Flail leg syndrome misdiagnosed as inflammatory myopathy a case report

Objective: To investigate the development and clinical characteristics of flail leg syndrome (FLS) and improve clinicians’ recognition ability of the disease. \quad Method：We reviewed the clinical data, electromyography, cerebrospinal fluid test, and lumbar MRI of a patient diagnosed with flail leg syndrome(FLS) in the seventh Affiliated Hospital of Sun Yat-sen University. \quad Results: Clinical symptoms of the patient limited in both lower limbs, including asymmetric distal muscle weakness and atrophy with conceal onset and slow development. There were also occurrences of increased tendon reflexes and muscle soreness as the disease progressing. Electromyography showed that the amplitude of motor nerve conduction of both lower limbs decreased even disappeared，indicating neurogenic injury.In addition, patient’s blood creatine kinase level was found slightly increased. \quad Conclusion: Flail leg syndrome is a variant type of ALS. It is relatively rare in clinical practice and usually shows slow progress. This case study would be helpful for clinicians to improve the diagnostic ability of FLS.