Legionella-Induced Rhabdomyolysis Unmasks Underlying Metabolic Myopathy

Introduction: We present a case of rhabdomyolysis that illustrates the importance of having a broad differential while evaluating the etiology of rhabdomyolysis. Case Description: 29-year-old male without any past medical history presented to the Emergency Department with headache, diarrhea, muscle weakness and pain for past 4 days. He was taking acetaminophen 1gm daily for myalgias for the past 3 days. Family history revealed sister with sickle cell trait. On examination, Temperature 103°F, HR 140 bpm, BP 140/90 mm Hg, respiratory rate 16/min, O2 saturation 100% on room air. His physical examination was unremarkable, except for significant tenderness on palpation of lower extremities. His laboratory data showed Na 131 mmol/L, K 2.9 mmol/L, AST/ALT: 162/889 U/L, creatine of 1.3mg/dl. Urinalysis showed 3+ blood, RBC 5-10/HPF and Granular cast 30-40/HPF. CK level was elevated to 96000U/L. His chest X-Ray showed right upper lobe consolidation. The nasal swab for COVID and flu were negative, and the urine test was positive for Legionella antigen. He was started on levofloxacin for treatment of legionella pneumonia. His CK levels continued to rise to 600,000U/L. Despite intravenous fluids, he became oliguric and required hemodialysis (HD) on day 4 of hospitalization. His extensive autoimmune and Myositis panel work-up for rhabdomyolysis was negative except for total and free carnitine levels which were elevated to 140 umol/L and 83 umol/L respectively, raising suspicion for Carnitine-palmitoyl transferase 1A deficiency which could present as myopathy triggered by fasting, fever or infection. He was discharged home on day 23 of hospitalization on HD and required HD for additional 5 weeks when he had renal recovery and was taken off dialysis. His kidney function continues to improve with the most recent serum creatine 1.2 mg/dL. He has been referred to a genetic clinic for further evaluation. Discussion: Myopathies can be dormant, until there is a second hit that can unmask them making individuals susceptible to severe rhabdomyolysis with a common condition such as legionella pneumonia. Hence, broad differential and thorough work up should be sought in the cases where clinical scenario does not explain the findings.