Hard metal pneumoconiosis

A hard metal pneumoconiosis is usually classified as a type of fibrotic pneumoconiosis where the precipitating agent consists of a hard metal (not a heavy metal) such as.

  • cobalt
  • tungsten/tungsten carbide alloys
  • or a mixture

A broader term used is hard metal lung disease (HMLD) which also takes into account the non-fibrotic stages/forms such as bronchitis/obliterative bronchitis caused by hard metal lung disease.

Clinical presentation can be similar to that of hypersensitivity pneumonitis, with some patients having episodes of work-related subacute disease and some patients evolving, more or less rapidly, to lung fibrosis 6

Hard metals are widely used for industrial purposes which require extreme hardness and high-temperature resistances, such as for cutting tools, oil well drilling, and jet engine exhaust ports 2. Hard metal utilisation plants can contain enclosed chamber and with each application, large volumes of fine aerosols can be created 3.

Histopathological manifestations of hard-metal disease can range from bronchitis to subacute fibrosing alveolitis to interstitial fibrosis 8.

Some authors outlined a set of diagnostic criteria which includes 8:

  • history of exposure to metal dust
  • characteristic clinical features, including shortness of breath, cough, and dyspnea on exertion over a prolonged period
  • radiologic findings of interstitial lung disease
  • histologic findings of interstitial lung disease or a giant cell interstitial pneumonia pattern (a large number of giant cells filling airspaces), with thickening of the interstitium and alveolar walls by mononuclear cells
  • histopathologic finding of metallic content in lung tissue

Plain chest radiographic features are non-specific. A chest radiograph may be normal or show a nodular, reticulonodular, or reticular pattern 7.

An exposure history of hard metal is essential in image interpretation. Described features are non-specific on their own and a dependent on the stage. These include 5:

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Article information

rID: 20928
System: Chest
Tag: cases
Synonyms or Alternate Spellings:
  • Hard metal pneumoconioses
  • Hard metal pulmonary disease
  • Hard metal interstitial lung disease (HM-ILD)
  • Hard metal interstitial lung disease
  • Hard metal lung disease
  • Hard-metal pneumoconiosis
  • Hard-metal pneumoconioses

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