Diffuse pulmonary haemorrhage

Diffuse pulmonary haemorrhage (DPH) is a sub type of pulmonary haemorrhage where bleeding into the lung is diffuse. If the bleeding is into the alveolar spaces this can be further sub classified as diffuse alveolar haemorrhage (DAH).

Clinical presentation

While the exact presentation can vary is has been classically associated with dyspnoea  in the setting of haemoptysis + / - an iron deficiency anaemia ⁷.

Pathology

Associations

• small vessel vasculitides : alveolar haemorrhage secondary to extensive parenchymal small-vessel vasculitis is typically more diffuse and initially causes more widespread lobular ground-glass opacification with gravity-dependent density gradients through to air-space consolidation, often with interspersed areas of ground-glass opacity ; these include
  • Wegener granulomatosis ²
  • other connective tissue disorders
    • systemic lupus erythematosus (SLE) ^4,6
• post bone marrow transplantation ³
• all-trans-retinoic acid (ATRA) syndrome ¹¹
• Goodpasture syndrome ¹⁰
• pulmonary haemosiderosis : idiopathic pulmonary haemosiderosis ⁷
• coagulative disorders : often require another precipitating source such as an infection to cause DPH ⁷.
• widespread metastatic lung disease : has been described as a very rare cause of DPH ⁵

Radiographic features

Plain film

While plain film appreances are non specific there may be evidence of bilateral air-space consolidation with relative apical sparing ⁷.

CT chest / HRCT

May show areas of widespread ground glass opacification + / - crazy paving pattern ⁸ + / - areas of consolidation. In the sub acute phase HRCT may show fine diffuse nodular densities ^9-10. In later stage there may also be evidence of interlobular septal thickening due to intralymphatic accumulation of haemosiderin.

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Differential diagnosis

For radiographic (plain film and CT) in the acute phase of DPH appearances consider

• mulitple localised pulmonary haemorrhages from diffuse aspiration of blood ⁷
• pulmonary oedema ¹
• diffuse pulmonary infection / diffuse pneumonia ¹

For HRCT appearances in the sub acute phase consider (i.e fine nodules)

• hypersensitivity pneumonitis ⁹