Pulmonary vascular disease and pleural disease Flashcards
What makes up the duel supply for pulmonary circulation?
pulmonary arteries
bronchial arteries
Low pressure systems
Thin walled vessels
low incidence of atherosclerosis
what is Pulmonary oedema and what does it cause?
accumulation of fluid in the lung in the interstitium and alveolar spaces
Can cause a restrictive pattern of disease
What causes Pulmonary oedema?
Haemodynamic (increase in hydrostatic pressure)
Due to cellular injury (alveolar lining cells or alveolar endothelium), localised - pneumonia, generalised - adult respiratory distress syndrome
What is ARDS (Adult respiratory distress syndrome)
Diffuse alveolar damage syndrome (DADS)
Shock lung - causes include sepsis, diffuse infection, severe trauma, oxygen
what is the pathogenesis of ARDS
Injury (eg: bacterial endotoxin) infiltration of inflammatory cells cytokines oxygen free radicals injury to cell membranes
what is the pathology of ARDS
Fibrinous exudate lining alveolar walls (hyaline membranes)
Cellular regeneration
Inflammation
outcome of ARDS
death
resolution
fibrosis (chronic restrictive lung disease)
neonatal RDS
Premature infants
Deficient in surfactant (type 2 alveolar lining cells)
Increased effort in expanding lung - physical damage to cells
What is an embolus
A detached intravascular mass carried by the blood to a site in the body distant from its point of origin
What are most types of emboli
Thrombi
others include: gas, fat, foreign bodies and tumour clumps
example: pulmonary embolus
Common, often subclinical, an important cause of sudden death and pulmonary hypertension
most of these emboli are thromboemboli
source of most pulmonary emboli
deep venous thrombosis (DVT) of lower limbs
Risk factors for PE (same for DVT)
- Factors in vessel wall (Eg: endothelial hypoxia)
- abnormal blood flow (venous stasis)
- Hypercoagulable blood (cancer patients, post-MI etc.)
Virchow’ triad
What is Virchow’s triad
The 3 factors for PE
Effects of PE
Sudden death
Severe chest pain/dyspnoea/haemoptysis
Pulmonary infarction
pulmonary hypertension
Effects of PE depend on
Size on embolus
cardiac function
respiratory function
pulmonary infarct (ischaemic necrosis)
embolus necessary but not sufficient
bronchial artery supply compromised (eg in cardiac failure)
pulmonary hypertension
primary (rare, young women)
Secondary
mechanisms of pulmonary hypertension
Hypoxia (vascular constriction)
increased flow through pulmonary circulation (congenital heart disease)
blockage (PE) or loss (emphysema) of pulmonary vascular bed
back pressure from left sided heart failure
morphology of pulmonary hypertension
medial hypertrophy of arteries intimal thickening (fibrosis) atheroma right ventricular hypertrophy extreme cases (congenital heart disease etc.)
Cor pulmonale
pulmonary hypertension complicating lung disease
Right ventricular hypertrophy
Right ventricular dilatation
Right heart failure
what is the pleura
a mesothelial surface lining the lungs and mediastinum
mesothelial cells designed for fluid absorption
hallmark of disease is the effusion
types of pleural effusion
transudate (low protein)
Exudate (high protein)
examples of transudate pleural effusions
cardiac failure
hypoproteinaemia
examples of exudate pleural effusions
pneumonia
TB
connective tissue disease
malignancy (primary or metastatic)
purulent effusion
full of acute inflammatory cells
empyema
can become chronic
pneumonthorax
air in pleural space due to trauma or rupture of bulla
pleural neoplasia
primary (benign or malignant mesothelioma) or secondary (common- adenocarcinomas - lung, GIT, ovary)
mesothelioma
Asbestos related
Increasing incidence
Mixed epithelial/mesenchymal differentiation
Dismal prognosis
differential diagnosis of malignant effusions
cytology, biopsy
difficult
immunohistochemistry for lineage specific antigens may help
medicolegal importance
