Study of H1 N1 influenza associated pneumonia patients admitted to tertiary care centre

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1 Original Article Study of H1 N1 influenza associated pneumonia patients admitted to tertiary care centre 1 Dr Kiran Bijapur, 2 Dr. S.M.Patankar 1P.G. student, Internal Medicine, Government Medical College, Miraj 2Associate Professor, Internal Medicine, Government Medical College, Miraj And PVPGH Sangli, Maharashtra, India Corresponding author : Dr S. M. Patankar Abstract: Background: Influenza viruses have been a critical cause of morbidity and mortality over many years. Epidemic nature and easy transmissibility have been the distinguishing features of these viruses. H1N1 subtype of influenza A infection has been a great cause of mortality in the recent years. There was a need to study whether there were any changes in the clinicoepidemiological pattern of the disease over last 2 years. We have Sstudied the various aspects of presentation and outcome of the disease from january 2015 july Methods: We conducted a retrospective data analysis of throat swab PCR confirmed influenza H1N1 A cases admitted from january 2015 july 2017 at a tertiary care centre. Results: There were no gender specific differences in the presentation. Significantly patients of young age were more involved. 75% of patients required icu care and 35% required ventilator support, mortality was more in those associated with co morbidities like DM, respiratory, CVS diseases and pregnancy. Key words - influenza, H1 N1 pneumonia INTRODUCTION In 1997, human cases of influenza caused by avian influenza viruses (A/H5N1) were detected in Hong Kong during an extensive outbreak of influenza in poultry. (1) Infections caused by the severe acute respiratory syndrome (SARS) associated corona virus challenged health care systems globally in March 2009 pandemic was caused by an influenza A/H1N1 virus that rapidly spread worldwide over the next several months. (2) The most extensive and severe outbreaks of influenza are caused by influenza A viruses, in part because of the remarkable propensity of the H and N antigens of these viruses to undergo periodic antigenic variation. Major antigenic variations (antigenic shifts), are seen only with influenza A viruses and may be associated with pandemics. Antigenic variation may involve the hemagglutinin alone or both the hem-agglutinin and the neuraminidase. Since 1977, H1N1 and H3N2 viruses have circulated simultaneously, resulting in outbreaks of varying severity. (3) In , the pandemic A/H1N1 virus appeared to circulate nearly exclusively. Thus the epidemiological trends and clinical presentation have changed frequently as per the antigenic variation. In Maharashtra state of India, H1N1 is in circulation since 2009 with several outbreaks till date. The present study aims to demonstrate the differences in the epidemiological, sex, age, associated co morbidities and clinical features of patients of H1N1 infection (Swine Origin Influenza Virus) who were admitted from January 2015 July 2017 at tertiary centre. 88

2 Materials and methods The present study was conducted at tertiary centre. Retrospective data of patients admitted to medicine wards with throat swab Polymerase Chain Reaction (PCR) positive for H1N1 b from January 2015 July 2017 was analyzed. Patients with H1N1 positive report treated on out-patient basis were not included. patients were treated with antibiotics cephalosporins 3 rd generation, floroquinolones, and anaerobic coverage along with oseltmavir. We studied the cases in terms of their demographic profile, clinical presentation including presence of risk factors, requirement of ICU care and invasive ventilation. The demographic variables included were: age, gender, and locality of the patient. We included cardiovascular disease, chronic respiratory disease, diabetes mellitus, pregnancy and immunocompromised state as risk factors for developing H1N1 related complications. Results During the period mentioned, there were 65 PCR confirmed cases of H1N1 infection. The age group most affected was years in both the survivor non-survivor group. As regards the locality of H1N1 infected patients; there were 61.53% cases from urban area and 38.47% from rural area, diabetes mellitus constituted the most important risk factor along with cardio-vascular disease and pregnancy Fever was the commonest symptom, Tachypnea, cough and throat pain were the most common complaints. Observations were made with respect to the requirement of intensive care and the utilization of ventilator for respiratory failure cases. 75% (n=49) required intensive care and 35% (n=23) required mechanical ventilation. Observations Table 1 Year No of patients admitted Patients were admitted in 2015, 2 patients in 2016, 13 patients in 2017 till July, it appears to be decreasing in frequency till 2016 and again increasing in Table 2 Age distribution Age Group Yrs Survivor Non Survivor Total > TOTAL Cases were more concentrated in younger age group Infection rate was more among the age group years. 89

3 Table 3 Locality Locality No Of Patients Percentage % Urban Rural Total More patients are infected in urban area than the rural. Table 4 Clinical Features Symptoms No Of Patients Percentage Fever Cough Breathlessness Throat Pain Presenting Symptom URTI Vomiting 7 10 Loose Motions 6 9 Signs Tachypnea Throat Congestion Fever Crepitations Most common complaint was, fever and presenting with involvement of respiratory system. 19 % of patients presented with GI manifestations like loose motion and vomiting, 89 90

4 Table 5 Associated co morbidities Co- No of Mortality morbidities patien Percentage percentage ts CVS (HT/IHD) COPD/ Respiratory illness Diabetes mellitus Immunocompromised status (37) 6 9 2(33) (37) Pregnancy 3 4 1(33) Others (14) No comorbidities (20) Mortality was more when the infection was associated with comorbidities more so with respiratory and cardiovascular disorders. Pregnancy is another independent risk factor for increased mortality in H1 N1 patients Table 6 Gender Distribution Sex No Of Patients Percentage Male Female Total Sex distribution is almost equal in both sexes, although appears slightly more in males

5 TABLE 7 ICU Requirement ICU Care Requirement No Of Patients Percentage Requirement Of ICU Care Ventilator Requirement /4 th of the patients required ICU care, and 35% required ventilator support. Those who required invasive ventilation were having poor prognosis. 91

6 mortality rates in patients associated with respiratory, cvs diseases, and pregnancy. 3/4th of patients required ICU care, those who required invasive ventilation were having poor prognosis. Acknowledgment: We would like to thank Medical record section center PVPGH, Sangli and GMC Miraj for granting us permission to carry out the concerned study. REFERENCES 1. The Writing Committee of the World Health Organization (WHO) Consultation on Human Influenza A/H5. Avian Influenza A (H5N1) Infection in Humans. N Engl J Med 2005; 353: Nelson Lee, David Hui, Alan Wu et al A Major Outbreak of Severe Acute Respiratory Syndrome in Hong Kong. N Engl J Med 2003; 348: Shanta M. Zimmer, and Donald S. Burke. Historical Perspective Emergence of Influenza A (H1N1) Viruses, N Engl J Med 2009; 361: Ashleigh R. Tuite, Amy L. Greer, Michael Whelan et al. Estimated epidemiologic parameters and morbidity associated with pandemic H1N1 influenza. CMAJ FEBRUARY 9, (2) 5. David M. Morens, Jeffery K. Taubenberger, Hillery A. Harvey, Matthew J. Memoli. The 1918 influenza pandemic: Lessons for 2009 and the future. Crit Care Med April ; 38(4 Suppl): e10 e Santiago Echevarría-Zuno, Juan Manuel Mejía-Aranguré Infection and death from infl uenza A H1N1 virus in Mexico: a retrospective analysis. Lancet 2009; 374: Rogelio Perez-Padilla, Daniela de la Rosa-Zamboni, Samuel Ponce de Leon. Pneumonia and Respiratory Failure from Swine-Origin Influenza A (H1N1) in Mexico. N Engl J Med 2009; 361: Akhilesh C. Mishra, Mandeep S. Chadha, Manohar L. Choudhary, Varsha A. Potdar. Pandemic Influenza (H1N1) 2009 Is Associated with Severe Disease in India. Plos one May 07, Archana Choudhry, Supriya Singh, Shashi Khare, Arvind Rai, D.S. Rawat, R.K. Aggarwal, L.S. Chauhan. Emergence of pandemic 2009 influenza A H1N1, India. Indian J Med Res 135, April 2012, pp Seema Jain, Laurie Kamimoto, Anna M. Bramley et al. Hospitalized Patients with 2009 H1N1 Influenza in the United States, April June N Engl J Med 2009; 361: J S Nguyen-Van-Tam1, P J M Openshaw2, A Hashim1, E M Gadd3, Risk factors for hospitalization and poor outcome with pandemic A/H1N1 influenza: United Kingdom first wave (May September 2009) Thorax 2010;65: Sean O Riordan, Michelle Barton, Yvonne Yau, Stanley E. Read, Upton Allen, Dat Tran. Risk factors and outcomes among children admitted to hospital with pandemic H1N1 influenza. CMAJ January 12, 2010 vol