I. Epidemiology: RSV

  1. Incidence: 2.1 Million children under age 5 years seek medical attention for RSV annually in the U.S.
  2. Annual epidemics occur winter to early spring
    1. Range: November to April
    2. Peak: January to February
  3. Overall hospitalization rate: 1-2% (90,000 per year in United States)
  4. Attack rates
    1. Daycare exposure: 100% infection rate
    2. Sibling exposure: 40% infection rate
  5. Cohorts Affected
    1. Children under age 2 years (usually 1-6 months old)
    2. Of infants at risk, 50% will be infected
      1. By age 2 years, nearly all children will have had one RSV infection (at least 90%)
        1. Prior infection is no protection against future infection
      2. RSV associated hospitalizations
        1. RSV hospitalizations due to Pneumonia: 20-25%
        2. RSV hospitalizations due to Bronchiolitis: 75%
    3. Older children and adults
      1. Common Cold-like Syndrome
      2. Rhinorrhea, Sore Throat, and cough
    4. Elderly and Immunocompromised patients
      1. Severe Pneumonia may result

II. Risk Factors

  1. Prematurity
  2. Complex Congenital Heart Disease
  3. Chronic lung disease
  4. Immunosuppression
  5. Neuromuscular disease
  6. Metabolic disorder
  7. Staat (2002) Semin Respir Infect 17:15-20

III. Pathophysiology: RSV

  1. Enveloped, nonsegmented, negative-strand RNA virus (Paramyxoviridae Family)
    1. Subtypes A (causes more severe disease)
    2. Subtypes B
  2. Transmission
    1. Close contact
    2. Fingers or fomites
    3. Self inoculation of Conjunctiva or anterior nares
    4. Coarse aerosols from coughing or sneezing
  3. Viral load peaks at 4 to 5 days
    1. Corresponds to peak illness severity at 3-5 days
  4. Incubation: 2 to 8 days
  5. Virus shedding: 3-8 days (up to 4 weeks in infants)
  6. Duration of illness (under age 2 years)
    1. Initial symptoms start to abate at 7 days
    2. Coughing and Wheezing often persist 2-3 weeks
    3. Median: 12 days
    4. Prolonged in 10% of cases as long as 4 weeks
  7. Re-infection with different RSV forms is common
    1. Prior RSV infection confers no immunity against new infection
  8. Infectious course
    1. Viral replication starts in the nasopharynx
    2. Spreads to the small Bronchiole epithelial lining
    3. Lower respiratory tract infection onset within 3 days with increased airway edema and mucous production, and ultimately tissue necrosis
    4. Results in small airway obstruction, air trapping and increased airway resistance

IV. Causes: Bronchiolitis

  1. Respiratory Syncytial Virus (RSV)
    1. Responsible for 50-80% of cases
  2. Human Metapneumovirus (MPV)
    1. Emerging paramyxovirus
    2. Similar presentation as RSV
    3. Hamelin (2004) Clin Infect Dis 38:983-90
  3. Parainfluenza
  4. Influenza
  5. Adenovirus
  6. Human Bocavirus

V. Symptoms

  1. Viral prodrome (initial 2-3 days)
    1. Coryza
    2. Rhinorrhea
  2. Typical symptoms in infants and young children
    1. Cough (98%)
    2. Low grade fever (75%)
    3. Labored breathing (73%)
    4. Wheezing (65%)
    5. Rhinorrhea
    6. Mild systemic symptoms
  3. Typical symptoms in older children
    1. Cough
    2. Coryza
    3. Rhinorrhea
    4. Conjunctivitis
  4. Severe illness
    1. Grunting
    2. Nasal flaring
    3. Intercostal retractions
    4. Tachypnea or Dyspnea
    5. Hypoxia and Cyanosis
    6. Apparent Life Threatening Event or Apnea
      1. Premature Infants or very young infants are at increased risk
      2. May occur without other signs of respiratory distress

VI. Signs

  1. Diffuse Wheezing
  2. Rhonchi
  3. Rales

VII. Differential Diagnosis

  1. See Wheezing
  2. Reactive airway disease
  3. High fever suggests alternative diagnosis (e.g. Pneumonia)

VIII. Evaluation: Age under 3 months

  1. Infants under age 30 days
    1. Complete full Neonatal Sepsis evaluation for febrile infants under 1 month of age (despite Bronchiolitis diagnosis)
  2. Infants under age 60 days
    1. Evaluation based on clinical evaluation
    2. Admit all infants under 60 days of age with Bronchiolitis due to apnea risk
  3. Infants ages 60-90 days of age
    1. Ill appearing, febrile infants should be evaluated for bacteremia (and coinfection)
    2. Non-toxic febrile infants at 60-90 days with Bronchiolitis do not need a bacteremia work-up
      1. Blood Cultures and Lumbar Puncture are not needed
      2. Urinalysis and Urine Culture should still be performed
      3. Ralston (2011) Arch Pediatr Adolesc Med 165(10):951-6

IX. Labs

  1. Blood Cultures not needed in routine cases
  2. Complete Blood Count (CBC) is not routinely recommended
  3. RSV swabs or washings of nasopharynx, throat, or Sputum
    1. Bronchiolitis (and RSV) is a clinical diagnosis based on symptoms and signs above and does not require lab testing for confirmation
      1. RSV is only one cause of Bronchiolitis (e.g. MPV, parainfluenza, Influenza, Adenovirus, bocavirus)
      2. A negative RSV does not exclude other Bronchiolitis cause
    2. Indications
      1. RSV is a clinical diagnosis and routine testing is not recommended
      2. Other diagnosis considered (e.g. Sepsis in age under 2-3 months)
        1. RSV positive puts a child at very low risk of serious bacterial infection
        2. Levine (2004) Pediatrics 113(6): 1728-34
      3. Inpatient room placement (shared inpatient rooms)
        1. Consider grouping patients with similar symptoms instead of basing on lab criteria
      4. Epidemiologic data to define start of outbreak
    3. Efficacy
      1. Test Sensitivity: 80-90%
      2. Test Specificity: 90-99%
  4. Urinalysis and Urine Culture
    1. Consider in patients with RSV severe enough to consider admission
    2. Urinary Tract Infections are present in 2-5% of RSV cases
      1. However this is similar to baseline UTI rate in asymptomatic children
      2. Urinalysis is controversial in febrile children with Bronchiolitis (some guidelines recommend)
  5. RSV is associated with a decreased risk of other conditions
    1. Decreased risk of Meningitis
    2. Decreased risk of bacteremia

X. Imaging: Chest XRay

  1. Indications
    1. Not routinely recommended in Bronchiolitis (very low yield)
    2. High fever
    3. Hypoxemia (Oxygen Saturation <90%)
    4. Severe symptoms
    5. Comorbid cardiopulmonary disease
  2. Findings consistent with Bronchiolitis
    1. Hyperexpansion
    2. Peribronchial thickening
    3. Variable infiltrates or Viral Pneumonia

XI. Management: Hospitalization Indications

  1. Apnea risk
    1. Witnessed apneic event
    2. RSV in infant under 2 months of age (some recommend under age 3 months)
      1. Especially full-term infant <1 month of age OR Preterm Infant at <48 weeks post-conception
      2. Willmerth (2006) Ann Emerg Med 48(4): 441-7
  2. Comorbidity (one or more non-functioning systems)
    1. Comorbid cardiopulmonary disease (e.g. Cystic Fibrosis, Congenital Heart Defect)
    2. Comorbid Immunodeficiency
  3. Dehydration
    1. Inability to maintain adequate hydration
    2. Feeding difficulty (due to respiratory distress)
  4. Respiratory distress
    1. See Respiratory Distress in Children with Pneumonia
    2. See Pediatric Early Warning Score (PEWS Score)
    3. Respiratory Rate >40 breaths per minute
      1. See Tachypnea for criteria based on age
    4. Retractions (intercostal, supraclavicular, abdominal)
    5. Oxygen Saturation <90%
    6. Lethargy
    7. Hypercarbia
    8. Chest XRay changes (e.g. Atelectasis)
    9. Cyanosis

XII. Management: Effective Measures

  1. General Measures
    1. Constantly reassess for signs of impending respiratory failure
      1. May be signaled by a 'normalization' of the Respiratory Rate (due to respiratory muscle Fatigue)
    2. Humidified Oxygen to keep Oxygen Saturation at 90% or better
    3. Hydration
    4. Suctioning of secretions
      1. Paramount intervention both during the acute evaluation and for home (especially for the obligate nose breathers age <2 years)
      2. Includes gentle Nasal Saline with suctioning (avoid trauma and secondary edema)
      3. Provide parents with a hospital-grade nasal suction bulb (but the Nasal Saline alone will likely clear the nasal mucus)
    5. Frequent feedings
      1. Parents should anticipate smaller volume feedings more frequently (at least every 3-4 hours) for the first 5 days of RSV
  2. Nebulizer
    1. Nebulized Albuterol
      1. May be effective in up to 50% of RSV patients (especially for children with history of Asthma or atopy)
      2. If improvement with trial then continue every 6 hours (if not, then supportive care only)
      3. Background
        1. Albuterol does not improve oxygenation in RSV
        2. Albuterol does not shorten hospital stay in RSV
        3. Albuterol may offer minor symptomatic relief in RSV
      4. References
        1. Turner (2003) Ann Emerg Med 42:709-11
    2. Nebulized Atrovent
      1. See Reactive Airway Disease
      2. Some evidence as of 2011 suggesting Atrovent is effective
    3. Nebulized racemic epinephrine
      1. Variable efficacy
      2. Use has declined since 2007
      3. Requires 2-4 hours of observation after administration due to transient effect with risk of rebound
      4. Wainright (2003) N Engl J Med 349:27-35
    4. Hypertonic Saline Nebulization
      1. Nebulizer dose: 4 ml of 3% hypertonic saline
      2. May shorten hospital stay
      3. Not effective in preventing hospitalization (may not be as useful for emergency care)
      4. Zhang (2008) Cochrane Database Syst Rev :CD006458
  3. Systemic Corticosteroids
    1. Do not decrease severity of illness or shorten the disease course
    2. Not recommended by American Academy of Pediatrics
    3. Atopic Patients and older patient's with Asthma may benefit
    4. Data is mixed and some studies have shown benefit (e.g. Systemic Dexamethasone with Nebulized Epinephrine)
      1. Csonka (2003) J Pediatr 143:725-30
      2. Plint (2009) N Engl J Med 360(20): 2079-89
    5. Some studies have shown benefit with decreased length of hospital stay (especially children under age 1 year old)
      1. Garrison (2000) Pediatrics 105(4): E44
      2. Alansari (2013) Pediatrics 132(4): e810-6
  4. Severe cases
    1. Nasal continuous positive airway pressure (nasal CPAP or nCPAP)
      1. Prevents airway collapse and Atelectasis
      2. Decreases work of breathing
      3. Effective and well tolerated
    2. Helium-Oxygen therapy
      1. Martinon-Torres (2002) Pediatrics 109:68-73
    3. Intubation
      1. Indicated in severe Hypoxia refractory to above measures
      2. Nasal CPAP has been effective at reducing the number of children requiring intubation for Bronchiolitis

XIII. Management: Emergency Department Approach

  1. Attempt to determine disposition (hospitalization versus home) in the first hour
  2. Step 1: Nasal Suctioning
    1. Assess patient (consider using a scoring system)
    2. Nasal Saline and suction
    3. Assess patient (consider using a scoring system)
  3. Step 2: Nebulized Albuterol
    1. Supply family with Albuterol for home if effective
    2. Consider Dexamethasone (or other Corticosteroid) in those who respond to Albuterol (or have atopic/RAD risks)
  4. Step 3: Racemic Epinephrine mixed with hypertonic saline
    1. Observe for at least 2-3 hours after dose
  5. References
    1. Sloas and Orman in Herbert (2014) EM:Rap 14(7): 1-3

XIV. Management: Therapies with variable or limited evidence

  1. Montelukast
    1. Improved post-RSV clinical symptoms (age 3-36 months)
    2. Bisgaard (2003) Am J Respir Crit Care Med 167:379-83
  2. Surfactant
    1. Tibby (2000) Am J Respir Crit Care 162:1251-6
  3. Aerosolized Ribavirin (Virazole)
    1. Use limited to immunosuppressed children with severe disease
    2. May be useful early at maximal viral load
    3. Variable efficacy
    4. Cost exceeds $1000 per day
    5. Randolph (1996) Arch Pediatr Adolesc Med 150:942-7

XV. Management: Therapies not found to be useful

  1. Theophylline does not change the clinical course
  2. Antibiotics without bacterial infection identified
  3. Inhaled Interferon alfa-2a
  4. RSV Immune globulin for acute treatment
    1. Indicated for prophylaxis in high risk infants
    2. No evidence for benefit in acute disease
  5. Palivizumab for acute treatment
    1. Indicated for prophylaxis in high risk infants
    2. No evidence for benefit in acute disease

XVI. Prevention

  1. General measures
    1. Avoid contagious exposures
    2. Avoid Passive Smoke Exposure
    3. Hand washing
  2. Medications
    1. RSV Immune Globulin (RSV-IG, Respigam)
    2. Palivizumab (Synagis)
      1. Given monthly for up to 5 months of RSV season (November 1 to March 1)
      2. See Palivizumab for indications
        1. Premature Infants born before 35 weeks gestation
        2. Cyanotic Congenital Heart Disease
        3. Chronic lung disease (Bronchopulmonary Dysplasia)
        4. Neuromuscular disorders

XVII. Prognosis

  1. Severe episodes: 10-20% of cases
    1. Present with dehydration, Hypoxemia, apnea, respiratory failure
    2. Admission rates: 19-45% of cases
    3. ICU Admission: 3% of cases
  2. Overall RSV case fatality rate: 1%
    1. Deaths: 372 per year in United States (90% are under age 1 year)
  3. More severe illness if comorbid underlying disease
    1. Congenital Heart Disease (RSV Mortality 37%)
    2. Bronchopulmonary Dysplasia
    3. Immunosuppression
    4. Age <3 months
    5. Weight <11 pounds (5 kg)
    6. Premature birth (<35 weeks gestation)
  4. Persistent reactive airway disease
    1. Wheezing episodes persist up to 5 years in 40% of children with RSV infection
    2. Wheezing episodes persist beyond 5 years in 10% of children with RSV infection

Images: Related links to external sites (from Google)

Ontology: Bronchiolitis (C0006271)

Definition (MSH) Inflammation of the BRONCHIOLES.
Concepts Disease or Syndrome (T047)
MSH D001988
SnomedCT 4120002
English Bronchiolitides, Bronchiolitis, BRONCHIOLITIS, Bronchiolitis, NOS, bronchiolitis, bronchiolitis (diagnosis), Bronchiolitis [Disease/Finding], Inflammation of the bronchioles, Bronchiolitis (disorder)
Portuguese BRONQUIOLITE, Bronquiolite
Spanish BRONQUIOLITIS, bronquiolitis (trastorno), bronquiolitis, Bronquiolitis
German BRONCHIOLITIS, Bronchiolitis
Japanese 細気管支炎, サイキカンシエン
Swedish Bronkiolit
Czech bronchiolitida, Bronchiolitida
Finnish Bronkioliitti
Russian BRONKHIOLIT, BRONKHIT KAPILLIARNYI, БРОНХИОЛИТ, БРОНХИТ КАПИЛЛЯРНЫЙ
French BROCHIOLITE, Bronchiolite
Croatian BRONHIOLITIS
Polish Zapalenie oskrzelików
Hungarian bronchiolitis
Dutch bronchiolitis, Bronchiolitis
Italian Bronchiolite

Ontology: Respiratory Syncytial Virus Infections (C0035235)

Definition (MSHFRE) Infections à Pneumovirus dues aux virus respiratoires syncitiaux. Les hommes et les bovins sont les plus touchés mais des cas ont pu être rapportés chez les ovins.
Definition (MEDLINEPLUS)

Respiratory syncytial virus (RSV) causes mild, cold-like symptoms in adults and older children. However, it can cause serious problems in young babies, including pneumonia and severe breathing problems. In rare cases it can lead to death. Premature babies and those with other health problems have the highest risk. A child with RSV may have a fever, stuffy nose, cough and trouble breathing. Tests can tell if your child has the virus.

RSV easily spreads from person to person. You can get it from direct contact with someone who has it or it by touching infected objects such as toys or surfaces such as countertops. Washing your hands often and not sharing eating and drinking utensils are simple ways to help prevent the spread of RSV infection. There is currently no vaccine for RSV.

Centers for Disease Control and Prevention

Definition (MSH) Pneumovirus infections caused by the RESPIRATORY SYNCYTIAL VIRUSES. Humans and cattle are most affected but infections in goats and sheep have been reported.
Definition (NCI) infection with respiratory syncytial virus, an RNA virus of the genus Pneumovirus, in the family Paramyxoviridae, with a tendency to form syncytia in tissue culture, that causes minor respiratory infection with rhinitis and cough in adults, but is capable of causing severe bronchitis and bronchopneumonia in young children; first isolated from chimpanzees with respiratory disease. SYN chimpanzee coryza agent, Rs virus. It is a disease associated with HIV infection.
Concepts Disease or Syndrome (T047)
MSH D018357
SnomedCT 186750007, 55735004
English RESPIRATORY TRACT, SYNCYTIAL VIRUS INFECTION, Infections, Respiratory Syncytial Virus, Respiratory Syncytial Virus Infections, Respiratory syncytial virus infection, NOS, RSV - Resp syn vir infect, Respirat syncyt virus infect, RESPIRATORY SYNCYTIAL VIRUS INFECT, INFECT RESPIRATORY SYNCYTIAL VIRUS, respiratory syncytial virus infection, respiratory syncytial virus infection (diagnosis), RSV Infections, RSV infection, Respiratory Syncytial Virus Infections [Disease/Finding], rsv infection, infection rsv, Respiratory syncytial virus infection NOS, Respiratory syncytial virus infection, RSV - Respiratory syncytial virus infection, Respiratory syncytial virus infection (disorder), Respiratory Syncytial Virus Infection
Italian Infezione da virus respiratorio sinciziale, Infezione da virus respiratorio sinciziale NAS, Infezioni da virus respiratori sinciziali
Dutch respiratoir syncytieel virusinfectie NAO, RSV infectie, respiratoir syncytieel virusinfectie, Infectie, respiratoir-syncytieelvirus-, Infecties, respiratoir-syncytieelvirus-, Respiratoir-syncytieelvirusinfectie, Respiratoir-syncytieelvirusinfecties
French Infection respiratoire par virus syncytial SAI, Infection à VSR, Infection respiratoire par virus syncytial, Infections à virus respiratoire syncytial
German RSV-Infektion, Pneumonie durch Respiratory syncytial Virus NNB, Respiratory Syncytial Virus-Infektion, Respiratorische Synzytialvirusinfektionen
Portuguese Infecção por vírus sincicial respiratório, Vírus sincicial respiratório NE, Vírus sincicial respiratório, Infecções por Vírus Respiratório Sincicial
Spanish Infección por VRS, Respiratory syncytial virus infection, Infección por virus sincitial respiratorio, Infección por virus sincitial respiratorio NEOM, infección por virus respiratorio sincicial (trastorno), infección por virus respiratorio sincitial, infección por virus respiratorio sincicial, infección por virus respiratorio sincitial (trastorno), infección por RSV, infección por VRS, Infecciones por Virus Sincitial Respiratorio
Japanese RSウイルス感染, RSウイルス感染NOS, RSウイルスカンセンNOS, RSウイルスカンセン, RSウイルス感染症, 呼吸シンチウムウイルス感染症
Swedish Respiratoriska syncytialvirusinfektioner
Czech viry respirační syncyciální - infekce, Infekce způsobená RSV, Infekce způsobená respiračními syncytiálními viry, Infekce způsobená RS virem NOS
Finnish RS-virusinfektiot
Russian RESPIRATORNO-SINTSITIAL'NOVIRUSNYE INFEKTSII, РЕСПИРАТОРНО-СИНЦИТИАЛЬНОВИРУСНЫЕ ИНФЕКЦИИ
Croatian RESPIRACIJSKI SINCICIJSKI VIRUS, INFEKCIJE
Polish Zakażenie wirusem RS, Zakażenie wirusem syncytialnym układu oddechowego
Hungarian Respiratory syncytial virus fertőzés k.m.n., respiratory syncytial virus fertőzés, Respiratoricus syncitialis virus fertőzés

Ontology: Metapneumovirus (C0949907)

Definition (MSH) A genus of the subfamily PNEUMOVIRINAE, containing two members: Turkey rhinotracheitis virus and a human Metapneumovirus. Virions lack HEMAGGLUTININ and NEURAMINIDASE.
Definition (CSP) genus of the subfamily pneumovirinae which includes human Metapneumovirus.
Concepts Virus (T005)
MSH D029121
SnomedCT 407501006
Swedish Metapneumovirus
Czech Metapneumovirus
Finnish Metapneumovirus
Russian RINOTRAKHEITA VIRUS TURETSKII, METAPNEUMOVIRUS, РИНОТРАХЕИТА ВИРУС ТУРЕЦКИЙ
Japanese 七面鳥鼻気管炎ウイルス, 鼻気管炎ウイルス-シチメンチョウ, 鼻気管炎ウイルス-七面鳥, メタニューモウイルス, シチメンチョウ鼻気管炎ウイルス
English metapneumovirus, Metapneumovirus, Metapneumoviruses, Genus Metapneumovirus (organism), Genus Metapneumovirus
Polish Metapneumowirus, Metapneumowirus ptaków, Metapneumowirus człowieka
Croatian METAPNEUMOVIRUS
Spanish género Metapneumovirus (organismo), género Metapneumovirus, Metapneumovirus, Metapneumovirus Aviar, Pneumovirus Aviar
French Métapneumovirus
German Metapneumovirus
Italian Metapneumovirus
Dutch Virus, metapneumo-
Portuguese Metapneumovirus