Bilateral Calf Pain In A High School Athlete

HISTORY: Our patient is a 17-year-old male with a past medical history of oppositional defiant disorder, Autism, ADHD, anxiety and depression on multiple psychiatric medications who presented to an urgent care with bilateral calf pain 24 hours after exercising at home by completing twenty body-weight calf raises. His pain was severe enough to prevent him from fully walking and he also endorsed dark urine. He was referred to the emergency department where his workup showed elevated creatine kinase of 16,189. He was admitted to the inpatient service for further workup and evaluation. PHYSICAL EXAMINATION: Bilateral Lower Extremity Exam: No significant swelling, ecchymosis, erythema or tightness to bilateral calves. Mild tenderness to palpation bilaterally in body of gastrocnemius, right worse than left. Full range of motion bilaterally at ankle. Strength 5/5 in resisted dorsi/plantar flexion. Patient able to bear weight and ambulate without assistance after day of IV fluids. Noted pes planus bilaterally. No toe-walking appreciated. DIFFERENTIAL DIAGNOSIS:1. Exertional Rhabdomyolysis 2. Medication-Induced Rhabdomyolysis 3. Bilateral Calf Strain 4. Becker’s Muscular Dystrophy 5. Bilateral Chronic Exertional Compartment Syndrome TEST AND RESULTS:Creatine Kinase: 16,189 (peak); 142 1-week post-discharge. Bilateral US Arterial and Venous Duplex: unremarkable arterial US and no signs of DVT. Autoimmune panel: negative. Duschene’s Muscular Dystrophy testing- negative. Becker’s Muscular Dystrophy panel- pending. FINAL WORKING DIAGNOSIS: Medication-induced rhabdomyolysis TREATMENT AND OUTCOMES: He was given IV fluids continuously during admission. Once his CK levels were at an acceptable level, he was restarted on his home medications. He was discharged after three days of inpatient management. We rechecked CK levels in the outpatient setting. Due to remote history of nonspecific autoimmune disease he was referred to rheumatology. He was instructed to follow up with psychiatry for medication management. He current medications include Zoloft, Geodon, and Guanfacine. He is held out of activity at this time while remaining workup is being completed. We will consider physical therapy to strengthen lower extremities in safe, controlled environment.