Rhabdomyolysis - not far from us

Author: Wang Yanying China Rehabilitation Research Center

Reviewer: Liu Huizhen, deputy chief physician of China Rehabilitation Research Center

In modern society, people are busy with work and fast-paced life. Lack of physical exercise is a common phenomenon, so most people choose to exercise intensively in their spare time. It was reported that a woman sat for a long time at work, and after getting home from get off work, she watched fitness videos and did aerobics for exercise. A few days later, she had sore limbs. At first, she thought it was caused by fatigue from exercise, and thought it would be fine in a few days, but the back pain became more and more severe, and the color of urine also turned into strong tea color, accompanied by dizziness, fatigue, and nausea, so she went to the doctor urgently. After the hospital inquired about the medical history in detail and completed relevant laboratory tests, it was found that many blood biochemical indicators were red, and she was diagnosed with rhabdomyolysis. Because of the combination of acute renal insufficiency, she was urgently admitted to the intensive care unit for intensive care and treatment. There are many similar cases in the clinic... Rhabdomyolysis is not far from us. If we understand its cause, it can be avoided in most cases. Today we will take a deeper look at the knowledge of prevention and treatment of rhabdomyolysis.

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1. What is rhabdomyolysis?

First, let's take a look at the classification of human muscles. Human muscles are divided into three types: smooth muscle, cardiac muscle, and skeletal muscle. Because there are stripes on the surface of cardiac muscle and skeletal muscle, they are called striated muscles. Rhabdomyolysis refers to the dissolution of skeletal muscle.

Rhabdomyolysis syndrome refers to multiple factors that affect the membrane of skeletal muscle cells, membrane channels and their energy supply, damaging the integrity of the muscle cell membrane, causing the destruction and disintegration of skeletal muscle cells, and the leakage of cell contents (such as myoglobin, creatine kinase, lactate dehydrogenase and ions) into the blood circulation. This is why substances in muscle cells can be detected in the patient's blood. 15% to 40% of patients have acute renal failure, and severe cases are even life-threatening.

2. Why does striated muscle dissolve?

The causes of rhabdomyolysis are complex and diverse, and can be generally divided into two categories: physical and non-physical.

(1) Physical factors: including violent trauma or prolonged severe compression of muscles, excessive and strenuous exercise, electric shock (high voltage or lightning), high fever or severe hypothermia.

(2) Non-physical factors: A variety of drugs and poisons can induce rhabdomyolysis, such as statins, benzodiazepine sedatives, macrolide antibiotics, etc.; alcoholism; organophosphorus pesticides, insect venom, snake venom, and heavy metals. Electrolyte imbalance: such as hypokalemia, hypophosphatemia, and hyponatremia. Endocrine and genetic metabolic diseases: hyperthyroid crisis, diabetic ketoacidosis, pheochromocytoma, etc.; genetic metabolic diseases such as muscle phosphorylase deficiency. Viral or bacterial infection. Autoimmune diseases: polymyositis and dermatomyositis, etc.

3. How to determine whether rhabdomyolysis has occurred?

The typical "triad" of rhabdomyolysis includes myalgia, fatigue, and reddish-brown urine. Patients often experience muscle pain, swelling, weakness, and stiffness in the thighs, shoulders, lower back, and other parts of the body. They may also experience muscle cramps, which affect the normal movement of the arms and legs. The patient's urine color deepens and may be soy sauce-colored, dark red, or brown. The urine volume may also decrease or even be anuric. If it progresses to acute renal insufficiency, symptoms such as loss of appetite, nausea, vomiting, and drowsiness may occur. If disseminated intravascular coagulation occurs, there will also be symptoms such as bleeding, anemia, palpitations, dyspnea, chills, and high fever. If characteristic symptoms of rhabdomyolysis such as myalgia, fatigue, and reddish-brown urine occur after taking medication or exercising in daily life, you should seek medical attention immediately.

4. What tests are needed for rhabdomyolysis?

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If rhabdomyolysis is suspected, the following tests may be involved after visiting the hospital.

(1) Creatine kinase and its isoenzymes : Creatine kinase (CK) is the most sensitive indicator of muscle cell damage. It is not only used for diagnosis, but also reflects prognosis. CK>1000U/L indicates muscle damage; CK>20,000U/L indicates myoglobinuria. In addition, after rhabdomyolysis occurs, serum transaminases and lactate dehydrogenase, which reflect muscle damage, increase to varying degrees.

(2) Myoglobinemia and myoglobinuria : When muscles are damaged, a large amount of myoglobin is released into the blood. Myoglobin can be detected in the plasma, which is called myoglobinemia. When myoglobin is filtered into the urine through the glomerulus, the urine may turn dark red-brown, which is called myoglobinuria.

(3) Renal function and electrolytes : When patients suffer from acute renal injury, their serum creatinine, urea nitrogen, and uric acid levels increase, with creatinine increasing significantly. In addition, their serum potassium and phosphorus levels may increase, while their serum calcium levels may decrease.

(4) Routine blood and urine tests : Some patients have increased white blood cells, anemia or thrombocytopenia; urine occult blood is mostly positive, and pigment casts may be present. New positive urine protein indicates renal tubular damage.

(5) Muscle imaging examination : Ultrasound examination can show that the affected muscles have blurred or even disappeared muscle texture, enhanced or varying echo strength, and are often accompanied by abnormal blood flow signals. CT can show swelling of damaged muscles and thickening of fascia. Muscle magnetic resonance imaging can indicate abnormal muscle signals.

5. How to treat rhabdomyolysis?

1. Remove the trigger

Removing the cause as soon as possible is the first step in treating rhabdomyolysis. If it is caused by excessive exercise, you need to stop exercising immediately and ensure adequate rest. If the muscles are violently injured or severely squeezed, the muscle trauma and compression must be relieved as soon as possible. If a suspicious drug is taken, it is necessary to stop taking the drug immediately. If it is caused by an infection in the body, active anti-infection treatment is required. If it is caused by high fever, it should be cooled down immediately.

2. Correct hypovolemia and prevent acute renal failure

In terms of drug treatment, early intravenous infusion therapy, adequate fluid replacement, ensuring effective circulating blood volume and renal perfusion, and increasing glomerular filtration and urine output are crucial to preventing acute renal failure. The treatment goal is to ensure a urine output of at least 300 ml per hour. Urine alkalinization therapy, the use of sodium bicarbonate can alkalinize urine, increase the solubility of urinary myoglobin and uric acid, while limiting tubular myoglobin and urate crystals, inhibiting myoglobin degradation, and blocking its nephrotoxic effects; in addition, sodium bicarbonate can treat metabolic acidosis and hyperkalemia, and its treatment goal is to achieve a urine pH value of 6.5 or above. After hypovolemia is corrected and a satisfactory urine output is achieved, the patient can be given diuretic therapy. Correct electrolyte abnormalities: Monitor serum ion levels and actively correct abnormalities in blood potassium, blood phosphorus, and blood calcium.

3. Blood purification therapy

If the patient has acute renal failure, oliguria or anuria, difficult-to-correct hyperkalemia or refractory metabolic acidosis, blood purification treatment should be initiated promptly. Continuous blood filtration can remove metabolic wastes such as urea and creatinine and abnormally elevated potassium ions in the blood. It can also remove harmful substances such as myoglobin and inflammatory factors, making the body's internal environment stable. Plasma exchange can effectively remove creatine kinase and assist in the treatment of autoimmune diseases. It can also be combined with blood perfusion to enhance the adsorption of harmful substances.

4. Compartmental incision and decompression

Finally, if compartment syndrome occurs, immediate compartment incision and decompression should be performed to avoid further muscle necrosis.

6. What are the effective methods to prevent rhabdomyolysis?

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(1) Exercise within your ability and avoid long-term high-intensity exercise. It is recommended that you exercise and do physical exercise in a well-ventilated environment with appropriate temperature and humidity. Gradually increase the intensity and difficulty of exercise according to your body's adaptation, and avoid long-term high-intensity exercise. Exercise scientifically and reasonably!

(2) When taking drugs that may cause rhabdomyolysis, you need to go to the hospital regularly to monitor relevant indicators.

(3) Avoid continuous work under high temperatures. If you suffer from heat stroke, take timely measures to cool down and seek emergency medical attention.

(4) Avoid excessive drinking and be careful of accidents.

(5) If muscle injury or compression occurs, call for emergency help or seek medical attention.

In short, we must maintain a positive and good lifestyle, seek medical attention as soon as we find any discomfort, and avoid delaying the disease.