Background: H1N1 influenza has a broad spectrum of clinical and radiological
manifestations. We witnessed a pandemic of H1N1 influenza in the year 2009, an epidemic in 2015
and it continues to cause localised outbreaks to this day causing significant mortality and morbidity.
The severity on a chest X-ray and its correlation with the outcome needs evaluation.
Objective: To assess the radiological manifestations of H1N1 influenza patients at a presentation in
the 2017 outbreak in India in a tertiary care setting and ascertain the most common pattern of
To determine the association between the radiological manifestations of H1N1 pneumonia and the
To ascertain if co-morbid conditions contributed to the adverse patient outcome.
Methods: A retrospective (December 2016 till July 2017) analysis of the clinico-radiological data of
all the inpatient cases positive for H1N1 was done at a tertiary care chest institute in Bangalore,
India. The patients’ outcome was divided into two groups. A: Recovered and discharged and B:
Death. The chest X-rays done at presentation to our hospital were used as the radiological tool.
Results: 75 patients were included in this study. Cough, dyspnea and fever were the usual presenting
symptoms with an average duration of 7 days, prior to presentation at our hospital. Bilateral midzone
and lower zone consolidation was the most common radiological pattern. Patients with a normal
chest X-ray had a significantly better outcome. An absence of pleural involvement and lower scores
on a severity scale were associated with a better outcome. Diabetes mellitus was the commonly
associated co-morbidity. The presence or absence of a co-morbidity did not influence the outcome.
Conclusion: In a resource-limited setting, chest X-rays can be used to prognosticate patients with
H1N1 influenza. The more the number of zones involved would implicate more complications and
greater risk of death.