What Is Rhabdomyolysis: Symptoms, Causes, Diagnosis, and Treatment

Introduction

Rhabdomyolysis is a complex medical condition that involves a rapid destruction of the skeletal muscle tissues along with the release of muscle proteins and other muscle cell contents to leak outside of the cells and into the bloodstream. This leakage includes the following muscle constituents:

• Electrolytes
• Creatine kinase (CK)
• Myoglobin
• Lactate dehydrogenase
• Aldolase

A classic characteristic of rhabdomyolysis is an increase of free ionized calcium within the cells. According to research, this trait is triggered by energy depletion and direct rupture of the plasma membrane. An increase in the level of calcium in the cells leads to cellular side effects, such as abnormal levels of reactive oxygen species and mitochondrial dysfunction, which eventually lead to muscle death. 

The effects of rhabdomyolysis tend to vary in people. Some may be asymptomatic (without symptoms) but with high levels of creatine kinase, while others may experience serious and life-threatening symptoms that are associated with high creatine kinase levels, acute renal failure, electrolyte imbalance, or blood clots throughout the bloodstream. 

To help diagnose this serious syndrome, doctors usually order certain laboratory tests to look for excessive levels of creatine phosphokinase and myoglobin along with a combination of the patient's clinical symptoms. The levels of CK in people with rhabdomyolysis may vary. However, CK levels that are above 5,000 U/L usually indicate a serious muscle injury. To compare, the normal range of CK is within 45-260 U/L.  

Symptoms

The symptoms of rhabdomyolysis may sometimes depend on the cause of rhabdomyolysis. However, the following signs and symptoms are some of the common indicators of the condition:

• Muscle tenderness
• Bruising
• Limb pain (about 50 percent of rhabdomyolysis cases)
• Swelling
• Fever
• Weakness
• Confusion
• Agitation
• Nausea
• Vomiting
• Arrhythmia (irregular heartbeat)
• Dark urine (brown, cola, or tea-colored urine)
• Oliguria (decreased urine output)
• Anuria (absence of urine)

Causes

Rhabdomyolysis is usually triggered by muscle damage or injury, which can be due to chemical, physical, or genetic causes. Although there can be different causes of rhabdomyolysis, its most common causes are:

• Crush injuries (injuries after natural disasters, vehicular accidents)
• Strenuous or vigorous exercises
• Certain medications
• Alcohol and/or drug abuse 

The physical causes of rhabdomyolysis include:

• Crush injuries
• Lightning strike
• Immobilization
• Overexertion injuries in untrained athletes
• Intense exercise (marathon running, long-distance cycling)
• Heat-related illnesses (heat stroke, heat cramps, heat exhaustion)
• Malignant hyperthermia (MH)
• Neuroleptic malignant syndrome (NMS)
• Third-degree burn (extensive)
• Ischemic causes or ischemic limb injury
• Pathological muscle exertion
• Exertional causes
• Overexertion in people who have sickle cell disease

Other possible causes may include:

• Genetic Disorders - Duchenne muscular dystrophy, McArdle’s disease, carnitine deficiency, and lactate dehydrogenase deficiency.

• Metabolic Disorders - Electrolyte imbalances, hypothyroidism, and diabetic ketoacidosis.

• Infections and Inflammation - Bacterial or viral infections, dermatomyositis, and polymyositis.

• Recreational Drugs and Toxins - Alcohol, cocaine, heroin, amphetamines, (MDMA) ecstasy, LSD, heavy metals, and venom from snakes or insects. 

• Medications - Cyclosporine, erythromycin, colchicine, and statins (atorvastatin, pravastatin, rosuvastatin).

Aside from the causes listed above, there are still many other potential causes of rhabdomyolysis. 

Diagnosis

The doctor will initially examine the large skeletal muscles in the patient's body, particularly those that are painful. Other laboratory tests, such as blood and urine tests, may also be performed to confirm the diagnosis. 

Determining the levels of the following substances can help determine the health of the muscles and kidneys:

• Creatine Kinase - An enzyme that is found in the brain, heart, skeletal muscles, and other tissues. 

• Creatinine (in blood and urine) - It is a waste product from the breakdown of muscle tissues. High levels of creatinine usually indicate kidney damage or renal disease.  

• Myoglobin (in blood and urine) - A protein and a muscle breakdown product. 

• Potassium - A mineral that can leak from injured muscles and bones. 

Increased levels of these substances can indicate signs of muscle injury or damage. 

Complications

There are two categories of rhabdomyolysis complications: early and late. 

Early Rhabdomyolysis Complications

• Cardiac arrest
• Heart arrhythmia
• Hepatic inflammation
• Hypocalcemia
• Hyperkalemia

Late Rhabdomyolysis Complications

• Acute kidney failure
• Disseminated intravascular coagulation (DIC)
• Compartment syndrome

Treatment

When rhabdomyolysis is early diagnosed and treated, a full recovery is expected. Kidney damage can even be reversed by doctors. However, there can be permanent damage if compartment syndrome is left untreated or not promptly treated. 

• Intravenous (IV) Fluids - People with rhabdomyolysis are often admitted to the hospital for treatment, which includes intravenous fluids to help prevent kidney failure and maintain the production of urine. 

• Dialysis - In rare cases, dialysis may be required to help the kidneys filter waste out of the blood. 

• Management of Calcium, Potassium, and Phosphorus Levels - Prompt management of electrolyte imbalances can help protect the organs in the body. 

• Fasciotomy - This is a surgical procedure performed to help relieve pressure, tension, and poor circulation, especially when there is potential nerve damage or muscle damage due to compartment syndrome. 

The causes of rhabdomyolysis are often reversible, but in some cases, patients may need close monitoring in the intensive care unit (ICU). 

Prevention

• Strenuous activities or workouts should not be performed during hot weather unless you become accustomed to it. 
• Avoid full-gear workouts when the weather is hot. 
• Take proper rest and hydration when training. 
• Aside from drinking water, electrolyte-rich drinks can be consumed as well. 
• Get regular CK tests if you take statin drugs. 
• Consume more foods that help lower cholesterol levels. 
• Eat foods that contain enough sodium to prevent hyponatremia (low sodium level). 

See a doctor if you think you are sick or have an infection. Muscle damage that may lead to rhabdomyolysis can be prevented if the illness is addressed right away. 

Precautions

People who train hard or exercise for the first time in hot weather should take extra precautions by understanding the risk factors of rhabdomyolysis, including its causes and symptoms. 

Symptoms of rhabdomyolysis should be taken seriously and may need an ER visit. Although rhabdomyolysis is a serious syndrome, a rapid identification and prompt treatment usually help in a faster recovery without any long-term damage. 

The early complications of rhabdomyolysis may involve severe hyperkalemia, which can trigger a cardiac arrest. The most serious late complication of rhabdomyolysis is acute kidney failure, which occurs in approximately 15 percent of people with rhabdomyolysis.