Pulmonary Infections Flashcards
What is pneumonia?
Inflammation of the lung parenchyma accompanied by its consolidation.
Define consolidation in the context of pneumonia.
Replacement of the air in alveoli by inflammatory exudate.
What happens to the lung during consolidation?
Lung loses its spongy appearance, becomes solid, dry, and granular.
What are the nonimmune mechanisms of the respiratory tract’s defense?
- Nasal defenses
- Laryngeal cough reflex
- Tracheobronchial mucosal lining
What are the immune mechanisms of the respiratory tract’s defense?
- Alveolar macrophages
- Immunoglobulins
- T lymphocytes
- Neutrophils
List predisposing factors for pneumonia.
- Immunodeficiency
- Cigarette smoking
- Alcoholism
- Congestive heart failure
- COPD
- Bronchial obstruction
- Diabetes mellitus
- Coma
How is pneumonia classified based on the patient’s health status?
- Primary: in a previously healthy person
- Secondary: in diabetics, alcoholics, and debilitated patients
What are the two classifications of pneumonia based on the course?
- Acute: fulminant clinical disease
- Chronic: a more protracted course
What are the pathological classifications of pneumonia?
- Pneumonia with consolidation: Lobar and bronchopneumonia
- Pneumonia without consolidation: interstitial pneumonitis
What is the etiological classification of pneumonia?
Identification of causative organisms.
Describe community-acquired acute pneumonias.
Bacterial in origin; follows a viral upper respiratory tract infection.
What is the main causative organism of community-acquired pneumonia?
Streptococcus pneumoniae (or pneumococcus).
In which groups of patients do pneumococcal infections occur?
- Patients with congestive heart failure, COPD, or diabetes mellitus
- Patients with congenital or acquired Ig defects
- In sickle cell disease or post-splenectomy
What are the four stages of inflammatory response in lobar pneumonia?
- Stage of congestion
- Stage of red hepatization
- Stage of gray hepatization
- Stage of resolution
What occurs during the stage of resolution in lobar pneumonia?
Lung parenchyma returns to normal.
Describe the characteristics of bronchopneumonia.
- Patchy consolidation affecting one or several lobes
- Bilateral and basal
- Areas appear as elevated, dry, granular grayish red to yellow foci
What is the fate and prognosis of community-acquired acute pneumonia?
With appropriate therapy, complete resolution is the rule.
List the complications of community-acquired acute pneumonia.
- Abscess formation
- Carnification
- Empyema
- Bacteremic dissemination
- Death in type 3 pneumococci infection
What are the causative organisms of community-acquired atypical pneumonias?
- Mycoplasma pneumoniae
- Viruses (influenza A or B, respiratory syncytial viruses, coronaviruses)
- Chlamydia pneumoniae
What is the clinical picture of atypical pneumonia?
- Acute febrile illness
- Fever, headache, malaise
- Cough with minimal sputum +/- respiratory distress
What defines hospital-acquired pneumonia?
Pulmonary infections acquired during a hospital stay.
What are common causative organisms of hospital-acquired pneumonia?
Gram-negative rods.
Describe aspiration pneumonia.
Occurs in markedly debilitated patients and those who aspirate gastric contents.
What are the causative organisms of chronic pneumonias?
- Nocardia asteroides
- Actinomyces israelii
- Mycobacterium tuberculosis and atypical mycobacteria
What organisms are commonly involved in pneumonias in the immunocompromised host?
- Cytomegalovirus
- Pneumocystis carinii
- Mycobacterium avium-intracellulare
- Invasive aspergillosis
- Invasive candidiasis
