Maternal deaths may occur as a direct
result of complications of pregnancy, or
indirectly due to a medical condition
worsened by pregnancy. Major direct
causes include pulmonary embolism,
antepartum haemorrhage, postpartum
haemorrhage, hypertension,eclampsia,
and puerperal sepsis. Indirect causes
include heart disease, epilepsy, and
some cancers.
Maternal mortality is lowest for 2nd
pregnancies. It rises with age, being
greatest for women over 40.
maxillaOne of a pair of bones that
together form the centre of the face, the
upper jaw, and the roof of the mouth.
Each maxilla contains a large air-filled
cavity (called the maxillary sinus) which
is connected to the nasal cavity.
McArdle’s diseaseA rare genetic disor-
dercharacterized by muscle stiffness
and painful cramps that increase during
exertion and afterwards.The cause is a
deficiency of an enzymein muscle cells
that stimulates breakdown of the carbo-
hydrate glycogeninto the simple sugar
glucose. The result is a build-up of glyco-
gen and low levels of glucose in the
muscles. Damage to the muscles occurs,
causing myoglobinuria (muscle-cell pig-
ment in the urine), which may lead to
kidney failure. There is no treatment, but
symptoms may be relieved by eating
glucose or fructose before exercise.
MDMAThe hallucinogenic substance
methylenedioxymethamfetamine, which
has the street name Ecstasy.
METhe abbreviation for myalgic enceph-
alomyelitis (see chronic fatigue syndrome).
measlesA potentially dangerous viral
illness that causes fever and a charac-
teristic rash. Measles mainly affects
children, but can occur at any age. The
virus is spread primarily by airborne
droplets of nasal secretions. It can be
transmitted during the incubation period
(8–14 days afterinfection) and up to 7
days after symptoms appear.
The illness starts with a fever, runny
nose, sore eyes, cough, and a general
feeling of being unwell. After 3–4 days,
a red rash appears, usually starting on
the head and neck and spreading to
cover the body. The spots sometimes
join to produce large red blotches, andthe lymph nodesmay be enlarged. After
3 days, the rash starts to fade and the
symptoms subside.
The most common complications are
ear and chest infections, which usually
occur 2–3 days after the rash appears.
Diarrhoea, vomiting, and abdominal
pain also occur. Febrile convulsions (see
convulsion, febrile) are also common,
but these are not usually serious. En-
cephalitisoccurs in about 1 in 1000
cases, causing headache, drowsiness,
and vomiting. Seizures and comamay
follow, sometimes leading to brain dam-
ageor even death. In very rare cases, a
progressive brain disorder known as
subacute sclerosing panencephalitis
develops years later. If measles occurs
during pregnancy, the fetus dies in about
a fifth of cases. However, there is no evi-
dence that measles causes birth defects.
There is no specific treatment for
measles. Plenty of fluids and paraceta-
molare given for fever, and antibiotic
drugsmay be given to treat bacterial
infections that occur as complications.
To help prevent measles, immunization
with the MMR vaccinationis recom-
mended at 12–15 months of age. This
produces immunity in about 90 per cent
of cases, with a booster shot given
before school or nursery school entry.
meatusA canal or passageway through
part of the body. The term usually refers
to the external auditory meatus, the
canal in the outer earthat leads from
the outside to the eardrum.
mebendazoleAn anthelmintic drug used
to treat worm infestationsof the intes-
tine. Possible adverse effects include
abdominal pain and diarrhoea.
mebeverineAn antispasmodic drugused
to treat irritable bowel syndrome.
Meckel’s diverticulumA common prob-
lem, present at birth, in which a small,
hollow, wide-mouthed sac protrudes
from the ileum. Symptoms only occur
when the diverticulum becomes infec-
ted, obstructed, or ulcerated. The most
common symptom is painless bleeding,
which may be sudden and severe, making
immediate blood transfusionnecessary.
Inflammation may cause symptoms very
similar to those of acute appendicitis.
Meckel’s diverticulum occasionally causesMAXILLA MECKEL’S DIVERTICULUMM