Case Presentation: A 21-year-old healthy female presented with diffuse muscle soreness, bilateral thigh pain, and one day of dark colored urine after an intense spin class five days prior. Two days prior, the patient presented to an urgent care clinic and was told that she had blood and protein in her urine likely due to a UTI and was prescribed an antibiotic and instructed to hydrate. The day prior to presentation, she reported worsening pain and stiffness in her legs, lower abdominal pain, and difficulty with ambulation, prompting presentation to the emergency room. She was found to have a CK>100,000 U/L, AST 1463 U/L, ALT 485 U/L, creatinine 0.5 mg/dL, negative pregnancy test, and UA with 3+ blood, 4 RBC. She was admitted and aggressively hydrated with intravenous fluids with an improvement of CK to 64,000 U/L the following morning and modest clinical improvement in pain and movement. However, on the third day of admission, she complained of increasing left leg swelling, prompting surgery consultation who found no signs of compartment syndrome. Bilateral lower extremity venous ultrasound was negative for DVT. Over the next couple of days, the patient’s labs and clinical symptoms continued to improve with hydration.
Discussion: Although rhabdomyolysis is not necessarily an uncommon medical diagnosis, there has been a recent surge in admissions particularly among young people due to the increasing popularity of spin cycling. Stationary bike “spin” class is a type of group exercise activity that pushes individuals beyond normal solo performance. Previous literature has described the risks of developing rhabdomyolysis particularly in individuals who maintain a sedentary lifestyle and rapidly engage in high-intensity exercise without a gradual build-up. Rhabdomyolysis typically has a serum CK>10,000 U/L, reaching a peak 24-72 hours from time of exercise. UA is usually positive for heme while showing few or no red blood cells. Other labs may show kidney and hepatic damage. Compartment syndrome is a severe complication caused by an increase in pressure within a closed anatomical space that can cause necrosis of muscles and nerves due to compromised perfusion. Signs include severe pain, swelling, numbness, pulselessness, or even paralysis and should prompt urgent surgical evaluation.Treatment of rhabdomyolysis is primarily fluid resuscitation to a goal of 200 to 300 mL per hour of urine output. Patients can also develop lab abnormalities such as hyperkalemia or hyperuricemia. While genetic testing for rhabdomyolysis is not routine practice, patients with recurrent episodes of rhabdomyolysis or exercise intolerance with severe cramping should prompt testing for conditions including metabolic myopathies. Although our patient was young and healthy, she was unaware of the dangers of engaging in a high intensity spin class. Additionally, she was misdiagnosed at the urgent care clinic resulting in a delay in appropriate treatment which could have been detrimental.
Conclusions: This case highlights the intersection of fitness culture and clinical awareness in the diagnosis and management of exercise-induced rhabdomyolysis, particularly among young, healthy individuals. Physicians should be aware of the increased risk of rhabdomyolysis particularly in sedentary individuals who rapidly increase their activity levels in exercises such as an intensive spin class.