title: McArdle Disease Misdiagnosed as Meningitis.
abstract: BACKGROUND McArdle disease is a glycogen storage disorder mainly characterized by exercise intolerance. Prolonged muscle contracture is also a feature of this condition and may lead to rhabdomyolysis (RM), which is a serious event characterized by acute skeletal muscle damage.  CASE REPORT A 44-year-old female patient presented with an acute contracture of the posterior neck muscles, causing severe nuchal rigidity. The contracture was induced during a dental extraction as she held her mouth open for a prolonged period, with her neck in a rigid position. She presented with severe pain in her ear and head, as well as fever, vomiting, and confusion. Based on her symptoms, she was initially misdiagnosed with bacterial meningitis and experienced an acute allergic reaction to the systemic penicillin she was subsequently administered. Lumbar puncture results were normal. High serum creatine kinase (CK) levels, recurrent exercise-related muscle symptoms, and a previous history of recurrent myoglobinuria raised the suspicion of an underlying neuromuscular condition. McArdle disease was confirmed by muscle biopsy and a genetic test, which revealed that the patient was homozygous for the R50X mutation in the PYGM gene. CONCLUSIONS This case illustrates that even seemingly innocuous movements, if rapid isotonic or prolonged isometric in nature, can elicit a muscle contracture in McArdle disease patients. Here, we highlight the need for careful management in this patient population even during routine healthcare procedures. The allergic reaction to antibiotics emphasises that misdiagnoses may result in iatrogenic harm.
authors.affiliation: MRC Centre for Neuromuscular Diseases and Division of Neuropathology, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom.|CAPES Foundation, Ministry of Education, Brasilia, Brazil.
authors.forename: Renata Siciliani
authors.initials: RS
authors.lastname: Scalco
authors.affiliation: MRC Centre for Neuromuscular Diseases and Division of Neuropathology, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: Sherryl
authors.initials: S
authors.lastname: Chatfield
authors.affiliation: Barts and the London School of Medicine and Dentistry, London, United Kingdom.
authors.forename: Muhammad Hyder
authors.initials: MH
authors.lastname: Junejo
authors.affiliation: MRC Centre for Neuromuscular Diseases and Division of Neuropathology, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Booth
authors.affiliation: MRC Centre for Neuromuscular Diseases and Division of Neuropathology, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom.
authors.forename: Jatin
authors.initials: J
authors.lastname: Pattni
authors.affiliation: Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, London, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Godfrey
authors.affiliation: MRC Centre for Neuromuscular Diseases and Division of Neuropathology, University College London Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom.|Dubowitz Neuromuscular Centre, Great Ormond Street Hospital, London, United Kingdom.
authors.forename: Ros
authors.initials: R
authors.lastname: Quinlivan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D003402:Creatine Kinase / Q000097:blood*; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D005260:Female; D006012:Glycogen Storage Disease Type V / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D008581:Meningitis / Q000175:diagnosis*; D018482:Muscle, Skeletal / Q000473:pathology; D009154:Mutation; D012206:Rhabdomyolysis / Q000209:etiology
chemical_list: D015415:Biomarkers; D003402:Creatine Kinase