Concomitant Dermatomyositis and Mitochondrial Myopathy with Atypical Features

초록

Objective: Dermatomyositis (DM) is classified as one of the idiopathic inflammatory myopathy, featuring symmetric and progressive proximal muscle weakness and characteristic cutaneous findings. DM rarely represents with dysphagia or neck muscle weakness. Mitochondrial myopathy (MM) shows variable symptoms of proximal muscle weakness, sensorineural hearing loss, ptosis, seizures, but it does not usually represent symptoms of dysphagia or neck muscle weakness. We report one rare case of concurrent DM and MM with atypical features of neck muscle weakness and dysphagia. Case: A 59-year old woman presented with skin rash and itching sensation on face, both arms, anterior chest, and back for several months. She complained of weakness of neck flexors and both proximal upper extremities. Typical skin features of DM; Gottron sign, Heliotrope rash, edema, cuticle dystrophy, and symmetrical erythematous rash on neck, dorsal hands, forearm, upper back, scalp were found. In manual muscle test (MMT), both shoulder flexors, abductors, and neck flexors were poor grade, both hip flexors, extensors, abductors were fair grade. Other muscles were good grade. She had difficulty in flexing her neck and could not sit up for herself. CK and LDH levels were increased to 2841 and 631 units, respectively. CPK isoenzyme electrophoresis showed a remarkable increase in CK-MM (2690 units). In thigh MRI, multifocal patchy hyper-intense lesions were seen at both iliopsoas, gluteus maximus, adductor longus/brevis muscles. These findings were compatible with inflammatory myopathy. After admission, dysphagia worsened gradually. Videofluoroscopic swallowing study (VFSS) showed massive aspiration when swallowing small amount of liquid, so percutaneous endoscopic gastrostomy (PEG) insertion was performed. Nerve conduction and electromyographic examination showed typical myopathy mostly affecting proximal upper and lower extremities and neck muscles. Under the diagnosis of DM, she was tr