silicosis is a fibrotic disease of the lungs caused by the inhalation and deposition of 
 free crystalline silicon dioxide ( sio2 ) or silica in the lung tissue1 .
silica exposure has long been a well - known occupational hazard in sandblasting , tunnelling , 
 mining , but also in a range of other professions .
although silica - associated diseases are 
 preventable , they remain common worldwide , particularly in developing countries2 .
there are several clinical and pathologic varieties of silicosis , including acute 
 silicosis , accelerated silicosis , chronic silicosis , and conglomerate silicosis ( progressive 
 massive fibrosis or complicated silicosis)3 .
development of different forms of silicosis is dependent on 
 duration of exposure , concentration and the surface of silica particles4 .
chronic ( nodular ) silicosis that develops after 1020  yr of 
 exposure to silica is the most frequent form of the disease2 .
acute silicosis is also referred to in the literature as 
 silicoproteinosis or silicolipoproteinosis , because of its typical histological pattern of 
 periodic acid - schiff - positive lipoproteinaceous material in the alveoli , producing a picture 
 of alveolar lipoproteinosis . whereas acute silicosis occurs after intense short exposures 
 within a few years after the initial exposure , accelerated silicosis develops within 5 to 
 10  yr of initial exposure to silica dusts5,6,7 .
radiologically , classic simple chronic silicosis is typically characterized by multiple 
 nodular opacities with predominance in the upper lobe and posterior part of the lung . with 
 increased duration and intensity of exposure ,
enlargement of hilar and mediastinal lymph nodes with calcification 
 at the periphery of the node is common7
. 
 accelerated silicosis may be radiologically similar to chronic silicosis , with more rapid 
 development of changes following initial exposure .
however , it may also possess features 
 typical for acute silicosis5 , 8 , 9 .
patients with 
 accelerated silicosis are at a higher risk of developing progressive massive fibrosis as 
 well as other complications5 , 10 . in acute silicosis ( silicolipoproteinosis ) , due to 
 intra - alveolar accumulation of lipoproteinaceous material , bilateral consolidation , 
 multifocal patchy ground - glass opacities with perihilar distribution and centrilobular 
 nodular opacities
accelerated silicosis is similar to acute silicosis in developing alveolar lipoproteinosis 
 with accumulation of granular lipoproteinaceous material containing alveolar surfactant in 
 alveolar spaces and interstitial inflammation .
in addition , accelerated silicosis is 
 associated with the presence of silicotic nodules that develop sooner than in chronic 
 silicosis2 .
a 38-yr - old man presented with progressive dry cough and dyspnoea on exertion of 6-month 
 duration .
his personal history indicated that he was a former smoker ( 10 pack - year cigarette 
 smoking history ) .
he completed his apprenticeship as a metal processor and worked in this 
 profession for 2  yr .
for the next ten years , he worked as a locksmith and then , for the last 
 5  yr prior to his disease , as a sandblaster .
he used compressed air and foundry sand 
 containing high amounts of silicon dioxide to blast stainless steel materials before welding 
 or welded products . on admission ,
high - resolution computed tomography ( hrct ) scans showed 
 interstitial shadowing and diffuse small nodules , a subpleural reticular pattern and 
 mediastinal lymphadenopathy in all areas ( subcarinal lymph nodes 29  20  mm ) ( fig .
complete laboratory 
 examination revealed positivity of antinuclear antibodies , increased levels of lactate 
 dehydrogenase ( 25.9 kat / l ) , gamma - glutamyl transferase ( 2.8 
 kat / l ) , circulating immune complexes ( 89 u ) , soluble il-2 receptor ( 1252 
 ku / l ) , iga ( 6.6 
g / l ) , ige ( 247 u ) and tumour markers thymidine kinase ( tk , 
 53.5
g / l ) , 2-microglobulin 
 ( 5.4  mg / l ) , neuron - specific enolase ( nse , 68.0 g / l ) and cytokeratin 
 fragment 19 ( cyfra 211 , 7.7
functional testing revealed mild 
 restrictive ventilatory impairment ( vc 3,550 ml = 76% , fev1 3,000 ml = 80% , fev1/fvc = 84% , 
 tlc = 67% ) and the diffusing capacity for carbon monoxide ( dlco ) was moderately reduced 
 ( 40% ) .
cytology of bronchoalveolar lavage fluid ( balf ) showed lymphocytic 
 alveolitis with a slightly increased percentage of eosinophils ( lymphocytes 46% , eosinophils 
 1% and alveolar macrophages 53% ) , numerous pigmentophages , crystals and pas - positive 
 amorphous material .
polarized light microscopy 
 examination of balf revealed birefringent crystals that conformed to sio2 . 

morphologically , transbronchial lung biopsy confirmed a combined picture of lymphocytic 
 alveolitis and alveolar lipoproteinosis with a tiny silicotic nodule of up to 1  mm .
2.transbronchial lung biopsy.the picture clearly shows a silicotic nodule ( asterisk ) and lung tissue with 
 thickened alveolar septa infiltrated with lymphocytes and histiocytes . in the alveoli , 
 pas - positive protein material is present , corresponding to surfactant in alveolar 
 lipoproteinosis ( upper arrow ) .
in some alveoli , there are optically empty spaces 
 previously occupied by cholesterol crystals ( lower arrow ) .
the picture clearly shows a silicotic nodule ( asterisk ) and lung tissue with 
 thickened alveolar septa infiltrated with lymphocytes and histiocytes . in the alveoli , 

pas - positive protein material is present , corresponding to surfactant in alveolar 
 lipoproteinosis ( upper arrow ) . in some alveoli , there are optically empty spaces 
 previously occupied by cholesterol crystals ( lower arrow ) .
six months later , hrct showed slightly progressing bilateral diffuse interstitial 
 thickening and diffuse nodules with a diameter < 2  mm , and stationary mediastinal 
 lymphadenopathy .
ventilatory impairment was worsened ( vc 2,920 ml = 63% , fev1 2,370 ml = 
 64% , fev1/fvc = 85% , tlc = 62% ) , whereas dlco was stationary ( 42% ) .
the patient underwent 
 video - assisted thoracoscopic surgery with biopsy of the mediastinal lymph node and left 
 upper lobe .
histological examination showed already diffuse fibrosis of the alveolar septa 
 with intensive reaction of intra - alveolar macrophages and apparently resolved lymphocytic 
 infiltrates . in some areas of the lung , alveolar lipoproteinosis persisted . dispersed 
 individual silicotic nodules of up to 1  mm
the subpleural lung regions 
 contain compact fibrotic lesions ( asterisk ) with numerous cholesterol crystals 
 ( arrows ) .
the final histological findings were endogenous lipid pneumonia and alveolar 
 lipoproteinosis with hyaline nodules suggesting silicosis .
the subpleural lung regions 
 contain compact fibrotic lesions ( asterisk ) with numerous cholesterol crystals 
 ( arrows ) .
given his occupational history and the fact that the patient worked as a sandblaster which 
 put him at a risk for developing silicosis , after completion of the diagnostic process , 
 industrial hygiene specialists were asked for objective assessment of professional exposure 
 at his workplace .
the assessment , completed approximately 10 months after clinical diagnosis 
 had been made , concluded that the patient had worked for at least 3  yr and 2 months 
 ( probably even as long as 5  yr ) as a sandblaster in a small closed room with neither natural 
 ventilation to the outside nor extraction .
moreover , for the first two years , he had only 
 been equipped with a respirator instead of adequate protective wear such as an air - fed 
 helmet with a filter .
foundry silica sand was found to contain 99% of sio2 . blasting 
 activity accounted for approximately 60% of his working time .
unfortunately , exact data on 
 dust loading associated with such massive exposure were unavailable as at the time of 
 assessment , the method was no longer used . however , quantification of workplace risk 
 conditions suggested a respirable fraction of sio2 of approximately 
 0.3  mg / m .
with respect to the evidence and disease dynamics , the patient s 
 condition was recognized as an occupational disease .
the patient was treated with systemic corticosteroids ( prednisone 40  mg daily initially ) 
 for 9 months . in the first 2  yr of the disease , the patient had several infections of the 
 upper and lower airways with fever and attacks of dry cough treated with antibiotics .
after 
 2  yr , significant signs of disease progression were revealed by chest x - ray and hrct scans , 
 with more pronounced mediastinal lymph node enlargement , diffuse ground - glass opacities , 
 foci of consolidation , reticular pattern , nodules and pleural thickening ( fig .
4.hrct scans after 2  years of disease progression . ) . the restrictive ventilatory impairment on spirometry
was worsened ( vc 2,100 ml = 
 45% , fev1 1,880 ml = 51% , fev1/vc = 90% , tlc = 50% ) .
dlco was moderately decreased ( dlco = 
 44% , dlco / va = 76% ) . during bronchoscopy ,
the 
 patient was diagnosed with exercise - induced hypoxemia and started on long - term home oxygen 
 therapy . due to the milky appearance of balf and presence of ground - glass opacities on hrct 
 scans , progression of secondary alveolar proteinosis was considered .
therefore , whole lung 
 lavage of the left lung was performed with 5,000 ml of saline under general anaesthesia . 

this brought no improvement of symptoms and findings on chest radiograph ; the functional 
 parameters were even worse ( vc = 40% , fev1 = 38% , fev1/vc = 76% , tlc = 46% ; dlco = 33% ) .
considering the progression of the disease and the lack of treatment options , 
 transplantation of the silicotic lung was indicated .
the patient died during the transplantation , less than five years from diagnosis , 
 due to massive pulmonary embolism .
furthermore , fibrosis of the alveolar septa and chronic inflammatory changes of the lung 
 interstitium were present .
acute and accelerated silicosis are commonly associated with heavy exposure to silica dust 
 and usually occur in sandblasting , silica flour milling , surface drilling , tunnelling and 
 other crushing operations3 .
sandblasting 
 involves projecting a stream of abrasive particles , mostly silica sand , onto a target 
 surface by compressed air or steam11 .
there have been reports of individual 
 cases of accelerated silicosis in foundry and masonry industries , such as an interesting 
 case of accelerated silicosis in small private agate mill workers in china12 , 13 . to our knowledge ,
numerous cases of acute / accelerated silicosis in turkish denim 
 sandblasters have been reported since 20058 , 9 , 11 . 

the common denominators of circumstances of occupational exposure were small plants with 
 massive exposure to silica during sandblasting in closed and poorly ventilated rooms , long 
 working hours and absence of adequate protective equipment11 .
histopathologically , accelerated silicosis is characterized by 
 picture similar to acute silicosis with developing alveolar lipoproteinosis and interstitial 
 inflammation , but in addition silicotic nodules are present2 .
histological changes in our patient are similar to findings from 
 lung biopsy described in two cases of acute silicosis in sandblasters11 . in the first case ,
silicotic nodule composed mainly of 
 bundles of interlaced collagen with minimal inflammatory reaction and accumulation of 
 lipoproteinaceous material within the alveoli were found . in the second case ,
exudative 
 alveolar lipoproteinosis associated with chronic inflammation , thickening of alveolar septa 
 with hypertrophic and hyperplastic type ii epithelial cells were described . in our case of 
 accelerated silicosis
, two biopsies were performed . a combined picture of lymphocytic 
 alveolitis and alveolar lipoproteinosis with a tiny silicotic nodule of up to 1  mm was 
 present in the first transbronchial lung biopsy .
6 month later , histological examination 
 showed already diffuse fibrosis of the alveolar septa with intensive reaction of 
 intra - alveolar macrophages , alveolar lipoproteinosis persisting in some areas of the lung , 
 and silicotic nodules of up to 1  mm .
a great 
 limitation for comparison of findings in transbronchial and surgical lung biopsies is the 
 difference in the size of biopsy specimens , so a time progression of morphological changes 
 could not have been correctly assessed . according to the literature
, increasing evidence shows that lung inflammation and apoptosis 
 are hallmarks of acute silicosis14 . in 
 animal models of acute silicosis , severe lung inflammation , alveolar lipoproteinosis , 
 apoptosis , induction of reactive oxygen species , production of proinflammatory 
 cytokine / chemokine , and tissue destruction
the accelerated acute inhalation model also led to the development 
 of acute - like injury ( e.g. apoptosis , inflammation , tissue destruction)15 .
animal models have shown that genes regulating fibrosis , 
 oxidative stress , and metalloproteases contribute to both acute and chronic silicosis , but 
 proinflammatory cytokines are associated with acute but not chronic silicosis14 .
radiographic findings in our patient comprised features of both acute and chronic 
 silicosis , with the development of acute changes later in the course of disease . on initial 
 presentation , hrct scans showed only interstitial thickening , diffuse small nodules and 
 mediastinal lymphadenopathy , characteristic for simple chronic silicosis .
apart from 
 progression of these radiographic findings , ground - glass opacities and areas of 
 consolidation typical for lipoproteinosis appeared after 2  yr follow - up .
increased serum levels of tumour markers tk , tpa , 2-microglobulin , nse and cyfra 21 - 1 were 
 observed in our patient . also neoplastic diseases ( e.g. lung cancer , lymphoproliferative 
 disorders , lymphangitic carcinomatosis ) were suspected in the current case due to the 
 elevation of tumour markers .
however , tumour was histologically found neither in biopsy 
 samples nor at autopsy . except for lung cancer ,
increased concentrations of tumour markers 
 have been shown also in benign pulmonary diseases , but only few studies have evaluated the 
 clinical significance of tumour markers in patients with silicosis16 . in primary pulmonary alveolar proteinosis ,
an increase in 
 cyfra 21 - 1 , carcinoembryonic antigen , ca 19 - 9 , ca 15 - 3 and tpa was observed in serum and 
 balf17 , 18 .
the elevation of tumour markers can be partly attributed also to 
 the presence of secondary alveolar proteinosis in this case of accelerated silicosis . 

recently a study has demonstrated increased serum concentrations of nse and ca 125 in 
 silicosis patients without malignancy16 . 

nse and ca 125 levels were significantly correlated with spirometric parameters and ldh 
 concentrations , thus predicting disease severity in silicosis patients16 .
these results support the finding of significantly 
 increased levels of nse in our case , whereas concentrations of ca 125 were in this patient 
 normal .
it is speculated that increased serum nse concentrations in silicosis may 
 originate from hyperplasia of neuroendocrine cells in the silicotic lungs .
the release of 
 nse into the peripheral circulation may be facilitated by the increased alveolocapillary 
 membrane permeability16 .
whole lung lavage ( wll ) is considered to be a therapeutic option both in silicosis and 
 pulmonary alveolar proteinosis . in silicosis patients
wll may remove large quantities of 
 dust , soluble materials , and inflammatory cells from the lungs and relieve respiratory 
 symptoms , but sustained improvement in lung function parameters has not been shown in a 
 clinical trial1 .
has described a case of acute silicoproteinosis treated with wll leading to 
 significant clinical , physiological and radiological improvement19 .
the patient had no recurrence of the disease after the 
 treatment . in the study of zhang et al .
wll has been shown as an effective 
 therapy especially for early and accelerated silicosis , but wll should be used cautiously in 
 the treatment of advanced silicosis21
. 
 lower progression rate on chest x - ray , slower decrease of functional parameters , improvement 
 of the cough and expectoration were found in the group of silicosis patients treated with 
 wll21 .
however , in our case wll brought 
 no clinical or radiological improvement and functional findings worsened .
lung transplantation ( lt ) is a potential alternative for end - stage silicosis , especially 
 for young patients1 , 22 , 23 .
. singer 
 et al . have reported a 2-fold increased mortality risk in subjects 
 undergoing lt for occupational lung diseases23 .
this risk of death was limited to the patients with non - silicotic 
 occupational lung diseases in the first post - transplantation year .
these observations differ 
 from an earlier single - centre report of poorer post - lt survival of patients with silicosis 
 in comparison with subjects with idiopathic pulmonary fibrosis23 , 27 .
unfortunately , 
 in the current case of accelerated silicosis neither lt led to a therapeutical success .
in the current case , a rare diagnosis of accelerated silicosis was confirmed by diagnostic 
 considerations and methods .
initially , the patient presented with progressive dry cough and 
 exertional dyspnoea . given his occupational history and known high - risk exposure to 
 respirable silica particles in his profession of a sandblaster , a possible occupational 
 aetiology was considered in the early diagnostic process .
eventually , this was confirmed by 
 histological , clinical , hygiene and autopsy findings .
although accelerated silicosis is a rare disease , it may be seen today , even in series of 
 cases related to  new 
an important factor is always 
 massive exposure to respirable silica particles , frequently potentiated by unsatisfactory 
 hygienic conditions in the workplace .
given the poor prognosis of this condition , its 
 potential development in association with high - risk industries should not be underestimated . 

careful prevention measures are necessary , in the form of both the maximum possible 
 reduction of workers exposure at the workplace and the use of suitable and effective 
 protective equipment .
 sandblasting is traditionally known as a high - risk profession for potential 
 development of lung silicosis . 
 reported is a case of a sandblaster with confirmed 
 accelerated silicosis , a condition rather rarely diagnosed in the czech republic . 
 
 initially , the patient presented with progressive dry cough and exertional dyspnoea . in 
 the early diagnostic process , 
 a possible occupational aetiology was considered given his 
 occupational history and known high - risk exposure to respirable silica particles confirmed 
 by industrial hygiene assessment at the patient s workplace . 
 the condition was confirmed 
 by clinical , histological and autopsy findings . 
 the patient died during lung 
 transplantation , less than five years from diagnosis . 
Introduction
Case Report
Discussion
Conclusion