Vascular Diseases of the Lung

Question 1

describe pulmonary edema and the 2 types

Answer 1

accumulation of fluid in the alveolar space leads to decreased diffusing capacity, hypoxemia, and shortness of breath

• cardiogenic (increased capillary wedge pressure)
• non-cardiogenic (NO increase in capillary wedge pressure)
  
  • ARDS
  • high altitude
  • neurogenic (head trauma, subarachnoid hemorrhage/intracranial hemorrhage, ECT, intracranial surgery, seizure)
  • pulm. embolism

Question 2

describe a pulmonary thromboembolism

Answer 2

• blood clot travels to the lungs lodging within a pulmonary artery or downstream brach
• originates in larger, deeper veins of the legs/pelvis

Question 3

list the risk factors for pulmonary thromboembolism

Answer 3

• risk factors:
  
  • immobility (airplane, bed rest)
  • surgery (orthopedic)
  • severe trauma (burns, multiple fractures)
  • CHF
  • oral contraceptive pills (elevated estrogen)
  • disseminated malignancy
  • hypercoagulability disorders
    
    • Factor V Leiden, protein S, protein C, antithrombin III def., lupus anticoagulant

Question 4

describe the pathophysiology of a pulmonary thromboembolis

Answer 4

• pathophys:
  
  • effect of PE is dependent upon:
    
    • size of embolus
    • cardiopulmonary status of patient
  • consequences of pulmonary arterial occlusion
    
    • increased PA pressure +/- vasospasm and release of mediators (TXA2, 5HT)
    • ischemia of pulm. parenchyma
  • acute increase in pressure on the right heart
  • hypoxia
    
    • atelectasis: reduced surfactant production in the ischemic area
    • some blood flow redirected to the normally hypoventilated areas of the lung
    • right –> left shunt through patent foramen ovale

Question 5

describe a saddle embolus

Answer 5

• large embolus lodges in the main PA bifurcation
• sudden death from:
  
  • hypoxia, or
  • acute RHF

Question 6

describe the effect of dual blood supply of the lungs

Answer 6

• lung parenchyma fed by:
  
  • pulmonary arteries
  • bronchial arteries
• ischemic necrosis (infarct) is an exception and occurs when combined with compromised CV status
  
  • hemorrhagic, wedge-shaped, peripheral

Question 7

describe the clinical features of pulmonary thromboembolism

Answer 7

• 60-80% asymptomatic
• 10-15% infarction
  
  • end artery occlusion + CV compromise
  • dyspnea
• 5% sudden death, acute cor pulmonale, shock
  
  • 60% of total pulmonary vasculature obstructed by:
    
    • large embolus
    • multiple simultaneous small emboli
• <3% pulmonary HT secondary to recurrent emboli

Question 8

describe pulmonary hypertension

Answer 8

• mean PA pressures reaches >1/4th of systemic pressure
• classification
  
  • secondary to decreased cross-sectional area of blood flow
    
    • obstructive or interstitial lung disease
    • recurrent pulmonary pulm. emboli
    • heart disease (mitral stenosis, L → R shunt)
  • primary
    
    • sporadic

Question 9

list a primary etiology of pulmonary hypertension

Answer 9

• TGF-beta = mediator of smooth muscle proliferation
  
  • 50% of familial cases have germline mutations in BMPR (bone morphogenic protein receptor) type 2
    
    • the protein normally binds to various TGF-beta pathway ligands and inhibits smooth muscle proliferation normally
    • mutated = induces smooth muscle prolif.

Question 10

describe secondary etiologies of pulmonary hypertension

Answer 10

• endothelial cell dysfunctional due to underlying disorder
  
  • decreased vasodilatory agents
  • increased vasoconstrictive agents
  • growth factor production

Question 11

describe clinical features of primary pulmonary hypertension

Answer 11

• primary pulmonary hypertension
  
  • young women
  • fatigue, syncope, DOE, chest pain
  • severe resp. insufficiency, cyanosis, death from RHF 2-5 years from diagnosis
  • treatment = vasodilators, antithrombotic agents and lung transplantation

Question 12

describe clinical features of secondary pulmonary hypertension

Answer 12

• secondary pulmonary hypertension
  
  • any age onset
  • reflects underlying disease (pulmonary or cardiovascular)
  • resp. insufficiency and right heart strain

Question 13

in pulmonary hypertension, ___ can be seen in the main elastic arteries

Answer 13

in pulmonary hypertension, atheromas can be seen in the main elastic arteries

Question 14

in pulmonary hypertension, ___ can be seen in the medium-sized muscular arteries

Answer 14

in pulmonary hypertension, intimal cell and smooth muscle cell proliferation → wall thickening can be seen in the medium-sized muscular arteries

Question 15

in pulmonary hypertension, ___ can be seen in the small arteries/arterioles

Answer 15

in pulmonary hypertension, thickening, medial hypertrophy, reduplication of the internal and external elastic lamina can be seen in the small arteries/arterioles

Question 16

in pulmonary hypertension ____ can be seen within a small artery at a branch point from a larger artery

Answer 16

in pulmonary hypertension plexiform lesions (multiple lumina) can be seen within a small artery at a branch point from a larger artery

Question 17

describe the images seen

Answer 17

Question 18

describe diffuse alveolar hemorrhage syndromes

Answer 18

• primary immune-mediated diseases which manifest as a triad of:
  
  • hemoptysis
  • anemia
  • diffuse pulmonary infiltrates
• includes the following:
  
  • Goodpasture syndrome
  • idiopathic hemosiderosis
  • Wegener granulomatosis

Question 19

describe Goodpasture syndrome

Answer 19

• pulmonary-renal syndrome
  
  • proliferative and rapidly progressive glomerulonephritis
  • hemorrhagic interstitial pneumonitis
• antibodies targeted to α3 chain of collagen IV
  
  • linear deposition of IgG along basement membranes
    
    • glomerular basement membranes or alveolar septa

Question 20

describe the gross and micro findings found in the lungs in Goodpasture syndrome

Answer 20

• gross:
  
  • heavy lungs, red-brown consolidation
• micro:
  
  • alveolar hemorrhage
  • patchy necrosis of alveolar walls
  • septal thickening and reactive type II cells
  • intra-alveolar hemosiderin

Question 21

describe what is seen in the image

Answer 21

Question 22

describe the treatment of Goodpasture syndrome

Answer 22

• plasmapheresis
• immunosuppressive therapy
• renal transplant required in severe cases

Question 23

describe Wegener granulomatosis (pulmonary angitis and granulomatosis)

Answer 23

• autoimmune disease
  
  • PR3-ANCA (classic anti-neutrophil cytoplasm antibodies, C-ANCA) in 95%
  • granulomas of the lung/upper resp. tract
  • vasculitis of small-medium sized vessels
  • glomerulonephritis

Question 24

describe clinical features of Wegener granulomatosis

Answer 24

• clinical features
  
  • middle aged to older individuals
  • M>F
  • lung and upper respiratory
    
    • pneumonitis with nodules and cavitary lesions (95%)
    • chronic sinusitis (90%)
    • mucosal ulcerations of nasopharynx (75%)
  • renal
    
    • hematuria, proteinuria
  • rashes, myalgias, fever, articular involvement, neuritis

Question 25

describe the histopathology of Wegener granulomatosis

Answer 25

• necrosis “geographic”
• neutrophilic micro-abscesses
• granulomas
  
  • palisaded
  • free giant cells
• vasculitis
  
  • necrotizing
  • capillaritis

Question 26

describe idiopathic pulmonary hemosiderosis

Answer 26

• rare
• children > adults
• unknown etiology
• histopathology similar to Goodpasture
  
  • no associated renal disease
  • no anti-BM antibody
• Rx = steroids and immunosuppression

Question 27

describe what is seen in the image

Answer 27

plexiform lesions, as seen in pulmonary hypertension