I
DIAPHRAGM MUSCLE
have
pre-existing
diabetes
mellitus.
Gestational diabetes disappears after the
birth,
but
it
is
associated
with
an
increased risk of the woman develop-
ing Type 2 diabetes in later life.
diabetic retinopathy
See
retinopathy
.
diagnosis
The process of identifying or finding
out the nature of a disorder. The doctor
listens to a patient’s account of his or
her illness, and may carry out a physical
examination. If further information is
needed, tests or imaging procedures may
be ordered after a provisional diagnosis
has been formed (see
Steps in diagnos-
ing a condition
box, previous page).
diagnostic ultrasound
The use of high-frequency sound waves
to form images of internal organs and
so help doctors to make diagnoses (see
ultrasound scanning
) .
Certain forms of
ultrasound scanning are used to form
moving images, such as images of the
flow of blood through the heart (see
Doppler echocardiography
) .
dialysis
A filtering technique used to remove
waste products from the blood and
excess fluid from the body as a treat-
ment for
kidney failure
.
WHY IT IS DONE
Each day, the kidneys normally filter
about 1,5 00 litres of blood. They help
to maintain the fluid and
electrolyte
bal-
ance of the body. Important minerals
and nutrients, such as potassium, sodi-
um, calcium, amino acids, glucose, and
water are reabsorbed into the blood.
Urea
,
excess minerals, toxins, and drugs
are excreted in the urine.
Dialysis is used to perform this func-
tion in people whose kidneys have been
damaged due to acute or chronic kidney
failure. Without dialysis, wastes accumu-
late in the blood and the electrolyte
levels become unbalanced; this may be
life-threatening. In chronic kidney fail-
ure, patients may need to have dialysis
several times a week for the rest of their
lives or until they can be given a
kidney
transplant
.
In acute kidney failure, dialy-
sis is carried out more intensively until
the kidneys are working normally.
HOW IT IS DONE
There are two methods: haemodialysis
and peritoneal dialysis. In both proce-
dures, excess water and wastes in the
blood pass across a membrane into a
solution called a dialysate, w hich is
then discarded.
Haemodialysis filters out wastes by
passing blood through an artificial kid-
ney machine. The process needs to be
performed three or four times a week,
and each session lasts two to six hours.
In peritoneal dialysis, the abdominal
cavity is filled with dialysate, w hich is
changed regularly, and the
peritoneum
(the membrane lining the abdominal
cavity) acts as a natural filter. The pro-
cedure is often carried out overnight or
continuously during the day and night.
RISKS
Both types of dialysis carry the risk of
upsetting body chemistry and fluid bal-
ance, w hich can cause complications.
In addition, peritoneal dialysis carries a
risk of infection in the peritoneum.
diamorphine
A synthetic, opioid
analgesic
similar to
morphine
;
diamorphine is another name
for
heroin
.
It is used to relieve severe pain
and to relieve distress in acute
heart failure
.
Diamorphine carries the risk of depen-
dence. It may cause nausea, vomiting, and
constipation. (See also
heroin abuse
. )
Dianette
A brand name for a combination of
cyproterone acetate
with
ethinylestradiol
(synthetic sex hormones). Dianette may
be used to treat severe
acne
or
hirsutism
(excessive hairiness) in women.
diaphragmatic hernia
The protrusion of an abdominal struc-
ture through the
diaphragm muscle
into
the thorax
(chest cavity). The most
common form of this problem is a
hia-
tus hernia
,
in w hich part of the stomach
protrudes through the space in the
diaphragm that is normally occupied
by the
oesophagus
.
diaphragm, contraceptive
A female barrier method of contracep-
tion in the form of a hemispherical
dome of thin rubber with a metal
spring in the rim. The diaphragm is
inserted into the vagina and positioned
over the cervix. (See also
contraception,
barrier methods
. )
diaphragm muscle
The dome-shaped sheet of muscle that
separates the chest from the abdomen.
The diaphragm is attached to the spine,
ANATOMY OF THE DIAPHRAGM
The diaphragm is attached to the spine, the lower pairs of ribs,
and the lower end of the sternum (breastbone). Its muscle fibres
converge on the central tendon, which is a thick, flat plate of dense
fibres. There are openings in the diaphragm for the oesophagus,
the phrenic nerve (which controls diaphragm movements and
hence breathing), and the aorta and vena cava (the body’s main
blood vessels).
R ib .
D ia p h r a g m
m u s c l e
A t t a c h m e n t
o f d i a p h r a g m
t o r i b c a g e
a n d s t e r n u m
I n f e r i o r
v e n a c a v a
O u tlin e
o f lu n g
C e n t r a l
t e n d o n
S p i n e
A o r t a
D
231
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