Theombosis And Embolism Flashcards
is air likely to embolise via the venous system?
no, Air enters the venous system but then passes through an interatrial or interventricular defect in the heart to the arterial system (paradoxical embolism)
if u have a thrombus in the carotid artery and embolism occurs it can go to _____
BRAIN
what r outcomes of thrombus? (5)
1) LYSIS (Most likely if thrombus is small)
2) PROPAGATION thrombus grows
3) ORGANISATION undergoes fibrous repair & forms fibrous scar on vessel wall
4) RECANALISATION bloodflow re- established but usually incompletely
5) EMBOLISM part of it breaks off and travels in BS.
**recurrent minor PE can lead to pulmonary hypertension.
bc u get generalised increase pressure in lungs
What an embolism?
When a thrombis breaks, and blocks a vessel.
Blockage of a vessel by solid, liquid, or gas away from its origin
**over 90% are THROMBO-EmBOLI
What is a saddle embolus?
a large pulmonary embolism that straddles the bifurcation of the pulmonary trunk, extending into the left and right pulmonary arteries.
Why does thrombois occur? (3)
explain virchows triad and how each one may leasd o formation if thrombus!
- VESSEL WALL ABNORMAILTY -atheroma >> mostly in artery -direct i jury -inflammation
- BLOOD FLOW ABNORMAL -stagnation ex (DVT) -turbulence
- BLOOD COMPONENT GONE WRONG ( hypercoagubility)
- ppl who smoke >> stivky blood
- Post partum>> area of placenta
- Post operation>> ur lying down too much (u can get stagnation
define 3 stages of pulmonary embolism?
-massive -major -minor > asymptomatic
how can nitrogen embolism form?
happens in divers when they come up to the surface too quickly and the dissolved nitrogen become GASEOUS nitrogen.
What is a paradoxical embolus?
emboli can pass through an inter-atrial or inter-ventricular defect and gain access to the SYSTEMIC circulation (ex those with ASD or PFO)
OR
emboli in the peripheral vein bypass the lungs and enter systemic circulation
what can thrombosis do to u ? (in arteries and veins)
ARTERIES -Cause ischemia>>infarct (depends if theres collateral circulation or not)
VENOUS -congestion ( bc pressure in vein increases) -edema (hydrostatic p. increases, forces fluid out of veins into interstitial fluid -ischemia -infarction
thromboembolic from systemic veins go to the ______
LUNGs
what does stagnation mean?
the state of not flowing or moving
what r predisposing factors/Risks of DVT?
- immobility/ bed rest
- Post-operative
- pregnancy, Post-partum (after birth)
- oral contraceptives (shmul)
- severe burns
- Cardiac failure
prevention and treatment of thromboembolic disease?
reduce risk by (prevent):
1) give stockings>they compress veins to prevent stagnation 2) flowtron boots> they inflate, activating muscle calf pump!
TREATMENT: (both r anticoagulents)
1) give IV heparin (doesn’t really dissolve thrombus, but prevents it from getting bigger)
2) oral Warfarin **starts with heparin (bc it starts quickly)
what is the main prophylaxis for deep vein thrombosis
Heparin
Subcutaneous __________is the main prophylaxis for DVT
Heparin
What is thrombosis?
Solid mass formation made from the constituents of the blood with the circulatory system, during LIFE (mu nafs clotting) Can occur in veins, arteries, THROMBIS AND CLOT R DIFFERENT THINGS
what r some types of embolism?
- air ( u need 150ml to cause air embolism)
- amniotic fluid (was a problem during abortion)
- nitrogen (when nitrogen GAS form in blood)
- medical equipment ( -tumour cells
How does thrombi look like? how would that differ in arterial and veins?
ARETERIAL
- granular
- lines of zahn
- pale
- less cell content (causing the paleness)
VENOUS -
- soft
- gelatinous
- Deep red (bc has a high cell content)
if u get a thrombus in ur abdominal aorta (infra renal portion) what consequence it this cause
it can go to leg DVT causing ischemia>> gangrene
how can u get fat embolism (ex in brain)
via long bone fracture. -fracture leads to release of marrow into bloodstream, and may get into the brain
what is venous Congestion?
venostatis>> slow BF in veins
term to describe> “painful superficial thrombi which have associated inflammation in the wall of the vein.”
thrombophlebetis
when do ‘occlusive’ thrombi usually occur?
when an atheroscelrotic plaque ruptures, a thrombi tend to form on top of it becoming occlusive.
(such thrombi in coronory arteries can be no bigger than a matche head>but can be fatal)
what is vegetation?
a thrombus on a cardiac valve. (most commonly left side)
can easily embolise.
can be infected too> mostly in IV drug abusers.
(looks like caulifloers florets 2-3cm long))
lol.
what r dangerous sources (locations) of thromboemboli? (3)
thrombi that form in the large veins of the Lower limbs
-femoral, ilial, popliteal veins
what r the clinical effects of thrombosis? (4)
- MI
- pulmonary embolism
- congestion and edema in venous bed
- repeated miscarrigaes du to thrombus of uteroplacental vasculature
80% of pulmonary emboli arise from thrombi in the deep veins of the _____&______
thigh and popliteal vein
what type of thrombus is this? describe its characteristics
Arterial thrombus> is a laminated structure
- lines of Zahn
- Pale in colour due to lower cell content
- Granular
in paradoxical emboli, thrombus manages to bypass the lungs and gain acess to the systemic circualtion.
exaplin 2 ways in which this can occur (hint: whether its a large emboli or small emboli)
Small emboli > manage to bypass the lungs by going through the Arterio-venous anastomoses in the pulmonary circulation (also fat droplets can ambolise this way too!)
Large Emboli> via PFO o r atrio-ventrciular septal defect (during coughing or lifting)
how can fat droplets embolise to the lungs in fat embolism?
they pass through the atrio-venous anastomoses in the pulmonary circulation.
Patients with Stroke r 4x likely to have a PFO when compared with general population…
therefore, paradoxical embolis should be considered in these young patients that present w/ ischemic stroke!
when can u get fat or marrow emboli?
what r the symptoms that may arise?
after trauma or liposuction.
when a bone is fractures, bone marrow fat cells that r injured break up and realease oil droplets. these oil droplets sticktogether & sucked into the ruptured veins.
(Respiratory & neurological symptoms)
mostly seen in those with pelvic or long bone fracture!
Describe how amniotic fluid embolism occurs and the symptoms it can cause.
how can it cause DIC?
During delivery, ceserian section, a tear in the amniotic membrane can occur and amniotic fluid can get into the maternal circulation.
ARDS, hypotension, seizures, loss of conciousness, DIC
(bc amnionic fluid has prothrombotic substances)
what the f**is a talc emboli?
no idea wt thos shit is
prevention and treatment of Thromboembolic disease
- Prophylaxis
- Aspirin
- Warafarin
- fliters
why is DVT asymptomatic in many people?
We can develop alternative channels in our veins so thats why swelling sometimes doesn’t appear. (More collatrels in the veins).
How does a thrombus form?
Platelets r the most formed elements in the blood, & they r more concentrated along the endothelium, (like a waterstream and pebbles.
theyre most likely to be caught by a valve.
1) form an aggregate (if blood flow is slow) more aggregate
2) Fibrinogen will bind platelets together
3) fibrin gorws out of the layer & traps RBC
4) White layer of platelets r covered by a red layer fibrin + RBC’s
5) the surf. of the red layer is thrombogenic and again platelets stick to exposed fibrin
6) a second white layer forms & process goes on
theyre making a layered sandwhich of white and red layer.
Give two reasons why a woman in late pregnancy is
predisposed to DVT?
In pregnancy the blood is hypercoagulable (1 mark) and the presence of a pelvic ‘tumour’ can compress venous outflow from the legs resulting in venous stasis
