What is myolysis? Let’s take a look at its causes!

Many people are unfamiliar with the term myolysis. In terms of its symptoms, people with myolysis generally experience muscle pain, swelling, and weakness. When the disease occurs, they may also experience fever or symptoms of acute renal failure such as oliguria or anuria. The consequences of this disease are serious and can be diagnosed through regular blood tests, urine tests, muscle tests and electrocardiograms.

Causes of myolysis

The causes of rhabdomyosarcoma are very complex. Foreign studies have pointed out that there are more than 190 acquired causes and more than 40 genetic causes. Common causes include excessive exercise, muscle crush injury, ischemia, metabolic disorders (hypokalemia, hypothyroidism, diabetic ketoacidosis), extreme body temperature (high fever, low fever), drugs, poisons, autoimmunity, infection, etc. Common genetic factors include creatine phosphodiesterase deficiency, botulinum toxin acyltransferase II deficiency and other causes. The main pathophysiological mechanisms include ischemic damage and ATP depletion, impaired sarcoplasmic reticulum calcium regulation, hypokalemia, and tissue oxidative stress. Among them, the direct damage of myoglobin to the kidneys is the most direct cause of acute renal failure.

When acute renal failure caused by rhabdomyolysis occurs, the pathology is acute tubular necrosis; the mechanism of occurrence is: ① tubular obstruction; ② tubular oxidative damage; ③ renal ischemia (including vasoconstriction and hypovolemia).

Clinical manifestations of myolysis

Symptoms of muscle involvement such as muscle pain, tenderness, swelling and weakness may be seen. There may also be manifestations of inflammatory response such as fever, general fatigue, increased white blood cell and (or) neutrophil ratio. Urine appearance: brown or red wine-colored urine. About 30% of patients with this disease will develop acute renal failure. When the acute renal failure is severe, oliguria, anuria and other manifestations of azotemia may be seen.

Myolysis test

1. Blood test

Biochemical examinations showed increased serum muscle enzymes and other muscle enzymes (creatine kinase, transaminase, aldolase, lactate dehydrogenase, etc.); increased levels of creatinine, urea nitrogen, and uric acid, hyperkalemia, hyperphosphatemia, and metabolic acidosis; may be accompanied by blood system abnormalities such as thrombocytopenia and disseminated intravascular coagulation; myoglobinemia.

2. Urine test

Myoglobinuria, urinalysis: proteinuria is common; urine sediment: no red blood cells or a small amount of red blood cells, granular casts, increased urine myoglobin, urine dicarboxylic acid excretion.

3. Muscle examination

(1) Bone 99TcMDP imaging shows high uptake in affected muscles.

(2) MRI examination showed swelling of the affected muscles and high signals on both T1 and T2 phases.

(3) Myogenic damage at the affected site of electromyography.

4. Electrocardiogram

Focus on examining the damage of hyperkalemia to the myocardium.