2.3 Lower Respiratory Tract Infections Flashcards
What are the distributions of pneumonia?
Lobar (entire lobe)
Bronchopneumonia (scattered in multiple lobes)
What are the 2 infectious agents of pneumonia?
Typical - bacteria (more common in adults)
Atypical - virus, mycoplasma (more common in children)
most common and known as “walking pneumonia”
mycoplasma pneumoniae
The inflammation of alveoli and bronchioles
Pneumonia
What is the most common cause of death from infectious disease in the US?
Pneumonia
More likely to occur in immunocompromised individuals
How does pneumonia usually bein?
with an URI
A region of normally compressible lung tissue that is filled with liquid instead of air
Pulmonary consolidation
How does pulmonary consolidation occur?
Through accumulation of inflammatory cellular exudate in the alveoli and adjoining ducts
List some symptoms of typical pneumonia
sudden onset of malaise, chills, fever, productive cough, fine crackles.
Later symptoms include: rust colored sputum, pleuritic pain
What is a prevention for typical pneumonia?
Pneumococcal vaccine
What are some treatments for typical penumonia?
Appropriate antibiotics
What causes atypical pneumonia?
Influenza, RSV
Describe the pathophysiology of atypical pneumonia
patchy involvement, confined to alveolar septum and pulmonary interstitium
Describe manifestations of atypical pneumonia
chest cold, fever, headache, muscle ache, cough, dry, hacking non productive coughs
Mycoplasma pneumonia, also known as ____
Atypical pneumonia
What are some treatments of atypical pneumonia?
Treatment only recommended in complex cases. However if mycoplasma atypical pneumonia:
macrolides, fluoroquinolones, tetracyclines
for viral: targeted antivirals
World’s foremost cause of death from a single infectious agent
Tuberculosis
It is also the cause of 26% of avoidable deaths in developing countries
Many drug resistant forms
Describe Mycobacterium tuberculosis hominis
Aerobic, rod shaped bacterium
Protective waxy capsule
Can stay alive in “suspended animation” for years
How is tuberculosis spread?
Airborne
Describe the events of an initial TB infection
Macrophages begin a cell-mediated immune response
This leads to cell-mediated immunity
Results in granulomatous lesions (Ghon complex) containing:
- macrophages
- T cells
- Inactive TB bacteria
Lung damage is more a result of the immune response than bacteria
Nodules in the lung tissue and lymph node as a result of TB
Ghon complex
Where is primary TB usually isolated?
In Ghon foci
When primary TB is in the ghon foci, bacteria is ____
in active and not contagious
What happens if immune response fails and primary TB is not isolated in the Ghon foci?
If immune response is inadequate, bacteria multiply in the lungs. This leads to progressive primary TB.
What happens in miliary TB?
Bacteria may erode blood vessels and spread through the body
This TB occurs because of a reinfection from inhaled droplet nuclei
Secondary TB
Describe what happens in Secondary TB
Reactivation of previously healed primary lesion
Immediate cell-mediated response walls off infection in airways
Bacteria damage tissues in the airways, creating cavities
What is a sign of chronic pneumonia?
Gradual destruction of lung tissue ; “Consumption”
How do they test for TB?
Screening - Mantoux tuberculin skin test
Often called PPD - purified protein derivative
A precipitate of species-nonspecific molecules obtained from filtrates of sterilized, concentrated cultures
Tuberculin
If exposed to TB, what type of reaction occurs?
type IV delayed hypersensitivity
Describe some symptoms of primary active TB
fever, weight loss, night sweats, fatigue, productive cough
Classification: Antimycobacterial treatment
Isoniazid
Describe the Action
Interferes with lipid and nucleic acid synthesis in actively growing tubercle bacilli
Often used with other antimycobacterials to reduce resistance
Classification: Antimycobacterial treatment
Isoniazid
Describe the Adverse Effects
peripheral neuropathies, n/v, hepatitis, bone marrow suppression, fever, local irritation at injection sites, gynecomastia, lupus syndrome
Classification: Antimycobacterial treatment
Rifampin & Rifapentine
Describe the Action
Inhibit RNA synthesis by blocking RNA transcription
Administered orally, rifampin can be given IV
Classification: Antimycobacterial treatment
Rifampin & Rifapentine
Describe the Adverse Effects
Steven johnson syndrome, TEN, N/V, hepatitis
Will cause orange-red discoloration of ALL body fluids
Common lower airway infections in children & infants
Acute bronchiolitis due to Respiratory syncytial virus (RSV)
Describe acute bronchiolitis in children/infants
Inflammatory obstruction of small airways and necrosis of cells lining lower airway
Increased airway resistance with decreased airflow
Inability to fully expire with air trapping
Decreased gas exchange in affected areas
Describe acute bronchiolitis manifestations in children/infants
Preceded by stuffy nose
Followed by wheezy cough, dyspnea, irritability
Breathlessness, rapid shallow breathing
Complication: respiratory failure
