Investigations & Prognosis

DVT Investigations
1) ultrasound (doppler) - transducer is placed over leg and send sound waves through the tissue, reflect back and waves is shown as a moving image on the screen. clot maybe visible. series done over a few days to see if the clot is growing or new one is developing

2) CT/MRI scans. computerized tomography (CT) and magnetic resonance imaging(MRI) - visual images of veins and show clot present. usually for pregnant ladies & renal problem people with dye-related problems.

3) blood test - elevated level of D-dimer (clot-dissolving substance). however, D-dimer is elevated in other things too. used for RULING OUT dvt or identifying those at risk of recurrence. look for inherited defects in clotting system as well.

4) venography - dye injected into large vein @ foot/ankle. x-ray creates image of veins to look for clots. abit invasive, so not less used.

DVT Prognosis
1) PE! 3% fatal!

2) 15% people get postphlebitic syndrome(post-thrombotic synd) - syndrome used to describe a collection of signs & symptoms
(a) oedema in legs (usually medial lower leg)
(b) pain
(c) skin discolaration
(d) dermatitis
(e) venous claudication
(f) nocturnal cramping
(g) ulceration
due to damage of veins from blood clot. this reduces blood flow to damaged areas. can occur a few years after DVT. (Rx: aspirin, diuretics, compression stockings)

PE Investigations
1) CXR - cannot diagnose PE but can rule out other conditions

2) V/Q scan - use small amts of radioisoptopes (SMALL AMT!) attached to radiopharmaceuticals which is inhaled to take pictures of movement of air in lungs. different radiopharm is injected into vein in arm & pictures of blood flow in blood vessels of lungs are taken. results are compared. normal lung scan can rule out PE but not DVT. thus not used much now.

*3) Spiral (helical) CT scan
CT: 2-d slices seen of organ by thin x-ray beams passing through organs. dye is used to visualize.
spiral CT: scanner rotates continously around body, to create 3-d images! faster - scan pulm arteries in <20secs. however, exposes to slightly more radiation then standard x-ray + allergic reaction to contrast medium.

4) Pulmonary angiogram - blood flow in lung arteries. most accurate diagnosis but requires high degree of skills & risks. usually performed when other tests fail to give Dx. catheter is inserted into femoral vein to pulm arteries. dye is injected and x-ray is taken.
risk: change in heart rhythm. dye may cause kidney damage with ppl with decrease renal function (usually temp). developing a hematoma at puncture site.

PE Prognosis
1) 1/3 undiagnosed - fatal

2) once had, increase recurrence risk

3) pulmonary HPT - large number of clots obstruct blood flow in lung blood vessles for long time causing right heart to be overworked

4) cor pulmonale - right ventricle enlarged & fails.