Pulmonary vascular disease Flashcards
Define hypertension.
Abnormally high BP.
What are the 2 main types of thromboembolic disease?
DVT and PE.
Where do most emboli originate?
Thromboses/clots in the leg veins. They travel upwards to the right side of the heart then the pulmonary arteries. Thrombi in bigger veins (ileofemoral and above) are more likely to embolise. Thrombi in smaller veins usually resolve on their own.
Where else can emboli originate?
Cardiac, septic (IDU’s), air embolus (post-trauma) and amniotic fluid embolus.
How does thromboembolic disease occur?
A thrombus is a blood clot that forms in a vein. An embolus is anything that travels through blood vessels until it reaches a vessel that is too small to let it pass - blood flow is then stopped by the embolus.
Describe Virchows triad.
3 catagories of factors that are throught to contribute to thrombosis. 1) Reduced blood flow: immobility, bed bound, travel, heart failure etc. 2) Abnormal vessels: post-MI, leg trauma, pelvic surgery. 3) Hypercoagulable stress: pregnancy, OCP, HRT, malignancy etc. Young person presents with DVT/PE? Check if they have an interited hypercoagulable state.
What are the signs and symptoms of DVT?
Leg swelling, tenderness, oedema and tight calves - not always present and can mimic other conditions.
Which investigations would be carried out if a DVT is suspected?
D-dimer blood test –> ultrasound –> venography.
Why is the D-dimer test helpful?
Looks for products of fibrin degradation which are break off products in clot formation. Non-specific and not helpful if positive, however if negative effectively excludes DVT/PE.
What is the gold standard for diagnosing venous thrombosis?
Venography - injecting a radiopaque liquid into a vein then radiography.
What is a PE?
When a blood clot (usually from deep veins of legs) lodges in the pulmonary arterial circulation. Usually multiple clots. 10% can cause pulmonary infarction. A large clot can cause a massive PE: hypoxia, hypotension, pain and collapse. Small clots usually lodge in lower lobes.
What are the symptoms of PE?
73% breathlessness, pleuritic chest pain in 66%, cough, haemoptysis and central cardiac chest pain if massive.
What are the signs of PE?
Unwell, cyanosed (blue), tachypnoea, tachycardia, fever, drop in BP due to circulatory collapse etc.
Which investigations can be used for PE?
ABG’s; raised troponin (poor indicator); D-dimer; ECG (abnormal in 70% but non-specific); CXR.
What is the first line test for chronic TED and how does it work?
V/Q scan. Inhalation of radioactive xenon then injection of technicium labelled albumin. Gamma camera compares - looking for an area that is ventilated but not perfused. Positive? Treat. Negative? Don’t treat. Intermediate? Further investigation required.
