Pulmonology Book

http://www.fpnotebook.com/

Respiratory Syncytial VirusAka: Bronchiolitis, RSV, Metapneumovirus

Advertisement

  1. Epidemiology: RSV
    1. Annual epidemics occur winter to early spring
      1. Range: October to May
      2. Peak: January to February
    2. Overall hospitalization rate: 1-2%
    3. Attack rates
      1. Daycare exposure: 100% infection rate
      2. Sibling exposure: 40% infection rate
    4. Cohorts Affected
      1. Children under age 2 years (usually 1-6 months old)
      2. Of infants at risk, 50% will be infected
        1. 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
  2. Pathophysiology: RSV
    1. Transmission
      1. Close contact
      2. Fingers or fomites
      3. Self inoculation of Conjunctiva or anterior nares
      4. Coarse aerosols from coughing or sneezing
    2. Viral load peaks at 4 to 5 days
    3. Incubation: 8 to 12 days
    4. Virus shedding: 2 weeks
    5. Duration of illness (under age 2 years)
      1. Median: 12 days
      2. Prolonged in 10% of cases as long as 4 weeks
    6. Re-infection with different RSV form is common
  3. Symptoms
    1. Onset
      1. Rhinorrhea
      2. Low grade fever
      3. Mild systemic symptoms
      4. Coughing
      5. Wheezing
    2. Severe illness
      1. Tachypnea or Dyspnea
      2. Hypoxia and cyanosis
      3. Apnea
  4. Signs
    1. Diffuse Wheezing
    2. Rhonchi
    3. Rales
  5. Differential Diagnosis
    1. Reactive airway disease
    2. Metapneumovirus (MPV)
      1. Emerging paramyxovirus
      2. Similar presentation as RSV
      3. Hamelin (2004) Clin Infect Dis 38:983
  6. Labs
    1. Blood and Urine Cultures not needed in routine cases
    2. RSV swabs or washings of nasopharynx, throat, or Sputum
      1. Not needed unless other diagnosis considered (Sepsis)
  7. Radiology: Chest XRay
    1. Hyperexpansion
    2. Peribronchial thickening
    3. Variable infiltrates
  8. Management
    1. Hospitalization Indications
      1. RSV in infant under 3 months of age
      2. Gestational age at birth <34 weeks
      3. Comorbid cardiopulmonary disease
      4. Comorbid Immunodeficiency
      5. Respiratory distress
        1. Respiratory Rate >60 to 70 breaths per minute
        2. Wheezing
        3. Oxygen Saturation <92%
        4. Lethargy
        5. Hypercarbia
        6. Chest XRay changes (e.g. Atelectasis)
    2. General Measures
      1. Humidified Oxygen
      2. Hydration
      3. Suctioning of secretions
        1. Includes Nasal Saline with suctioning
    3. Nebulizer
      1. Nebulized Atrovent
        1. See Reactive Airway Disease
        2. Some recent evidence suggests Atrovent is effective
      2. Nebulized Albuterol or other Bronchodilator
        1. Albuterol with variable efficacy
        2. Albuterol does not improve oxygenation in RSV
        3. Albuterol does not shorten hospital stay in RSV
        4. Albuterol may offer minor symptomatic relief in RSV
        5. Albuterol causes tachycardia, Tremor, hyperactivity
        6. Use should be evaluated for each RSV patient
          1. Routine use is not recommended
        7. References
          1. Turner (2003) Ann Emerg Med 42:709
      3. Nebulized racemic epinephrine
        1. Variable efficacy - recent studies show no benefit
        2. Wainright (2003) N Engl J Med 349:27
      4. Nebulized hypertonic saline with Terbutaline
        1. Terbutaline 0.5 ml (5 mg) in 2 ml 3% saline
        2. Study used three times daily for 5 days
        3. Found to be safe and effective in infants
        4. Sarrell (2002) Chest 122:2015
    4. Systemic Corticosteroids
      1. Not recommended by American Academy of Pediatrics
      2. Atopic Patients may benefit
      3. Some studies have shown benefit
        1. Associated with decreased rate of hospitalization
        2. Associated with reduced symptom duration
          1. Most effective if used early in course
        3. Reference
          1. Garrison (2000) Pediatrics :
          2. Csonka (2003) J Pediatr 143:725
    5. Montelukast
      1. Improved post-RSV clinical symptoms (age 3-36 months)
      2. Bisgaard (2003) Am J Respir Crit Care Med 167:379
    6. Severe cases
      1. Severe Hypoxia may require intubation
      2. Helium-Oxygen therapy
        1. Martinon-Torres (2002) Pediatrics 109:68
      3. Surfactant
        1. Tibby (2000) Am J Respir Crit Care 162:1251
  9. 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. Aerosolized Ribavirin (Virazole)
      1. May be useful early at maximal viral load
      2. Other studies with minimal if any benefit
        1. Cost: $1320/day wholesale
        2. Randolph (1996) Arch Pediatr Adolesc Med 150:942
    5. RSV Immune globulin for acute treatment
      1. Indicated for prophylaxis in high risk infants
      2. No evidence for benefit in acute disease
    6. Palivizumab for acute treatment
      1. Indicated for prophylaxis in high risk infants
      2. No evidence for benefit in acute disease
  10. 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 5 months of RSV season (November 1 to March 1)
        2. See Palivizumab for indications
  11. Prognosis
    1. Overall RSV case fatality rate: 1%
    2. More severe illness if comorbid underlying disease
      1. Congenital Heart Disease (RSV Mortality 37%)
      2. Bronchopulmonary Dysplasia
      3. Immunosuppression
  12. References
    1. Panitch (2003) Pediatr Infect Dis J 22:S83
    2. Jafri (2003) Pediatr Infect Dis J 22:S89
    3. Steiner (2004) Am Fam Physician 69:325

Bronchiolitis (C0006271)

Definition (MSH)Inflammation of the bronchioles.
ConceptsDisease or Syndrome (T047)
ICD9466.1
MSHD001988
EnglishBronchiolitides, Bronchiolitis
Spanishbronquiolitis
Parent ConceptsInfection (C0021311), Lung diseases (C0024115), Bronchus and Bronchiole (C0549578), Bronchitis (C0006277), Non-Neoplastic Lung Disorder (C1335019), Bronchiolar disease (C0264364)
SourcesCOSTAR, CST, DXP, MEDLINEPLUS, MSH, MTHICD9, NCI, NDFRT, OMIM, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)


Respiratory Syncytial Virus Infections (C0035235)

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.
ConceptsDisease or Syndrome (T047)
MSHD018357
EnglishINFECT RESPIRATORY SYNCYTIAL VIRUS, RESPIRATORY SYNCYTIAL VIRUS INFECT, Respiratory syncytial virus infection, Respiratory Syncytial Virus Infections, RSV - Respiratory syncytial virus infection, RSV Infections
Spanishinfeccion por RSV, infeccion por virus respiratorio sincitial, infeccion por VRS
Parent ConceptsPneumovirus Infections (C0206615), Viral Respiratory Tract Infection (C0877203), Duplicate concept (C1274013)
SourcesDXP, MEDLINEPLUS, MSH, NCI, NDFRT, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)


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.
ConceptsVirus (T005)
MSHD029121
EnglishGenus Metapneumovirus, Metapneumovirus, Metapneumoviruses
Spanishgenero Metapneumovirus
Parent ConceptsParamyxoviridae (C0030465), Pneumovirinae (C0206534)
SourcesCSP, MSH, NCBI, SCTSPA, SNOMEDCT
Derived from the NIH UMLS (Unified Medical Language System)



Navigation Tree