4- pathology of pulmonary vascular & pleural disease

Question 1

what vessels supply pulmonary circulation?

Answer 1

dual supply from pulmonary arteries + bronchial arteries

Question 2

what about the pulmonary circulation means low incidence of atherosclerosis?

Answer 2

low pressure system with thin walled vessels means low incidence of atherosclerosis at normal pressure (as high pressure bashes against walls causing problems but this low pressure so ok)

Question 3

what does pulmonary oedema cause?

Answer 3

causes restrictive pattern of disease because volume in functional lung tissue

causes:
- increased hydrostatic pressure (pressure against walls)
- cell injury causing alveolar lining cells injury and alveolar endothelium injury

Question 4

what is pulmonary oedema?

Answer 4

pulmonary oedema = accumulation of fluid in lung (in interstitium + alveolar spaces)

Question 5

what are
a) localised
b) generalised
effects of cell injury from pulmonary oedema?

Answer 5

a) pneumonia
b) adult respiratory distress syndrome (ARDS) →not disease, reflection of what lung looks like in response to injury

Question 6

what is shock lung?

Answer 6

colloquial term used to describe ARDS in setting of shock. causes of shock lung include sepsis, diffuse infections (virus, mycoplasma), severe trauma, oxygen - long list of things that lead to state of shock that can lead to ARDS

so these things cause shock that mean decreased perfusion to vital organs including lung leading to ARDS

Question 7

what is diffuse alveolar damage syndrome (DADS)?

Answer 7

widespread damage to alveoli and surrounding lung tissue from inflammation, infection, trauma etc that causes ARDS

Question 8

what is pathogenesis of ARDS?

Answer 8

injury e.g. bacterial endotoxin causing:
- infiltration of inflammatory cells
- cytokines released
- oxygen free radical released
- injury to cell membranes

Question 9

what is the pathology of ARDS?

Answer 9

• fibrinous exudate lining of alveolar walls = called hyaline membrane disease
• cellular regeneration
• inflammation

Question 10

what is the result of hyaline membrane in ARDS?

Answer 10

it’s like fibrin wall being layed down, so no diffusion so big problem (you can keep giving more oxygen but doesn’t help much as oxygen just stays in alveoli)

Question 11

what are the 3 options of outcomes of ARDS?

Answer 11

• death (has varying morbidity levels)
• resolution
• fibrosis (scarring) mostly remains (chronic restrictive lung disease)

Question 12

is ARDS the same thing as neonatal respiratory distress syndrome?

Answer 12

no! they are different things
= neonatal RDS is caused by lack of surfactant protein (type 2 alveolar lining cells produce) - produce at 36 weeks so lack in neonates →more info on paediatric lecture (in guided study or workshop page if resp)

Question 13

what is embolus? what are they made up of?

Answer 13

• detached intravascular mass carried by blood to site of body distant from point of origin
• most emboli are thrombi - others include gas, fat, foreign bodies + tumour clumps

Question 14

what are the main risk factors for pulmonary embolism?

Answer 14

same as DVT (deep vein thrombosis) = virchow’s triad
1. stasis of blood flow (abnormal blood flow)
2. endothelial injury
3. hypercoagulability

Question 15

what are possible effects of pulmonary embolism?

Answer 15

• sudden death
• severe chest pain/dyspnoea/haemoptysis
• pulmonary infarction
• pulmonary hypertension - blocked artery = high pressure can see with JVP
• fever

Question 16

what severity of effect of PE depend on?

Answer 16

• size of embolus
• cardiac function
• respiratory function

Question 17

can you detect small PE?

Answer 17

they’re clinically silent sometimes - can be seen as recurrent pulmonary hypertension

Question 18

what does pulmonary infarct look like on pathology + x-ray?

Answer 18

triangle wedge shape of different colour

Question 19

what is primary pulmonary hypertension and what is it also known as?

Answer 19

idiopathic pulmonary hypertension = rare and progressive disease mostly affecting young women

Question 20

what is secondary hypertension?

Answer 20

pulmonary hypertension that arises as consequence of underlying medical conditions or external factors that affect pulmonary circulation

Question 21

how does chronic hypoxia lead to pulmonary hypertension?

Answer 21

chronic hypoxia →vascular constriction which increases resistance and leads to elevated pulmonary arterial pressure and pulmonary hypertension. can occur in COPD, ILD etc

Question 22

how do congenital heart diseases lead to pulmonary hypertension?

Answer 22

in some congenital heart disease like atrial septal defect, patent ductus arteriosus etc there’s increased flow through pulmonary circulation which increases volume + pressure →pulmonary hypertension

Question 23

how does PE or emphysema lead to pulmonary hypertension?

Answer 23

blockage (PE) or emphysema leading to loss of pulmonary vascular bed. PE blocks and builds pressure as more blood has to go to areas where no PE which means more pressure on those areas →pulmonary hypertension

Question 24

how does left side heart failure lead to pulmonary hypertension?

Answer 24

back pressure from left sided heart failure →means increased pressure in LA so can lead to back transmission of pressure to pulmonary circulation

Question 25

why is pulmonary hypertension bad?

Answer 25

• increased workload on RV (more resistance means RV has to contract harder to get blood there which can cause enlargement of RV and weakened too). this can eventually lead to right heart failure and reduced cardiac output
• hypoxaemia as high pressure can impair gas exchange so reduced oxygen

Question 26

what is morphology of pulmonary hypertension (what it looks like)?

Answer 26

• medial hypertrophy of arteries
• intimal thickening (fibrosis)
• atheroma
• RV hypertrophy
• plexogenic necrosis (in pulmonary hypertension)

Question 27

what is plexogenic necrosis?

Answer 27

just specific histological finding in primary pulmonary hypertension (that’s all i need to know)

Question 28

what is cor pulmonale?

Answer 28

condition characterised by RV enlargement + dysfunction due to pulmonary hypertension secondary to lung disease such as COPD

Question 29

what are disorders of pleura?

Answer 29

• pleurisy (inflammation)
• pleural effusion (excess fluid)
• pneumothorax (air or gas in pleural space)
• haemothorax (blood in pleural space)

Question 30

what is
a) transudate
b) exudate
in context of pleural effusion. what causes each of them?

Answer 30

a) transudate (low protein) = cardiac failure + hypoproteinaemia

b)exudate (high protein) = pneumonia, TB, connective tissue disease, malignancy (primary or metastatic)

Question 31

what is purulent effusion?

Answer 31

pus in pleural cavity = full of acute inflammatory cells - most likely it’s infection, can also see in PE

• empyema (pus abscess)
• can become chronic

Question 32

what are 2 causes of pneumothorax?

Answer 32

• air in pleural space - trauma
• rupture of bullae - spontaneous

Question 33

what are primary and secondary pleural neoplasms?

Answer 33

• primary = at that site - benign (rare), malignant mesothelioma (line)
• secondary = direct extension of lung tumour that goes into pleural space - common (adenocarcinomas - lung, GIT, ovary)