Page 94 - Concise Pathology for Exam Preparation ( PDFDrive )

4 Haemodynamic Disorders, Thrombosis and Shock 79

Q. Differentiate between arterial and venous thrombi.

in
Ans. Differences between arterial and venous thrombi are tabulated Table 4.5.

TABLE 4.5. Differences between arterial and venous thrombi
Features Arterial thrombi � Venous thrombi
Sites Common in cerebral, iliac and Superficial varicose veins and deep veins of
coronary,

femoral arteries (vessels with active leg, eg, femoral and iliac veins (vessels

blood flow) with less active blood flow)
endothelial
venous
Pathogenesis Due to injury (as in Due to stasis
athero-
turbulent
sclerosis or blood flow)
the

blood
Progression Grows in a retrograde direction from Extends in direction of flow

point of
attachment
Occlusion Do not occlude lumen completely Invariably occlusive

Gross Grey-white, friable, prominent lines of Dark red with fibrin strands; lines of Zahn

Zahn less prominent or
absent
Zahn
Microscopy Lines of show paler layers of Constituted by more of RBCs and less of

fibrin

and platelets alternating with darker fibrin
RBCs
layers of
vital
Complications Ischaemia/infarction of organs Embolism, oedema, ulceration
Q. Differentiate between antemortem and post-mortem clot.
Ans. Differences between antemortem and post-mortem clot are tabulated Table 4.6.
in
TABLE 4.6. Differences between antemortem and post-mortem clot
Features Antemortem clots/thrombi Post-mortem clots
sedimentation
part of
a dead
Origin Formed as normal haemostasis Form in person due to

blood

or pathological derangement of and settling down of components
living
clotting pathway in a person
Gross • Dry, granular, firm and friable • Gelatinous, soft and rubbery
• Lines of Zahn are prominent in • Dark red, dependent portion of clot is

the

arterial thrombi called currant jelly and yellow superna-

red
called
tant, free of cells is chicken fat
the
bifurcation
cast of
Shape Do not form a the vessel Take the shape of vessel or its
forms a cast of vessel
the
Attachment to Present; strong Very weak

vessel wall
Location Anywhere in body In dependent parts of body
the
the
Q. Write briefly on fate of a thrombus.
Ans. thrombus may undergo:
A
of
to
1.
Propagation (accumulation additional platelets and fibrin leading progression)
2. (propagating tail fragments give rise emboli)
Embolization
to
or
3. (fibrinolysis usually on the first second day)
Dissolution

4. endothelial cells, smooth muscle and
Organization and recanalization (ingrowth
of
fibroblasts)
Inflammation and fibrosis (central liquefaction, bacterial seeding and influx of
5.
inflammatory cells)
Sequence of events in evolution of a thrombus (Flowchart 4.7):
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