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.