There may also be speech loss or visual
disturbance. If the tumour invades the
skull bone, there may be thickening and
bulging of the skull.
Meningiomas can be detected by
X-rayor CT scanning, and MRIof the
skull, and can often be completely re-
moved by surgery. Otherwise, treatment
is by radiotherapy.
meningitisInflammation of the menin-
ges(membranes covering the brain and
spinal cord), usually due to infection.
Viral meningitis tends to occur in epi-
demics in the winter; it is relatively mild.
Bacterial meningitis is life-threatening.
It is mainly caused by the HAEMOPHILUS
INFLUENZAE bacterium, and MENINGO-
COCCUStype B and C bacteria.
The infection usually reaches the
meninges via the bloodstream from an
infection elsewhere in the body. Less
commonly, it passes through skull cavi-
ties from an infected ear or sinus, or
from the air following a skull fracture.
The main symptoms are fever, severe
headache, nausea and vomiting, dislike
of light, and a stiff neck. In viral menin-
gitis, the symptoms are mild and may
resemble influenza. In bacterial menin-
gitis, the main symptoms may develop
over only a few hours, followed by
drowsiness and, occasionally, loss of
consciousness. In about half the cases
of meningococcal meningitis, there is
also a rash under the skin that does not
fade with pressure (see glass test). The
rash starts as pin-prick spots that can
join to give a bruise-like appearance.
To make a diagnosis, a lumbar puncture
is performed. Viral meningitis needs no
treatment and usually clears up within a
week or two with no after-effects. Bacte-
rial meningitis is a medical emergency.
It is treated with intravenous antibiotic
drugs. With prompt treatment, a full re-
covery is usually made. However, brain
damage may occur in some cases.
Vaccines are now given to protect chil-
dren against 2 of the major types of
bacterial meningitis: those caused by
the HAEMOPHILUS INFLUENZAEbacterium
and the MENINGOCOCCUStype C bacte-
rium (see immunization). For other types
of bacterial meningitis, antibiotic drugs
are given as a protective measure to
people who have come into contact
with the infection.
meningoceleA protrusion of the spinal
cord meningesunder the skin that is
caused by a congenital defect in the
spine (see spina bifida).
meningomyeloceleAnother name for
myelocele(see spina bifida).
meniscectomyA surgical procedure in
which all or part of a damaged meniscus
(cartilage disc) is removed from a joint,
almost always from the knee. Menis-
cectomy may be carried out when
damage to the meniscus causes the
knee to lock or to give way repeatedly.
The procedure cures these symptoms
and reduces the likelihood of premature
osteoarthritis in the joint.
Arthroscopymay be carried out to
confirm and locate the damage, and the
damaged area removed by instruments
passed through the arthroscope.
Alternatively, the meniscus may be
removed through an incision at the side
of the patella(kneecap).
In either case, there may be an in-
creased risk of osteoarthritis in later
life, but this is less than if the damaged
meniscus had been left in place.
meniscusA crescent-shaped disc of
cartilaginous tissue found in several
joints. The kneejoint has 2 menisci, and
the wrist joints, and the temporo-
mandibular jointsof the jaw, have one
each. The menisci are held in position
by ligamentsand help to reduce friction
during joint movement.
menopauseThe cessation of menstrua-
tion, which usually occurs between the
ages of 45 and 55. The term is usually
used to refer to a period of physical and
psychological changes that occur as a
result of reduced oestrogenproduction.
Symptoms of menopause include hot
flushesand night sweats; vaginal dry-
ness caused by thinning of the vaginal
skin; and a decrease in vaginal secre-
tions. The vagina shrinks and loses
elasticity, and becomes prone to minor
infections. Vaginal dryness may also
make sexual intercourse more difficult
and painful (see vaginitis). The neck of
the bladder and urethra undergo similar
changes, which can result in a feeling of
needing to urinate frequently.MENINGITIS MENOPAUSE
M