PULMONARY FIBROSIS
PULMONARY STENOSIS
P
branches in the lung by an
embolus,
usually after a deep vein thrombosis
(see
thrombosis, deep
vein). If the em-
bolus is large enough to block the main
pulmonary artery, or if there are many
clots, the condition is life-threatening.
Pulmonary embolism is more likely
after recent surgery, pregnancy, and
immobility. A massive embolus can
cause sudden death. Smaller emboli
may cause severe shortness of breath,
rapid pulse, dizziness, chest pain made
worse by breathing, and coughing up of
blood. Tiny emboli may produce no
symptoms, but, if recurrent, may even-
tually lead to
pulmonary hypertension
.
A diagnosis may be made by a
chest
X-ray, radionuclide scanning,
and pul-
monary
angiography.
An
ECG
and
venography
may also be performed.
Treatment depends on the size and
severity of the embolus. A small one
gradually dissolves and
thrombolytic
drugs
may be given to hasten this pro-
cess.
Anticoagulant drugs
are given to
reduce the chance of more clots. Surgery
may be needed to remove larger clots.
pulmonary fibrosis Scarring and thick-
ening of lung tissue, usually as a result
of previous lung inflammation. It may
be confined to an area of the lung affec-
ted by a condition such as
pneumonia
or
tuberculosis
, or it may be widespread
through the lungs (see
fibrosing alveoli-
tis). Shortness of breath is a common
symptom. Diagnosis is confirmed by
chest X-ray
. Treatment depends on the
cause, but in most cases the fibrosis is
irreversible and treatment aims to pre-
vent the condition from progressing.
pulmonary function tests A group of
procedures used to evaluate lung func-
tion, to confirm the presence of some
lung disorders,
and to ensure
that
planned surgery on the lungs will not dis-
able
the
patient.
The
tests include
spirometry
, measurement of lung vol-
ume,
assessment of the
degree
of
bronchospasm
with a
peak-flow meter
,
and a test of
blood gases
.
pulmonary hypertension A disorder
in which the blood pressure in the arter-
ies supplying the lungs is abnormally
high. Pulmonary hypertension develops
in response to increased resistance to
blood flow through the lungs. To main-
tain an adequate blood flow, the right
side of the heart must contract more
vigorously than before. Right-sided
heart
failure
may later develop.
Causes of pulmonary hypertension may
include chronic obstructive pulmonary
disease (see
pulmonary disease, chronic
obstructive
), a
pulmonary embolism
,
pul-
monary fibrosis
, and some congenital
heart diseases (see
heart disease, con-
genital
), but it can also develop without
an obvious cause. Symptoms, which
include enlarged veins in the neck,
enlargement of the liver, and general-
ized
oedema
, only develop when heart
failure occurs. Treatment is aimed at the
underlying disorder (if known) and the
relief of the heart failure.
Diuretic drugs
and
oxygen therapy
may be given.
pulmonary incompetence A rare de-
fect of the pulmonary
valve
at the exit of
the heart's right
ventricle.
The valve fails
to close properly, allowing blood to leak
back into the heart. The cause is usually
rheumatic fever
,
endocarditis
, or severe
pulmonary hypertension
.
pulmonary oedema Accumulation of
fluid in the lungs, usually due to left-
sided
heart failure
. It may also be due to
chest infection, inhalation of irritant
gases, or to any of the causes of gener-
alized
oedema.
The main symptom is
breathlessness, which is usually worse
when lying flat and may disturb sleep.
There may be a cough, producing frothy,
sometimes pink, sputum. Breathing may
sound bubbly or wheezy.
A diagnosis is made by a
physical
examination
and by a
chest X-ray
. Treat-
ment may include
morphine
,
diuretic
drugs
,
aminophylline
, and
oxygen therapy
;
artificial
ventilation
may also be given.
pulmonary stenosis A
heart
condition
in which the outflow of blood from the
right
ventricle
is obstructed, causing the
heart to work harder to pump blood to
the lungs. The obstruction may be
caused by narrowing of the pulmonary
valve
at the exit of the
ventricle
; by nar-
rowing of the pulmonary artery, which
carries blood to the lungs; or by narrow-
ing of the upper part of the ventricle.
Pulmonary stenosis is usually
congeni-
tal
, and may occur alone or with a set of
472
previous page 470 BMA Illustrated Medical Dictionary read online next page 472 BMA Illustrated Medical Dictionary read online Home Toggle text on/off