Case history
Case history #1
A 63-year-old man presents with a 5-year history of slowly progressive leg weakness. Recently he has had multiple falls and experiences difficulties with fine tasks using his hands. Neurological examination shows atrophy of iliopsoas, quadriceps, and finger flexors bilaterally. Manual muscle strength test finds predominant weakness in finger/wrist flexors compared with finger/wrist extensors. Additionally, it demonstrates neck flexion 3/5, neck extension 4/5, arm abduction 4/5, forearm flexion 4/5, hip extension 3/5, hip flexion 2/5, knee extension 2/5, knee flexion 2/5, ankle dorsiflexion 4/5, and ankle plantar flexion 5/5. The rest of the neurological examination is unremarkable except for reduced patellar reflexes.
Case history #2
A 42-year-old woman presents with progressive muscular weakness and recurrent facial oedema. The oedema started 3 months ago and worsened to the point that she was unable to open her mouth or eyes. Concomitant to her facial rash, she experiences intermittent difficulty in swallowing. Her weakness results in an inability to rise from a chair or ascend stairs. Skin examination demonstrates blue-purple discoloration on the upper eyelids with oedema. Her muscle strength is 3/5 on bilateral hip flexion and 3/5 on bilateral shoulder abduction. The rest of the neurological examination is normal.
Other presentations
Extramuscular manifestations may be predominant in idiopathic inflammatory myopathy (IIM). The extramuscular manifestations found in the respective IIM-subtype are as follows.
Skin
Rash including heliotrope rash, Gottron's papules, Gottron’s sign, inverse Gottron’s sign, mechanics hands, poikiloderma, holster sign, shawl sign, and V sign.[1][2]
Frequently found in patients with dermatomyositis and anti-synthetase syndrome, may also be seen in patients with immune-mediated necrotising myopathy or overlap myositis but this is less common.[4][5] Patients with overlap myositis may exhibit cutaneous features of the predominant connective tissue disease they present with, for example, scleroderma, telangiectasia.[4]
Lungs
IIM-associated interstitial lung disease occurs more commonly among the anti-synthetase syndrome, dermatomyositis and overlap myositis subtypes, and may precede, or be present without muscular symptoms.[1][6]
Other pulmonary manifestations in IIM include drug-induced pneumonitis, pulmonary capillary angiitis, and pulmonary failure due to thoracic muscle weakness.
Heart
Myocarditis may occur in patients with dermatomyositis, overlap myositis and anti-synthetase syndrome. This has not been reported in patients with sporadic inclusion body myositis.[7] However, overt cardiac disease has only been reported in around 10% of IIM patients, subclinical involvement is more common, in up to 75% of patients.[4]
Patients with IIM are at an increased risk of experiencing an acute coronary syndrome when compared to the general population.[7]
Gastrointestinal
Dysphagia is most prominent in dermatomyositis, inclusion body myositis and overlap myositis.[1][4]
Joints
Arthralgia and arthritis may occur in all IIM-subtypes except for sporadic inclusion myositis and immune-mediated necrotising myopathy.[1][4]
Peripheral vascular system
Raynaud’s phenomenon may occur in patients with dermatomyositis, anti-synthetase syndrome and overlap myositis.[1][4]
Constitutional symptoms
Systemic features such as fever and weight loss may occur.
Use of this content is subject to our disclaimer