A Rare Case of Herpes Simplex Virus (HSV)-Associated Rhabdomyolysis

Introduction: Viral myopathy is an important cause of massive rhabdomyolysis leading to acute renal failure. Many cases involving influenza A and B, Epstein Barr virus, and adenovirus have been reported. To my knowledge, this is only the second case of rhabdomyolysis secondary to herpes virus in a previously healthy patient that has been reported in the English literature. Case Description: A 23-year-old female without significant past medical history presented to the ER for muscle aches, fevers, and hematuria. No recent trauma, increased exercise, or drug use was reported. The exam was notable only for genital ulceration. Labs were notable for BUN of 52 mg/dL, creatinine of 6.09 mg/dL, AST of 2,126 U/L, and ALT of 424 U/L. Creatine kinase elevated to 426,700 U/L. Ethanol < 10 mg/dL. Viral testing for HIV, Parvovirus B19, RSV, Influenza A, Influenza B, and COVID were all negative. Anti-JO-1 antibodies and complete myositis-specific autoantibody were both negative. Urine analysis showed no active sediment but urine protein: creatine ratio was 3.7 g/day. A kidney biopsy showed 1) diffuse acute tubular injury with extensive myoglobin casts and 2) mild acute interstitial nephritis. HSV-2 serum PCR was positive and valacyclovir was started. She remained anuric and hemodialysis was initiated. A muscle biopsy was performed to rule out autoimmune myositis. Creatinine was 5.6 mg/dL on discharge. Repeat creatinine at two weeks post-discharge was 1.9 mg/dL. The patient remained off dialysis and the muscle biopsy was read as necrotizing myopathy. No morphologic evidence of glycolysis, lipidosis, or mitochondrial myopathy was seen. Discussion: Herpes virus is a rare cause of rhabdomyolysis leading to acute renal failure. As with other viral myopathies, muscle weakness accompanies this condition and can range from myalgias to myolysis. Rhabdomyolysis can be life-threatening and early recognition and treatment can prevent renal dysfunction. Evaluation for HSV should be included in the workup for viral myopathy.Myoglobin cast