4- pathology of pulmonary vascular & pleural disease Flashcards
what vessels supply pulmonary circulation?
dual supply from pulmonary arteries + bronchial arteries
what about the pulmonary circulation means low incidence of atherosclerosis?
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)
what does pulmonary oedema cause?
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
what is pulmonary oedema?
pulmonary oedema = accumulation of fluid in lung (in interstitium + alveolar spaces)
what are
a) localised
b) generalised
effects of cell injury from pulmonary oedema?
a) pneumonia
b) adult respiratory distress syndrome (ARDS) →not disease, reflection of what lung looks like in response to injury
what is shock lung?
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
what is diffuse alveolar damage syndrome (DADS)?
widespread damage to alveoli and surrounding lung tissue from inflammation, infection, trauma etc that causes ARDS
what is pathogenesis of ARDS?
injury e.g. bacterial endotoxin causing:
- infiltration of inflammatory cells
- cytokines released
- oxygen free radical released
- injury to cell membranes
what is the pathology of ARDS?
- fibrinous exudate lining of alveolar walls = called hyaline membrane disease
- cellular regeneration
- inflammation
what is the result of hyaline membrane in ARDS?
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)
what are the 3 options of outcomes of ARDS?
- death (has varying morbidity levels)
- resolution
- fibrosis (scarring) mostly remains (chronic restrictive lung disease)
is ARDS the same thing as neonatal respiratory distress syndrome?
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)
what is embolus? what are they made up of?
- 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
what are the main risk factors for pulmonary embolism?
same as DVT (deep vein thrombosis) = virchow’s triad
1. stasis of blood flow (abnormal blood flow)
2. endothelial injury
3. hypercoagulability
what are possible effects of pulmonary embolism?
- sudden death
- severe chest pain/dyspnoea/haemoptysis
- pulmonary infarction
- pulmonary hypertension - blocked artery = high pressure can see with JVP
- fever
what severity of effect of PE depend on?
- size of embolus
- cardiac function
- respiratory function
can you detect small PE?
they’re clinically silent sometimes - can be seen as recurrent pulmonary hypertension
what does pulmonary infarct look like on pathology + x-ray?
triangle wedge shape of different colour
what is primary pulmonary hypertension and what is it also known as?
idiopathic pulmonary hypertension = rare and progressive disease mostly affecting young women
what is secondary hypertension?
pulmonary hypertension that arises as consequence of underlying medical conditions or external factors that affect pulmonary circulation
how does chronic hypoxia lead to pulmonary hypertension?
chronic hypoxia →vascular constriction which increases resistance and leads to elevated pulmonary arterial pressure and pulmonary hypertension. can occur in COPD, ILD etc
how do congenital heart diseases lead to pulmonary hypertension?
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
how does PE or emphysema lead to pulmonary hypertension?
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
how does left side heart failure lead to pulmonary hypertension?
back pressure from left sided heart failure →means increased pressure in LA so can lead to back transmission of pressure to pulmonary circulation
why is pulmonary hypertension bad?
- 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
what is morphology of pulmonary hypertension (what it looks like)?
- medial hypertrophy of arteries
- intimal thickening (fibrosis)
- atheroma
- RV hypertrophy
- plexogenic necrosis (in pulmonary hypertension)
what is plexogenic necrosis?
just specific histological finding in primary pulmonary hypertension (that’s all i need to know)
what is cor pulmonale?
condition characterised by RV enlargement + dysfunction due to pulmonary hypertension secondary to lung disease such as COPD
what are disorders of pleura?
- pleurisy (inflammation)
- pleural effusion (excess fluid)
- pneumothorax (air or gas in pleural space)
- haemothorax (blood in pleural space)
what is
a) transudate
b) exudate
in context of pleural effusion. what causes each of them?
a) transudate (low protein) = cardiac failure + hypoproteinaemia
b)exudate (high protein) = pneumonia, TB, connective tissue disease, malignancy (primary or metastatic)
what is purulent effusion?
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
what are 2 causes of pneumothorax?
- air in pleural space - trauma
- rupture of bullae - spontaneous
what are primary and secondary pleural neoplasms?
- 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)
