Page 99 - Concise Pathology for Exam Preparation ( PDFDrive )

84 SECTION I General Pathology

Q. Differentiate between red and white infarcts.

Ans. Differences between red/haemorrhagic and white/pale/anaemic infarcts are tabulated
in Table 4.7.

TABLE 4.7. Differences between red/haemorrhagic and white/pale/anaemic infarcts

Features Red infarct � White infarct

Organs involved Spongy organs like lung and gastrointestinal tract Solid organs, like heart, spleen and
kidney
Cause Venous occlusion Arterial obstruction
solid
Seen Seen in organs where the solid-
• In loose tissues that allow collection of ity of
blood or
the tissue prevents haemor-

tissues with dual blood supply (lungs, GIT). rhage that can seep through from

Haemorrhage seeps into such an infarct when adjoining capillaries and tissues

flow is re-established. with end arterial circulation
• In tissues that were previously congested due to

sluggish venous outflow
• When blood flow is site with
re-established in a

previous arterial occlusion, eg, after coronary
angioplasty

Morphology Congested and red due to haemorrhage; turns Becomes progressively pale

brown and firm with time but never appears

pale. Hemosiderin-laden macrophages are pres-
ent in numbers.
large
Margins Not sharply defined Sharply defined
Oedema Present Absent
Q. Write briefly on renal infarcts.
Ans. Renal infarcts are often multiple and pale appearance.
in
be
• �May bilateral.
• �Have wedge-shaped base resting under the capsule with the apex towards medulla.
a

narrow rim
is

is

of

• � A renal tissue under the capsule spared because its blood supply
derived from capsular vessels.
• �Microscopically, affected area shows coagulative necrosis due hypoxia.
to
Q. Define and classify shock. Describe its pathogenesis and clinical

presentation.
of

is
as

a
Ans. Shock defined clinical state cardiovascular collapse characterized by the

inadequate perfusion the cells and tissues resulting hypotension and cellular hypoxia.
of
in
it
If uncompensated, may lead impaired cellular metabolism and death.
to
Aetiology and Classification

in

1. the circulating blood volume. Causes
Hypovolaemic Characterized by reduction
include
(a)
Severe haemorrhage (trauma and surgery)
Fluid
(b) loss (severe burns, crush injuries, vomiting and severe diarrhoea)
2.
Cardiogenic shock: Due failure the myocardial pump. Results from:
of
to
Deficient emptying
(a)

(i) Myocardial infarction

(ii) Rupture the heart
of
(iii) Cardiac arrhythmias

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