The North Carolina Medical Society recently posted a notice from the CDC about hemorrhagic pneumonia [hat-tip, Homebody at PFI_Forum]:
The CDC says that there have been some anecdotal reports of possible “hemorrhagic pneumonia” cases among influenza patients who have died or been hospitalized for severe illness. The phrase “hemorrhagic pneumonia” is somewhat outdated, and most clinicians will not use the term to describe this condition, which can be a very rare complication of viral respiratory infection. Some other terms that can be used to describe this include diffuse alveolar hemorrhage (DAH), which can be caused by infections but doesn’t have to be, and hemorrhagic pneumonitis. In any event, it’s a serious complication that will sometimes lead to acute respiratory distress syndrome (ARDS). It occurs very rarely as a complication of seasonal influenza, and there is some concern that it might be more common in H1N1 infections.
The CDC is asking state health officials to look out for possible cases that may involve clusters of patients who might have these symptoms, or a large proportion of cases with these symptoms (e.g., 4 of 5 deaths). They will invariably be among the most severely ill influenza patients (i.e., deaths, ICU patients).
This is a hard diagnosis to make, and the most telling symptom may be hemoptysis (bloody sputum, frothy bloody cough), although not all cases will have it.
- Acute onset of rather more severe respiratory infection (dyspnea–difficulty breathing–is common)
- Hemoptysis is often seen on initial presentation (~70% of cases)
- CXR and physical exam will suggest alveolar infiltrates (radiographic opacities)
- Diagnosis is usually made by BAL (brochoalveolar lavage) and pathology testing (increasingly more hemorrhagic fluid/secretions from sequential BAL
Email sent by Regional Liaison Officer, Region IV, H1N1 Response Surveillance and Epidemiology Team, Centers for Disease Control and Prevention
Questions concerning possible cases or this email may be directed to Medical Epidemiologist Zach Moore, MD, at the North Carolina Division of Public health at firstname.lastname@example.org.
The fact that the CDC is looking for a more severe form of H1N1 is notable. The fact that they are looking for clusters suggests that they think there is a distinct strain causing severe symptoms. As I have argued in a number of blogs, it is possible that there are multiple strains of the new H1N1 virus circulating, some of which may cause more severe disease than others.
Looks like the CDC thinks so too.
Too bad they aren’t telling the public.