Summaries Chapter 13: The lung Flashcards
What does ARDS stand for?
Acute respiratory distress syndrome
What is ARDS?
ARDS is a clinical syndrome of progressive respiratory insufficiency caused by diffuse alveolar damage in the setting of sepsis, severe trauma, or diffuse pulmonary infection.
Which cells play an important role in the pathogenesis of ARDS and why?
Neutrophils and their products have a crucial role in the pathogenesis of ARDS by causing endothelial and epithelial injury
How can ARDS be characterized under an histologic picture?
Alveolar edema, epithelial necrosis, accumulation of neutrophils, and presence of hyaline membranes lining the alveolar wall and ducts.
What is emphysema?
Emphysema is a chronic obstructive airway disease characterized by enlargement of air spaces distal to terminal bronchioles.
What are subtypes of emphysema?
centriacinar (most common: smoking- related), panacinar (seen in α1-anti-trypsin deficiency), distal acinar, and irregular.
Fill in: Smoking and inhaled pollutants cause ongoing accumulation of inflammatory cells, which are the source of … such as elastases that irreversibly damage alveolar walls.
proteases
Patients with uncomplicated emphysema present with …. (symptoms)
increased chest volumes, dyspnea, and relatively normal blood oxygenation at rest (“pink puffers”)
What are the signs/symptoms of most patients with emphysema? (& Why)
concurrent chronic bronchitis, since cigarette smoking is a risk factor for both.
How is chronic bronchitis defined?
as persistent productive cough for at least 3 consecutive months in at least 2 consecutive years.
What is the most important risk factor for chronic bronchitis?
Smoking (but air pollutants may contribute)
Chronic airway obstruction largely results from big/small airway disease and coexistent …. (2 diseases)
small, chronic bronchiolitis and emphysema respectively
How does histologic examination of chronic bronchitis look like?
Histologic examination demonstrates enlargement of mucus-secreting glands, goblet cell metaplasia, and bronchiolar wall fibrosis.
How is asthma characterized?
by reversible bronchoconstriction caused by airway hyperresponsiveness to a variety of stimuli.
What is atopic asthma most often cause by? What are important mediators?
TH2 and IgE-mediated
immunologic reaction to environmental allergens. The TH2 cytokines IL-4, IL-5, and IL-13 are important mediators
What is atopic asthma characterized by?
early-phase (immediate) and late-phage reactions
What are triggers for nontoxic asthma?
Triggers for nonatopic asthma are less clear but include viral infections and inhaled air pollutants, which also can trigger atopic asthma.
What are key inflammatory cells that are found in all subtypes of asthma, and how?
Eosinophils, the products of oesinophil (such as major basic protein) are responsible for airway damage
What adds an irreversible component to asthma?
Airway remodeling (sub-basement membrane thickening and hypertrophy of bronchial glands and smooth muscle)
Is asthma restrictive or obstructive?
Obstructive
Diffuse interstitial fibrosis of the lung gives rise to restrictive lung diseases characterized by increased/reduced lung compliance and increased/reduced forced vital capacity
Reduced and reduced
Is the FEV to FVC ration normal in chronic interstitial lung diseases?
Yes
Diseases that cause diffuse interstitial fibrosis are heterogeneous/homogeneous
heterogeneous
What is the unifying pathogenic factor of chronic interstitial lung diseases?
Injury to the alveoli, leading to activation of macrophages and release of fibrogenic cytokines such as TGF-β
Idiopathic pulmonary fibrosis is prototypic of restrictive lung diseases. How is it characterized?
By patchy interstitial fibrosis, fibroblastic foci, and formation of cystic spaces (honeycomb lung). This histologic pattern is known as usual interstitial pneumonia (UIP)
What is pneumoconioses?
Pneumoconioses encompass a group of chronic fibrosing diseases of the lung resulting from exposure to organic and inorganic particulates, most commonly mineral dust.
Which (inflammatory) cells play a central role in the pathogenesis of lung injury and how?
Pulmonary alveolar macrophages, by promoting inflammation and producing reactive oxygen species and fibrogenic cytokines
How do coal dust-induced and simple coal workers’s pneumoconiosis present?
(you don’t have to know all by heart, this is just to show you there are multiple)
Coal dust–induced disease varies from asymptomatic anthracosis, to simple coal worker’s pneumoconiosis (coal macules or nodules, and centrilobular emphysema), to progressive massive fibrosis (PMF), manifested by increasing pulmonary dysfunction, pulmonary hypertension, and cor pulmonale.
What is the most common pneumoconiosis in the word?
Silicosis (of crystalline silica)
True/false: Silicosis usually present with asymptomatic silicotic nodules to progressive massive fibrosis (PMF)
True, but individuals can also have an increased susceptibility to tuberculosis, the range is wide
Asbestos exposure is linked with six diseases processes. Name them.
(seriously don’t learn this)
- Parenchymal interstitial fibrosis (asbestosis)
- Localized fibrous plaques, or, rarely, diffuse pleural fibrosis
- Pleural effusions
- Lung cancer
- malignant pleural and peritoneal mesothelioma
- Laryngeal cancer
True/false: family members of workers exposed to asbestos are at increased risk for cancer
True
How is sarcoidosis diagnosed/what is the cause?
Sarcoidosis is a multisystem disease of unknown etiology; the diagnostic histopathologic feature is the presence of noncaseating granulomas in various tissues
What immunologic abnormalities are found in sarcoidosis?
high levels of CD4+ TH1 cells in the lung that secrete cytokines such as IFN-γ.
What are the clinical manifestations of sarcoidosis?
Clinical manifestations include lymph node enlargement, eye involvement (sicca syndrome [dry eyes], iritis, or iridocyclitis), skin lesions (erythema nodosum, painless subcutaneous nodules), and visceral involvement (liver, skin, bone marrow). Lung involvement occurs in 90% of cases, with formation of granulomas and interstitial fibrosis.
Fill in: Almost all large pulmonary artery thrombi are … in origin, usually arising from the deep veins of the lower leg.
embolic
What are risk factors of pulmonary embolism?
prolonged bed rest, knee or hip surgery, severe trauma, congestive heart failure, use of oral contraceptives (especially those with high estrogen content), disseminated cancer, and genetic causes of hypercoagulability.
True/false: Majority of emboli are silent
True (60-80%)
A minority of the lung emboli (5%, typically large “saddle emboli”) cause complications. Such as which?
Right-sided heart failure, shock, sudden death; and the remainder cause pulmonary infarction
Is the risk for recurrence of a lung embolism high?
Yes
What is the most common cause of community-acquired bacterial pneumonia?
S. pneumoniae (the pneumococcus)
The pneumococcus (community acquired) usually has lobar pattern of involvement. What are the four stages?
- Congestion
- Red hypatization
- Gray hepatization
- Resolution
What are other common causes of bacterial pneumonias in the community?
(I really don’t think you should learn this, but there are quite a lot of pages on it in the book, it’s only touched upon in the lecture)
H. influenzae and M. catarrhalis (both associated with acute exacerbations of COPD), S. aureus (usually second- ary to viral respiratory infections), K. pneumoniae (observed in chronic alcoholics), P. aeruginosa (seen in individuals with cystic fibrosis, in burn victims, and in patients with neutropenia), and L. pneumophila, seen particularly in organ transplant recipients.
How are viral pneumonias characterized?
by respiratory distress out of proportion to the clinical and radiologic signs, and by inflammation that is predominantly confined to alveolar septa, with generally clear alveoli.
What are common causes of viral pneumonia?
Influenza A and B, respiratory syncytial virus, human metapneumovirus, parainfluenza virus, and adenovirus
(I personally think influenza is important, and a very recent one is of course COVID!)
What is tuberculosis?
Tuberculosis is a chronic granulomatous disease caused by M. tuberculosis, usually affecting the lungs, but virtually any extrapulmonary organ can be involved.
Initial exposure to mycobacteria results in development of a … (i) that confers … (ii) and leads to … (iii) (as determined by a positive result on the tuberculin skin test).
i. cellular immune response
ii. resistance
iii. hypersensitivity
(Tuberculosis) Fill in: The TH1 subset of CD4/CD8 T cells has a crucial role in cell-mediated immunity against mycobacteria; mediators of inflammation and bacterial containment include … (3 answers)
CD4, IFN-γ, TNF, and nitric oxide.
What is the histopathologic hallmark of host reaction to tuberculosis in immunocompetent individuals?
The presence of granulomas, usually with caseous necrosis
Primary pulmonary tuberculosis in immunocompetent individuals is asymptomatic/symptomatic
asymptomatic
What does primary pulmonary tuberculosis result to?
Healed lesions, typically in sub-pleural focus and a draining lymph node
How does secondary (reactivation) tubuerculosis arise and how does it manifest?
in previously exposed individuals when host immune defenses are compromised, and usually manifests as cavitary lesions in the lung apices.
True/false: Both progressive primary tuberculosis and secondary tuberculosis can result in systemic seeding, causing life-threatening forms of disease such as miliary tuberculosis and tuberculous meningitis.
True!
Is HIV-seropositive status an important risk factor for development or recrudescence of active tuberculosis?
Yes
What are the three major historic subtypes of carcinoma of the lung?
Adenocarcinoma (most common), squamous cell carcinoma, small cell carcinoma
What is the most important risk factor for lung cancer?
Smoking
What do precursors lesions include?
atypical adenomatous hyperplasia and adenocarcinoma in situ for adenocarcinomas and squamous dysplasia for squamous cancer.
Tumors 3 cm or less in diameter characterized by pure growth
along preexisting structures without stromal invasion are
called … in situ.
adenocarcinoma
How are SCLCs best treated? Why?
Chemotherapy, because almost all are metastatic at presentation
How are non-SCLCs best treated?
The other carcinomas may be curable by surgery if limited to the lung
What is an excellent example of personalized cancer therapy?
Targeted therapies, such as EGFR inhibitor therapy for adenocarcinomas with EGFR mutations, can be effective, immunotherapies are under development and show promise.
Lung cancers commonly cause variety of … syndromes.
paraneoplastic
