Page 95 - Concise Pathology for Exam Preparation ( PDFDrive )

80 SECTION I General Pathology

Fibrin­rich thrombus
Lysosomal enzymes
from leukocytes Organization
Central Gradual ingrowth of granulation
softening tissue, subendothelial smooth
muscle cells and mesenchymal
cells into the fibrin­rich thrombus
Secondary
bacterial infection
Formation of capillary channels
within the thrombus
Septic emboli
Surface of the thrombus gets covered with
endothelial cells and capillary channels begin
another
to anastomose from one end to
Re­establishment of continuity of the lumen
(recanalization)

Thrombus converts into a vascularized subendothelial
mass of connective tissue

Eventual incorporation into the wall of vessel

mesenchymal
that a
Contraction of cells so fibrous lump
or thickening remains to mark the site
FLOWCHART 4.7. Sequence of events in evolution of a thrombus.
Q. Classify emboli.
Ans. Emboli are classified based on:
(a)
Physical state of emboli
• �Solid: Atheromatous, thromboemboli and tumour emboli
• �Liquid: Fat, bone marrow and amniotic fluid emboli
• �Gaseous: Air emboli (seen decompression sickness)
in
(b) Site of origin

• �Cardiac emboli (left side heart)
of
• �Arterial emboli (atheromas and aneurysms)
• �Venous emboli (deep vein thrombosis)
• �Lymphatic emboli (tumour emboli)
Presence or absence of secondary infection
(c)
• �Sterile/bland emboli
• �Septic emboli
(d) Flow
t

o

• �Paradoxical emboli/crossed emboli: Emboli crossing over from venous circulation
arterial circulation vice-versa; deep leg vein emboli cross pulmonary circulation
t
o
o
r
t
o
and then systemic arterial circulation.
• �Retrograde emboli: Travel against the direction blood flow, eg, retrograde spread

of
of prostatic carcinoma spine via intraspinal veins. Increased pressure the body
in
to
or
cavities during coughing straining carries emboli from large thoracic ducts and
abdominal veins.
Q. Write briefly on the aetiopathogenesis and complications of
pulmonary embolism.
in
Ans. one the most common problems encountered hospitalized bedridden
or
is
It
of
its
of
It
be
patients. may fatal, causing occlusion pulmonary artery and branches.
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