pulmonary vascular disease Flashcards
pulmonary circulation
deoxygenated blood comes from right ventricle and goes to pulmonary trunk and goes to right and left pulmonary arteries
goes to lobar and segmental branches, pulmonary capillaries which wrap around alveoli and feed to pulmonary veins
go to left atrium
the alveoli are entirely supplied by
pulmonary arteries
systemic circulation
bronchial arteries supply the lung stroma
left lung bronchial arteries
2 (superior and inferior)
right lung bronchial arteries
has 1
bronchial arteries
run as far as the small bronchioles where they form capillary networks
drain to bronchial veins and pulmonary veins (small component)
what is the main blood supply of the lungs
pulmonary circulation
smaller % bronchial circulation
loss of pulmonary circulation
results in infarction of terminal airways, but blood still partly flows around infarct and venous blood pools
infarct is red rather than pale
loss of bronchial arterial circulation
blood flow not compromised
pulmonary infarct
an infarct is an area of ischemic necrosis caused by occlusion of the vascular supply to the affected tissue
causes of pulmonary infarct
thrombus, embolus, vasospasm, expansion of atherosclerotic plaque, torsion or compression of vessels, trauma, vasculitis
commonest cause of of pulmonary infarct in the lung
small/medium sized PE
lung infarcts tend to be
peripheral
wedge shaped
hemorrhagic
Pulmonary emboli
a detached intravascular solid, liquid or gaseous mass that is carried by the blood from its point of origin to a distant site, where it often causes tissue dysfunction or infarction
classification of emboli
solid vs liquid vs gas
arterial vs venous
type of embolic material
types of embolic material
- thromboembolism
- air/gas
- fat
- amniotic fluid emboli
- septic emboli
- foreign. body
pathogenesis of venous thromboemboli
increased blood platelets
the formation of a blood clot
formation of thromboembolic masses
embolism
acute provoking factors of formation of emboli
surgery, burns, trauma, period of immobilisation, commencement of oestrogen therapy, pregnancy
chronic predisposing factors of formation of emboli
clotting abnormality, obesity, smoking, hypertension n, malignancy
mechanical problem of PE
ventilation perfusion mismatch
large embolus can lead to
can lead to right heart failure and sudden death
smaller emboli symptoms
shortness of breath, sudden onset, chest pain
multiple small emboli symptoms
may be asymptomatic or have lower grade symptoms
3 possible sequelae of of embolus
- lysis
- superimposed thrombus/inflammation/extension of infarct
- organisation and recanalization
air emboli
trauma, surgical
gas emboli
often nitrogen
divers
at high pressure more nitrogen dissolves into blood
rapid return to low pressure results in bubbles forming in the microvasculature - brain,, lungs joints, heart
fat and marrow emboli
usually happen because of trauma
fragments of fat or marrow enter the circulation
adipocytes with or without associated haematopoietic marrow elements
release of free fatty acids from fat globules causes toxic injury to the endothelium, platelet activation and recruitment go white blood cells
fat embolism syndrome
1-3 days after injury
pulmonary insufficiency
tachypnoea, dyspnoea neurological symptoms
amniotic fluid emboli
rare critical complication for labour
amniotic fluid getting into blood stream
dyspnoea, cyanosis and shock
headaches, seizures and coma
septic emboli
colonies of bacteria and fungi can detach and lodge/proliferate elsewhere
pulmonary hypertension
defined as a mean pulmonary artery pressure greater than or equal to 25mm Hg at rest or mean pressure > 30mm Hg during exercise
causes of pulmonary hypertension
- increase in pulmonary blood flow
- increase in pulmonary vascular resistance
- increase in left heart resistance to blood flow
- idiopathic
5 groups of pulmonary hypertension
- pulmonary arterial hypertension
- pulmonary hypertension owing to left heart disease
- pulmonary hypertension owing to lung disease and/or hypoxia
- chronic thromboembolic pulmonary hypertension
- pulmonary hypertension with unclear multifactorial mechanisms
pulmonary arterial hypertension
idiopathic, hereditary or drug and toxin induced
associated with autoimmunity
group 3 - lung disease and/or hypoxia
COPD
sleep disordered breathing
alveolar hypoventilation disorders
chronic exposure to high altitudes
group 5 - unclear multifactorial mechanisms
haematological disorders eg.g myeloproliferative diseases
sarcoidosis. vasculitis, langerhans call histiocytosis
metabolic disorders
pathological findings in pulmonary hypertension
muscular vessels
more elastic and scarred
atherosclerosis
right ventricular hypertrophy
pathogenesis of vascular changes - mutations in BMPR2
dysfunction of endothelial cells and vascular smooth muscle cells
patient presentation of pulmonary hypertension
right heart failure
failure to oxygenate
arrhythmias
in idiopathic group death from right heart failure usually ensues with 2 to 5 years
treatment of pulmonary hypertension
treat the trigger
vasodilators have been used with varying success in those with group 1 or refractory disease
lung transplantation provides definitive treatment for selected patients
diffuse pulmonary haemorrhage
usually immunologicaly mediated or inflammatory diseases
good pasture syndrome
uncommon autoimmune disease in which kidney and lung injury are caused by circulating autoantibodies against the non collagenous domain of the a3 chain of collagen IV
the antibodies initiate inflammatory destruction of the basement membrane in renal glomeruli and pulmonary alveoli, giving rise to rapidly progressive glomerulonephritis and necrotising hemorrhagic interstitial pneumonitis
Granulomatosis with pulmonary angiitis
systemic inflammatory disorder
aetiology and pathogenesis are not clear
autoimmune vasculitis
