Features of the course of community-acquired pneumonia on a background of influenza A(H1N1)pdm09
Sergeeva I.V., Demko I.V.

Krasnoyarsk State Medical University named after Professor V.F. Voyno-Yasenetsky

Influenza A(H1N1)pdm09, in addition to high contagiousness, differs from seasonal influenza by the increased development of complicated forms.
Aim: to study the features of the course of community-acquired pneumonia on a background of influenza A(H1N1)pdm09.
Patients and methods: 169 patients aged 18 to 85 years were examined between 2009 and 2016. The diagnosis of community-acquired pneumonia was verified on the basis of clinical and epidemiological data at the time of admission to the hospital, X-ray and laboratory diagnostic methods. Criteria for the severity were: the degree of respiratory failure, the severity of the intoxication syndrome, the volume of inflammatory infiltration, the presence of complications, the decompensation of comorbidities. Severe community-acquired pneumonia was registered in 96 (56.8%) patients, in 73 patients (43.2%) - community-acquired pneumonia of moderate severity.
Results: the course of community-acquired pneumonia on a background of influenza A(H1N1)pdm09 in the patients examined by us was characterized by an acute onset, manifested by severe intoxication syndrome and respiratory tract disease, the degree of manifestation of which depended on the severity of the disease. In 56.8% of cases, severe course of pneumonia was registered, mainly in young people aged 18-29 years with a burdened premorbid background with a predominance of metabolic syndrome, which determined its leading role in the development of severe pneumonia on a background of influenza A(H1N1)pdm09. According to the X-ray examination in patients with severe pneumonia, bilateral pneumonia with total and fractional lesion was more often diagnosed (64.6%), unilateral pneumonia prevailed in the group of patients with moderate pneumonia (83.5%) with predominant localization in the right lung (68, 5%). A feature of hematological parameters in severe pneumonia was a slight leukocytosis with thrombocytopenia, which increased depending on the day of admission. In the biochemical parameters of severe pneumonia, there was an increase in C-reactive protein (CRP), creatinine, aspartate aminotransferase (AST), creatine phosphokinase (CPK), total protein reduction, which is regarded as a manifestation of multiple organ on the background of endogenous intoxication. 
Conclusion: community-acquired pneumonia against the background of influenza A(H1N1)pdm09 occurs in severe form, which is based on the syndrome of a pronounced systemic inflammatory response.

Key words: influenza A(H1N1)pdm09, community-acquired pneumonia, patients, severity of the course, premorbid background, laboratory diagnostic methods.
For citation: Sergeeva I.V., Demko I.V. Features of the course of community-acquired pneumonia on a background of influenza A(H1N1)pdm09 // RMJ. 2017. № 18. P. 1280–1285.