Appendix 2: MCQ
A patient presents with trouble walking up stairs and rising from the bed or toilet with some muscular pain. She has a history of interstitial lung disease and psoriasis. On examination, in addition to proximal leg weakness, you observe cracked skin on the fingers and Raynaud’s phenomenon. EMG reveals low amplitude, short duration motor units. What labs would you consider for assisting with diagnosis?
CK
Myositis panel
Serum immunofluorescence
Ganglioside antibodies
The correct answer is B. This patient is presenting with a constellation of interstitial lung disease, rash, inflammatory myopathy, mechanic’s hands and raynaud’s phenomenon, which is typical for Antisynthetase syndrome, although differential diagnosis will be broader. A Myositis panel is the blood test that may confirm Antisynthetase syndrome by revealing one of the eight antibodies known to cause this. Depending on institution, the panel may also include testing for other myopathies. A CK will be elevated, but not diagnostic, as it is not specific. Serum immunofluorescence may be helpful in work up, but is also non-diagnostic. Ganglioside antibodies are probably not useful because the EMG revealed this is a myopathy and not a neuropathy.
A patient comes to you for a second opinion after his primary physician diagnosed him with dematomyositis. He thinks he has ALS because he is short of breath, progressively weak and has fatigue. He is upset that treatment with oral prednisone has not helped much and he has significant side effects and wants to start Riluzole instead. On reviewing his diagnostic testing, you notice that his muscle biopsy did not have perivascular inflammation typical for dermatomyositis and there are no inclusion bodies. Myositis panel reveals Anti-Jo1 antibodies. The next step in treatment is:
Start Riluzole
Physical therapy
Referral to psychiatry for anxiety
Trial of Rituximab
The correct answer is D. This patient was diagnosed with dermatomyositis, which explains the inflammatory myopathy, rashes and possibly constitutional symptoms, however does not account for the dyspnea and lack of biopsy evidence typical for dermatomyositis (perivascular infiltration). The presence of Anti-Jo antibodies is diagnostic, so consideration for ALS is not necessary at this time. We first should further address and treat the inflammatory myopathy. Physical therapy is beneficial in conjunction with medical treatment, but not on its own. The patient’s anxiety is probably situational due to illness and magnified by corticosteroid use, so psychiatry referral is not necessary at this time.