I was sent to the ICU after running a marathon. It was not sudden death, but muscle dissolution!

Author: Zhang Guoqiang, Chief Physician of China-Japan Friendship Hospital

Chairman-elect of the Emergency Medicine Branch of the Chinese Medical Association

Reviewer: Wang Lixiang, Chief Physician, Third Medical Center, PLA General Hospital

I often hear news reports that some people ended up in the ICU after running marathons.

It is because of strenuous exercise that muscle cells necrosis occurs and rhabdomyolysis syndrome occurs.

Can muscles still dissolve?

Let’s learn more about the disease rhabdomyolysis syndrome.

1. What is rhabdomyolysis syndrome?

First, let’s understand what striated muscle is and where it exists in the body.

Motor muscles and skeletal muscles are called striated muscles.

Figure 1 Original copyright image, no permission to reprint

Rhabdomyolysis syndrome occurs when the cell membrane structure of skeletal muscle is destroyed. Many components within the cell, such as myoglobin, myosin, creatine kinase, and some small molecules, escape from the cell into the blood, causing the skeletal muscle to dissolve, leading to a series of clinical manifestations. This syndrome is called rhabdomyolysis syndrome.

The causes of rhabdomyolysis syndrome are divided into physical factors and non-physical factors.

Physical factors refer to long-term compression, squeezing, and overload exercise. Physical factors cause changes in the structure of cell membranes, leading to rhabdomyolysis;

Non-physical factors refer to certain diseases. Congenital diseases, such as creatine phosphorylase deficiency, and acquired diseases, such as diabetic ketoacidosis, thyroid dysfunction, electrolyte imbalance, high fever, and low body temperature, can all lead to rhabdomyolysis.

In addition, diet and medication may also cause rhabdomyolysis syndrome, such as eating some aquatic products; lipid-lowering drugs, β2 receptor agonists, anti-infection and antiviral drugs, and anti-psychotic drugs may all cause rhabdomyolysis.

2. What are the possible symptoms of rhabdomyolysis?

First, local muscle pain will occur.

After muscle dissolution, muscle function is affected, and you will feel weak and tired.

The color of urine changes. The myoglobin and myosin in the cells enter the blood and are excreted through the kidneys, resulting in brown urine. The appearance of brown urine may indicate damage to kidney function.

Figure 2 Original copyright image, no permission to reprint

The incidence of rhabdomyolysis syndrome itself is not very high, with more than 70% of patients suffering from mild symptoms. They may recover quickly after simple treatment. About 30% of patients will experience changes in urine color.

3. What are the dangers of rhabdomyolysis syndrome?

After the striated muscle dissolves, myoglobin and myosin escape from the cells into the blood and must be excreted through the kidneys. Because they are large molecules, they may cause blockage of the renal tubules, acute renal failure, and renal insufficiency.

After small molecules come out of cells, they may cause a series of reactions in the body, leading to failure of other organs, shock, and even death. For example, the potassium ion concentration inside cells is higher than outside cells. A large amount of potassium ions inside cells enter the blood, leading to hyperkalemia, which is fatal and can directly lead to cardiac arrest, which is relatively rare.

After rhabdomyolysis syndrome occurs, the first thing to pay attention to is kidney function; the second is to pay attention to circulation problems, whether there is shock, and whether there is coagulation dysfunction; the third is to pay attention to blood potassium.

If you experience muscle pain, weakness, or changes in urine color, you should be highly alert to rhabdomyolysis and go to the hospital immediately. The doctor will do some related tests based on the medical history, such as creatine kinase test. If the creatine kinase is very high, 5 times higher than the normal value, it indicates that the muscle cells are damaged. If myoglobin is found in the blood and urine, it can be confirmed that it is rhabdomyolysis.

After the diagnosis is confirmed, the cause should be found to facilitate treatment.

4. How to treat rhabdomyolysis syndrome?

If there is a clear inducement, the first choice is to remove the inducement.

For example, if it is caused by running, you must not do strenuous exercise anymore; if it is caused by taking medicine, you must stop taking the medicine; if it is caused by eating seafood, you must stop eating it; if it is caused by high fever, you must receive cooling treatment; if it is caused by hypothermia, you must perform rewarming to raise the body temperature; if it is caused by electrolyte imbalance, it is very important to adjust the electrolytes.

The cell membrane structure of muscle cells is destroyed, and the substances in the cells enter the blood. How can they be discharged?

First, drink plenty of water. Drink as much water as your heart can bear, and excrete it through the kidneys in the urine. Do not drink too much water during the anuria and oliguria period, because the kidneys cannot excrete it after drinking, which increases the burden on the heart.

Figure 3 Original copyright image, no permission to reprint

Second, alkalize the urine, which also helps excretion. Oral or intravenous sodium bicarbonate, or drinking baking soda water can also help;

Third, blood purification is the ultimate trump card. If the above methods cannot solve the problem, kidney function deteriorates and enters the oliguria stage, blood purification may be necessary, that is, dialysis, which helps excretion and is also helpful for regulating the internal environment.

Is there any drug that can treat rhabdomyolysis?

There is currently no drug to treat rhabdomyolysis syndrome. The main thing is to remove the cause, expel the substances that flow out of the cells, and deal with possible complications.

How long does it usually take to treat rhabdomyolysis?

Mild cases of rhabdomyolysis syndrome can be completely cured within a week; if it affects kidney function, it may take 1-3 months to cure, so the treatment time depends on the severity of the disease.

If rhabdomyolysis syndrome is not caused by congenital disease factors, it is generally curable. If treated in a timely and proper manner, there will be no sequelae.