Chapter 15- Lungs Flashcards
Where do the lungs form from?
Central wall of the foregut
What is the morphological difference between bronchi and bronchioles?
Bronchi have cartilage and subepithelial mucous glands (bronchioles have neither)
What type of epithelium makes up the respiratory tree?
Psuedostratified columnar ciliated epithelium
What part of the respiratory doesn’t possess respiratory epithelium?
The vocal cords
What are the two types of alveolar epithelium and their functions?
- Type I pneumocytes- gas exchange
2. Type II pneumocytes- surfactant synthesis
When are Type II pneumocytes properly formed?
After 28wks gestation
What are the congenital anomalies of the lungs?
- Pulmonary hypoplasia- small lungs due to compression/impeded expansion
- Foregut cysts- abnormal detachment of primitive foregut
- Pulmonary sequestration- parts of lung lack connection to the airway system
What are the types of foregut cysts and their characteristics?
- Branchial cleft- on lateral aspect, lined by squamous cells
- Bronchogenic cysts- lined by ciliated respiratory epithelium, can contain cartilage, mucous glands, etc
What is the most common form of foregut cyst?
Branchial cleft
What are the types of pulmonary sequestration and where do they occur?
- Extralobar- external to lungs
2. Intralobar- within lung parenchyma
What is atelectasis?
Lung collapse
What are the two categories of atelectasis and what distinguishes them?
- Neonatal- incomplete lung expansion
2. Acquired- collapse of a previously inflated lung
What are the forms of acquired atelectasis and their characteristics?
- Resorption- complete airway obstruction
- Compression- pleural space expanded by fluid
- Contraction- local/generalized fibrotic changes
Where does the mediastinum shift in the different types of acquired atelectasis?
Resorption- towards the collapsed lung
Compression- away from the collapsed lung
What is pulmonary edema caused by?
Increased hydrostatic pressure or capillary permeability
What is the lung morphology of chronic congestion?
Brown and firm with interstitial fibrosis
Hemosiderin laden macs/heart failure cells
What are the hemodynamic causes of pulmonary edema?
- Increased hydrostatic pressure
- Decreases oncotic pressure
- Lymphatic obstruction
- Edema due to alveolar wall injury
- Direct injury
- Indirect injury
- Undetermined origin (high altitude)
What is acute lung injury (ALI)?
Inflammation associated with increased pulmonary vascular permeability due to endothelial and epithelial cell death
What is the severe form of ALI?
Acute respiratory distress syndrome (ARDS)
What is the histological presentation of ALI?
Diffuse alveolar damage
What are the causes of ALI?
Infection
Trauma
Toxic exposure
Pancreatitis
Uremia
Immune reactions
What is acute interstitial pneumonia?
ALI with the absence of etiology
What is the morphology of the lungs in ALI?
Firm, red, boggy and heavy
What is the pathology of obstructive pulmonary disease?
Increased airflow resistance
What are the types of obstructive pulmonary diseases?
- Emphysema
- Chronic bronchitis
- Asthma
- Bronchiectasis
What is the pathology of restrictive pulmonary diseases?
Reduced expansion of the lung parenchyma and decreased total lung capacity
What is the cause of emphysema?
Irreversible enlargement of airspaces
Alveolar wall destruction with minimal fibrosis
What are the characteristics of patients with emphysema?
Barrel chested and dyspneic
Sit hunched
Breathe through pursed lips
What is the key to diagnosis of emphysema?
Impaired expiratory airflow via spirometry
Emphysema and chronic bronchitis together are termed what?
COPD
What are the types of emphysema and their characteristics?
- Centriacinar- occurs in central/proximal areas of upper lobes, smokers
- Panacinar- uniform, in lower zones, alpha1-antitrypsin deficiency
- Distal acinar- distal acinus, adjacent to fibrosis/scars, spontaneous pneumothorax
- Airspace enlargement with fibrosis- associated with scarring, irregular emphysema
What is the morphology of emphysema in young smokers?
Small airway inflammation
Goblet cell hyperplasia
Inflammatory infiltrates in bronchial walls
Muscle hypertrophy (wall thickening)
What is the function of alpha1-antitrypsin?
Inhibits proteases
Protects tissues from inflammatory enzymes
What is the definition of chronic bronchitis?
Persistent cough with sputum production for at least three months in at least two consecutive years
No other identifiable cause apparent
What is the morphology of chronic bronchitis?
Chronic irritation by inhaled substances
Mucous gland hypertrophy
Goblet cell metaplasia in bronchiolar epithelium
Bronchiolitis- wall thickening (fibrosis and muscle hypertrophy)
What can long term chronic bronchitis lead to?
Acute decline in lung function
Cor pulmonale
Heart failure
Respiratory epithelial dysplasia with malignant transformation
What is the morphology of asthma?
Episodic bronchocontriction
Inflammation of bronchial walls
Increased mucous secretion
Airway remodelling
Curschmann spirals- whorled mucous plugs
Charcot-Leyden crystals- eosinophilic granule debris
What are the types of asthma?
- Atopic/allergic- Type I mediated hypersensitivity (IgE)
Nonatopic- respiratory infections, chemical irritants, drugs
What is the morphology of bronchiectasis?
Abnormal dilation of airways due to necrotizing infection
Scarring
Fibrous pleural adhesions
What can cause bronchiectasis?
Congenital or hereditary conditions
Infections
Bronchial obstruction
Chronic inflammatory diseases (RA, SLE, IBD, COPD)
What are chronic diffuse interstitial (restrictive) pulmonary diseases characterized by?
Inflammation
Interstitial tissue fibrosis
Reduced lung capacity, volume and compliance without obstruction
Where do restrictive pulmonary diseases occur?
- Chronic interstitial and infiltrative diseases
2. Chest wall disorders
What are the major categories of restrictive pulmonary diseases?
- Fibrosing
- Granulomatous
- Eosinophilic
- Smoking related
- Other
What are the restrictive pulmonary fibrosing diseases?
- Idiopathic pulmonary fibrosis
- Nonspecific interstitial pneumonia
- Cryptogenic organizing pneumonia
- Pulmonary involvement in autoimmune diseases
- Pneumoconioses
- Asbestos related diseases
What are the characteristics of idiopathic pulmonary fibrosis?
Progressive, patchy interstitial fibrosis
Heterogeneity (new fibroblastic foci with older areas of fibrosis)
Honeycomb lung- bands of fibrous tissue
Usual interstitial pneumonia histologically
What is the pathology of idiopathic pulmonary fibrosis?
Epithelial injury/activation
Immune response
Pro-fibrogenic factors
How does nonspecific interstitial pneumonia differ from IPF?
Diffusely fibrosing
Lacks heterogeneity
Better prognosis
What is the morphology of cryptogenic organizing pneumonia?
Masson bodies- loose, fibrous tissue plugs
No interstitial fibrosis or honeycombing
What is the cause of pneumoconioses?
Neoplastic lung reaction to inhaled foreign particles
What does the development of pneumoconioses depend on?
Amount of dust retained
Size, shape and particle buoyancy
Physiochemical reactivity and solubility
Addition affects
What are two common forms of pneumoconioses?
- Coal workers’- massive fibrosis
2. Silicosis- nodular fibrosis
What is coal workers’ pneumoconioses also known as?
Anthracosis
What form of silicon dioxide is more fibrogenic?
Crystalline
What is the pathology of asbestos related diseases?
Pleural plaques and effusions
Lung carcinoma, mesothelioma, laryngeal cancer
What affects the disease causing capacity of asbestos?
Size, shape and solubility
What is a key morphological feature of asbestos related disease?
Asbestos bodies- golden brown beaded rods with a translucent centre
What are the types of pulmonary restrictive granulomatous diseases and their characteristics?
- Sarcoidosis- systemic, bilateral, noncaseating, disease of exclusion
- Hypersensitivity pneumonitis- caused by inhaled dust or Ags, affects alveoli
What are the different forms of hypersensitivity pneumonitis?
- Farmer’s lung- actinomycete spores
- Pigeon breeders’ lung
- Humidifier or air conditioner lung
What is pulmonary eosinophilia characterized by?
Interstitial or alveolar eosinophil infiltrates
What are the types of pulmonary eosinophilia?
- Acute with respiratory failure
- Simple (Loeffler syndrome)
- Tropical
- Secondary
- Idiopathic chronic eosinophilic pneumonia
What are the types of pulmonary restrictive smoking related diseases and their characteristics?
- Desquamative interstitial pneumonia- intra-alveolar brown smoker’s macs, mild inflammation, minimal fibrosis
- Respiratory bronchiolitis associated interstitial lung disease- patchy smoker’s macs with peribronchiolar inflammation and mild fibrosis
- Pulmonary Langerhans cell histiocytosis- focal collections of Langerhans cells, progressive fibrosis
What is the pathology of pulmonary alveolar proteinosis (PAP)?
Surfactant accumulation in alveoli and bronchioles
What pulmonary disorders involve the vascular system?
- PE and infarction
- Pulmonary hypertension
- Diffuse pulmonary hemorrhage syndromes
What leads to PE and infarction?
Hypercoaguable states
Respiratory compromise- lack of perfusion
Hemodynamic compromise- increased pulmonary arterial resistance
What causes pulmonary hypertension?
- Chronic obstructive or interstitial lung disease
- Congenital or acquired heart disease with LSHF
- Recurrent PE
- Connective tissue diseases
- Obstructive sleep apnea
- Rare idiopathic or familial forms
What are the different groups of pulmonary hypertension?
- Pulmonary arterial
- Secondary to LSHF
- From lung parenchymal disease
- Chronic thromboembolic
- Multifactorial
What are different types of diffuse pulmonary hemorrhage syndromes?
- Goodpasture’s- BM destruction, necrotizing hemorrhagic interstitial pneumonitis
- Idiopathic pulmonary hemosiderosis- children with alveolar hemorrhage
- Wegner granulomatosis- vasculitis, hemoptysis
What are pneumonias classified by?
Specific etiologic agents or clinical setting
What are the two patterns of bronchopneumonia?
- Lobular- patchy
2. Lobar- large portion or entire lobe
What are the stages of inflammatory response in lobar bronchopneumonia?
- Congestion- vascular engorgement
- Red hepatization- exudation
- Grey hepatization- RBC disintegration
- Resolution- exudate broken down
What infectious organisms are commonly seen in the gross room?
Tb
Histoplasmosis
Blastomycosis
Coccidioidomycosis
What are the major complications of lung transplantation?
Infection and rejection
When do 50% of all patients experience chronic rejection of lung transplants?
3-5yrs
What cancer has the highest mortality?
Lung
What type are 95% of lung cancers?
Carcinomas
What polymorphism increases the risk of developing lung cancer with smoking?
P450 mono-oxygenase
What are the precursor lesions associated with lung cancer?
Squamous cell dysplasia and carcinoma in situ
Atypical adenomatous hyperplasia
Adenocarcinoma in situ
Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia
What is the most common lung cancer?
Adenocarcinoma
What are the characteristics of adenocarcinoma of the lung?
Peripheral mass
Leptic pattern- tumour cells crawl along alveolar septae
Small, metastasize early
Nodules surrounding mass are physically connected
What precursor lesions are associated with adenocarcinoma of the lung?
Atypical adenomatous hyperplasia
Adenocarcinoma in situ
What are the characteristics of squamous cell carcinoma of the lung?
Occur in or near hilum
Large masses
Associated with smoking
What precursor lesions are associated with squamous cell carcinoma of the lung?
Squamous metaplasia or dysplasia
What is the most malignant lung cancer?
Small cell carcinoma
What are the characteristics of SCC?
Central or hilar
Small cells with scant cytoplasm, salt and pepper chromatin, nuclear molding
Abundant necrosis
Neuroendocrine features
Always high grade
Associated with smoking
What is SCC treated with?
Chemo
What are the characteristics of large cell carcinoma?
Undifferentiated neoplasm
What lung cancers can metastasize?
All
What is the most common site of lung cell metastasis?
Adrenals
What are secondary pathologies of lung cancers?
Superior vena cava syndrome- edema or head and arm
Paraneoplastic syndrome- hormone release from tumour
What can diffuse idiopathic pulmonary neuroendocrine cell hyperplasia develop?
Tumourlets (benign cysts)
Carcinoids
What is the most common site of metastatic cancer development?
Lungs
What can cause pleural effusions?
- Increased hydrostatic pressure
- Increased vascular permeability
- Decreased oncotic pressure
- Increased negative intrapheural pressure
- Decreased lymphatic drainage
What is pneumothorax?
Air or gas in the pleural cavity
What is tension pneumothorax?
Defect that allows air to enter the lung during inspiration but prevents its exit
Compression on contralateral lung and mediastinum
Are pleural tumours normally metastatic?
Yes
What are the types of pleural tumours?
- Solitary fibrous- dense, rarely malignant
- Malignant mesothelioma- spreads to pleural space, effusion, lung ensheathed by tumour tissue, related to asbestos exposure
