search
for
 About Bioline  All Journals  Testimonials  Membership  News


Iranian Journal of Pediatrics
Tehran University of Medical Sciences Press
ISSN: 1018-4406 EISSN: 2008-2150
Vol. 21, Num. 2, 2011, pp. 200-204
Full Text HTML

Iranian Journal of Pediatrics, Vol. 20, No. 2, Apri l-June, 2011, pp. 200-204

Clinical Presentation of Novel Influenza A (H1N1) in Hospitalized Children

 Gholamreza Soleimani1, MD; Marzieh Akbarpour2, MD

Department of Pediatrics, Zahedan University of Medical Sciences, Ali e-bne Abitaleb Hospital, Zahedan, Iran

Received: Feb 07, 2010; Final Revision: Jul 28, 2010; Accepted: Oct 24, 2010

Code Number: pe11036

Abstract

Objective: Human pandemic influenza H1N1 virus as the cause of febrile respiratory infection ranging from self-limited to severe illness has spread globally during 2009. Signs and symptoms of upper and lower respiratory tract involvement, fever, sore throat, rhinitis, myalgia, malaise, headache, chills and fatigue are common. In this article we report the clinical presentation of Influenza A (H1N1) in our hospitalized children.
Methods: Between September and October 2009, all children requiring hospitalization for suspected H1N1 infection were transferred to Pediatric Infectious Diseases ward. For all patients the throat swab was taken for PCR testing to confirm or exclude the diagnosis of H1N1 Influenza A. Case patients consisted of H1N1-positive patients. Age, sex, symptoms, signs, laboratory data, CXR changes, details of therapy, duration of admission and patient outcome were documented.
Findings: Twenty patients were H1N1 positive. Mean age of the patients was 65.50±9.8 months. Fever and coughs were with 55% the most commonly reported symptoms. Other presentations included vomiting (55%), abdominal pain (25%), cyanosis and dyspnea (5%), body ache (40%), rhinorrhea (80%), sore throat (35%), head stiffness (5%) and loss of conciousness (5%). The median temperature of the patients was 38.5ºC. Chest X-Ray changes were noted in 13 out of 20 patients (65%). Mean leukocyte and platelet was 6475 and 169000 respectively. Seventeen (85%) patients were treated with Oseltamivir, 3 patients received adjuvant antibiotics. The mean duration of admission was 3 days. Three patients required intensive care support and all of them expired due to superinfection.
Conclusion: Our data confirm that the presentation of influenza in children is variable and 2009 H1N1 influenza may cause leucopenia and thrombocytopenia.

Key Words: Influenza; Infectious Diseases; H1N1; Oseltamivir

Introduction

Human Swine Influenza A [H1N1] is a highly transmissible infection which has predominantly affected children and young adults[1]. In the United States to date, most confirmed cases of S-OIV (swine-origin influenza A [H1N1] virus) infection have been characterized by self-limited, uncomplicated febrile respiratory illness and symptoms similar to those of seasonal influenza (cough, sore throat, rhinorrhea, headache, and myalgia); approximately 38% of cases have also vomiting or diarrhea, neither of which is typical of seasonal influenza[2].

As with seasonal influenza, some patients with 2009 H1N1 influenza present without fever[3].      Young children are less likely to have the usual influenza signs and symptoms, such as fever and cough[4]. Influenza illness in infants and children may present similarly to other respiratory viruses, and symptoms and presentation may be different than its presentation in adults[3]. Infants may present with fever and lethargy, and may not have cough or other respiratory symptoms.

Symptoms of severe disease in infants and young children may include apnea, tachypnea, dyspnea, cyanosis, dehydration, altered mental status, and extreme irritability[5]. In addition, infants and young children may experience diarrhea more frequently than older children and adults[3]. This study describes clinical and laboratory characteristics and outcomes of pediatric patients in Zahedan with 2009 influenza A [H1N1] infection.

Subjects and Methods

This is a prospective study. All patients (up to 14 years) who were hospitalized in Pediatric Infectious Diseases ward in Ali ebne Abitaleb hospital, Zahedan, Iran, for suspected H1N1 infection (at least 24 hours with an influenza-like illness: fever, cough or sore throat), with history of close contact with infected patients by H1N1 virus) between September and October 2009, were considered for the investigation.

For all patients the throat swab was taken for PCR testing (a real-time reverse-transcriptase–polymerase-chain-reaction assay) to confirm or exclude the diagnosis of H1N1 Influenza A.      Nasopharyngeal specimens were collected using swabs and placed into Universal Transport Media before transport. The specimen was tested at the Bu Ali infectious disease Laboratory Institute for pandemic [H1N1] 2009 virus, using real-time reverse-transcriptase polymerase chain reaction (RT-PCR) reagents. Patients with H1N1-negative test were excluded from the study.

Demographic data, underlying medical disease, clinical signs and symptoms, laboratory tests, radiographic changes, details of therapy, duration of admission and disease outcome were documented. The temperature was measured axillary. Three weeks after discharge, patients were followed in outpatient clinic to evaluate general condition and laboratory data.

This study was approved by the ethics committees of Zahedan University of Medical Sciences. Variables were expressed as means (standard deviation). All data analyses were performed using SPSS, version 16.

Findings

Of 132 patients viral swabs was taken. In 20 patients (60% males and 40% females) H1N1 test was positive. Mean age of patients was 65.50±9.8 months (range: 6 to 144 months). The most common admission symptoms were fever and cough (n=11). Other common presentations included poor feeding 16 (80%), rhinorrhea 16 (80%), vomiting 11 (55%), body ache 8 (40%), and sore throat 7 (35%). Table 1 shows the clinical characteristics of patients. One of our patients presented with vomiting, high grade fever, body ache and neck stiffness, his cerebro-spinal fluid (CSF) analysis was normal without any cells.

The patients were admitted to hospital in average 2 days (range 1 to 5 days) after symptom onset. None of the patients had an underlying medical condition. Table 2 shows the vital signs of patients. Three patients were admitted to the pediatric intensive care unit (PICU), and required mechanical ventilation. Chest X ray changes were noted  in  13 out of 20 patients (65%) including 10 (55%) with bilateral infiltrates and 3 (15%) with unilateral involvement on chest radiograph. Among these 13 patients, one patient developed bilateral pleural effusion during her hospital stay and one developed unilateral empyema. Three of the 20 patients had microbiologic evidence of secondary bacterial infection by CSF and blood cultures.

Fourteen (75%) patients received antiviral treatment with Oseltamivir. Two (10%) patients were not treated with antivirals, 1 (5%) treated with antibiotic and 3 (15%) patients received antibiotics and Oseltamivir. None of patients had received seasonal influenza vaccination. Mean length of hospital stay was 4.2±4.6 (range: 1 to 20) days. Patients had not a history of travel to foreign countries prior to admission.

Table 2 shows laboratory findings of the patients. The mean white blood cell count (WBC) was 6475.0 (4.9) and the mean lymphocyte count was 40.37% (±11.9) (range: 20-58%). Eleven patients (55%) had WBC less than 4000. Three patients had leukocytosis due to superinfection (pneumonia, empyema) that required intensive care support and all of them expired. Ten patients  (50%) had platelets less than 150000.

Eighteen patients (90%) were followed 3 weeks after discharge and their cell counts were normal.

Discussion

A novel swine-origin influenza A virus was identified as the cause of outbreaks of febrile respiratory infection ranging from self-limited to severe illness[2]. The most commonly reported symptoms of influenza A [H1N1] virus in different studies include cough, fever, sore throat, malaise and headache [6-9].

The signs and symptoms of influenza caused by pandemic H1N1 influenza A virus are similar to those of seasonal influenza, although gastro­intestinal manifestations appear to be more common with pandemic H1N1 influenza[10].      Vomiting and diarrhea have been reported more often with 2009 H1N1 influenza than with seasonal influenza[1]. Dawood et al mentioned that 25% of their patients had diarrhea, and 25% had vomiting[2]. In another study, diarrhea or vomiting was reported in 39% of patients, including 42% of children (i.e., patients under the age of 18 years) and 37% of adults (those ≥18 years)[11].

In the same way, the most frequent symptoms in our patients were fever, cough, poor feeding, rhinorrhea, vomiting, body ache and Sore throat. None of our patients had diarrhea, but about half of them complained from vomiting. None of our patients had diarrhea, but about half of them complained from vomiting.

Several severe clinical syndromes associated with influenza A 2009 H1N1 infection may be seen[12]. Other unusual presentations of influenza A [H1N1] virus were conjunctivitis, earache, hematemesis, epistaxis, croup, apnea, acute abdomen, spontaneous pneumomedias-tinum complicating pneumonia, altered mental state[8,9,13,14].

One of our patients was a 10 year old girl that presented with loss of consciousness (Glassco coma score = 9) and seizure. Her CSF contained white blood cells (segmented: 40%, lymphocyte: 60%). The patient was treated with Oseltamivir.      After some days, she had to be intubated because of respiratory failure and acute respiratory distress syndrome and died. An 8 year old boy had empyema and unfortunately two days after thoracotomy expired in pediatric intensive care unit.

Critical illness due to 2009 influenza A [H1N1] in Canada occurred rapidly after hospital admission, often in young adults, and was associated with severe hypoxemia, multisystem organ failure, a requirement for prolonged mechanical ventilation, and the frequent use of rescue therapies[15]. In the same way, our critical ill patients were intubated and because of respiratory failure required mechanical ventilation.

In a study by Jain et al that collected data on 272 patients hospitalized at least 24 hours for influenza-like illness and had positive tests for the 2009 H1N1 virus report that a significant proportion of hospitalized patients had findings on chest radiography that in 40% were consistent with pneumonia, and the majority had bilateral infiltrates. They suggested that better studies were needed to correlate radiographic findings with the cause of pneumonia during influenza outbreaks[11].

In another article that reviewed the chest radiographic and CT findings in patients with presumed/laboratory-confirmed influenza A [H1N1] virus infection conclude that the radiographs are normal in more than half of patients with S-OIV [H1N1] infection, but manifest as extensive bilateral air-space disease in hospitalized patients requiring advanced mechanical ventilation. These patients are also at risk for developing plural effusion, which should be carefully sought for on contrast-enhanced CT scans[16].

In the present study, similar to other studies, bilateral involvement on chest radiograph was the most common presentation. The chest CT scan of one of the patients showed mediastinal adenopathy, ground glass opacity, thickness of interlobular septa, bilateral consolidation with pleural effusion and Non cardiogenic pulmonary edema. 

In a large U.S.A. case series of hospitalized patients with 2009 H1N1 virus infection during the first 2 months of the pandemic, the following laboratory abnormalities were observed: Leukopenia 20%, leukocytosis 18%, thrombo­cytopenia 14%, thrombocytosis 9%[11]. In a study of individuals with probable pandemic H1N1 influenza A infection, relative lymphopenia (≤21 percent of white blood cells) without leukopenia was observed in 23 of 25 adults, but in only 3 of 16 children[17].

In critically ill children with H1N1 influenza of swine origin in the UK lymphopenia and thrombocytopenia was reported in some cases[8].       In our study about half of patients had leukopenia and/ or thrombocytopenia; their blood cell count was normal after 3 weeks.

Jain et al reported that seventy five percent of their patients received antiviral treatment with Oseltamivir. Data suggest that the use of antiviral drugs was beneficial in hospitalized patients especially when this therapy was initiated early[11].

As a limitation of this study, some of patients were excluded from the study because they did not want to be admitted in hospital and the group may not be representative of hospitalized patients.

Conclusion

Our data shows that in the H1N1 outbreak under study the presentation of influenza in children was variable and H1N1 influenza virus caused leukopenia and thrombocytopenia.

Acknowledgment

The authors thank all colleagues in pediatrics ward and Research Center for Children and Adolescents Health for their help in preparing data.

Conflict of Interest: None

References

  1. Fitzgerald DA. Human swine influenza A [H1N1]: Practical advice for clinicians early in the pandemic. Paediatr Respir Rev 2009; 10(3):154-8.
  2. Dawood FS, Jain S, Finelli L, et al. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med 2009;360(25):2605-15.
  3. Interim Recommendations for clinical Use of Influenza Diagnostic Tests During the 2009-10 Influenza Season. Available at:       http://www.cdc.gov/h1n1flu/guidance/diagnostic_tests.htm. Access date: Dec 25, 2009.
  4. United States Centers for Disease Control and Prevention. Interim guidance for clinicians on the prevention and treatment of swine-origin influenza virus infection in young children. Available at: http://www.cdc.gov/swineflu/childrentreatment.htm. Access date: Apr 29, 2009.
  5. Epidemiology, clinical manifestations, and diagnosis of pandemic H1N1 influenza ('swine influenza').htm. Access date: December 27, 2009.
  6. World Health Organization. Human infection with new influenza A (H1N1) virus: clinical observations from Mexico and other affected countries, May 2009. Wkly Epidemiol Rec 2009; 84(21):185-9.
  7. CDC. Update: Swine-origin influenza A (H1N1) virus infections in a school, New York City, April 2009. MMWR 2009; 58(17):470-2.
  8. Witkop CT, Duffy MR, Macias EA, et al. Novel influenza A (H1N1) outbreak at the U.S. Air Force Academy. Epidemiology and viral shedding duration. Am J Prev Med 2010;38(2):121-6.
  9. Hackett S, Hill L, Patel J, et al. Clinical characteristics of paediatric H1N1 admissions in Birmingham, UK. Lancet 2009;374(9690):605-7.
  10. Thorner AR. Epidemiology, clinical manifestations, and diagnosis of pandemic H1N1 influenza ('swine influenza'). Available at: http://www.uptodate.com/ patients/content/topic.do?topicKey=~56lKlZbYWciMeh6&source=see_link. Access date: May 28, 2009.
  11. Jain S, Kamimoto L, Bramley AM, et al. Hospitalized patients with 2009 H1N1 influenza in the United States, April-June 2009. N Engl J Med 2009; 361(20):1935-44.
  12. Fowler R, Jouvet P, Christian M, et al. Critical illness due to influenza A 2009 H1N1. Critical Care Rounds. Available at:  http://www.canadiancriticalcare.org/H1N1%20CCRounds%20Oct%2023%2009.pdf Access date: Oct 2009.
  13. Louie J, Winter K,  Harriman K, et al. Virus infection_California, April-May, 2009 hospitalized patients with Novel Influenza A (H1N1). JAMA 2009; 302(2):137-40.
  14. Hasegawa M, Hashimoto K, Morozumi M, et al. C Spontaneous pneumomediastinum complicating pneumonia in children infected with the 2009 pandemic influenza A (H1N1) virus. Clin Microbiol Infect 2010; 16(2):195-9.
  15. Kumar A, Zarychanski R, Pinto R, et al. Critically ill patients with 2009 influenza A (H1N1) infection in Canada. JAMA 2009; 302(17):1872-9.
  16. Agarwal PP, Cinti S, Kazerooni EA. Chest radiographic and CT findings in novel swine-origin influenza A (H1N1) virus (S-OIV) infection. AJR Am J Roentgenol 2009; 193(6):1488-93.
  17. Cunha BA, Pherez FM, Schoch P. Diagnostic importance of relative lymphopenia as a marker of swine influenza (H1N1) in adults. Clin Infect Dis 2009;49(9):1454-6.

Copyright 2011 - Iran Journal of Pediatrics


The following images related to this document are available:

Photo images

[pe11036t2.jpg] [pe11036t1.jpg]
Home Faq Resources Email Bioline
© Bioline International, 1989 - 2024, Site last up-dated on 01-Sep-2022.
Site created and maintained by the Reference Center on Environmental Information, CRIA, Brazil
System hosted by the Google Cloud Platform, GCP, Brazil