Lower Respiratory Tract Infections (LRIs) Flashcards
Unlike URIs that are common, LRIs are…
Respiratory tract infections remain a major cause of morbidity from acute illness in the North America
- single most common reason patients seek emergency medical attention
What is the reason why we don’t have more infections?
b/c of host defenses
The respiratory tract has an elaborate system of host defenses, including humoral immunity, cellular immunity, and anatomic mechanisms
• Infections only occur when host defenses are impaired
What are the 3 most common LRIs?
- Bronchitis
- Bronchiolitis
- Pneumonia
Are URIs and LRIs linked?
URI lead to most common LRIs (drain downward)
- moving more infective agent lower into lung tissue
• majority of pulmonary infections follow colonization of the upper respiratory tract with pathogens, where they gain access to the lung via aspiration of OROPHARYNGEAL SECRETIONS
• Less common, microbes enter the lung via the blood from an extra pulmonary source or by inhalation of infected aerosolized particles
What are the variety of host factors that determines if an infection is caused by an invading microorganism?
• patient age (v. young & v. old most commonly)
• lifestyle/ habits (smoking, vaping, workplace, etc.)
• anatomic features of the airway (surgeries , damage, etc. that affected lung tissue & lead to scarring that makes them more susceptible)
• specific characteristics of the infecting agent (if highly variant, highly pathogenic it can make even a v. healthy person sick)
What do most LRIs in children and adults most commonly result from?
either viral or bacterial invasion of LUNG PARENCHYMA
What is lung parenchyma?
lower ends of bronchioles, leading to alveolar sacs (severe –> O2 isn’t carried to blood)
What is Bronchitis?
is an inflammatory condition of the large and small airways→the tracheobronchial tree (large/major valves leading to lungs)
• excludes alveoli
When does Bronchitis occur?
Occurs year-round, but more commonly peaks during
the winter months (when cold/flu season increase)
What are the 2 types of Bronchitis?
- Acute bronchitis (AB)
- Chronic bronchitis (CB)
Acute bronchitis (AB) =
inflammation of the epithelium of the large airways resulting from infection or smoke inhalation
• AB symptoms are short-lived and last <1 month (b/c starts with URI & goes downward usually)
(ex: coal miners or smokers)
Chronic bronchitis (CB) =
chronic cough producing sputum lasting more than 3 months for 2 consecutive years without an underlying etiology of bronchiectasis or tuberculosis
What is the predominant infectious agents associated with AB accounting for 85% to 95% of occurrences?
Respiratory viruses
a primary bacterial etiology for AB is rare (b/c lots of mech’s to prevent it going down)
*secondary bacterial infections may be involved in patients with underlying disease(s) = co-morbidity
LRIs start as _____, but become problem if it becomes ______ (& if it is co-morbidity)
viral
bacterial
What are Acute Bronchitis Signs and symptoms?
starts as a URI
cough?
if yes, Cough may persist for up to 3 or more weeks
• Painful Cough +/- mucopurulent sputum
than it is AB
if no, than it is URI
Which infections are fevers most common in?
adenovirus, influenza virus, and M. pneumoniae infections
How do you diagnose Acute Bronchitis?
made on the basis of a characteristic history and physical examination, and should be differentiated from asthma or bronchiolitis
• these diseases are usually associated with WHEEZING, shortness of breath (DYSPNEA), and HYPOXEMIA (low of oxygenation)
What is the best diagnose/treatment plan for AB?
For majority of affected patients, an etiologic diagnosis is unnecessary and will not change the prescribing of routine supportive care
• Hydration, anti-pyretic/ analgesic (Aspirin or Acetaminophen), vaporizers (hydrate & maintain broncial airway function)
• COPD patients experiencing an acute exacerbation benefit from a short course of corticosteroid treatment (lower inflammation)
(bacterial cultures are no good b/c of contamination, and viral cultures are unnecessary unless COPD, congestive heart failure &/or immunocompromisation is there)
What is the bacterial AB treatment plan?
When possible, antibiotic therapy should be directed toward the anticipated respiratory pathogen(s)
• due to the increasing antimicrobial resistance, antibiotics should be only be administered upon culture serology or PCR confirmation in patients not responding to supportive care
What is the Viral AB treatment plan?
antiviral drug combinations are being explored as a treatment approach (b/c resistance is growing for antivirals)
Annual flu vaccination is recommended (depends on the formulation each year)
What is Bronchiolitis?
is an acute viral infection of the lower respiratory tract bronchioles that affects approximately 50% of children during the first year of life and 100% by 2 years of age
- b/c their bronchioles are v. narrow so even a small amount of inflammation can be severe
When does Bronchiolitis peak? & what is it a major cause of? & who does it affect
Peaks during winter months
of hospitalizations within 1st year of life
Also affects elderly and immunocompromised patients
What are the Bronchiolitis symptoms and etiology?
1 to 4 days of symptoms (eg, nasal congestion, rhinorrhea/runny nose, cough, and low-grade fever) indicative of an URI
• self-limiting and symptoms diminish within 7 to 10 days with resolution within 28 days
• infants frequently are dehydrated
