Background/Purpose:  Oropharyngeal dysphagia (OPD) is an ominous finding in autoimmune myositis (AIM), yet few studies have evaluated the disease subsets at higher risk for this life-threatening complication. Recent AIM classifications have identified three dominant entities: pure dermatomyositis (DM), necrotizing autoimmune myositis (NAM), and overlap myositis (OM). Pure polymyositis (PM) is uncommon and is an exclusion diagnosis. The aim of the present study was to describe, in relation to DM, NAM and OM, the clinical and laboratory characteristics associated with OPD.

Methods:  A retrospective cohort of patients diagnosed with AIM between January 2001 and January 2016 was identified in two academic hospitals affiliated with the University of Montreal. All patients with objective OPD, defined by an abnormal videofluoroscopy swallow study (VFSS) and/or the need for percutaneous gastrojejunostomy (PGJ), were included. Severe dysphagia was defined as aspiration visualized on VFSS and/or the need for PGJ and/or aspiration pneumonia. The associations between OPD and various characteristics, including diagnostic subsets of AIM, clinical and laboratory features, and the presence of cancer within 3 years of AIM diagnosis, were examined.

Results:  Within the total cohort of 180 patients with a diagnosis of AIM, the main subset was OM (n=94, 52.2%) and the other subsets were distributed as follows: 46 pure DM, 37 NAM, and 3 PM. Objective OPD was present in 26 patients (14.4%). An abnormal VFSS was documented in 25 patients and 9 patients had a PGJ. For this dysphagic cohort, the mean age (+/-SD) was 62.9 (+/- 10.7) years and 61.5% were women. The main diagnostic subset was pure DM (n=12, 44.4%), while 6 patients had NAM, and 8 had OM. Among the 8 OM patients, 6 had concomitant distal oesophageal dilatation on chest CT, 5 of which had scleroderma features. Each of the DM-specific autoantibodies (aAbs) (TIF, NXP2, Mi-2 and SAE) was represented among the pure DM patients, while HMGCR and SRP aAbs were only found in NAM. In OM, only one patient had Jo-1 aAbs, while RNA polymerase III, PM-Scl and U1RNP aAbs were also seen. Cancer was found in 24/180 patients and was more prevalent among the dysphagic (n=10/26, 38.5%) compared to the non-dysphagic patients (n=14/154, 9.1%) (p=0.0005). Dysphagic patients in the DM subset showed the highest rate of cancer (n=8, 66.7%). Severe OPD was identified in 11/26 patients. Six of them had DM, all with an associated cancer. Severe dysphagia was also present in 3 NAM and 3 OM. OPD was treated with methylprednisolone pulses as induction therapy in 15 patients, and IVIG in 21. Evolution of OPD was generally favorable, and complete remission was seen in 17 patients (65.4%). However, in the subset of cancer-associated pure DM, only 2 patients (25%) had resolution of OPD. Overall, 6 patients with OPD died, of which 3 had pure DM associated with cancer.

Conclusion: Our study demonstrates that pure DM is the dominant AIM subset associated with objective OPD. Cancer is significantly more prevalent among the dysphagic patients, specifically in the pure DM subset. Based on this evidence, clinicians are urged to aggressively investigate pure DM patients with OPD for evidence of cancer.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/oropharyngeal-dysphagia-in-autoimmune-myositis/