LUNG DISEASES OF VASCULAR ORIGIN Flashcards
Pulmonary circulation
Dual blood supply
oBronchial arteries
oPulmonary arteries
Virchow’s triad
- Damage to vessel walls e.g. arteritis
- Obstruction e.g. thrombus
- Variations in intravascular pressure
THROMBOSIS( abnormalities of blood flow)
The commonest cause of turbulence is an ulcerated atherosclerotic
plaque
Causes of stasis include:
• Aneurysms
• Myocardial infarcts
• Mitral stenosis and atrial fibrillation
• Sickle cell disease (luminal obstruction)
Abnormalities of blood constituents/ hypercoagulability
Genetic (Primary) Hypercoagulable states
- Protein C deficiency
- Protein S deficiency
- Anti-thrombin 3 deficiency
- Mutations in factor 5 gene
- Prothrombin gene mutations
- Increased levels of factors
- VIII, IX, XI or fibrinogen
Prolonged bed rest/ immobilization • Myocardial infarction • Cancer • Anti-phospholipid antibody syndrome • Disseminated intravascular coagulopathy (DIC) • Heparin-induced thrombocytopenia • Prosthetic valves • Hyperoestrogenic states • Combined oral contraceptive use (COC) • Smoking (increased lipids) • Nephrotic syndrome • Hyperoestrogenic states (pregnancy and postpartum
Abnormalities of blood vessel wall
causes of damage include:
• Ulcerated atheromatous plaques
• Traumatic injury
• Inflammatory vascular injury
Types Of Emboli
- Thrombo-embolism
- Amniotic fluid emboli
- Body tissue emboli
- Fat and bone marrow emboli
- Air emboli
- Tumour emboli
- Foreign body emboli
- Parasitic emboli
Pulmonary Embolus
• Sites of thrombus formation: o Leg veins: 95% o Pelvic veins o Intracranial venous sinuses • Most common site for thrombo-emboli is the pulmonary circulation - pulmonary embolism • 60-80% pulmonary TE are silent
With time they organize and are incorporated into the wall
• Sudden death, cor pulmonale or CVS collapse occurs if >60% of
vasculature occluded
• Rarely a leg vein thrombus may enter the arterial side of the
circulation if an arterio-venous shunt is present
Pulmonary Thromboembolism
• Originate from deep pelvic or calf vein
• Paradoxical emboli
• Left to right blood flow
o VSD
o ASD
• Size & location of embolus – clinical presentation
o Saddle embolus – sudden death
o One main pulmonary artery occlusion – sudden death
o Occlusion of lobar or segmental artery – +/- distal lung infarction
o Multiple small emboli – pulmonary arterial hypertension
Amniotic fluid emboli
Associated with difficult labour or caesarean section
• Presentation: -Sudden severe dyspnoea -Cyanosis -Shock- Diffuse alveolar damage -Neurologic impairment • Headache • Seizures • Coma
- DIC
- Histologic findings in pulmonary artery branches
- Squamous epithelial cells
- Lanugo hair
- Fat
- Meconium
- Mucin
- Complications
- Diffuse alveolar damage – hyaline membranes
- Fibrin thrombi in vascular beds
Body tissue emboli
- Associated with trauma or lacerations of the brain & liver
* Severe hepatic necrosis
Fat and bone marrow emboli
- Risk factors
- Trauma
- Fractures
- Vigorous cardiopulmonary rescuscitation
- Bone marrow infarction due to sickle-cell disease or steroid therapy
- Fat embolism syndrome
- Pulmonary insufficiency
- Neurologic symptoms
- Anaemia
- Thrombocytopaenia
- Diffuse petechial rash
Fat globules • Marrow elements • Haematopoietic elements • Fat stains – oil red O and Sudan black • Frozen section
parasitic embolism
- Various parasites migrate through the lungs
- Dirofilaria immitis
- Filarial parasites (e.g. Wuchereria)
- Strongyloides
- Ascaris
- Schistosom
Tumour embolism
- Embolic carcinomatosis
* Mechanism for tumour metastasis
Foreign body emboli
- Intravenous entry of various fragments
- Cotton
- Talc
- Plastic catheters and tubing
- Microscopy
- Foreign material
- Foreign body giant cell reaction
- Vessel wall destruction
Air embolism
- Risk factors
- Surgery
- Coronary bypass
- Laparoscopic surgery
- Trauma with laceration of veins
- Intravenous injection
- Ventilation therapy
- Therapeutic insufflation of fallopian tubes
- Hyperbaric decompression
- Obstruction to blood flow – pulmonary oedema and death
• Frothy blood in pulmonary vessels • Dilation of right heart and contracted left heart • Empty circular spaces within a column of blood • Atelectasis, emphysematous change and haemosiderin laden histiocytes
Pulmonary infarction
- Dual blood supply
- Infarction uncommon
- Pre-existing cardiac or pulmonary disease
- Low flow state
- Pulmonary artery occlusions
- Haemorrhagic
- Wedge shaped
- Pleural based infarcts
- Vasculitis infarcts
- Round
- Thrombosed blood vessel centrally located
Pulmonary embolism and infarction
Pulmonary infarction
- Commonly affect lower lobes
- Multiple lesions are commonly seen
- Typically extend to periphery of the lung, forming a wedge
Haemorrhagic • Early stages: raised redblue • Within 2 days: Paler then red-brown • Later: gray white
Haemorrhagic area: ischaemic necrosis of alveolar walls, bronchioles
and vessels
• Neutrophilic infiltrate if infected
Pulmonary hyperinfection
definition: Mean pulmonary artery pressure greater than or
equal to 25mmHg at rest
• Classified into 5 groups according to the WHO
. Pulmonary arterial hypertension
2. Pulmonary hypertension secondary to left-heart failure
3. Pulmonary hypertension stemming from lung parenchymal disease or
hypoxaemia
4. Chronic thromboembolic pulmonary hypertension
5. Pulmonary hypertension of multifactorial basis
Pulmonary arterial hypertension
Examples:
Autoimmune diseases
-Systemic sclerosis involving pulmonary vasculature and/ or
interstitium
Idiopathic/primary pulmonary arterial hypertension
-Mutations in BMPR2 locus result in pulmonary vascular
thickening and occlusion
Pulmonary hypertension secondary to left-heart
failure( EXAMPLE)
Antecedent congenital or acquired heart disease
-Mitral stenosis causes an increase in left atrial pressure that
is eventually transmitted to the arterial side of the pulmonary
vasculature
Pulmonary hypertension stemming from lung
parenchymal disease or hypoxaemia( EXAMPLE)
Examples:
Chronic obstructive or interstitial lung diseases
• Mechanism: disease results in obliteration of alveolar capillaries thus
increasing pulmonary resistance to blood flow
Obstructive sleep apnea
• Obesity and hypoxaemi
Chronic thromboembolic pulmonary hypertension
Example
Recurrent thromboemboli
-Mechanism: reduces functional area of pulmonary vascular
bed
pulmonary Hypertension
Morphology
All forms associated with: • Medial hypertrophy of muscular and elastic arteries • Pulmonary arterial atherosclerosis • Right ventricular hypertrophy
Diffuse pulmonary haemorrhage
syndromes
• Goodpasture syndrome
• Idiopathic pulmonary
haemosiderosis
• Polyangiitis with granulomatosis
Goodpasture syndrome
• Uncommon
• Seen predominantly in teens or 20s and active smokers
• Autoimmune disease involving the kidney and lung
• Caused by circulating antibodies against collagen IV
• Trigger that initiates the production of antibodies is still
unknown
• Antibodies initiate inflammatory destruction to basement
membranes in the renal glomeruli and pulmonary alveoli
• Results in : rapidly progressive glomerulonephritis
necrotizing haemorrhagic interstitial pneumonitis
Clinical
• Respiratory: haemoptysis, focal pulmonary consolidation
• Common cause of death is uraemia
• Treatment: immunosuppression
Idiopathic pulmonary haemosiderosis
• Rare
• Pathogenesis is unknown
• Commonly seen in young children
• Adult cases have been reported
• Presentation: productive cough, haemoptysis, anaemia
associated with diffuse pulmonary infiltration
Polyangiitis with granulomatosis
• Previously Wegener granulomatosis • Autoimmune involving upper respiratory tract and/ or lungs • Presentation: haemoptysis Important diagnostic features • Capillaritis • Scattered poorly formed granulomas
