Chapter 15: Lung Flashcards
Types of foregut cysts
- bronchogenic
- esophageal
- enteric
Types of atelectasis
- resorption (obstruction): complete obstruction with resorption of oxygen and mediastinal shift toward atelectasis
- compression: pleural filling, etc; with mediastinal shift away from atelectasis
- contraction: fibrotic chnages prevent full expansion
Causes of pulmonary edema
- hemodynamic (increased hydrostatic pressure, decreased oncotic pressure)
- microvascular/alveolar injury (inhalations, shock, burns, etc)
- other (high altitude, neurogenic)
Pathologic features of organizing phase of ARDS
- type II pneumocyte hyperplasia
- granulation tissue response in alveolar walls, sometimes resolving with fibrosis
Pathogenesis of ARDS
- imbalance of pro and anti-inflammatory mediators
- interleukins and other cytokines cause neutrophil activation and sequestration in the lung
- neutrophils release proteases that damage the lung and loss of surfactant preventing the alveoli from expanding
What is the most prevalent alveolar lining cell?
-type I pneumocyte (95% of cells)
Types of chronic lung disease
- obstructive
- restrictive: divided into chronic fibrosing diseases and chest wall disorders
What part of the lung is affected in centriacinar emphysema
- the respiratory bronchioles, with alveolar sparing
- more pronounced in upper lobes
What is the pattern of injury in panacinar emphysema?
- entire acinus from respiratory bronchioles to distal alveoli is distended
- more common in lower lung zones and is associated with alpha 1 antitrypsin deficiency
What is the best hypothesis for the pathogenesis of damage in COPD?
Protease-antiprotease hypothesis
How does lung damage occur in smoking?
- neutrophils and macrophages accumulate in the lungs possibly due to chemoattractant effects or production of ROS
- these cells release granules including elastases, causing lung damage
Microscopic features of COPD
- early changes: goblet cell metaplasia, inflammation and smooth muscle hyperplasia
- established: large blebs with large pores of Kohn such that septa appear to be floating; mild centriacinar fibrosis
Causes of death in emphysema
1) Respiratory acidosis and coma
2) Right heart failure
3) Massive lung collapse due to ptx
Define chronic bronchitis
-persistent cough with sputum production lasting at least 3 months in at least 2 consecutive years
Main features of asthma
- increased airway responsiveness resulting in bronchoconstriction
- mucus hypersecretion
- inflammation
Potential mediators in asthma
- leukotrienes: bronchoconstriction, increased vascular permeability
- histamine: bronchoconstriction
- prostaglandins
- platelet activating factor
- cytokines: IL1, IL6, TNF
Findings in status asthmaticus
- hyperinflation
- mucus plugs grossly visible
- eosinophils and Charcot-Leyden crystals
- airway remodelling: thickened bronchial wall with sub-basement membrane fibrosis, muscular hypertrophy and increased goblet cells
Define bronchiectasis
- permanent dilatation of bronchi and bronchioles due to destruction of muscle and elastic tissue by chronic/recurrent infection
- probably requires both obstruction and infection
Causes of bronchiectasis
- inherited (CF, Kartagener syndrome)
- infectious (viral, bacterial (tb) and fungal)
- obstruction (by tumor, etc)
- chronic conditions including lupus, IBD, RA and post-transplant and chronic GVHD
Possible complications of bronchiectasis
- cor pulmonale
- amyloidosis
- brain abscess
Major categories of chronic interstitial lung disease
- fibrosing
- granulomatous
- eosinophilic
- smoking related
- other (e.g. PAP)
Features of NSIP
- better prognosis than UIP; best prognosis is in cellular pattern
- cellular and fibrosing forms
- temporal and spatial homogeneity
- no fibroblastic foci or honeycombing
Features of COP
- subpleural accentuation
- intraalveolar plugs of organizing connective tissue (Masson bodies)
- no interstitial fibrosis or architectural distorsion
Types of lung involvement in RA
- chronic pleuritis
- interstitial fibrosing
- pulmonary rheumatoid nodules
- pulmonary hypertension
Factors determining the development of a pneumoconiosis
- amount inhaled
- size of the particles (worst size: 1-5 microns b/c these reach terminal airways)
- particle solubility
- additional effects of other irritants (e.g. smoking)
Features of silicosis
- early, nodules in upper lobes
- later, collagenized scars, sometimes with central necrosis
- concentric layers of hyalinized collagen surrounded by a dense capsule of more condensed collagen with polarizable birefrigent particles
Oncogenic effects of asbestos
- ROS generation
- toxic chemicals attached to the fibres
Features of asbestos
-fibrosis that begins around respiratory bronchioles and becomes diffuse and leads to honeycombing; identical to UIP except has asbestos bodies
Immunologic pathogenesis in sarcoidosis?
- T cell mediated response to an unidentified antigen driving by CD4 cells
- CD4:CD8 ratios> 5:1
- increased levels of Th1 cytokines IL2 and TNFgamma -> T cell expansion and macrophage activation
Histologic features of hypersensitivity pneumonitis
- bronchiolocentric interstitial pneumonitis with lymphocytes, plasma cells and macrophages
- non caseating granulomas
- interstitial fibrosis
- intraalveolar infiltrate in 50%
Categories of pulmonary eosinophilia
- acute eosinophilia with respiratory failure
- simple eosinophilia (Loeffler syndrome)
- tropical eosinophilia (filiaria)
- secondary eosinophilia (fungi, parasites, hypersensitivity, allergy, aspergillosis, vasculitis)
- idiopathic chronic eosinophilic pneumonia
Histologic features of DIP
- intraalveolar macrophages with iron pigment
- sparse septal inflammation (lymphocytes, plasma cells, sometimes eos)
What are causes of secondary PAP?
- hematologic and other malignancies
- immunodeficiency
- silicosis and other inhalational disorders
Treatments for acquired PAP
- whole lung lavage
- GM-CSF administration
Main consequences of pulmonary embolism
- respiratory compromise: nonperfused, ventilated segment
- hemodynamic compromise: increased resistance to pulmonary blood flow
Causes of death in pulmonary embolism
- sudden death if a large saddle embolism due to obstructed blood flow
- acute cor pulmonale
-multiple small emboli over time lead to pulmonary htn
Classification of pulmonary hypertension
1) Pulmonary arterial hypertension
2) Associated with left heart disease
3) Associated with chronic interstitial lung disease
4) Associated with recurrent emboli
5) Other
Effects of BMPR2 in vascular smooth muscle?
-inhibits proliferation and favours apoptosis
Mechanism of development of secondary pulmonary hypertension?
-Endothelial dysfunction resulting from initial damage, e.g. shear stress, fibrin
Histologic features of pulmonary hypertension
- medial hypertrophy of muscular and elastic arteries
- pulmonary artery atheromas
- right ventricular hypertrophy
- intimal fibrosis
- plexiform lesion (most common in familial and idiopathic forms): tuft of capillary formations that spans the lumen of thin walled small arteries
- dilated vessels and arteritis may also be present
Complications of pneumonia
- empyema
- abscess
- septic embolism to other organs causing metastatic abscesses
Histologic features of atypical pneumonia
- interstitial mononuclear inflammation and edema (rarely with neutrophilis)
- may have superimposed bacterial infection and intraalveolar exudates
Describe the influenza virus
- eight helices of ssRNA
- lipid bilayer with viral hemaglutinin and neuraminidase which determine subtype
Cause of influenza epidemics
-antigenic drift: mutations in H and N that allow avoidance of host T cell response
Causes of lung abscesses
- septic embolism
- pneumonia
- malignancy
- aspiration pneumonia
- direct infection from trauma, adjacent organs, etc
Histologic features of blastomycosis
- suppurative granulomas
- 5-15 micron yeasts that exhibit broad based budding
What is the San Joachin Valley fever complex
- pulmonary coccidiodomycosis
- erythema multiforme
- erythema nodosum
- fever
Histologic features of coccidio
- resembles histoplasmosis granulomas
- intracellular 20-60 micron yeasts filled with endospores
- if endospores are released: pyogenic inflammation
Morphologic features of chronic lung transplant rejection
- bronchiolitis obliterans, sometimes completely occluding the airways
- active inflammation may or may not be present
- findings often patchy therefore may not be sampled on biopsy
Common cytogenetic abnormalities in mesothelioma
del 1p, 3p, 6q, 9p, 22q
p16 mutations
not usually p53 mutations
SV40 sequences in > half
Histochemical and immunohistochemical features of mesothelioma
- contain acid mucopolysaccharide
- CEA negative
- CK positive, particularly perinuclear
- calretinin, WT1, CK5/6, D2-40 positive
- long microvilli by EM
