GREY MATTER
by the antibiotic drug
chloramphenicol
,
w hich is not usually prescribed for
newborns, but may be passed to a baby
via the mother’s bloodstream. Newborn
babies’ bodies cannot process or excrete
the drug effectively, so very high levels
build up. An affected infant is cold and
has grey skin (see
cyanosis
)
due to cir-
culatory collapse (see
shock
) .
If the condition is detected early, and
the drug is discontinued, the infant may
recover fully. Treatment with chloram-
phenicol
should
be
avoided
in late
pregnancy and during breast-feeding.
grey matter
Regions
of the
central nervous system
consisting mainly of closely packed and
interconnected
nerve
cell bodies and
their branching dendrites. (In contrast,
the nerve cells’
axons
,
w hich conduct
nerve impulses, make up the
white matter
of the central nervous system.)
Grey matter is found mostly in the
outer layers of the
cerebrum
(the main
mass of the
brain
that is responsible for
advanced
mental
functions)
and
in
deeper regions of the brain, such as the
basal ganglia
. Grey matter also makes up
the core of the
spinal cord
.
grief
A painful emotion, usually caused by
loss of a loved one. (See
bereavement.
)
grip
The ability of the
hand
to hold objects
firmly. The
hand
has
an
opposable
thumb (which can touch each of the
fingers), specialized skin on the palm
and fingers to give adhesion, and a
complex system of muscles, tendons,
joints, and nerves that enables precise
movements of the
digits
.
The hand is
capable of performing two types of
grip: grasping,
in
w hich
the
whole
hand is used, and pinching, a precise
hold using the thumb and one finger.
Gripping ability is greatly reduced by
conditions that cause muscular weak-
ness or impairment of sensation in the
hands. Such conditions include
stroke
or
nerve injury
,
and disorders that affect the
bones or joints of the hand or wrist,
such as
arthritis
or a
fracture
.
gripe
Severe abdominal pain (see
colic
).
grippe
An outdated term of French origin for
any illness resembling
influenza
.
griseofulvin
An oral
antifungal drug
.
Griseofulvin is
particularly useful for infections affect-
ing the scalp, beard, palms, soles of the
feet, and nails. Common side effects are
headache, dry mouth, abdominal pain,
and
photosensitivity
(increased sensitivity
of the
skin
to
sunlight). Long-term
treatment with the drug may cause liver
or bone marrow damage
Groenouw’s corneal dystrophy
An inherited disorder of the eye. There
are two forms of the condition: type I
(granular) and type II (macular).
Granular corneal dystrophy is an auto-
somal dominant disorder
(see
genetic
disorder
s) characterized by small granu-
lar opacities in the top layers of the
cornea
.
It develops in the first ten years
of life. Macular corneal dystrophy is an
autosomal recessive disorder typified
by a diffuse haze w ith areas of dense
corneal opacity. It develops in young
people up to the age of
2 0
.
Treatment for discomfort associated
with the disorder may include
antibiotic
eye-drops.
Severe
cases
may
require
laser surgery or a corneal transplant.
groin
The hollow between the lower abdo-
men and the top of the thigh.
groin, lump in the
A swelling in the
groin
.
The most com-
mon cause is enlargement of a lymph
node due to an infection (see
glands,
swollen
) .
Another common cause is a
hernia
,
in w hich the abdominal contents
protrude through a weak area in the
abdominal wall. Rarely, in males, an
undescended testis may lead to a lump
in the groin (see
testis, undescended
) .
Treatment depends on the cause.
groin strain
Pain and tenderness in the
groin
as a
result of overstretching a
muscle
,
typi-
cally while running or playing sport.
The muscles commonly affected are the
adductors (on the inside of the thigh)
and the rectus femoris (at the front of
the thigh). Groin strain is most often
treated with
physiotherapy
,
but recovery
may be slow.
grommet
A
small
tube
that
may
be
inserted
through an incision in the
eardrum
dur-
ing surgery to treat
glue ear
,
usually in
children (see
myringotomy
) . T h e
grommet
equalizes the pressure on both sides of
the eardrum, permitting mucus to drain
down the
eustachian tube
into the back
of the throat.
Grommets are usually allowed to fall
out as the hole in the eardrum closes;
this generally occurs six to
1 2
months
after insertion.
group therapy
Any treatment of psychological prob-
lems in w hich a group of patients is
given therapy together. The group meets
regularly, under the guidance of a thera-
pist, in order to discuss their problems.
Interaction between the members of the
group is thought to be beneficial.
Group
therapy may be useful for
people with personality problems and
for those w ho are suffering from
alcohol
dependence
,
drug dependence
,
anxiety dis-
orders,
and
eating disorders
.
growing pains
Vague aches and pains that occur in the
limbs of children aged between six and
12 years old. Pains are usually felt at
night, often in the calves. The cause is
unknown, but the pains seem to be
unrelated to the growing process itself.
Growing pains are of no medical sig-
nificance and need no treatment. In
contrast, pains that occur in the m orn-
ing, cause a limp, or prevent normal use
of a lim b are not growing pains and
should be assessed by a doctor.
growth
An abnormal proliferation of cells in a
localized area (see
tumour
) .
Growth is
also increase in size, usually as a result
of increasing age (see
growth, childhood
).
growth, childhood
The increase in size that occurs as a
child develops. Growth is usually m oni-
tored
by
measuring
height,
weight,
and, in babies, head circumference.
The period of fastest growth occurs
before birth. Growth is still rapid in the
first few years of life, especially in the
first year, but the rate decreases during
childhood.
Puberty
marks another major
period of growth, w hich continues until
adult height and weight are reached,
usually at age 16 to 17 in girls and bet-
ween 19 and 21 in boys. See
growth
charts
(p.352).
The
body
shape
changes
during
childhood because different areas grow
at different rates. For example, at birth,
the head is already about three quarters
350
previous page 349 BMA A Z Family Medical Encyclopedia   2004 read online next page 351 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off