Path - Lecture 4 (pulomary Vascular Diseases ) Flashcards
Pulmonary Thromboembolism
-DVT related
The pathophysiologic consequences of pulmonary thromboembolism depend largely on:
- The size of the embolus
2.the cardiopulmonary status of the patient
two important consequences of pulmonary arterial occlusion:
1.an increase in pulmonary artery pressure from blockage of flow and
2.Ischemia of the downstream pulmonary parenchyma
Pathogenesis of pulmonary thromboembolism
1.Perfusion of atelectatic lung zones
2.The decrease in cardiac output causes a widening of the difference in arterial-venous oxygen saturation.
3.Right-to-left shunting of blood may occur through a patent foramen ovale
Morphology of pulmonary embolism - large embolus
-large embolus may embed in the pulmonary artery
-it may also lodge in the major branches or lodge astride the bifurcation as a saddle embolus
-increase in pulmonary artery pressure
-right sided heart failure
Morphology of pulmonary thromboembolism In small vessels
-impact medium sized and small sized pulmonary arteries
-hemorrhage may occur as a result of ischemic damage to the endothelial cells (leading to capillary rupture).
-With compromised cardiovascular status (congestive heart failure or underlying lung disease) infarction results.
Pulmonary embolism clinical features
-dyspnea
-tachypnea
-tachycardia
-pleuritic chest pain
-chronic cor pulmonale
Pulmonary Hypertension
Pulmonary artery pressure greater than or equal to 25 mm Hg at rest
What are the classifications of pulmonary HTN
-LVF and mitral stenosis
-recurrent tiny thromboembolism
-COPD ,Brochiectasis ,ILD
-idiopathic
Pathogenesis of idiopathic pulmonary htn
-inactivating germ line mutations in
the gene encoding bone morphogenetic
protein receptor 2 (BMPR2)
-Defects in BMPR2 signaling leads to dysfunction of endothelium and proliferation of vascular smooth muscle cells in the pulmonary vasculature
Morphology of pulmonary htn
-medium sized arteries walls thicken
-Small arteries/arterioles = Thickening, medial hypertrophy, reduplication of
the internal and external elastic lamina
-RV hypertrophy
-plexiform lesions
Clinical features of primary pulmonary htn
• Young women
• Fatigue, syncope, dyspnea on exertion, chest pain
• Severe respiratory insufficiency, cyanosis, death from right heart failure 2-5 years from diagnosis
Clinical features of secondary pulmonary htn
• Any age onset
• Reflects underlying disease (pulmonary or cardiovascular)
• Symptoms of respiratory insufficiency and right heart strain
Diffuse Alveolar Haemorrhage Syndromes
Immune mediated diseases which manifest as :
Hemoptyisis , anemia ,diffuse pulmonary infiltrates
-good pasture syndrome
-Wegners granulomatosis
-idiopathic hemosiderosis
GOODPASTURE SYNDROME - epidemiology
-Pulmonary-renal syndrome: proliferative and rapidly progressive
glomerulonephritis and hemorrhagic interstitial pneumonitis
- teens and 20s
-males
-
Pathogenesis of good pastures syndrome
• Kidney and lung injury are caused by circulating autoantibodies against the non-collagenous domain of the α3 chain of collagen IV.
• The antibodies initiate inflammatory destruction of the basement membrane in renal glomeruli and pulmonary alveoli
• Linear deposition of IgG along basement membranes – glomerular basement membranes (kidney) or alveolar septa (lung)
Morphology of good pasture
-gross : heavy lungs , red consolidation
-micro :
-Intra-alveolar hemorrhage
• Patchy necrosis of alveolar walls
• Intra-alveolar hemosiderin
• Septal thickening and reactive hypertrophy of type II cells
Clinical findings in good pastures
-Hemoptysis,anemia,pulmonaryinfiltrates
• Featuresofglomerulonephritis–hematuria,edema,uremia
-focal consolidations
-linear deposits of Ig along the basement membrane
Idiopathic pulmonary hemosiderosis
-children >adults
-histo similar to good pastures
-no association with renal disease
-no anti BM antibody
Acquired atelectasis
-Refers either to incomplete expansion of the lungs (neonatal atelectasis) or to the collapse of previously inflated lungs
-decreased oxygenation
-ventilation perfusion imbalance
RESORPTION ATELECTASIS
-stems from obstruction of an airway
-excessive secretions in the smaller bronchi
-Aspiration of foreign bodies
-Intrabronchial tumors
Clinical features of resorption atelectasis
• Ipsilateral deviation of trachea and mediastinum
• Ipsilateral diaphragmatic elevation
• Absent breath sounds and absent
vocal vibratory sensation (tactile
fremitus)
• Collapsed lung does not expand on
inspiration
Compression Atelectasis
-compressed by air ,fluid or tumor
-accumulate in the pleural cavity and increases pressure
-Trachea and mediastinum shift away from the affected lung
Contraction atelectasis
-Occurs when focal or generalized pulmonary or pleural fibrosis prevents full lung expansion
Course and complications of atelectasis
-is usually reversible
-treat promptly
