What is involved? (including coding of cases)
SABRE Case Studies and Information
Caplan’s Syndrome – Rheumatoid Pneumoconiosis
A
coal miner developed rheumatoid arthritis aged 52. He had worked in the coal
mining industry for 32 years, with 8 years on the coal face, at a time when dust
levels were high. He presented with joint pains, but when examination revealed
rheumatoid nodules on his elbows, he commented that he had noticed these for
approximately two years and that he had joint pain for about the same time,
which he had attributed to “getting old”. Typical “Caplan nodules” were
seen on his chest radiograph (Fig 1). He died aged 57 from a coronary
thrombosis. Post-mortem lung examination confirmed the diagnosis and also showed
background nodulation compatible with coalworkers’ pneumoconiosis (Fig 2).
Caplan’s
syndrome was first described in 1953 in coal workers who had both progressive
massive fibrosis and seropositive rheumatoid arthritis.
It has since been described in other pneumoconioses caused by silica
inhalation and non-asbestos silicate minerals. Chest radiographs showed rounded
opacities ranging from 0.5 to 5cm in diameter, different from the opacities due
to coal workers’ pneumoconiosis or PMF, and peripheral in distribution.
The nodules were characteristically well defined by their layered
pattern. Histopathology
showed central necrosis surrounded by new concentric layers of collagen
interspersed with polymorphonuclear leukocytes and a few macrophages.
This region represented the active zone of inflammation and could be used
to differentiate from non-rheumatoid pneumoconiotic nodules.
Nodules
normally develop with onset of joint disease but can occasionally occur before
any symptoms. They may remain stable in size for months or years, but also
enlarge as new lesions develop, and occasionally spontaneously regress. Other
manifestations of rheumatoid arthritis (e.g. pleural effusion, basal
interstitial fibrosis) may also be found.
The relationship between level and duration of dust exposure and the
development of disease is controversial, but exposure to anthracite coal appears
to be a particular risk factor. An increased incidence of circulating positive
rheumatoid factor among miners with PMF has been reported, but Caplan’s
syndrome has also been described in young miners with little or no coal
workers’ pneumoconiosis following short exposures. It is of interest that the
syndrome occurred more commonly in the Welsh mines and that incidence has fallen
markedly with dust control measures.
Figure 1.
Figure 2.
