Radiology.

ANTISYNTHETASE SYNDROME AND ITS ASSOCIATION WITH INTERSTITIAL LUNG DISEASE-A CLINICAL AND RADIOLOGICAL REVIEW

Naresh Kumar,Bhavya Basetti, Rajoo Ramachandran, Prabhu Radhan,Venkata Sai P.M.

Department of Radio diagnosis,Sri Ramachandra Institute of Higher Education and Research, Porur, Chennai,Tamil Nadu, India.

Corresponding Author: Bhavya Basetti

Abstract:

Anti-synthetase syndrome is a rare autoimmune disorder with autoantibodies formed against aminoacyl t-RNA synthetase enzyme. It is manifested in the form of fever, myositis, arthritis, interstitial lung disease, and Raynaud’s phenomenon. We present the radiological findings of the pulmonary manifestation of this rare syndrome in a 63-year-old female who presented to the emergency department with complaints of breathlessness. Early diagnosis and timely management are vital as the disease usually resolves with a course of steroids, but if neglected may lead to complications.

Keywords: – ASS- Anti synthetase syndrome, ILD- Interstitial lung disease, HRCT- High resolution computed tomography, ARS- Aminoacyl-tRNA synthetases.

Introduction:- 

Anti-synthetase syndrome (ASS) is quite a rare condition among the idiopathic inflammatory myopathies. The hallmark of this disease is the presence of serum autoantibodies that recognize aminoacyl-tRNA synthetases. It can occur in up to one-third of patients with dermatomyositis or polymyositis [1]. We report a case of anti-synthetase syndrome with emphasis on the radiological findings which helped in arriving at an early diagnosis and thereby altered the further course of management and prognosis of the patient.

 CASE REPORT:

 A 63-year female presented to our emergency department with complaints of breathlessness and difficulty in swallowing for a duration of 2 months and occasional fever spikes. There was also a history of blackish discoloration of all fingers, multiple joint pain and swelling for a month. There were no complaints of oral ulcers or photosensitivity.On physical examination, her vitals were within normal limits. Raynaud’s phenomenon was present, with well-demarcated hyperkeratotic lesions on the radial and palmar aspects of the fingers in both her hands, characteristic of mechanic’s hand lesions. There was also a pitting type of pedal edema involving both feet. Musculoskeletal examination revealed swelling and tenderness of bilateral wrist and metacarpophalangeal joints.On chest auscultation, fine crepitations were heard in the bilateral lower zones. Cardiovascular examination revealed a pan systolic murmur. Her neurological exam did not reveal any focal neurological deficit.

On routine blood investigations, the patient was found to be anemic (hemoglobin- 10.0 g/dl) with low levels of vitamin B12. Routine biochemical as well as liver and renal function tests were normal. Her erythrocyte sedimentation rate (20 mm/hr, normal: 5-10 mm/hr) and C-reactive protein (69 mg/L, normal: 0-10 mg/L] were found elevated. Creatine kinase [CK] and Lactate dehydrogenase [LDH] levels were elevated measuring 581 U/L and 500 U/L respectively.

The rheumatology workup showed a negative rheumatoid factor and anti-cyclic citrullinated protein antibodies. Serological examination revealed elevated antinuclear antibody (ANA) level while antineutrophil cytoplasmic autoantibodies (p-ANCA and c-ANCA), dsDNA, and lupus anticoagulant were negative.Her blood cultures came out negative for the following organisms: influenza A and B, Mycoplasma pneumonia, Mycoplasma pneumonia, Chlamydia, Q fever, respiratory syncytial virus, adenovirus, legionella pneumophilia. The pneumococcal antigen serology turned out to be negative.

The electromyography findings were suggestive of a myopathic pattern. Electrocardiogram showed sinus tachycardia with positive serum Troponin T and negative Troponin I (probably myopathic). The chest radiograph (posteroanterior view) (fig. 1) showed- right hilar prominence, bilateral scattered reticular opacities. Mild blunting of both costophrenic angles was also seen.

                                                                                             

  Figure 1 (a & b): prominent right hilum (asterisk) with scattered reticular opacities (arrows in 1.a &1.b) and blunting of bilateral costophrenic angles (arrow heads in 1.a).

 On further evaluation, high-resolution computed tomography (HRCT) study (fig. 2) was performed which showed bilateral diffuse ground-glass opacities with interlobular septal thickening and areas of patchy consolidation changes in basal segments of bilateral lower lobes. Few scattered areas of ground-glass opacities were also noted in the subpleural aspect of bilateral upper lobes & left lingula, suggestive of underlying non-specific interstitial pneumonia with organizing pneumonia pattern.Additional findings include enlarged lymph nodes in the upper and lower paratracheal, subcarinal and right hilar regions. Few lymph nodes showed focal calcification within (fig. 3)

 


Figure 2 (a, b & c): Axial sections of CT thorax in lung window showing diffuse scattered areas of ground glass opacities in the sub pleural aspect of bilateral upper lobes (asterisks in 2.a) & left lingula (asterisk in 2.b) with interlobular septal thickening(arrow head in 2.b) and areas of patchy consolidation changes(circle in 2.c) in basal segments of bilateral lower lobes- suggestive of non-specific interstitial pneumonia with areas of organizing pneumonia.

  

Figure 3 (a & b): Axial view of CT thorax in mediastinal window shows few enlarged lymph nodes noted in upper and lower paratracheal, sub crinal (arrow in 3.a) and right hilar regions (arrow in 3.b). Few of the nodes showed calcifications.

A contrast-enhanced CT abdomen study was done which revealed no foci of sepsis. Incidental findings of left ectopic kidney and hiatus hernia were noted (Fig. 4).