Pulmonary haemophilus influenzae infection refers to infection of lung with the organism Haemophilus influenzae which is a gram-negative bacillus.
Haemophilus influenzae is an important pneumonia pathogen because of its severity, high incidence of complications and high mortality. The organism frequently colonizes the human upper respiratory tract, especially the nasopharynx, and is considered to form part of the normal respiratory flora. Most H. influenzae infections are the result of direct extension from the nasopharynx to the lower respiratory tract.
While no particular feature is specific the number of patterns may be present which include
- ground-glass opacities: common
- bronchial wall thickening
- centrilobular nodules
- confluent areas of consolidation
- tree-in-bud nodules
These abnormalities may have a predilection for the peripheral lung parenchyma.
Pleural effusions may be seen in a small portion of patients while mediastinal lymph node enlargement is uncommon.
Treatment and prognosis
Mortality rates in patients with H. influenzae pneumonia have been reported as ranging around 10-42%.
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