Respiratory Pathology Flashcards
What are the main components of the respiratory system?
larynx Nasal passages
Define acinus in the respiratory system.
An acinus is composed of respiratory bronchioles alveolar ducts
What are the walls of alveoli responsible for?
Gas exchange within the lungs.
What is pulmonary hypoplasia?
Underdeveloped lungs with decreased weight and acini often due to issues that impede lung expansion.
What are foregut cysts?
Abnormal detachment from the foregut classified as bronchogenic
Define pulmonary sequestration.
An area of lung tissue that lacks connection to the airway and has an abnormal blood supply.
What is Hyaline Membrane Disease (HMD)?
A condition in premature infants caused by a lack of surfactant leading to respiratory distress.
What is bronchopulmonary dysplasia?
A chronic lung disease in infants typically following HMD
Define pneumonia.
An infection of the lung parenchyma caused by impaired lung defenses or reduced host immunity.
What are the two main types of pneumonia based on anatomic distribution?
Bronchopneumonia (patchy lung consolidation) and lobar pneumonia (consolidation of a lobe).
What is community-acquired pneumonia?
Pneumonia acquired from the general environment often in healthy individuals
List common causes of community-acquired bacterial pneumonia.
Streptococcus pneumoniae Haemophilus influenzae
What characterizes lobar pneumonia?
Consolidation of a large portion of or an entire lung lobe.
Describe the four stages of lobar pneumonia.
Congestion red hepatization
What are the risk factors for healthcare-associated pneumonia?
Hospitalization nursing home residency
What is aspiration pneumonia?
Pneumonia from inhaling gastric contents often seen in debilitated patients.
Define chronic pneumonia.
A persistent lung infection often caused by organisms like Mycobacterium tuberculosis and Histoplasma capsulatum.
What is chronic obstructive pulmonary disease (COPD)?
A group of lung diseases characterized by increased airway resistance including emphysema and chronic bronchitis.
Describe emphysema.
A chronic respiratory condition with irreversible enlargement of airspaces and destruction of alveolar walls.
What are the primary types of emphysema?
Cenriacinar (centrilobular)
Panlobular
Distal acinar (paraseptal)
Irregular
What enzyme imbalance contributes to emphysema?
Protease-antiprotease imbalance specifically due to α1-antitrypsin deficiency.
List symptoms of emphysema.
Dyspnea barrel chest
Define chronic bronchitis.
A chronic cough with sputum production for at least 3 months in 2 consecutive years.
What causes chronic bronchitis?
Exposure to irritants like tobacco smoke leading to mucus hypersecretion and inflammation.
What are typical symptoms of chronic bronchitis?
Persistent productive cough dyspnea
What characterizes asthma?
Episodic bronchoconstriction due to airway hyperresponsiveness and inflammation.
What is atopic asthma?
An IgE-mediated hypersensitivity reaction triggered by allergens.
Describe non-atopic asthma.
Asthma without allergen sensitization often triggered by viral infections.
What is drug-induced asthma?
A form of asthma triggered by medications like aspirin causing a decrease in prostaglandin E2.
What causes bronchiectasis?
Destruction of bronchial smooth muscle and elastic tissue due to chronic infections.
What is restrictive lung disease?
A group of lung conditions with reduced lung expansion and lung volume.
List categories of chronic interstitial lung disease.
Fibrosing
Usual interstitial pneumonia (idiopathic pulmonary fibrosis)
Nonspecific interstitial pneumonia
Cryptogenic organizing pneumonia
Connective tissue disease-associated
Pneumoconiosis
Drug reactions
Radiation pneumonitis
Granulomatous
Sarcoidosis
Hypersensitivity pneumonitis
Eosinophilic
Smoking Related
What is idiopathic pulmonary fibrosis (IPF)?
A progressive lung disease with interstitial fibrosis and respiratory failure.
Describe pulmonary embolism.
Obstruction of the pulmonary artery by emboli often thrombi from deep leg veins.
What is the main cause of pulmonary hypertension?
Elevated pulmonary artery pressure due to increased resistance or blood flow.
Define lung carcinoma.
A primary malignant tumor of the lung often associated with smoking and environmental factors.
What are the main types of lung carcinoma?
Adenocarcinoma squamous cell carcinoma
What is a carcinoid tumor?
A low-grade malignant tumor of neuroendocrine cells representing 1-5% of lung tumors.
What symptoms are associated with carcinoid tumors?
Cough hemoptysis
What is pneumonia?
An infection of the lung parenchyma that occurs when normal lung defenses are impaired.
What are common causes of impaired lung defenses that lead to pneumonia?
Impaired cough reflex damage to the mucociliary escalator
List the clinical features of pneumonia.
Fever and chills productive cough with yellow-green (pus) or rusty (bloody) sputum
How is pneumonia diagnosed?
Through chest X-ray sputum Gram stain and culture
What are the three classic patterns of pneumonia on chest X-ray?
Lobar pneumonia bronchopneumonia
Define lobar pneumonia.
Characterized by consolidation of an entire lobe of the lung.
What are the most common bacterial causes of lobar pneumonia?
Streptococcus pneumoniae (95%) and Klebsiella pneumoniae.
What are the four classic stages of lobar pneumonia?
Congestion red hepatization
What is congestion in lobar pneumonia?
Vascular engorgement and edema due to congested vessels.
Describe red hepatization in lobar pneumonia.
Exudate neutrophils
What characterizes bronchopneumonia?
Scattered patchy consolidation centered around bronchioles; often multifocal and bilateral.
What organisms are commonly associated with bronchopneumonia?
Staphylococcus aureus Haemophilus influenzae
Define interstitial (atypical) pneumonia.
Characterized by diffuse interstitial infiltrates often with mild upper respiratory symptoms.
What are the typical symptoms of interstitial pneumonia?
Relatively mild symptoms such as minimal sputum production and low-grade fever.
What types of organisms cause interstitial pneumonia?
Bacteria or viruses such as Mycoplasma pneumoniae and Chlamydia pneumoniae.
What is aspiration pneumonia?
Pneumonia due to inhalation of oropharyngeal contents commonly seen in alcoholics and comatose patients.
What bacteria are most often associated with aspiration pneumonia?
Anaerobic bacteria in the oropharynx including Bacteroides fusibacterium
What is the most common cause of community-acquired pneumonia?
Streptococcus pneumoniae usually seen in middle-aged adults and elderly.
What groups are commonly affected by Klebsiella pneumoniae?
Malnourished and debilitated individuals such as the elderly in nursing homes
What unique characteristic does Klebsiella pneumoniae pneumonia have?
It produces a thick mucoid capsule resulting in gelatinous or “currant jelly” sputum.
What complication is often associated with Klebsiella pneumoniae?
Lung abscess formation.
What is a high-yield association for Staphylococcus aureus pneumonia?
It is the most common cause of secondary pneumonia often following viral respiratory infections
What is Haemophilus influenzae commonly associated with?
Community-acquired pneumonia especially in those with chronic obstructive pulmonary disease (COPD).
What is a common cause of pneumonia in cystic fibrosis patients?
Pseudomonas aeruginosa.
What types of pneumonia can Moraxella catarrhalis cause?
Community-acquired pneumonia and pneumonia in COPD patients.
What is a high-yield association for Legionella pneumophila?
Community-acquired pneumonia commonly in the elderly or immunocompromised
Why is Mycoplasma pneumoniae a common cause of atypical pneumonia?
It often affects young adults such as military recruits or college students.
What are two complications of Mycoplasma pneumoniae?
Autoimmune hemolytic anemia and erythema multiforme.
Why is Mycoplasma pneumoniae not visible on Gram stain?
It lacks a cell wall.
What is the second most common cause of atypical pneumonia in young adults?
Chlamydia pneumoniae.
What is a high-yield association for respiratory syncytial virus (RSV)?
It is the most common cause of atypical pneumonia in infants.
What is Cytomegalovirus (CMV) associated with?
Atypical pneumonia often in individuals undergoing post-transplant immunosuppressive therapy.
What groups are at higher risk for Coxiella burnetii pneumonia?
Farmers and veterinarians; it causes Q fever.
How is Coxiella burnetii different from other rickettsiae?
It causes pneumonia does not require an arthropod vector
What is pneumonia?
An infection of the lung parenchyma that occurs when normal lung defenses are impaired.
What are common causes of impaired lung defenses that lead to pneumonia?
Impaired cough reflex damage to the mucociliary escalator
List the clinical features of pneumonia.
Fever and chills productive cough with yellow-green (pus) or rusty (bloody) sputum
How is pneumonia diagnosed?
Through chest X-ray sputum Gram stain and culture
What are the three classic patterns of pneumonia on chest X-ray?
Lobar pneumonia bronchopneumonia
Define lobar pneumonia.
Characterized by consolidation of an entire lobe of the lung.
What are the most common bacterial causes of lobar pneumonia?
Streptococcus pneumoniae (95%) and Klebsiella pneumoniae.
What are the four classic stages of lobar pneumonia?
Congestion red hepatization
What is congestion in lobar pneumonia?
Vascular engorgement and edema due to congested vessels.
Describe red hepatization in lobar pneumonia.
Exudate neutrophils
Describe gray hepatization in lobar pneumonia.
Degradation of red cells within the exudate leading to a grayish color.
What characterizes bronchopneumonia?
Scattered patchy consolidation centered around bronchioles; often multifocal and bilateral.
What organisms are commonly associated with bronchopneumonia?
Staphylococcus aureus Haemophilus influenzae
Define interstitial (atypical) pneumonia.
Characterized by diffuse interstitial infiltrates often with mild upper respiratory symptoms.
What are the typical symptoms of interstitial pneumonia?
Relatively mild symptoms
such as minimal sputum production and low-grade fever.
What types of organisms cause interstitial pneumonia?
Bacteria or viruses such as Mycoplasma pneumoniae and Chlamydia pneumoniae.
What is aspiration pneumonia?
Pneumonia due to inhalation of oropharyngeal contents commonly seen in alcoholics and comatose patients.
What bacteria are most often associated with aspiration pneumonia?
Anaerobic bacteria in the oropharynx including Bacteroides
What is the most common cause of community-acquired pneumonia?
Streptococcus pneumoniae usually seen in middle-aged adults and elderly.
What groups are commonly affected by Klebsiella pneumoniae?
Malnourished and debilitated individuals such as the elderly in nursing homes
What unique characteristic does Klebsiella pneumoniae pneumonia have?
It produces a thick mucoid capsule resulting in gelatinous or “currant jelly” sputum.
What complication is often associated with Klebsiella pneumoniae?
Lung abscess formation.
What is a high-yield association for Staphylococcus aureus pneumonia?
It is the most common cause of secondary pneumonia often following viral respiratory infections
What is Haemophilus influenzae commonly associated with?
Community-acquired pneumonia especially in those with chronic obstructive pulmonary disease (COPD).
What is a common cause of pneumonia in cystic fibrosis patients?
Pseudomonas aeruginosa.
What types of pneumonia can Moraxella catarrhalis cause?
Community-acquired pneumonia and pneumonia in COPD patients.
What is a high-yield association for Legionella pneumophila?
Community-acquired pneumonia commonly in the elderly or immunocompromised
Why is Mycoplasma pneumoniae a common cause of atypical pneumonia?
It often affects young adults such as military recruits or college students.
What are two complications of Mycoplasma pneumoniae?
Autoimmune hemolytic anemia and erythema multiforme.
Why is Mycoplasma pneumoniae not visible on Gram stain?
It lacks a cell wall.
What is the second most common cause of atypical pneumonia in young adults?
Chlamydia pneumoniae.
What is a high-yield association for respiratory syncytial virus (RSV)?
It is the most common cause of atypical pneumonia in infants.
What is Cytomegalovirus (CMV) associated with?
Atypical pneumonia often in individuals undergoing post-transplant immunosuppressive therapy.
What groups are at higher risk for Coxiella burnetii pneumonia?
Farmers and veterinarians; it causes Q fever.
How is Coxiella burnetii different from other rickettsiae?
It causes pneumonia does not require an arthropod vector
What are restrictive lung diseases?
Diseases characterized by restricted filling of the lung decreased TLC and FVC
What are common causes of restrictive lung diseases?
Interstitial diseases of the lung or chest wall abnormalities (e.g. massive obesity).
What is idiopathic pulmonary fibrosis?
A condition with fibrosis of the lung interstitium likely due to cyclical lung injury.
What induces fibrosis in idiopathic pulmonary fibrosis?
TGF-β released from injured pneumocytes.
What secondary causes of interstitial fibrosis should be excluded in idiopathic pulmonary fibrosis?
Drug exposure (e.g. bleomycin
What are the clinical features of idiopathic pulmonary fibrosis?
Progressive dyspnea and cough subpleural fibrosis on lung CT
What is the treatment for idiopathic pulmonary fibrosis?
Lung transplantation.
What are pneumoconioses?
Interstitial fibrosis caused by chronic occupational exposure to small fibrogenic particles.
How do pneumoconioses cause fibrosis?
Alveolar macrophages engulf foreign particles and induce fibrosis.
What is sarcoidosis?
A systemic disease with noncaseating granulomas in multiple organs commonly affecting African American females.
What likely causes sarcoidosis?
An unknown antigen triggering a CD4+ T-cell response.
Where are sarcoid granulomas most commonly found?
In the hilar lymph nodes and lungs leading to restrictive lung disease.
What is coal workers’ pneumoconiosis?
Also known as “black lung
“ caused by carbon dust exposure, typically seen in coal miners.
What is pulmonary hypertension?
High pressure in the pulmonary circuit with mean arterial pressure > 25 mm Hg (normal is 10 mm Hg).
What are the main characteristics of pulmonary hypertension?
Atherosclerosis of the pulmonary trunk smooth muscle hypertrophy of pulmonary arteries
What are the main clinical features of pulmonary hypertension?
Exertional dyspnea right-sided heart failure
How is pulmonary hypertension classified?
Primary (idiopathic) or secondary based on etiology.
What is primary pulmonary hypertension?
A form of pulmonary hypertension seen in young adult females with unknown etiology.
What genetic mutation is linked to some cases of primary pulmonary hypertension?
Inactivating mutations of BMPR2 which lead to vascular smooth muscle proliferation.
What are common causes of secondary pulmonary hypertension?
Hypoxemia (e.g. COPD
What is acute respiratory distress syndrome (ARDS)?
Diffuse damage to the alveolar-capillary interface leading to alveolar damage and severe respiratory distress.
What causes alveolar damage in ARDS?
Leakage of protein-rich fluid into alveoli forming hyaline membranes and causing edema.
What are clinical features of ARDS?
Hypoxemia cyanosis
What conditions can lead to ARDS?
Sepsis trauma
How do neutrophils contribute to ARDS?
Neutrophil activation releases proteases and free radicals damaging type I and II pneumocytes.
What is the treatment approach for ARDS?
Treat underlying cause and use ventilation with positive end-expiratory pressure (PEEP).
What are possible complications during recovery from ARDS?
Interstitial fibrosis due to loss and damage of type II pneumocytes.
What is neonatal respiratory distress syndrome (NRDS)?
Respiratory distress due to inadequate surfactant levels in newborns.
What is the role of surfactant in the lungs?
Surfactant reduces surface tension in alveoli preventing collapse after expiration.
What cells produce surfactant and what is its main component?
Type II pneumocytes produce surfactant
What are risk factors for neonatal respiratory distress syndrome?
Prematurity
cesarean delivery
How is fetal lung maturity assessed?
By the lecithin-to-sphingomyelin ratio in amniotic fluid; a ratio > 2 indicates sufficient surfactant production.
What are clinical features of neonatal respiratory distress syndrome?
Increased respiratory effort tachypnea
What are complications of NRDS?
Hypoxemia can cause patent ductus arteriosus and necrotizing enterocolitis while oxygen therapy risks free radical injury (blindness
What is pneumothorax?
Accumulation of air in the pleural space which can cause lung collapse.
What is spontaneous pneumothorax and who is most at risk?
Spontaneous pneumothorax is often due to rupture of an emphysematous bleb
What is a tension pneumothorax?
A pneumothorax where air enters the pleural space but cannot exit pushing the trachea to the opposite side.
How is tension pneumothorax treated?
It is a medical emergency treated with chest tube insertion.
What is mesothelioma?
A malignant neoplasm of mesothelial cells associated with asbestos exposure.
What are clinical features of mesothelioma?
Recurrent pleural effusionsdyspnea
What is anthracosis?
A mild form of carbon dust exposure seen in urban pollution, resulting in carbon-laden macrophages.
What is anthracosis?
A mild form of carbon dust exposure seen in urban pollution, resulting in carbon-laden macrophages.
What is silicosis
An occupational lung disease from silica exposure, common in sandblasters and silica miners.
What is silicosis
An occupational lung disease from silica exposure, common in sandblasters and silica miners.
What are the pathological findings in silicosis?
Fibrotic nodules in the upper lobes of the lungs.
What is a significant risk associated with silicosis?
Increased risk of tuberculosis, as silica impairs macrophage phagolysosome formation.
What is a significant risk associated with silicosis?
Increased risk of tuberculosis, as silica impairs macrophage phagolysosome formation.
What is berylliosis?
An occupational lung disease from beryllium exposure, commonly seen in aerospace industry workers.
What are the pathological findings in berylliosis?
Noncaseating granulomas in the lung, hilar lymph nodes, and systemic organs.
What are the pathological findings in asbestosis?
What are asbestos bodies? Long, golden-brown fibers with associated iron, confirming asbestos exposure.
What is hypersensitivity pneumonitis? A granulomatous reaction to inhaled organic antigens, such as “pigeon breeder’s lung.”
What are the clinical features of hypersensitivity pneumonitis? Fever, cough, and dyspnea hours after exposure, which resolves with removal of the antigen.
What is pulmonary hypertension? A condition of high pressure in the pulmonary circuit, defined as mean arterial pressure > 25 mm Hg.
What vascular changes are seen in pulmonary hypertension? Atherosclerosis of the pulmonary trunk, smooth muscle hypertrophy in pulmonary arteries, and intimal fibrosis.
What are plexiform lesions? Complex vascular lesions seen in severe, long-standing pulmonary hypertension.
What are the clinical features of pulmonary hypertension? Exertional dyspnea and signs of right-sided heart failure.
What are the two main classifications of pulmonary hypertension? Primary (unknown cause) and secondary (related to underlying conditions).
Who is typically affected by primary pulmonary hypertension? Young adult females.
What genetic mutation is associated with some forms of primary pulmonary hypertension? Inactivating mutations of BMPR2, leading to vascular smooth muscle proliferation.
What conditions commonly lead to secondary pulmonary hypertension? Hypoxemia (e.g., COPD, interstitial lung disease) or increased pulmonary circuit volume (e.g., congenital heart disease).
How can recurrent pulmonary embolism lead to pulmonary hypertension? It increases resistance and pressure within the pulmonary vasculature.
Lung and pleural fibrosis with plaques, increasing the risk for lung carcinoma and mesothelioma.
