MUTISM
MYDRIATIC DRUGS
mutism
Refusal or inability to speak.
Mutism may occur as a symptom of
profound congenital
deafness
,
severe
manic-depressive illness
,
catatonic
schiz-
ophrenia
,
or a rare form of
conversion
disorder
. The term may also apply to a
religious vow of silence.
Elective mutism is a rare childhood
disorder (usually starting before age 5),
in which the child can speak properly
but refuses to do so most of the time.
Akinetic mutism describes a state of
passivity caused by some brain tumours
or by
hydrocephalus
.
People with akin-
etic mutism are incontinent, require
feeding, and respond at most with a
whispered "yes" or "no".
myalgia
Medical term for
muscle
pain.
myalgic encephalomyelitis
Also known
as ME (see
chronic fatigue syndrome)
.
myasthenia gravis
A rare disorder in
which the muscles become weak and
tire easily. The muscles of the eyes,
face, throat, and limbs are most com-
monly affected.
Myasthenia gravis is an
autoimmune
disorder.
In many cases, abnormalities
in the thymus gland are present, and in
some cases a
thymoma
is found. Women
are affected more often than men.
The disease is extremely variable in its
effects. In most cases, it causes droop-
ing eyelids, double vision, a blank facial
expression, and a weak, hoarse, nasal
voice that is hesitant and becomes slur-
red during extended conversation. The
arm and leg muscles may also be affec-
ted. In severe cases, the respiratory
muscles may become weakened, caus-
ing breathing difficulty.
Diagnosis of the condition is often
made by injecting the drug edrophonium
into a vein. This temporarily restores
power to the weak muscles.
Blood tests
and
EMG
are also sometimes used.
CT
scanning
or
MRI
may also be performed
to look for a thymoma.
Treatment with drugs that facilitate
transmission of nerve impulses often
restores the patient's condition to near
normal. In some cases, the condition
often improves, and is sometimes cured
by thymectomy (removal of the thymus
gland). Regular exchanges of the pati-
ent's
plasma
for fresh plasma may be
carried out in severe cases.
Cortico-
steroid drugs
may be given. In a minority
of patients,
paralysis
of the throat and
respiratory muscles may lead to death.
mycetoma
An uncommon tropical infec-
tion affecting skin and bone and caused
by
fungi
or by actinomycetes (bacteria
that form long chain-like colonies). It
usually occurs on one limb, producing a
hard swelling and a discharge of pus.
Infections caused by actinomycetes are
treated with
antibiotic drugs.
Surgical
removal of diseased tissue may be nec-
essary for a fungal infection.
mycology
The study of
fungi
.
mycoplasma
Any of a group of
bacteria
that are the smallest type capable of
free existence. Mycoplasmas are about
the same size as
viruses
but, unlike
viruses, they are capable of reproducing
outside
living
cells.
One
species,
MYCOPLASMA PNEUMONIAE
,
causes pri-
mary atypical
pneumonia
.
mycosis
Any disease caused by a fun-
gus. (See
fungi; fungal infections
.)
mycosis fungoides
A rare type of
lym-
phoma
that primarily affects the skin of
the buttocks, back, or shoulders. The
cause of mycosis fungoides is unknown.
In its mildest form, it produces a non-
itchy, red, scaly rash, which may spread
slowly or remain unaltered for many
years. In more severe forms, thickened
patches of skin,
ulcers
, and enlarged
lymph nodes
may develop.
The diagnosis is confirmed with a
skin
biopsy.
Treatment may include
PUVA,
radiotherapy
, nitrogen mustard,
anti-
cancer drugs,
and
corticosteroid drugs.
mydriasis
Dilation (widening) of the
pupil of the eye. It occurs in the dark, if
a person is emotionally aroused, after
the use of certain eye-drops (such as
those containing
atropine
), and after
consumption of alcohol.
mydriatic
drugs
A group of drugs
used to treat
uveitis
and to dilate the
pupil during examination of the inside
of the eye and for surgery. Mydriatics
work by relaxing the circular muscles of
the
iris
, causing the pupil to dilate.
Common mydriatic drugs include
tropi-
camide
, cyclopentolate, homatropine,
and
phenylephrine
. (See also
cyclople-
gia; miotic drugs.)
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