Atypical extrapulmonary presentations of severe respiratory syncytial virus infection requiring intensive care

Clinical epidemiology and disease burden of bronchiolitis in hospitalized children in China: a national cross-sectional study

BACKGROUND

Bronchiolitis is a common acute lower respiratory tract infection (ALRTI) and the most frequent cause of hospitalization of infants and young children with ALRTI. Respiratory syncytial virus is the main pathogen that leads to severe bronchiolitis. The disease burden is relatively high. To date, few descriptions of the clinical epidemiology and disease burden of children hospitalized for bronchiolitis are available. This study reports the general clinical epidemiological characteristics and disease burden of bronchiolitis in hospitalized children in China.

METHODS

This study included the face sheet of discharge medical records collected from 27 tertiary children's hospitals from January 2016 to December 2020 that were aggregated into the FUTang Update medical REcords (FUTURE) database. The sociodemographic variables, length of stay (LOS) and disease burden of children with bronchiolitis were analyzed and compared using appropriate statistical tests.

RESULTS

In total, 42,928 children aged 0-3 years were hospitalized due to bronchiolitis from January 2016 to December 2020, accounting for 1.5% of the total number of hospitalized children of the same age in the database during the period and 5.31% of the hospitalizations for ALRTI. The male to female ratio was 2.01:1. Meanwhile, more boys than girls were observed in different regions, age groups, years, and residences. The 1-2 year age group had the greatest number of hospitalizations for bronchiolitis, while the 29 days-6 months group had the largest proportion of the total inpatients and inpatients with ALRTI in the same age group. In terms of region, the hospitalization rate of bronchiolitis was the highest in East China. Overall, the number of hospitalizations from 2017 to 2020 showed a decreasing trend from that in 2016. Seasonally, the peak hospitalizations for bronchiolitis occurred in winter. Hospitalization rates in North China in autumn and winter were higher than those in South China, while hospitalization rates in South China were higher in spring and summer. Approximately, half of the patients with bronchiolitis had no complications. Among the complications, myocardial injury, abnormal liver function and diarrhea were more common. The median LOS was 6 days [interquartile range (IQR) = 5-8], and the median hospitalization cost was 758 United States dollars (IQR = 601.96-1029.53).

CONCLUSIONS

Bronchiolitis is a common respiratory disease in infants and young children in China, and it accounts for a higher proportion of both total hospitalizations and hospitalizations due to ALRTI in children. Among them, children aged 29 days-2 years are the main hospitalized population, and the hospitalization rate of boys is significantly higher than that of girls. The peak season for bronchiolitis is winter. Bronchiolitis causes few complications and has a low mortality rate, but the burden of this disease is heavy.

Comprehensive Analysis of Severe Viral Infections of Respiratory Tract admitted to PICUs during the Winter Season in Turkey

OBJECTIVES

To analyze the course of seasonal viral infections of respiratory tract in patients hospitalized in pediatric intensive care units (PICU) of 16 centers in Turkey.

MATERIALS AND METHODS

It is a retrospective, observational, and multicenter study conducted in 16 tertiary PICUs in Turkey includes a total of 302 children with viral cause in the nasal swab which required PICU admission with no interventions.

RESULTS

Median age of patients was 12 months. Respiratory syncytial virus (RSV) was more common in patients over one year of age whereas influenza, human Bocavirus in patients above a year of age was more common (p <0.05). Clinical presentations influencing mortality were neurologic symptoms, tachycardia, hypoxia, hypotension, elevated lactate, and acidosis. The critical pH value related with mortality was ≤7.10, and critical PCO2 ≥60 mm Hg.

CONCLUSION

Our findings demonstrate that patients with neurological symptoms, tachycardia, hypoxia, hypotension, acidosis, impaired liver, and renal function at the time of admission exhibit more severe mortal progressions. Presence of acidosis and multiorgan failure was found to be predictor for mortality. Knowledge of clinical presentation and age-related variations among seasonal viruses may give a clue about severe course and prognosis. By presenting the analyzed data of 302 PICU admissions, current study reveals severity of viral respiratory tract infections and release tips for handling them.

HOW TO CITE THIS ARTICLE

Kockuzu E, Bayrakcı B, Kesici S, Cıtak A, Karapınar K, Emeksiz S, et al. Comprehensive Analysis of Severe Viral Infections of Respiratory Tract admitted to PICUs During the Winter Season in Turkey. Indian J Crit Care Med 2019;23(6):263-269.

Liver Dysfunction in Severe Sepsis from Respiratory Syncytial Virus

A 1-month-old child was admitted at our pediatric intensive care unit (PICU) in a very critical state with generalized cyanosis, grunting, high fever, tachypnea, tachycardia, severe hypotension with capillary refill time > 5 seconds, and no palpable pulse. The child was apparently doing well until a few hours before admission. On admission to PICU, his clinical diagnosis was consistent with severe sepsis with his sequential organ failure assessment scores of 7 to 8 points. We started rapid restoration of circulation with aggressive volume replacement and empiric antimicrobial therapy. Despite optimal supportive therapy, the patient showed severe liver injury leading to liver failure, making the treatment more challenging. His simplex real-time reverse transcriptase polymerase chain reaction assay and enzyme linked immune sorbent assay documented respiratory syncytial virus (RSV) infection. Through our case report we would like to highlight the extrapulmonary manifestations of RSV infections and the importance of liver dysfunction during sepsis.

Early Fluid Overload Prolongs Mechanical Ventilation in Children With Viral-Lower Respiratory Tract Disease

OBJECTIVES

Viral-lower respiratory tract disease is common in young children worldwide and is associated with high morbidity. Acute respiratory failure due to viral-lower respiratory tract disease necessitates PICU admission for mechanical ventilation. In critically ill patients in PICU settings, early fluid overload is common and associated with adverse outcomes such as prolonged mechanical ventilation and increased mortality. It is unclear, however, if this also applies to young children with viral-lower respiratory tract disease induced acute respiratory failure. In this study, we aimed to investigate the relation of early fluid overload with adverse outcomes in mechanically ventilated children with viral-lower respiratory tract disease in a retrospective dataset.

DESIGN

Retrospective cohort study.

SETTING

Single, tertiary referral PICU.

PATIENTS

One hundred thirty-five children (< 2 yr old) with viral-lower respiratory tract disease requiring mechanical ventilation admitted to the PICU of the Academic Medical Center, Amsterdam between 2008 and 2014.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The cumulative fluid balance on day 3 of mechanical ventilation was compared against duration of mechanical ventilation (primary outcome) and daily mean oxygen saturation index (secondary outcome), using uni- and multivariable linear regression. In 132 children, the mean cumulative fluid balance on day 3 was + 97.9 (49.2) mL/kg. Higher cumulative fluid balance on day 3 was associated with a longer duration of mechanical ventilation in multivariable linear regression (β = 0.166; p = 0.048). No association was found between the fluid status and oxygen saturation index during the period of mechanical ventilation.

CONCLUSIONS

Early fluid overload is an independent predictor of prolonged mechanical ventilation in young children with viral-lower respiratory tract disease. This study suggests that avoiding early fluid overload is a potential target to reduce duration of mechanical ventilation in these children. Prospective testing in a clinical trial is warranted to support this hypothesis.

Paramyxovirus Infection: Mortality and Morbidity in a Pediatric Intensive Care Unit

OBJECTIVES

We investigated mortality and morbidity of patients admitted to a pediatric intensive care unit (PICU) with paramyxovirus infection.

METHODS

A retrospective study between October 2002 and March 2015 of children with a laboratory-confirmed paramyxovirus infection was included.

RESULTS

In all, 98 (5%) PICU admissions were tested positive to have paramyxovirus infection (respiratory syncytial virus =  66, parainfluenza  =  27 and metapneumovirus  =  5). The majority of admissions were young patients (median age 1.05 years). Bacteremia and bacterial isolation in any site were present in 10% and 28%, respectively; 41% were mechanically ventilated, and 20% received inotropes. The three respiratory viruses caused similar mortality and morbidity in the PICU. Fatality (seven patients) was associated with malignancy, positive bacterial culture in blood, the use of mechanical ventilation, inotrope use, lower blood white cell count and higher C reactive protein (p  =  0.02-0.0005). Backward binary logistic regression for these variables showed bacteremia (odds ratio [OR]: 31.7; 95% CI: 2.3-427.8; p  =  0.009), malignancy (OR: 45.5; 95% CI: 1.4-1467.7; p  =  0.031) and use of inotropes (OR: 15.0; 95% CI: 1.1-196.1; p  =  0.039) were independently associated with non-survival. March and July appeared to be the two peak months for PICU hospitalizations with paramyxovirus infection.

CONCLUSIONS

Infections with paramyxoviruses account for 5% of PICU admissions and significant morbidity. Patient with premorbid history of malignancy and co-morbidity of bacteremia are associated with non-survival. March and July appeared to be the two peak months for PICU admissions with paramyxoviruses.

Bronchiolitis

Everyone on the planet is exposed to respiratory syncytial virus (RSV) infection by the age of 2 years. Most infants admitted to the pediatric intensive care unit (PICU) for respiratory support during this infection are previously healthy, but their principal risk for needing PICU treatment is young age. That is, if you are born in October/November in the northern hemisphere, then your first winter exposure to RSV is likely to be when you are less than 4 months of age and vulnerable because of poor respiratory mechanical reserve (Alonso et al. 2007). However, if you are born in May/June, then you will be 7–8 months during your first winter exposure to RSV, much bigger and stronger and have more efficient thoracic and diaphragmatic mechanics. In the PICU, the main predictors of severe outcome in previously well infants appear to be young age, presence of apnea, and pulmonary consolidation on admission chest radiograph (Tasker et al. 2000; Lopez Guinea et al. 2007). Taken together, we can say that more severe RSV bronchiolitis in PICU practice is typically a problem of pulmonary consolidation, poor respiratory mechanics, and poor reserve, in the younger infant.

Cardiac dysfunction in pneumovirus-induced lung injury in mice

OBJECTIVE

To determine biventricular cardiac function in pneumovirus-induced acute lung injury in spontaneously breathing mice.

DESIGN

Experimental animal study.

SETTING

Animal laboratory.

SUBJECTS

C57Bl/6 mice.

INTERVENTION

Mice were inoculated with the rodent pneumovirus, pneumonia virus of mice.

MEASUREMENTS AND MAIN RESULTS

Pneumonia virus of mice-infected mice were studied for right and left ventricular function variables by high-field strength (7 Tesla) cardiac MRI at specific time points during the course of disease compared with baseline. One day before and at peak disease severity, pneumonia virus of mice-infected mice showed significant right and left ventricular systolic and diastolic volume changes, with a progressive decrease in stroke volume and ejection fraction. No evidence for viral myocarditis or viral presence in heart tissue was found.

CONCLUSIONS

These findings show adverse pulmonary-cardiac interaction in pneumovirus-induced acute lung injury, unrelated to direct virus-mediated effects on the heart.

Changes in cardiac output and stroke volume as measured by non-invasive CO monitoring in infants with RSV bronchiolitis

OBJECTIVES

The primary aim of the study was to determine the changes, if any, in cardiac output (CO) and stroke volume (SV) in normal infants with RSV bronchiolitis. The secondary aim was to determine whether changes in CO (ΔCO) and SV (ΔSV) are associated with changes in respiratory rate (ΔRR).

METHODS

Non-invasive CO recordings were obtained within 24 h of admission and discharge. Changes in CO, SV, and HR measurements were compared using paired t-tests. The effect of fluid boluses during the first 24 h (<60 or ≥60 cc/kg) on CO was assessed by 2 way ANOVA with time and group as main effect. The relationship between ΔRR and ΔCO or ΔSV was assessed by linear regression. Data is presented as Mean ± SEM and mean differences with 95 % confidence interval (p < 0.05 considered significant).

RESULTS

15 infants with RSV bronchiolitis were studied. CO (1.31 ± 0.13 to 1.11 ± 0.11 l/min (0.21 [0.04-0.37]) and SV (9.42 ± 1.10 to 7.75 ± 0.83 ml/beat (1.67 [0.21-3.12]) decreased significantly while HR (142.1 ± 4.0 to 145.2 ± 3.1 beats/min 3.0 [-5.3 to 11.3]) was unchanged. SV (p = 0.02) and CO (p = 0.04) significantly decreased only in the 7 infants that received ≥60 cc/kg. ΔRR correlated significantly with ΔCO (r (2) = 0.28, p = 0.04); but not with ΔSV (r (2) = 0.20, p = 0.09).

CONCLUSIONS

∆CO was related to ΔSV and not Δ HR. The ∆CO and ΔSV were affected by fluid boluses. ΔRR correlated with ΔCO. Non-invasive CO monitoring can trend CO and SV in infants with bronchiolitis during hospitalization.

Identification and management of severe respiratory syncytial virus

PURPOSE

Identifying children at risk for severe respiratory syncytial virus (RSV) so that the most appropriate management strategies can be implemented, thereby reducing the morbidity associated with this disease, is discussed.

SUMMARY

RSV infection is associated with a variety of clinical manifestations, ranging from mild cold-like symptoms to more severe disease. The majority of infants infected with RSV develop mild upper respiratory tract disease during their initial RSV infection. However, more severe RSV disease can occur when the lower respiratory tract becomes involved, with symptoms escalating to include significant wheezing and chest-wall retractions, as well as cyanosis and tachypnea in the most severe cases. Extrapulmonary manifestations of RSV disease also have been observed, such as sepsis-like syndrome and arrhythmias. Factors that increase the risk of acquiring RSV infection have been identified, along with factors that increase the risk of severe RSV disease. The American Academy of Pediatrics (AAP) recommends that clinicians assess risk factors for severe disease when making decisions regarding evaluation and management of children with bronchiolitis. There is currently no curative treatment for RSV infection, and management primarily involves the treatment of specific symptoms. The AAP developed clinical practice guidelines to provide an evidence-based approach to the diagnosis and management of bronchiolitis in children aged one month to two years, with detailed recommendations on which therapies are appropriate for children with more severe RSV disease.

CONCLUSION

The AAP developed specific guidelines for the management of RSV bronchiolitis; however, treatment is primarily supportive and has been shown to be suboptimal in many patients. Because of the limitations associated with the management of RSV disease, prevention remains of paramount importance, especially in patients at high risk for severe disease.

Influenza and respiratory syncytial virus in infants and children: relationship with attendance at a paediatric emergency unit and characteristics of the circulating strains

A study was carried out on 2,696 Italian children, aged 0-14 years. The goals were: (1) to define the age-related impact of acute respiratory infections (ARI), measured as the risk of attendance at the Paediatric Emergency Room, (2) to better define the importance and proportion of influenza and respiratory syncytial virus (RSV) infections and (3) to acquire deeper knowledge of the influenza strains circulating in infants and children. A standardised emergency unit attendance risk (EUAR) was calculated, by age group for ARI. Specific EUARs were also calculated for the two pathogens. Pharyngeal swabs were tested by polymerase chain reaction (PCR) for influenza and RSVs. Isolation in Madine-Darby canine kidney cells (MDCK) and Hep cells, haemagglutination inhibition (HI) testing and HA1 gene sequence analysis were performed for influenza viruses. Most of the patients enrolled were aged 0-5 years, 1,139 (84.6%) and 1,061 (78.5%) in the two seasons, respectively. The most represented age class was that of 1 year olds (331 cases in 2001-2002 and 301 in 2002-2003). The highest EUAR for ARI was in patients aged 0-3 years (16.8 and 12.9 during the two seasons). The same was observed on calculating this risk by specific pathogens: 17.4 and 5.5 for influenza and 13.0 and 12.7 for RSV. Virological analysis was performed on 2,696 samples, 595 of which proved positive (22%). The highest number of isolates (326) came from patients aged 1-3 years. RSVs were more often identified than influenza viruses in infants aged up to 1 year (32 vs. 20 isolates). Of 265 strains isolated in 2001-2002, 103 were RSVs (87 type A, 16 B) and 162 were influenza (90 type A, 72 B). HI showed that influenza B viruses were related to two lineages, B/Victoria/2/87 (32%) and B/Yamagata/16/88 (68%). Of 330 strains isolated in 2002-2003, 102 were RSVs (91 type A, 11 B) and 228 were influenza viruses (220 type A, 8 B). A/H3N2 strains belonged to two clusters, A/Panama/2007/99-like and A/Fujian/411/02-like, a new variant. This paper discusses the possible role of the identified flu strains in determining EUARs among the population by age class.

Extrapulmonary manifestations of severe respiratory syncytial virus infection--a systematic review

INTRODUCTION

Respiratory syncytial virus (RSV) bronchiolitis is the most important cause for admission to the paediatric intensive care unit in infants with lower respiratory tract infection. In recent years the importance of extrapulmonary manifestations of RSV infection has become evident. This systematic review aimed at summarizing the available evidence on manifestations of RSV infection outside the respiratory tract, their causes and the changes in clinical management required.

METHODS

Databases searched were Medline (1950 to present), EMBASE (1974 to present), PubMed and reference lists of relevant articles. Summarized were the findings of articles reporting on manifestations of RSV infection outside the respiratory tract in patients of all age groups.

RESULTS

Extrapulmonary manifestations reported in previous observational studies included cardiovascular failure with hypotension and inotrope requirements associated with myocardial damage as evident from elevated cardiac troponin levels (35-54% of ventilated infants), cardiac arrhythmias like supraventricular tachycardias and ventricular tachycardias, central apnoeas (16-21% of admissions), focal and generalized seizures, focal neurological abnormalities, hyponatraemia (33%) associated with increased antidiuretic hormone secretion, and hepatitis (46-49% of ventilated infants). RSV or its genetic material have been isolated from cerebrospinal fluid, myocardium, liver and peripheral blood.

CONCLUSION

The data summarized indicate a systemic dissemination of RSV during severe disease. Cerebral and myocardial involvement may explain the association of RSV with some cases of sudden infant death. In infants with severe RSV infection cardiac rhythm, blood pressure and serum sodium need to be monitored and supportive treatment including fluid management adjusted accordingly.

Review of treatment of bronchiolitis related apnoea in two centres

AIMS

To determine whether the use of negative pressure ventilation (NPV) was associated with a lower rate of endotracheal intubation in infants with recurrent apnoea secondary to acute bronchiolitis.

METHODS

Retrospective review of two paediatric intensive care units (PICU) databases and case notes; one PICU offered NPV.

RESULTS

Fifty two infants with bronchiolitis related apnoea were admitted to the two PICUs (31 to the NPV centre). There were no significant differences between infants in the two centres in age and weight on admission, gestational age at birth, birth weight, history of apnoea of prematurity or chronic lung disease, days ill before referral, respiratory syncytial virus status, oxygen requirement before support, and numbers retrieved from secondary care centres. Respiratory support was provided to all 31 infants in the NPV centre (23 NPV, 8 PPV), and 19/21 in the non-NPV centre (18 PPV, 1 CPAP); the NPV centre had lower rates of endotracheal intubation rates (8/31 v 18/21), shorter durations of stay (median 2 v 7 days), and less use of sedation (16/31 v 18/21). In the two years after the NPV centre discontinued use of NPV, 14/17 (82%) referred cases were intubated, with a median PICU stay of 7.5 days.

CONCLUSIONS

The use of NPV was associated with a reduced rate of endotracheal intubation, and shorter PICU stay. A prospective randomised controlled trial of the use of NPV in the treatment of bronchiolitis related apnoea is warranted.

Viruses and sudden infant death

Viral respiratory infections are the most likely trigger for sudden infant death syndrome (SIDS). SIDS cases commonly have evidence of respiratory tract inflammation, a preceding history of symptoms of minor illness and occur in winter peaks coinciding with respiratory viral epidemics. Respiratory infections are a common cause for infants presenting with sudden events, involving apnoea and hypoxaemia and there are physiological mechanisms by which infants may develop sudden and severe, potentially life-threatening hypoxaemia. The rate of SIDS has fallen in the last 15 years. This is probably more to do with the reasons for the fall in deaths from respiratory causes rather than changes in sleeping position. Further falls in SIDS death rates may occur with reductions in cigarette smoking, encouragement of breastfeeding and minimising the potential for young infants to acquire respiratory infections. Early identification and recognition of life-threatening features of infections may further minimise the risks of sudden death.

A formidable challenge: the diagnosis and treatment of viral myocarditis in children

It is generally well accepted that one third of patients with viral myocarditis experience a complete recovery of normal cardiac function, one third improve clinically but show residual cardiac dysfunction, and one third experience chronic heart failure and die or require heart transplantation. It is hoped that a better understanding of the underlying cause and pathogenesis of this disease will increase the number of patients who experience a complete recovery. New advances in both the diagnosis and treatment of viral myocarditis continue to enter clinical practice at a rapid pace, and it is likely that a genomic approach to the diagnostic evaluation and treatment of this disease will become possible in the near future. Viral myocarditis, however, will remain a significant diagnosticand therapeutic challenge to both physicians and scientists alike.

Clinical and laboratory study of newborns with lower respiratory tract infection due to respiratory viruses

OBJECTIVES

To determine the prevalence of lower respiratory tract infection due to respiratory viruses in the neonatal period at admission to the neonatal intensive care unit and to compare the clinical, laboratory and radiological aspects of the clinical course, according to the etiological agent, in the neonatal period.

METHODS

Ninety newborns were studied, from January 1999 to January 2001, with bronchiolitis and/or pneumonia. The newborns were classified into three groups, according to the etiological agent identified initially: viral infection (group A), mixed viral-bacterial infection (group B), and bacterial infection (group C).

RESULTS

The virus was identified in 72 newborns (80.0%); the most prevalent was respiratory syncytial virus (RSV) (44.4%), followed by influenza A virus (22.2%). Coughing, wheezing and an interstitial infiltrate were significantly more frequent in newborns with viral infection. Mixed infection was more associated with sepsis. There was a correlation between viral infection and low values of initial and subsequent white blood cell count and C-reactive protein. RSV was the most important virus in these patients.

CONCLUSIONS

It was observed that, although the majority of viral respiratory infections had a favorable course, some patients presented a serious and prolonged clinical manifestation, especially when there was concomitant bacterial infection.

Mechanical ventilatory support in infants with respiratory syncytial virus infection

OBJECTIVE: To present a review of current knowledge of the use of mechanical ventilatory support in the management of infants with respiratory failure secondary to infection with respiratory syncytial virus (RSV). DATA SOURCES: MEDLINE and manual search for case reports and clinical trials that address management strategies for respiratory support of infants with RSV infection. Data Extraction and Synthesis: Critical appraisal of reported epidemiologic and clinical data regarding risk factors, pathophysiology, and efficacy of respiratory therapy. There is an increasing number of hospital admissions for RSV infection with a variable proportion of infants who need mechanical ventilatory support. The mortality rate is estimated to be <1% in infants without preexisting respiratory or cardiac disorders vs. <5% in those with preexisting respiratory or cardiac disorders. Optimal ventilator settings need to be refined according to the dominant obstructive or restrictive pattern with the aim to avoid barovolutrauma. The role of noninvasive ventilation and additional therapies (heliox, beta(2) agonists, surfactant) is not conclusively established. The indications for high-frequency oscillatory ventilation with the possible adjunction of inhaled nitric oxide deserve further study. Extracorporeal membrane oxygenation plays a minor role in severe cases that are refractory to conventional treatment. CONCLUSIONS: Conventional ventilation strategies are usually adequate for treating infants with severe RSV infection. Particular attention must be paid to the dominant pathophysiologic mechanism in a given condition. Prospective trials are needed to validate alternative therapeutic options and to improve the outcome of the rare but most severe cases that are difficult to control.

Myocardial injury in children with respiratory syncytial virus infection

OBJECTIVE

Respiratory syncytial virus (RSV) infection is associated with a number of extrapulmonary manifestations, including a sepsis-like syndrome characterized by any combination of hypothermia, fever, apnea, hypovolemia, and myocardial dysfunction. We hypothesized that RSV can have a direct injurious effect on the myocardium of infants and children that can be detected by the presence of cardiac troponin I (cTnI), a highly sensitive and specific marker of myocardial injury, in the blood of patients infected with the virus.

DESIGN

Serial cTnI measurements were obtained from patients admitted with documented RSV infection to the pediatric intensive care unit (PICU).

PARTICIPANTS

Data were collected and analyzed from 22 RSV infected patients and 11 control patients.

RESULTS

Elevated levels of cTnI were detected in 54.5% (12/22) of the study population during their PICU admission. The average cTnI level was significantly higher in the RSV infected group than in controls. There was a significant association between the presence of a positive troponin assay and the occurrence of a cardiovascular event, the need for inotropic support, and the requirement of mechanical ventilation. Patients who required inotropic support had a significantly higher cTnI level than the rest of the study population.

CONCLUSION

A large percentage of children admitted to the PICU with RSV infection have myocardial damage as detected by the use of commercially available troponin assays. Additionally, in a portion of these patients, this damage is clinically significant, leading to cardiovascular instability and the need for inotropic support.

RSV infection in infants and young children. What's new in diagnosis, treatment, and prevention?

RSV is the most important respiratory pathogen in infants and young children. About 1% of primary RSV infections result in hospitalization. The virus is spread by large droplets of secretions or contact with contaminated secretions. Infants infected with RSV may demonstrate poor feeding, rhinorrhea, apnea, lethargy, wheezing, and respiratory distress. Diagnosis may be made by clinical signs and symptoms (especially those observed during epidemics), by chest radiographs showing hyperinflation, or by rapid antigen detection with immunofluorescence of nasopharyngeal aspirates. Risk factors for severe disease accompanied by complications include chronic heart disease, chronic lung disease, immunodeficiency, HIV, and prematurity. Immunity is incomplete and of short duration, and reinfection is common. Treatment remains supportive and consists of oxygen administration, hydration, and diligent monitoring. Use of corticosteroids, bronchodilators, antibiotics, and ribavirin is controversial and is dependent largely on physician preference. Use of ribavirin should be reserved for patients who have severe underlying conditions associated with increased mortality rates. Intravenous RSV Ig has been replaced by palivizumab, which is generally recommended for infants at high risk for severe RSV, including those with a history of prematurity and those with chronic lung disease.

Successful treatment of severe dysrhythmias in infants with respiratory syncytial virus infections: two cases and a literature review

OBJECTIVES

To describe severe myocardial manifestations in two infants with respiratory syncytial virus infection and to review published literature reporting cardiac involvement in patients with respiratory syncytial virus disease.

DESIGN

Case report and literature review.

SETTING

Tertiary care pediatric intensive care unit (ICU).

PATIENTS

Two infants admitted to the pediatric ICU for dysrhythmias and severe myocardial dysfunction and infected with respiratory syncytial virus.

INTERVENTIONS

Conventional cardiovascular, antidysrhythmic, and respiratory support, as well as extracorporeal membrane oxygenation and high-frequency oscillatory ventilation.

MEASUREMENTS AND MAIN RESULTS

Both patients had respiratory syncytial virus infections and clinical evidence of severe myocarditis, with dysrhythmias, cardiomegaly, and cardiogenic shock. Both infants survived their hospitalizations. To our knowledge, these two patients are the first reported cases of myocarditis in infants with respiratory syncytial virus infection.

CONCLUSIONS

Severe myocardial dysfunction and dysrhythmias may accompany respiratory syncytial virus infection in some infants and may be reversible with aggressive supportive therapy.

The clinical picture presented by premature neonates infected with the respiratory syncytial virus

During the course of a 3-year epidemic of respiratory syncytial virus (RSV) in an Neonatal Intensive Care Unit, we examined premature neonates for the clinical features of RSV infections and the risk factors predisposing towards transmission of the disease. Seventy-nine infants with a median gestational age of 31 weeks were tested in 113 episodes of clinical deterioration for the presence of RSV antigen in nasopharyngeal secretions. Forty-seven results were positive and 66 negative. Bradycardia, which is gestational-age dependent, was the main presenting clinical symptom of an RSV infection in 75% of cases. The probability of an RSV-positive result in an episode with bradycardia, hypercapnia and fever was calculated to be 0.75. The only identifiable epidemiological risk factor was the total number of symptomatic RSV-infected infants in the ward. CONCLUSION. Bradycardia may indicate the presence of an RSV infection: the appropriate tests should be carried out and infection control reinforced immediately.

Viral respiratory infections

Viral infections constitute more than 60% of acute lower respiratory illnesses. Respiratory syncytial virus (RSV) and parainfluenza viruses are the most frequent etiologic agents. After transmission by large droplet aerosol or direct contact, the viruses gain entry into host cells through specific viral surface proteins; subsequently, pathogenetic mechanisms cause tissue injury and result in clinical disease. In the intensive care unit the mainstay of treatment is primarily supportive. Nonspecific treatment may include nebulized beta-agonists, aminophylline, and steroids. Ribavarin is the only specific antiviral agent approved for respiratory syncytial virus infection but its efficacy remains controversial. New therapies and vaccines offer hope for improved outcome from viral respiratory infections such as RSV.