenous saline solution to change the acid-base balance of the urine.
- Muscle injury may be extremely painful, and narcotic pain medications may be needed to control symptoms.
What Is the Follow-up for Rhabdomyolysis?
Creatinine kinase levels in the blood stream tend to peak within 24 hours after injury, and patients are typically monitored until these levels return closer to the normal range.
Potassium levels peak within a few hours of muscle damage, but if there is associated kidney impairment, the ability of the body to clear excess potassium into the urine is also impaired. If dialysis is not required, the patient will need to be monitored until potassium levels return to the normal range.
The cause for rhabdomyolysis will need to be addressed and corrected. Follow-up will depend upon the underlying condition.
How Can I Prevent Rhabdomyolysis?
The risk of rhabdomyolysis exists for patients taking statin and fibrate medications for high cholesterol control. Information is often provided to these patients to be aware of the symptoms of rhabdomyolysis.
Exercise programs and routines need to be thoughtfully planned to prevent rhabdomyolysis. This includes avoiding exercising in extreme heat conditions and drinking adequate fluids. Both these situations can lead to dehydration, which increases the risk of muscle damage.
Is Rhabdomyolysis Life Threatening?
Rhabdomyolysis is the cause for a significant percentage of patients with kidney failure. While the mortality rate for this disease is approximately 5%, the risk of death depends the underlying health of the patient, the amount of muscle damage and other associated injuries. If kidney failure occurs, the mortality rate can increase significantly.
Complications of muscle breakdown can be minimized by early recognition of rhabdomyolysis and medical intervention that may include aggressive intravenous fluid hydration.