PATH 3810 Pathology of Respiratory System

atelectasis

incomplete expansion of lungs or collapse of previously inflated air space

atelectasis

resorption atelectasis

occurs when obstruction prevents air from reaching distal airways

common cause is mucus plug in bronchus

compression atelectasis

associated with accumulation of fluid, blood, or air in pleural cavity (pleural effusion, pneumothorax)

contraction atelectasis

occurs when local or generalized fibrotic changes in lung or pleura limit expansion and increase elastic recoil during expiration

emphysema

emphysema

irreversible enlargement of the airspaces distal to terminal bronchioles

destruction of alveolar walls without fibrosis

mild chronic inflammation featuring macrophages, CD8+, CD4+, and neutrophils

emphysema leads to

destruction of connective tissue due to imbalance of proteases and oxidative stress

acute respiratory distress syndrome

manifestation of severe acute lung injury

progressive respiratory insufficiency due to inflammatory processes

ARDS

ARDS

ARDS outcome

mortality rate of 60% but 40% in US

survivors may have persistent impairment

obstructive pulmonary disease

characterized by a limitation of airflow and decreased expiratory rate

major diffuse obstructive disorders

• emphysema

• chronic bronchitis

• asthma

• bronchiectasis

asthma

chronic inflammatory disorder of the conducting airways that causes recurrent episodes of wheezing, breathlessness, chest tightness, and cough

reversible and intermittent bronchoconstriction with chronic bronchial inflammation and increased mucus production

intrinsic (non-atopic) asthma

triggered by nonimmune stimuli such as aspirin, pulmonary viral infection, cold air, physiologic stress, exercise, pollutants

atopic (extrinsic) asthma

genetic predisposition to type I hypersensitivity

T cells stimulate B cells which activate eosinophils, IgE production, and mucus production

atopic asthma acute phase

inflammatory mediators and mast cells trigger parasympathetic bronchoconstriction, mucus production, vasodilation, and vascular permeability

atopic asthma late phase

eosinophil, neutrophil, T cell infiltration

synthesis of cellular mediators

pneumonia

inflammation of the lung parenchyma with exudate

pneumonitis

inflammation of the lung interstitium without exudate

bronchopneumonia

patchy consolidation involving one or more than one lobe

lobar pneumonia

regional consolidation contiguous spaces of part or all of a lobe filled with exudate

lobar pneumonia stages

1. congestion

2. red hepatization

3. grey hepatization

4. resolution

acute pneumonia

pneumonia: early organization of exudates

advanced organizing pneumonia with transformation of exudates to fibromyxoid masses

bronchopneumonia

pneumonia with inflammatory processes in bronchial, bronchiolar, and alveolar lumens

cranioventral consolidation of lungs

suppurative bronchopneumonia

suppurative bronchopneumonia

fibrinous bronchopneumonia

fibrinous bronchopneumonia

pneumonic mannheimiosis (gross)

pneumonic mannheimiosis (microscopic)

atypical pneumonia

respiratory distress disproportionate to clinical and radiologic signs

inflammation localized to alveolar septa

interstitial pneumonia

pneumonia in which inflammatory process is localized to the components of alveolar walls

may lead to fibrosis

interstitial pneumonia (gross)

interstitial pneumonia (microscopic)

embolic pneumonia

centered on blood vessels: arterioles and capillaries

agent is delivered via bloodstream

characterized by random multifocal lesions in lobes

embolic pneumonia (gross)

embolic pneumonia (microscopic)

granulomatous pneumonia

characterized by activation of alveolar and interstitial macrophages together with CD4 T cells and can involve neutrophils and multinucleate giant cells

granulomatous pneumonia

tuberculosis

communicable chronic granulomatous disease caused by Mycobacterium tuberculosis

tuberculosis pathogenesis

Th1 CD4 T cells play a role in cell-mediated immunity against mycobacteria

mediators include IFN-y, IL-12, TNF, and nitric oxide synthase

tuberculosis (gross)

granuloma (microscopic)

tuberculosis

pneumothorax

air or gas in pleural sac

hemothorax

blood collection in pleural cavity

usually due to ruptured aortic aneurysm

chylothorax

pleural collection of milky lymphatic fluid containing microglobules of lipid

pyothorax

collection of pus in pleural cavity

hemothorax

chylothorax

pyothorax

squamous cell carcinoma

arise centrally in major bronchi, preceded by metaplasia or dysplasia

adenocarcinoma

peripherally located carcinoma

bronchioloalveolar carcinoma

subtype of adenocarcinoma

precursor lesions of squamous cell carcinomas

squamous cell carcinoma

atypical adenomatous hyperplasia

precursor lesion of invasive adenocarcinoma

bronchioalveolar carcinoma

invasive adenocarcinoma