Viral Pneumonia - Cross Flashcards
Viruses cause (typical or atypical) pneumonia?
Atypical
Viruses causes (lobar or diffuse) findings in lung?
Diffuse pictures in lungs, absence of physical findings of consolidation
WBC count in viral pneumonia?
Only moderate elevation of WBC
Alveolar walls infiltrated with what type of cells in viral pneumonia?
Mononuclear cells, as opposed to polymorphonuclear cells in bacterial pneumonia
Nearly all viruses that cause pneumonia can cause what else?
URTIs (upper respiratory tract infections) aka “common colds”
List some risk factors that predispose to extension of infection in viral pneumonia?
Extremes of age (very young, very old)
Malnutrition
Alcoholism
Underlying debilitating illnesses (does Marfan’s count?)
List the 3 steps in the general mechanism of disease/ infection seen in viral pneumonia?
- attachment to respiratory epithelium
- viral replication causes cell death and inflammation
- resulting damage and impairment of local defenses (mucociliary clearance) can predispose to bacterial superinfections
Which virus is the most common cause of respiratory tract infections that result in physician visits each year?
Influenza
Which virus causes the most number of deaths each year?
Influenza; 36,000 deaths each year. Mortality highest in elderly and children under 2 years old
Influenza
viron shape?
envelope?
genetic material - single or double strand? sense?
helical, enveloped, single stranded, negative sense, linear RNA
RSV
virion shape?
envelope?
type of genetic material - single or double strand? sense?
RSV
pleomorphic
enveloped
single stranded, negative sense, linear RNA
Adenovirus
envelope?
type of genetic material? single or double strand?
Adenovirus
Nonenveloped
double stranded, linear DNA
Parainfluenza virus
envelope?
type of genetic material? single or double stranded?
envelope
single stranded, linear, nonsegmented RNA
Coronavirus - SARS
envelope?
type of genetic material? stranded? sense?
coronavirus - SARS
enveloped
single stranded positive sense RNA
3 proteins involved with influenza?
hemagglutinin, neuraminidase, M2 ion channel
Hemagglutinin function? How many subtypes?
- binds to cell surface receptor and promotes viral entry.
- 3 subtypes (H1 - H3)
2 Neuraminidase functions ? How many subtypes?
- cleaves neuraminic acid to release progeny virus from infected cell
- Also degrades protective layer of mucus in respiratory tract
- 2 Subtypes (N1, N2)
M2 ion channel purpose?
Essential for viral infectivity
Which type of influenza only infects humans? (A or B)
Influenza B
Influenza A can infect animals
Which type of influenza is associated with epidemics and pandemics?
Influenza A
Influenza B causes sporadic outbreaks
Which type of influenza is classified by subtypes? Importance of these subtypes?
Influenza A, Single subtypes predominate throughout the world at any given time.
Influenza B is not classified by any subtypes
Widespread infection in 1 geographic community? Epidemic or pandemic
Epidemic.
Pandemic = widespread infection over multiple geographic locations
Which causes pandemics? (drift or shift)
Antigenic shift.
Reassortment with ANIMAL virus associated with shift or drift?
Reassortment with animals = shift.
Spontaneous mutations associated with shift or drift?
Spontaneous mutations = drift
All individuals are susceptible in shift or drift?
Shift
Influenza transmission route?
airborne respiratory droplets
What causes myalgias seen in influenza virus?
Cytokines being released
4 ways to diagnose influenza? Which is most specific (can tell subtypes) ? Which not usually used
- RT-PCR (most specific/sensitive, can tell subtypes)
- direct fluorescent antibody
- Rapid viral antigen test
- Viral culture (not usually used)
Treatment for influenza? Which one causes bronchospasm and is rarely used?
Oseltamivir or Zanamivir.
Zanamivir can cause bronchospasms and is rarely used
Major complications of influenza (2)?
Secondary or viral pneumonia
Reye’s Syndrome
Reye’s syndrome characterized by?
Encephalopathy and liver degeneration