Collective occurrence of rhabdomyolysis after high-intensity resistance training--- A prospective study

Background: Rhabdomyolysis is a syndrome characterized by muscle necrosis and release of intracellular muscle components into systemic circulation. Common causes include high-intensity exercise, crush injury, high fever, drugs, and inflammation. Here, we have a prospective observational study of collective rhabdomyolysis caused by infrequent short-term high-intensity exercise. Methods: The patients were a group of adolescents, of which 35 developed severe muscle pain and dark-brown urine after military training and were hospitalized, while others developed mild symptoms and returned to school after relief of symptoms following outpatient treatment. We used SPSS 13.0 to calculate the sample mean and standard deviation of various laboratory indicators. Results: The average serum creatinine kinase was 33532.43±39982.95 U/L, and average serum lactate dehydrogenase was 1816.97±1413.59 U/L at the time of admission. When they were discharged, the above two indicators became 1902.2±1366.37 U/L and 210.31±61.27 U/L. Signs and symptoms improved in all patients after the intravenous injection of average 5000ml within 5.5 days of normal saline and balance solution and implementation of a bed rest regimen. No complications occurred (e.g., acute renal failure, disseminated intravascular coagulation, or electrolyte imbalance). All patients were relieved of symptoms and discharged after an average of 5.47 days of hospitalization. Of these, 20 patients were prescribed medical treatment and returned to the clinic within 1 month after discharge. Conclusions: Suddenly and dramatically increase the amount of exercises in a short period of time is easy to cause rhabdomyolysis. We hope that everyone can avoid similar situations.

All patients were relieved of symptoms and discharged after an average of 5.47 days of hospitalization. Of these, 20 patients were prescribed medical treatment and returned to the clinic within 1 month after discharge.
Conclusions: Suddenly and dramatically increase the amount of exercises in a short period of time is easy to cause rhabdomyolysis. We hope that everyone can avoid similar situations. Background Rhabdomyolysis (RM) is caused by movement, extrusion, hyperthermia, drugs, inflammation, and other sources of striated muscle destruction and disintegration. It causes leakage of muscle-cell components, such as creatine kinase and myoglobin, into the blood circulation, which is associated with a series of syndromes that cause internal environmental disorders, including acute kidney injury (AKI).

Methods
Patients were aged 10-16 (average 13.94) years from a city middle school who attended military training. The students had undergone outdoor high-intensity military training on the morning of December 6, 2017, including outdoor long-distance running (3-8 km), 80-400 squats, and other activities. The outdoor temperature was 32°-35°C, and the relative humidity was 95%. Most students (approximately 60) experienced muscle soreness in the thighs, calves, and abdomen; some had darkbrown urine. After 3 days of rest, muscle pain, brown discoloration of urine, and other symptoms had resolved in most students; however, 35 students were hospitalized owing to persistent dark-brown discoloration of urine. , and blood electrolytes [K + , Na + , Cl -, Ca 2+ ,and P]), routine urinalyses (creatinine, urea nitrogen, uric and acid), and blood gas analysis. All patients met the following diagnostic criteria: (1) appearance of symptoms after a large number of exercises; (2) presence of corresponding clinical manifestations of rhabdomyolysis, such as muscle pain, tenderness, swelling and weakness, general malaise, brown discoloration of urine, oliguria, anuria, and fever; (3) CK levels five-fold greater than the normal range; and (4) the absence of other causes for CK elevation.
The morphology of these red blood cells was primarily in the form of normal red blood cells.
All patients were treated with a large amount of fluid replacement, and correction of electrolyte and acid-base imbalances with intravenous infusion of 5% sodium bicarbonate injection(for urinary alkalization) and compound sodium chloride injection. 24 patients also received liver protection with intravenous infusion of magnesium isoglycyrrhizinate injection or polyene phosphatidylcholine injection. None of the 35 patients had any complications, such as acute renal failure or multi-organ system failure. The average hospital stay was 6.74 days (median, 7 days). A total of 19 patients participated in the return visit in January after discharge. The blood and urine results were shown in

Discussion
This report presents a case of collective rhabdomyolysis, which developed following rigorous exercise in a group of patients who underwent military training.
Rhabdomyolysis constitutes a group of common clinical syndromes with complex and diverse causes.
Rhabdomyolysis was first described in 1946, and much of the subsequent literature focused on military trainees undergoing significant physical stress [1] . In 1997, the incidence of rhabdomyolysis in adults was estimated at 26,000 cases annually, with myriad and often multifactorial causes [2] .
Strenuous exercise has been reported as one of the most frequent causes, both on China and the world; however, the collective incidence of rhabdomyolysis owing to strenuous exercise has rarely been reported. Exertional rhabdomyolysis has one common cause: too much, too fast, and too soon of an exercise too novel [3] . Patients who are physically untrained seem to have a greater risk of developing clinically significant exertional rhabdomyolysis, although rhabdomyolysis has been known to occur in trained athletes [4] [5] . The serum aminotransferase level is usually elevated in rhabdomyolysis, and these enzymes originate from the skeletal muscle [6] . When performing highintensity exercise, rhabdomyolysis is more likely to occur in individuals who do not routinely exercise, rather than in athletes. General education in Southeast Asian countries (e.g., China, South Korea, and Japan) is based on exam-oriented education. Students are expected to spend considerable amounts of time focused on classroom learning and homework, while physical exercise is considered as "wasting time" and "not relating to learning." This has led to a general lack of daily physical activity among students in Southeast Asia, especially among girls.