|LETTER TO EDITOR
|Ahead of print publication
An atypical presentation of antisynthetase syndrome
Mayank Kapoor1, Minakshi Dhar1, Sukdev Manna2
1 Department of Internal Medicine, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
2 Department of Rheumatology, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India
|Date of Submission||25-May-2020|
|Date of Acceptance||06-Jun-2020|
Department of Internal Medicine, All India Institute of Medical Sciences, Rishikesh - 249 203, Uttarakhand
Source of Support: None, Conflict of Interest: None
Antisynthetase antibody syndrome is an autoimmune condition characterized by autoantibodies against aminoacyl transfer-RNA synthetases. The various features including interstitial lung disease (ILD), myositis, Raynaud's phenomenon, arthritis, and mechanic hands may present at different points in time, the diagnosis being challenging in the absence of specific antibody assays. Here, we report an elderly female with antisynthetase antibody syndrome having only select features of this syndrome, many of these being atypical, leading to a delayed diagnosis.
| Case Details|| |
A 66-year-old female developed symmetric inflammatory polyarthritis of the small and large joints for the past 4 years. Two years into the illness she started complaining of progressive breathlessness. The female developed fever 4 months before the presentation. The development of proximal muscle weakness 2 months later raised a suspicion for the antisynthetase syndrome (ASSD). She also reported progressive dysphagia for a month and a half. On examination, reducible boutonniere deformity was noted bilaterally. Skin thickening was noted over all the fingers distal to the proximal interphalangeal joint and around the oral aperture along with a decrease in mouth opening. The chest examination revealed bilateral velcro crepitations in the infrascapular region.
She was anemic (hemoglobin 8.9 g%) and had polymorpho-leukocytosis (total counts, 19360/mm3 with 80% polymorphs) though renal and hepatic function tests were normal (AST-51 and ALT-52). Muscle enzymes were elevated (CPK-863 and LDH-864). Computerized tomography of the thorax showed features suggestive of usual interstitial pneumonia (UIP) and ILD, with honeycombing, reticular abnormalities, and subcarinal lymphadenopathy (3 cm) and electromyography was suggestive of the myopathic pattern. Muscle biopsy revealed preserved fascicular architecture, polygonal fibers with mild variation in size, few scattered necrotic, and myophagocytic fibers with occasional hypertrophic round fibers having internalized nuclei and few regenerating fibers but no active inflammation. Rheumatoid factor and anticyclic citrullinated peptide-2 antibody turned out to be negative, and there was an absence of joint erosions, while anti-Jo-1 antibodies were positive by immunoblot method, suggesting a diagnosis of ASSD. Glucocorticoids at a dose of 1 mg/kg of prednisolone led to symptomatic improvement and reduced arthritis over the next 3 months, although her deformities persisted [Figure 1].
| Discussion|| |
The presence of deforming arthritis and UIP ILD had prompted a diagnosis of rheumatoid arthritis, but nonerosive nature and seronegativity suggested an alternate diagnosis. The onset of myositis later in the disease course led to a suspicion of ASSD. Anti-Jo-1 is fairly specific for the diagnosis, the criteria requiring one or more of ILD, Raynaud's phenomenon, arthritis, fever (in the absence of other cause), and mechanic hands in the presence of antibody. The patient had skin thickening along with a decrease in the oral opening. Recently, an overlap has been suggested between anti-PM-Scl and antisynthetase syndrome owing to shared pathogenesis, and anti-PM-Scl positive inflammatory myopathies can present clinically such as ASSD., Although here anti-PM-Scl antibodies were absent, anti-Jo-1 syndrome may present with sclerodermatous skin changes, which is an important finding. The presence of mechanic hands has also been described in 35% of dermatomyositis and 15.4% of scleroderma. Involvement of lungs is seen with higher frequency (86%) amongst ASSD individuals showing Anti-Jo-1 positivity. Non-Specific Interstitial pneumonia (NSIP) is the commonest type, while UIP, organizing pneumonia or diffuse alveolar damage pattern maybe seen in <20 % individuals. ILD is associated with an excessive mortality rate of about 40%. Notably, most patients with ASSD are partial to begin with, a full spectrum of manifestations being seen in only two-thirds on a 2-year follow-up period. Raynaud's phenomenon is present in about 66% of early ASSD and may precede myositis by several years, although was absent in this case. Arthritis is seen mostly in seropositive antisynthetase individuals (64%–83%) compared with seronegative (18%). Fever may be seen in about 20% of cases. Here, mechanic hands were absent, high-resolution computed tomography suggested UIP instead of NSIP pattern, and sclerodermatous skin changes were present. This case is an important learning lesson for a high suspicion for antisynthetase among physicians for the diagnosis as partial and atypical symptoms are common.
| Conclusions|| |
- ASSD can present with a myriad of features
- Anti-Jo-1 can present with sclerodermatous skin changes and myositis
- Awareness of partial forms among physicians is important for the diagnosis.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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