Page 96 - Concise Pathology for Exam Preparation ( PDFDrive )

4 Haemodynamic Disorders, Thrombosis and Shock 81

Sources

of
Thrombi from large veins lower legs (most commonly deep vein thrombosis and less
of
commonly superficial veins leg and pelvis).
Pathogenesis
as
a
• �Thrombus whole, loosely attached tail, gets detached from origin, and
its
is
or
its
to
it
carried through venous channels the right side heart where enters pulmonary
of
circulation.
it
at
large
of
• � If enough, gets impacted the bifurcation the main pulmonary artery (saddle
its
or
embolus) lodges the right ventricle outflow tract.
in
or
• �Multiple, small emboli may occlude smaller pulmonary vessels.
• �Emboli may pass through atrial ventricular septal defects from right side left side
or
to
to
of the heart enter into arterial circulation (paradoxical emboli).
Clinical Features
of
Cough, severe pleuritic pain, shortness breath, occasionally haemoptysis and haemor-
rhagic pleural effusion
Sequelae and Complications

Most emboli remain silent and undergo resolution. Others may cause
to
or
• �Sudden death due right-sided heart failure (cor pulmonale) cardiovascular collapse
of
of
or
(obstruction .60% the pulmonary circulation massive pulmonary embolism)
to
of
of
• �Pulmonary haemorrhage due obstruction terminal branches pulmonary artery
of
to
• �Pulmonary infarction due obstruction end-arteriolar pulmonary branches

• �Pulmonary hypertension with right-sided heart failure (multiple emboli clogging pulmonary

capillary circulation)
Q. Write briefly on fat embolism.
is
Ans. Fat embolism defined obstruction arterioles and capillaries by fat globules
of
as
or
with without marrow elements.
Causes
to
or
• �Trauma long bones soft tissue (fracture with embolization fatty marrow)
of
• �Extensive burns
• �Pancreatitis
• �Diabetes mellitus
• �Vigorous cardiopulmonary resuscitation
Pathogenesis
• �Mechanical obstruction: Fat globules occlude pulmonary systemic circulation (brain,
or
kidneys and other organs) cause platelet and RBC aggregation leading hypoxia
to
of
to
that tissue/organ.
• �Biochemical injury (Flowchart 4.8)
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