our patient presented with accelerated silicosis starting as gradually progressive shortness of breath for about 1 year , progressing to chronic type 1 respiratory failure .
this was followed by development of full blown mctd , with combined features of rheumatoid arthritis , scleroderma and systemic lupus erythematosus with severe arthritis , myositis and joint contractures .
this was a case report of a 32-year - old stone crusher presented with gradually progressive breathlessness , initially on exertion and later , also at rest for 1 year .
at the same time , he also noticed raynaud 's phenomenon involving the fingers and toes . over the next 6 months , he developed a gradual binding down of the skin over the dorsa of hands , forearms , face and leg .
the patient also had severe joint pains predominantly involving all joints of the hands , including the wrist joint and the knees bilaterally .
patient had been working as a stone crusher for the past 6 years . on examination ,
the patient had diffuse hyperpigmentation , visible respiratory distress with a respiratory rate of 34/min with mild pallor .
arterial blood gas analysis revealed type 1 respiratory failure with pao2- 54 mmhg , ph - 7.38 , paco2- 38 mmhg . testing for immune markers revealed antinuclear antibody ( ana ) positive-9 ( if assay ) , anti - double stranded - deoxyribonucleic acid positive , anti - scl70 igg antibody positive  86 u / l , anti - u1 ribonucleoprotein ( rnp ) antibodies positive in high titers , anti - cyclic citrullinated peptide and rheumatoid factor positive .
contrast enhanced computed tomography of the chest was suggestive of diffuse intra and interlobular septal thickening with fibrosis and randomly situated nodules [ figure 1 ] .
transbronchial lung biopsy was compatible with silicosis and revealed focal interstitial fibrosis interspersed with pigment laden macrophages and refractile material .
low dose prednisonolone ( 20 mg od ) was given in view of the arthritis .
methotrexate at a dose of 25 mg weekly was also started along with proton pump inhibitors and physiotherapy .
his hypoxia has also improved on therapy , but he continues to be on supplemental oxygen .
some patients have features of more than one rheumatic disease and thus do not fit into traditional classification . patients with combination of clinical finding similar to those of systemic lupus erythematosus ,
progressive systemic sclerosis , polymyositis , rheumatoid arthritis and with unusually high titers of circulating ana with specificity for nuclear rnp are considered to have mctd .
hypotheses implicating modified self - antigens and/or infectious agents in the pathogenesis of mctd have been advanced , but none have been proven yet .
crystalline silica ( quartz ) particles less than 1  are the most pathogenic in silicosis .
this constitutes a permanent stimulus for the fibroblasts , which increase their production of collagen leading to cutaneous sclerosis , vascular occlusion and pulmonary fibrosis , which explains the myriad clinical features of scleroderma and mctd .
 silica exposure has been implicated with the development of various connective tissue diseases . 
 we report a case of 32-year - old stone crusher who developed silicosis with mixed connective tissue disorder ( mctd ) 6 years after exposure to silica . 
 this association of silicosis with mctd has never been reported from the indian subcontinent , although the problem of this pneumoconiosis remains rampant . 
 this rare association urges us to report this case . 
INTRODUCTION
CASE REPORT
DISCUSSION