3 RSV And Croup Flashcards
Syndrome of fever, hoarseness and barking couch in children 6-18 months of age
Croup - complication of URI that creates tracheal constriction below the vocal cords
Main cause of Croup
Parainfluenza virus
PIV type 1 > PIV type 2»_space;> RSV
Parainfluenza is a type of ….
Paramyxovirus
Nonsegmented, negative sense ssRNA genome that is structurally similar to but distinct from influenza virus in biological properties and pathogenesis
What do paramyxoviruses look like?
Virion is enveloped with protein spikes
Currently 4 known serotypes
Clinical manifestations of PIV infection
Respiratory tract entry via droplets from infected individuals —> replication in upper respiratory tract epithelial cells (esp nasal turbinates and ciliated epithelium)
2-6 day incubation
SSx: harsh cough, rhinitis, sore throat, SOB
2-3% of total PIV infections —> Croup (where PIV invades lower airways)
PIV illness in adults is typically experienced as …
No specific URI, not croup
Unless immunocompromised
Common complications of PIV infection
Otitis media (PIV causes Eustachian tube dysfunction —> negative pressure in middle ear —> antagonizing clearance of nasopharyngeal bacteria)
Parotitis
When do we see a seasonal upsurge in PIV cases?
Fall-winter
Prevalent in children
What is the difference in epidemiology between the three types of PIV?
Types 1 and 2 exhibit a complex, sometimes alternating epidemic periodicity in autumn
Type 3 is endemic (most children will get it by age 1) with sporadic epidemic outbreaks more frequent in late winter or spring
Do you get lifelong immunity after PIV infection?
Nope
Virus somehow interferes with full immune memory establishment
BUT repeat infections are usually mild
Main reservoir for infant PIV infections
Adults and caregivers
How do we diagnose PIV?
Direct viral isolation from nasal washings or throat swabs
PIV virions are stable and may be maintained for several days in viral transport medium
Direct fluorescent antibody or reverse transcriptase PCR tests on cells/syncytial
How is PIV treated?
Supportive treatment
No vaccines
Another paramyxovirus, very similar to PIV
Respiratory Syncytial Virus (RSV)
Clinical manifestation of RSV infection
Viral infection in the epithelium of the nose, throat, and bronchi
SSx are actually due to the inflammatory response
SSx: Cough, dyspnea, cyanosis, and sometimes croup (but PIV much more common cause of infant croup)
How do we diagnose RSV?
Rapid antigen tests available
Nucleic acid tests
Testing important - cases cannot be diagnosed based on clinical SSx
Treatment for RSV
Supportive therapy for the most part but there are some meds too…
Immune globulin (monoclonal, Palivizumab) for high risk patients as a preventative measure (but must have multiple perfusion during RSV season to ensure high titer)
Ribavirin (controversial, but effective if symptomatic treatments fail)
Most common etiology of lower respiratory tract infections in children <4
RSV - annual outbreaks every winter
Peak incidence is in infants <1 year
Highest rate of hospitalization is in teh 2-3 month age group
Who is at higher risk for severe disease and complications from RSV infection?
Children with underlying diseases:
Premature birth
CV/Resp abnormalities (account for 50% of all hospitalizations)
Children born when are at higher risk for severe RSV disease?
Those born a few months before RSV season (because maternal antibodies decline over time, leaving infant vulnerable during the height of the season)
Novel coronavirus infection with high case fatality rate
SARS - an example of an emerging infection, now presumed extinct
Similar to MERS (Middle East Respiratory Syndrome
