An Unusual Case of Proximal Limb Muscle Weakness

The patient, a 55-year-old female presented with a recent onset of bilateral leg weakness and falls at home. Medical history was remarkable only for rosacea. Clinical examination revealed weakness of bilateral shoulder girdle muscles and bilateral hip flexor muscles. Her exam was otherwise normal. Creatine kinase levels were mildly elevated (475 [normal: 43-274 U/L]) and the C-reactive protein level was 63.9 (normal: 0-10 mg/dl). Myositis antibody panel, including HMG-CoA reductase antibody was negative. EMG/NCS revealed small, short duration motor units and early recruitment on needle EMG of the proximal left deltoid and left gluteus medius muscles without evidence of membrane instability.