1.Pulmonary Vascular Disease1.Pulmonary Vascular Disease2.Pleural Disease2.Pleural Disease

Prof. Frank Carey

Pulmonary CirculatuionPulmonary Circulatuion Dual supply

Pulmonary arteries Bronchial arteries

Low pressure system Pulmonary artery receives entire cardiac

output (a filter)

Low pressure system….Low pressure system…. Thin walled vessels Low incidence of atherosclerosis

At normal pressures

Pulmonary OedemaPulmonary Oedema

Accumulation of fluid in the lung Interstitium Alveolar spaces

Causes a restrictive pattern of disease

Pulmonary Oedema (causes)Pulmonary Oedema (causes)

1. Haemodynamic ( hydrostatic pressure)

2. Due to cellular injuryi. Alveolar lining cellsii. Alveolar endotheliumLocalised – pneumoniaGeneralised – adult respiratory distress syndrome

(ARDS)

ARDSARDS Diffuse alveolar damage syndrome

(DADS) Shock lung

Causes include sepsis, diffuse infection (virus, mycoplasma), severe trauma, oxygen

Pathogenesis of ARDSPathogenesis of ARDS

Injury (eg bacterial endotoxin) Infiltration of inflammatory cells Cytokines Oxygen free radicals Injury to cell membranes

Pathology of ARDSPathology of ARDS Fibrinous exudate lining alveolar walls

(hyaline membranes) Cellular regeneration Inflammation

ARDS with hyaline membraneARDS with hyaline membrane

ARDS – cellular reactionARDS – cellular reaction

Outcome of ARDSOutcome of ARDS

Death Resolution Fibrosis (chronic restrictive lung disease

Neonatal RDSNeonatal RDS Premature infants Deficient in surfactant (type 2 alveolar

lining cells Increased effort in expanding lung

physical damage to cells

EmbolusEmbolus A detached intravascular mass carried by

the blood to a site in the body distant from its point of origin

Most emboli are thrombi – others include gas, fat, foreign bodies and tumour clumps

Pulmonary EmbolusPulmonary Embolus

Common Often subclinical An important cause of sudden death and

pulmonary hypertension

95% + of emboli are thromboemboli

Source of most pulmonary Source of most pulmonary emboli…..emboli…..

Deep venous thrombosis (DVT) of lower limbs

Risk factors for PE are those for DVT…. Risk factors for PE are those for DVT….

1. Factors in vessel wall (eg endothelial hypoxia)

2. Abnormal blood flow (venous stasis)3. Hypercoaguable blood (cancer patients,

post-MI etc)

- Virchow’s triad

Effects of PEEffects of PE

Sudden death Severe chest pain/dyspnoea/haemoptysis Pulmonary infarction Pulmonary hypertension

Effects of PE depend on…Effects of PE depend on…

Size of embolus Cardiac function Respiratory function

Effect of embolus size…Effect of embolus size…

Large emboli Death Infarction Severe symptoms

Small emboli Clinically silent Recurrent

pulmonary hypertension

Pulmonary Infarct (ischaemic Pulmonary Infarct (ischaemic necrosis)necrosis)

Embolus necessary but not sufficient Bronchial artery supply compromised (eg

in cardiac failure)

Pummonary EmbolusPummonary Embolus

Pulmonary infarct – Pulmonary infarct – tumour tumour embolusembolus

Pulmonary HypertensionPulmonary Hypertension

Primary (rare, young women) Secondary

Pulmonary Hypertension Pulmonary Hypertension (mechanisms)(mechanisms)

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 Morphology of pulmonary hypertensionhypertension

Medial hypertrophy of arteries Intimal thickening (fibrosis) Atheroma Right ventricular hypertrophy Extreme cases (congenital heart disease,

primary pulmonary hypertension) – plexogenic change/necrosis

Pulmonary artery – intimal fibrosisPulmonary artery – intimal fibrosis

Plexiform lesion – primary pulmonary Plexiform lesion – primary pulmonary hypertensionhypertension

““Cor Pulmonale”Cor Pulmonale” Pulmonary hypertension complicating lung

disease Right ventricular hypertrophy Right ventricular dilatation Right heart failure (swollen legs, congested

liver etc)

Cardiomegaly due to right ventricular Cardiomegaly due to right ventricular dilatationdilatation

Right ventricular hypertrophy and Right ventricular hypertrophy and dilatationdilatation

The PleuraThe Pleura A mesothelial surface lining the lungs and

mediastinum Mesothelial cells designed for fluid

absorption Hallmark of disease is the effusion

Pleural EffusionPleural Effusion Transudate (low

protein) cardiac failure hypoproteinaemia

Exudate (high protein) pneumonia TB connective tissue

disease malignancy (primary

or metastatic)

Pleural effusionPleural effusion

Purulent EffusionPurulent Effusion

Full of acute inflammatory cells Empyema Can become chronic

PneumothoraxPneumothorax

Air in pleural space Trauma Rupture of bulla

Large bullaeLarge bullae

Pleural NeoplasiaPleural Neoplasia Primary

benign (rare) malignant mesothelioma

Secondary common (adenocarcinomas - lung, GIT, ovary)

MesotheliomaMesothelioma

Asbestosis related Increasing incidence Mixed epithelial/mesenchymal

differentiation Dismal prognosis

MesotheliomaMesothelioma

Pleural biopsy - mesotheliomaPleural biopsy - mesothelioma

Metastases in PleuraMetastases in Pleura

Differential diagnosis of Differential diagnosis of malignant effusions…..malignant effusions…..

Cytology, biopsy Difficult Immunohistochemistry for lineage specific

antigens may help Medicolegal importance