Lung infections 1 Flashcards
What does viral pneumonia cause?
What viruses are responsible?
(1) Acute interstitial pneumonitis
(2) Influenza, cytomegalovirus
What are characteristics of acute interstitial pneumonitis?
3
(1) Thickening of alveolar wall with (2) edema and (3) inflammatory cells
What bacteria are responsible for bacterial pneumonia?
Bronchopneumonia (3) Lobar pneumonia (1)
Bronchopneumonia:
(1) Staph aureus
(2) H. influenzae
(3) Strep pneumoniae
Lobar pneumonia:
(4) Strep pneumoniae
Which patients tend to get lobar pneumonia?
(1) Debilitated patients
(2) Alcoholics
What are radiographic features of lobar pneumonia?
4
(1) Single lobe involved with bulging fissure
(2) Abscess with cavity formation
(3) Pleural effusion and empyema (pus in pleural cavity)
(4) Septicemia following acute episode
What are predisposing factors for lobar pneumonia?
5
(1) Cirrhosis
(2) Renal failure
(3) Malignancy
(4) Diabetes
(5) Sickle cell disease
What are features of bronchopneumonia?
3
(1) Acute patchy infection located around small airways
(2) Microscopically: intra-alveolar process
(3) Inflammation with destruction of alveoli
What is red hepatization of the lung?
Lung appears thick and red like the liver:
Acute phase of pulmonary consolidation occurring secondary to untreated bronchopneumonia
What is grey hepatization of the lung?
Lung appears like liver but grey from breakdown of red cells
How do patients with necrotizing pneumonia and abscess formation present?
(4)
(1) Fever
(2) Pleuritis
(3) Putrid sputum
(4) Late complication - empyema (infection of pleural space resulting in pus)
What happens in pulminary cavitation secondary to abscess?
2
(1) Inability to cough up sputum, (2) leading to necrosis and constant reinfection
What are some differences between viral and bacterial pneumonia?
Viral: infection of membranous pneumocytes resulting in alveolar injury leading interstitial pneumonitis
Bacterial: Intra-alveolar infection, alveolar injury not necessary, acute inflammatory response, leads to lobar/bronchopulmonary pneumonia
What are the two forms of tuberculosis?
(1) Primary infection - Ghon complex, occurring in children
(2) Secondary infection - reactivation TB, affecting adults
What are the characteristics of primary pulmonary tuberculosis?
(4)
(1) Children most often infected
(2) Peripheral lung infection with granuloma formation
(3) Ghon complex: (a) parenchymal subpleural nodule with active infection and (b) enlarged caseous lymph nodes draining parenchymal nodule
(4) Rarely progresses
What are the characteristics of reactivation pulmonary tuberculosis?
(4)
(1) Adults affected
(2) Upper lobe disease with necrotizing granulomas
(3) Cavitation of upper lobe
(4) Hematologic dissemination leads to extra-thoracic sites of disease
Which organisms are acid fast?
3
(1) Mycobacterium species
(2) Actinomyces
(3) Nocardia
Which species of Mycobacterium does not cause granuloma formation?
M. avium intracellularae (atypical Mycobacterium)
Which fungi are filamentous?
4
(1) Aspergillus
(2) Mucor
(3) Petrolidium
(4) Penicillium
Which fungi are yeasts?
4
(1) Cryptococcus
(2) Blastomyces
(3) H. capsulatum
(4) Candida
What are the characteristics of aspergillus?
(1) Ubiquitous in soil
(2) Isolation from sputum does not imply pathogenicity
(3) Form broad septate hyphae with acute-angle branching
(4) Form conidiophores in culture
What are the three pulmonary manifestations of Aspergillus?
(1) Mycetoma (fungus ball)
(2) Invasive aspergillosis
(3) Hypersensitivity pneumonitis
What can Aspergillus hypersensitivity pneumonitis lead to?
2
(1) Bronchiectasis or (2) pulmonary fibrosis
What are the characteristics of Cryptococcus?
4
(1) Soil fungus found in pigeon feces
(2) Encapsulated budding yeast
(3) Visualized with India ink (halo from capsule)
(4) Presents radiographically as localized pulmonary lesion
What are the clinical features of Cryptococcus infection?
3
(1) Often asymptomatic
(2) Headache and fever
(3) Involvement of skin, bones, heart, and other systems
What are the characteristics of Blastomyces dermatitidis?
4
(1) Causes granuloma formation
(2) Primary infection usually subclinical
(3) Infection through inhalation
(4) Presents radiographically as solitary pulmonary mass
What are the clinical features of Blastomyces infection?
2
(1) Mild fever, cough, malaise
(2) Macules on hand and face
What are the characteristics of Coccidiodes immitis?
2
(1) Soil fungus that infects through inhalation (often after earthquakes)
(2) Illness usually asymptomatic
What are the clinical features of Histoplasma infection?
7
(1) Primary histoplasmosis:
(a) 95% benign
(b) Multiple calcified nodules/nodes
(2) Chronic/reinfection histoplasmosis
(a) Early chronic disease - upper lobe consolidation, fever, chest pain
(b) Chronic cavitary disease, like Tb
(c) Disseminated histoplasmosis
What is Pneumocystis jiroveci?
Opportunistic pathogen that only infects immunocompromised hosts, leading to interstitial lung disease
How is Pneumocystis infection diagnosed?
3
(1) Bronchoalveolar lavage
(2) Lung biopsy
(3) Can’t be cultured because no sputum (dry cough)
What is the treatment for Pneumocystis jiroveci?
2
(1) Trimethoprim-sulfamethoxazole (Bactrim)
(2) Aerosolized pentamidine
What are causes of diffuse pulmonary infiltrate?
4
(1) Pneumocystis jiroveci
(2) Viral pneumonitis
(3) Drug reaction
(4) Interstitial lung disease
What are causes of focal pulmonary infiltrate?
5
(1) Staph aureus
(2) Aspergillus
(3) Candida
(4) Tumors
(5) Cryptococcus
