MENTAL AGE
MESENTERY
Menstruation is often irregular for the
first few years, and for several years
before the
menopause.
mental age
A measurement of the intel-
lectual development of a person, with
regard to the normal age at which that
level of achievement is attained. For
example, a 13 year-old child with
learning
difficulties
may have a mental age of 5.
mental handicap
Impaired intellectual
development, also known as general
learning difficulties
or disability.
Mental Health Act
The Mental Health
Act (1983) details the rights of patients
with
mental illness
and the grounds for
detaining mentally ill people against
their will. It also outlines forms of legal
guardianship for such patients.
When a person is endangering his or
her own or other people's health or
safety (for example, threatening harm
or suicide) because of a recognized
mental illness, he or she may be com-
pulsorily taken into hospital to be given
treatment. If a person breaks the law
because of a mental disorder, the courts
may remand him or her to hospital.
mental hospital
A hospital, formerly
known as an asylum, specializing in the
treatment of psychiatric illness.
Most admissions to mental hospitals
are for acute psychiatric illness. The
majority of admissions are voluntary,
but in some cases detention under the
Mental Health Act
may be necessary.
mental illness
A general term that des-
cribes any form of psychiatric disorder.
mental retardation
See
Learning diffi-
culties
.
menthol
An alcohol prepared from mint
oils. Menthol is an ingredient of several
over-the-counter inhalation preparations
used to treat a blocked or stuffy nose.
meprobamate
An
antianxiety drug
used
in the treatment of
anxiety
and
stress
. It
also acts as a muscle relaxant.
meptazinol
A weak opioid
analgesic
drug
used for the short-term relief of
moderate to severe pain, such as after
surgery and during childbirth. Possible
adverse effects include nausea, vomit-
ing, and dizziness.
mercaptopurine
An
anticancer drug
used to treat certain types of
leukaemia.
Adverse effects include nausea, mouth
ulcers, and appetite loss. Rarely, it may
cause liver damage,
anaemia
, and ab-
normal bleeding.
mercury
The only metal that is liquid at
room temperature. Mercury is used in
thermometers
,
sphygmomanometers
, and
fillings for teeth (see
amalgam
,
dental
).
mercury poisoning
Toxic effects of
mercury on the body. The most com-
mon cause of mercury poisoning is
breathing in vapour given off by liquid
mercury, usually as a result of industrial
exposure. Swallowing a small amount
of liquid mercury is unlikely to lead to
poisoning.
Mercury compounds may
cause poisoning by absorption through
the intestines (causing nausea, vomit-
ing, diarrhoea, and abdominal pain) or
the skin (causing severe inflammation).
After entering the body, mercury accu-
mulates in organs, principally the brain
and kidneys. Mercury deposits in the
brain cause tiredness, incoordination,
excitability, tremors, and numbness in
the limbs. In severe cases, there may
be impaired vision and
dementia
.
De-
posits of mercury in the kidneys may
lead to
kidney failure
.
Treatment may involve
chelating agents
,
which help the body to excrete the mer-
cury quickly; haemodialysis (see
dialysis
);
and induced vomiting or pumping out
the stomach, if mercury has been swal-
lowed within the previous few hours.
mesalazine
A drug used to treat
ulcera-
tive colitis
.
Adverse effects of mesalazine
include nausea, diarrhoea, abdominal
pain, and headache.
mescaline
A
hallucinogenic drug
obtain-
ed from the Mexican peyote cactus.
mesenteric lymphadenitis
An acute
abdominal disorder, mainly affecting
children, in which
lymph nodes
in the
mesentery
become inflamed. The main
symptoms of pain and tenderness in
the abdomen may mimic appendicitis.
There may also be mild fever. Mesen-
teric lymphadenitis usually clears up
rapidly, needing only
analgesic drugs
to
reduce pain and fever.
mesentery
A membrane that attaches
organs to the abdominal wall. The term
is used particularly to refer to the mem-
branous fold that encloses the small
intestine, attaching it to the back of the
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