Morphology of Pneumonia - General Flashcards
A 35-year-old man presents with fever (chills (cough (and rust-colored sputum))) His chest X-ray reveals lobar consolidation. Gram stain of the sputum shows lancet-shaped (gram-positive diplococci) What is the most likely diagnosis (and how would you confirm it)? What is the pathogenesis of this condition?
Streptococcus pneumoniae.
Diagnosis: Confirmed via sputum culture or blood culture.
Pathogenesis: Invasion of respiratory epithelium by S. pneumoniae leading to inflammation and consolidation.
A 68-year-old woman with a history of COPD is admitted with fever (cough (and shortness of breath)) What are the three most common bacterial causes of acute exacerbation of COPD (and what are their distinguishing features)?
Haemophilus influenzae
Moraxella catarrhalis
Streptococcus pneumoniae.
Features include purulent sputum (increased dyspnea (and history of smoking)).
An intravenous drug user presents with fever (cough (and chest pain)) He has a history of endocarditis
What type of pneumonia is he most susceptible to?
What are the potential complications of this type of pneumonia?
Aspiration pneumonia.
Complications: Abscess formation (necrotizing pneumonia (and pleural effusion)).
A 40-year-old man develops pneumonia after a recent trip to a hotel with a water-cooling tower He complains of high fever (cough (and muscle aches)) What is the likely causative organism (and how would you diagnose it)? What are the risk factors for this type of pneumonia?
Legionella pneumophila.
Diagnosed via urine antigen test.
Risk factors include travel to endemic areas (exposure to contaminated water systems).
A 20-year-old college student presents with fever (headache (and a dry cough)) Chest X-ray reveals patchy interstitial infiltrates
What are the likely causes of this pneumonia?
How do they differ from typical bacterial pneumonia?
Mycoplasma pneumoniae.
Atypical pneumonia: Dry cough (low-grade fever (and patchy infiltrates on X-ray)).
Differs from typical bacterial pneumonia which has a sudden onset and purulent sputum.
A 70-year-old man with a history of heart disease is hospitalized with severe pneumonia following a flu-like illness What is the role of antigenic drift and antigenic shift in the emergence of new influenza strains?
Mutations that evade immune detection. Antigenic drift leads to small genetic mutations while antigenic shift results in major changes in the virus’s surface proteins.
A young child develops bronchiolitis after a viral infection Explain the morphologic changes seen in viral pneumonia (and how it can lead to complications like obliterative bronchiolitis)
Interstitial inflammation with lymphocyte infiltration. This inflammation can lead to fibrosis (airway obstruction (and complications like obliterative bronchiolitis)).
Discuss the pathogenesis of influenza virus infection (focusing on the roles of hemagglutinin and neuraminidase proteins)
Both proteins help in the entry and release of the virus from host cells. Hemagglutinin allows viral attachment to the host cell receptors while neuraminidase aids in the release of new viral particles.
What are the potential long-term sequelae of viral pneumonia?
All of the above. Long-term sequelae of viral pneumonia can include lung fibrosis (chronic cough (and impaired lung function)).
A patient on mechanical ventilation develops a new fever and purulent sputum What are the most common organisms associated with hospital-acquired pneumonia (and why is this condition a serious concern)?
Pseudomonas aeruginosa. This condition is serious due to the risk of resistant organisms (and sepsis).
A 75-year-old man with a history of stroke develops pneumonia after aspirating gastric contents Describe the pathophysiology of aspiration pneumonia and its potential complications.
Aspiration pneumonia results from the inhalation of oropharyngeal contents causing an inflammatory response in the lungs.
Complications include lung abscess and necrotizing pneumonia.
Explain the role of microaspiration in lung pathology.
Microaspiration occurs when small amounts of gastric or oropharyngeal contents are inhaled into the lungs causing localized inflammation and infection. This can contribute to conditions such as aspiration pneumonia and chronic pulmonary disease.
A 50-year-old man with poor dental hygiene presents with fever (cough (and foul-smelling sputum)) Imaging reveals a cavitary lesion in his right lung What is the most likely diagnosis (and what are the common causative organisms)?
Lung abscess. Common causative organisms include Anaerobes Streptococcus and Staphylococcus aureus.
Describe the various mechanisms by which bacteria can be introduced into the lungs leading to lung abscess formation.
Aspiration of oral or gastric contents (hematogenous spread (or direct extension from adjacent infected areas)).
A lung abscess is discovered in a 60-year-old smoker Why is it essential to rule out underlying carcinoma in this case?
Because lung abscesses in older smokers may be associated with malignancy. Lung cancer can present with similar symptoms (and early detection is crucial for prognosis).
A 45-year-old man from the Mississippi River valley presents with cough (fever (and weight loss))
A chest X-ray shows calcified nodules in his lungs
What is the most likely diagnosis?
and how is it acquired?
What are the clinical features of this condition?
Histoplasmosis. Acquired through inhalation of spores from bird or bat droppings.
Clinical features include cough (fever (weight loss (and calcified nodules on X-ray))).
