Idiopathic pneumonia syndrome

Idiopathic pneumonia syndrome (IPS) refers to diffuse lung injury which can occur following haematopeotic stem cell transplantation where neither an infectious nor non-infectious etiology can be found.

Epidemiology

The incidence of IPS is thought to be around 12% following haematopoetic stem cell transplantation.

Clinical presentation

Clinical presentation can vary from being asymptomatic to full blown acute respiratory distress syndrome. Its median onset time is around 40-50 days following transplantation, but there is an early peak in the first 14 days, followed by a lower but consistent incidence up to around 80-100 days.

Pathology

Its etiology is thought to be multifactorial inclusive of chemoradiotherapeutic insults and graft versus host disease . There are two main histopathological patterns

  • interstitial pneumonitis
  • diffuse alveolar damage

Radiographic features

Plain radiograph / CT
  • would typically show diffuse airspace and/or intestinal infiltrative opacification

See also