08.20 - Viral Pneumonia (Cross) - Questions Flashcards
Nearly all viruses that cause pneumonia can cause ___ as well
URTI’s
Atypical Pneumonia (viruses) is an acute febrile respiratory disease characterized by
(1) Pathcy inflammatory changes; (2) Absence of consolidation; (3) Lack of alveolar exudates
Path findings of Atypical Pneumonia
Alveolar walls infiltrated with mononuclear cells (Lymphocytes, Some plasma cells)
Persistent cough and severe wheezing in 3 month old boy
RSV
Features of RSV-1
Pleomorphic; Enveloped; Negative-sense; Single-stranded; Linear RNA
Dx tests of RSV-1
RT-PCR on nasal swab or washings; Rapid antigen test on nasal swab or washings
Which common group is not at risk for RSV pneumonia
45-year-old male with 20 pack-year smoking history
In healthy adults, RSV presents as
common cold –> One way it may be transferred to infants
Usual natural course of RSV in previously healthy infants
Bronchiolitis resolves w/out complications; Mortality rate low (2%)
What patients can be severely affected by RSV
Premature; <12 weeks of age; Cardiopulmonary dz; Immunodeficiency
Tx and Prevention Options for RSV
Palivizumab; Supportive care w/ hydration, albuterol, oxygen; Ribivirin not recommended
Palivizumab
mAb against F protein - prevents binding of virus to host cell
mAb against F protein - prevents binding of virus to host cell
Palivizumab
Ribivirin in RSV
Routine use in children not recommended
Why is RSV one of most likely viral infections to have a picture on step 1
Giant Cell (Syncitia) formation
In whom is adenovirus most severe? Most commonly tested?
More severe in infants; Common in military
Tx of Adenovirus
None
Transmission of Adenovirus
Aerosol, Fecal-Oral, Direct inoculation
Most common cause of respiratory tract infections that result in physician visits and hospitalizations in the US
Influenza
Most common causes of post-viral secondary bacterial pneumonia
Strep Pneumo, then Staph Aureus
2 important surface proteins found on influenza virus
Hemagluttinin; Neuraminidase
Hemagluttinin
Attach influenza virus to its cellular target
Attach influenza virus to its cellular target
Hemagluttinin
Neuraminidase
Facilitates release of newly formed influenza virions
Facilitates release of newly formed influenza virions
Neuraminidase
Surface F Protein
Causes respiratory epithelial cells to fuse and form multinucleated giant cells (RSV)
Causes respiratory epithelial cells to fuse and form multinucleated giant cells (RSV)
Surface F Protein
Spike (S) Protein
Mediates fusion between Coronavirus and host cell membrane
Mediates fusion between Coronavirus and host cell membrane
Spike (S) Protein
How is influenza transmitted and what type of pathology occurs during infection?
Respiratory droplets; Necrosis of superficial layers of respiratory epithelium
What results in emergence of new viral strains each year
Antigenic drift
Antigenic drift results from
spontaneous mutations in viral genome as it replicates
Antigenic shift results from
Reassortment of genome segments (encoding HA and NA genes in flu)
Non-segmented negative strand RNA viruses: Shift or Drift
Drift, but not shift, because polymerase makes a lot of mistakes
Confirmatory dx of influenza
RT-PCR of Nasopharyngeal Swab
Rapid Urine Antigen Test is used in
Legionella, Strep Pneumo
3 dx tests of influenza
RT-PCR; Direct fluorescent Ab; Rapid viral antigen test
How should patient with influenza be treated
Oseltamavir, Zanamavir, Abx for secondary bacterial pneumonia
Influenza important sequelae
Reye’s Syndrome
Adenovirus important sequelae
Bronchiectasis, Bronchiolitis Obliterans
RSV improtant sequelae
Asthma
Reye’s Syndrome
Encephalopathy and Liver Degeneration; In children following viral infections
What virus causes SARS
Coronavirus
What virus causes MERS
Coronavirus
Hantavirus multiplies in
Pulmonary capillary endothelial cells –> Bilateral pleural effusions w/ interstitial infiltrates of mononuclear cells
Transmission of Hantavirus
Aerosol inhalation of rodent excreta (deer mouse)
2 important points on HMPV
Respiratory droplets; Winter months
Which virus is typically associated with croup and inspiratory stridor?
HPIV-1
Typical presentation of Parainfluenza Viruses
Mild URTI, Croup, Bronchiolotitis and Pneumonia
Prognosis of Parainfluenza virus
Good, most children recover after a few days. Reinfection common.
