Acute Respiratory Distress Syndrome

Today we saw a case of a patient with subacute progressive hypoxemic respiratory failure for which no infectious etiology could be confirmed.

Many different pathogens can cause sepsis, which in turn can be associated with ARDS. In terms of specific pathogens, the following are reported to cause ARDS (outside of the usual pneumonia --> sepsis --> ARDS):

• Bacterial
  
  • S. pneumoniae
  • Gram negative rods including Pseudomonas
  • Legionella, Chlamydophilia, Mycoplasma
  • Tuberculosis
• Viral
  
  • Influenza A (and B) particularly H5N1 but also H1N1 and seasonal
    
  • Coronavirus (SARS)
  • Varicella Zoster (in primary infections)
• Parasite
  
  • Plasmodium Falciparum

A non-infectious syndrome, Acute Interstitial Pneumonia (AIP) can mimic the features of ARDS pathophysiologically, radiographically, and on biopsy. Some studies suggest that AIP is as common as the infectious causes.

Guidelines for the management of severe sepsis (including ARDS) are available here.