Small Group: Viral Respiratory Disease Flashcards
1. Define the following: pneumonia bronchiolitis pharyngitis rhinitis "influenza-like illness" bronchitis asthma
pneumonia: inflammation of the lung parenchyma characterized by consolidation
bronchiolitis: inflammation of the bronchioles often associated with bronchopneumonia
pharyngitis: inflammation of the throat
rhinitis: inflammation of the mucous membrane of the nose
“influenza-like illness”: a set of symptoms characterized by headache, fever, malaise and myalgia (e.g., high temperature, extremely tired, muscle aches)
bronchitis: inflammation of one or more bronchi; most often caused by viruses (and smoking)
asthma: a condition marked by recurrent attacks of paroxysmal dyspnea with wheezing due to spasmodic contraction of the bronchi and associated with excessive production of mucus and edema
- Name the viruses that are the most frequent causes of respiratory infections.
Rhinovirus, Parainfluenza virus, Coronavirus, Respiratory syncytial virus, Influenza virus and Adenovirus
(Metapneumovirus may cause up to 10% of respiratory tract infections; other epidemiological information is sparse. Human Bocavirus may also cause frequent respiratory infections in children).
- List any antiviral medications used against these viruses and describe how they work?
Amantadine and Rimantadine for susceptible strains of Influenza A. Bind to M2 protein in viral envelope blocking ion channel function required for penetration and
complete uncoating of the virus.
Zanamivir and oseltamivir are neuraminidase inhibitors active against both Influenza A and B.
Aerosolized Ribavirin for severe RSV disease in infants and children. Ribavirin is a nucleoside analog that interferes with several processes: genome replication, mRNA synthesis, etc.
Palivizumab, a monoclonal antibody against an RSV protein that blocks viral entry may be used prophylactically via monthly IM injection in high-risk infants
(prematurity, lung disease, congenital heart disease)
Intranasal ipratropium decreases nasal secretions and
sneezing in Rhinovirus infections, as a result of its anti-cholinergic effect.
Pleconaril inhibits Rhinovirus attachment to host cells and appears to decrease duration and severity of symptoms in colds caused by Rhinovirus, but has not received FDA
approval.
- Discuss which of these viruses have vaccines that are licensed for use.
Seasonal influenza A and B
Inactivated, trivalent and quadrivalent vaccines administered via IM injection are available for seasonal influenza A (H1N1 and H3N2) and influenza B (1 or 2
strains).
Live-attenuated intranasal spray versions are also available for people meeting specific criteria.
- Discuss how seasonality can be used in the diagnosis of viral respiratory illnesses.
in mid-october the chief possibilities are rhino, parainfluenza, enterovirus, adenovirus, metapneumovirus and Boca virus;
mid winter influenza, RSV, corona virus and adenovirus most likely
young children (smaller bronchioles) in winter season exposed to adult who had a cold likely RSV, more serious in boys (immunity is incomplete)
- List and discuss laboratory tests that are appropriate for diagnosing viral respiratory illnesses.
a cold usually requires no lab work
CXR for suspected lower respiratory infection (interstitial is likely viral or PCP); pulse ox to check oxygenation, CBC to check WBC differential
RSV antigen test
Sputum gram stain and culture difficult
rapid influenza essay can dx. influenza
- Explain the mechanisms of pathogenesis that lead to the physical findings in flu, RSV and cold.
flu virus replicates in epithelial cells causing lysis and impairment of cilia, cytokine release leads to symptoms
RSV causes edema and bronchospasm in small airways
cold virus inhabits epithelium of respiratory tract causing inflammation
- List and discuss secondary bacterial infections that are of concern including anatomic location and likely bacteria, relevant to each case below.
secondary bacterial pneumonia: S. pnuemoniae, S. aureus and H. influenzae
sinusitis, otitis media
- Discuss strategies to prevent respiratory viral illnesses..
use facial tissues and frequent hand washing, alcohol antibacterials, people who are ill should stay home
breast feeding can be protective, specifically against RSV, monoclonal antibody can be given prophylactically for premature infants
Flu vaccination (not always immunogenic or match circulating strains), zanamivir and oseltamivir can be used prophylactically in certain high-risk groups
- Understand how respiratory viruses are transmitted person to person.
hand contact with infected person or contaminated object;
Describe other non-viral causes of cold symptoms.
(90% are initiated by viruses) mycoplasma pneumonia and Chlamydophilia penumonaie are sporadic (mildly epidemic), Group A,C, G strep, H flu and S. pneumonia can be primary or secondary pathogens and pertussis may begin as a cold-like illness
What symptoms associated with a cold may be worrisome?
higher fever, earache, chest pain, sinus pain, air hunger, productive cough, and increased malaise
symptoms persisting for more than a week or worsening symptoms (OM or sinusitis in an adult)
Discuss treatment for cold symptoms.
in the absence of definitive indication of bacterial or other complications, only symptomatic treatment is usually given
several glasses of water, hot soups, nasal decongestant (chronic use can cause rebound), cough suppressants, lozenges, ibuprofin
RSV can be treated with humidified O2, albuterol to help bronchospasm, supportive care, and aerosolized ribavirin may be helpful
for flu- fluids, antipyretics; look out for secondary bacterial pneumonia
