Page 86 - Concise Pathology for Exam Preparation ( PDFDrive )

4 Haemodynamic Disorders, Thrombosis and Shock 71

Q. Write briefly on renal oedema.

Ans. Oedema due renal dysfunction typically appears first loose connective tissue,
to
in
eg, the eyelids (periorbital oedema).

• �Causes of renal oedema include nephrotic syndrome, glomerulonephritis (acute

glomerulonephritis, rapidly progressive glomerulonephritis) and acute tubular injury.

Nephrotic syndrome characterized by persistent and heavy proteinuria causing

is
a

reduced plasma oncotic pressure leading generalized severe oedema.
to

in
of

a

• �Also, reduction the plasma volume causes activation the renin–angiotensin–
aldosterone mechanism, thereby causing retention sodium and water oedema.
or
of
to
• �Nephritic oedema mainly due excessive reabsorption sodium and water the
of
in
is
to
is
to
as
It
renal tubules and not due protein loss. milder compared nephrotic oedema.

or

• �In acute tubular injury, which due shock toxic chemicals, tubules lose their
is

to

of
in
capacity for selective renal concentration the glomerular filtrate resulting increased
reabsorption and oliguria.
Q. Write briefly on cardiac oedema.
is
a
of
Ans. Cardiac oedema mostly manifestation congestive heart failure, and occurs due
of
to activation series mechanisms that increase venous capillary pressure, promote
a
of
sodium and water retention by the kidneys and expansion the extracellular fluid (see
of
of
Flowchart 4.2 for the pathogenesis oedema).
Q. Write briefly on pulmonary oedema.
i
i
n
r
Ans. Defined fluid accumulation the spaces and parenchyma the lungs, pulmonary
s
f
o
a
a
s
o
oedema may lead respiratory failure due impaired gas exchange. mainly two
t
o
f

i
t
I

t
o

types—

Cardiogenic pulmonary oedema (caused by congestive cardiac failure or left

1.

of

to

ventricular failure which lead inadequate removal blood from the pulmonary

circulation)
Noncardiogenic pulmonary oedema (caused by injury to lung parenchyma or
2.
vasculature the lung)
of
Q. Write briefly on subcutaneous oedema.
to
of
or
Ans. Subcutaneous oedema can be diffused localized the most dependent part
the body positioned the greatest distance below the heart (legs while standing and the
at
sacrum while recumbent). This type oedema called dependent oedema and pitting
is
of

is
in nature (ie, pressure over oedematous subcutaneous tissue displaces the interstitial fluid,

leaving finger-shaped depression).
a
Q. Write briefly on cerebral oedema.
be
to
a
Ans. Cerebral oedema can localized (eg, due space occupying intracranial lesion

to
or
or
an
like abscess tumour) generalized (due extensive brain pathology injury). The
or

latter causes narrowing the sulci while the gyri are swollen and flattened against the
of

skull.
Q. Differentiate between cardiac and renal oedema.
Ans. The differences between cardiac and renal oedema are tabulated Table 4.2.
in
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