NEURAPRAXIA
NEURODERMATITIS
NORMAL VERTEBRA
Genetic factors play a part in neural
tube defects, which show multifactorial
inheritance
.
Couples who have had an
affected child or who have a family his-
tory of neural tube defects should seek
genetic counselling
.
The risk of a neural
tube defect occurring can be substant-
ially reduced if the mother takes
folic
acid
supplements for a month before
conception and during the early part of
the pregnancy.
Ultrasound scanning
and
amniocen-
tesis
allow accurate antenatal testing for
neural tube defects.
neurapraxia
A type of
nerve injury
in
which the outward structure of a nerve
appears intact, but some of the con-
ducting fibres have been damaged or
have degenerated and thus do not
transmit signals normally.
neurasthenia
An outdated term that
literally means “nervous exhaustion”. It
was once used to describe a number of
physical and mental symptoms, includ-
ing loss of energy, insomnia, aches and
pains,
depression
, irritability, and re-
duced concentration.
neuritis
A term that literally means
inflammation of a nerve. True nerve in-
flammation may be caused by infection
(for example by a virus in
herpes zoster
or by a bacterium in
Hansen's disease).
The term neuritis is also often applied
to nerve damage or disease from causes
other than inflammation. It has become
virtually synonymous with
neuropathy
.
neuroblastoma
A tumour of the
adre-
nal glands
or the sympathetic nervous
system (which is part of the
autonomic
nervous system
). Most neuroblastomas
develop in the adrenal glands or in the
sympathetic nerves along the back wall
of the abdomen. Less commonly, tum-
ours develop in the sympathetic nerves
of the chest or neck.
Neuroblastomas are the most com-
mon extracranial (outside the skull),
solid tumour of childhood. Most cases
develop during the first
10
years of life,
especially in the first 5.
Common symptoms include a lump in
the abdomen, tiredness, weight loss,
aches and pains, paleness, and irritabil-
ity. Diarrhoea, high blood pressure, and
flushing of the skin sometimes occur.
The diagnosis of a neuroblastoma is
from
MRI
and
CT scanning
, blood tests,
urine tests, and
biopsy
of the bone
marrow and any accessible tumours.
Treatment consists of surgical removal
of the tumour, followed by
radiotherapy
.
Anticancer drugs
and a
bone marrow
transplant
may also be required. The
outlook varies because neuroblastomas
range from being relatively harmless to
aggressively cancerous.
neurocutaneous disorders
A group
of conditions characterized by abnor-
malities of the skin and of the nerves
and/or the central nervous system.
The best known of these neurocut-
aneous disorders is
neurofibromatosis
,
in which there are brown patches on the
skin and numerous fibrous nodules on
the skin and nerves. Another example is
tuberous sclerosis
, which is character-
ized by small skin-coloured swellings
over the cheeks and nose, mental defic-
iency, and epilepsy.
neurodermatitis
An itchy, eczema-like
skin
condition
caused
by
repeated
scratching. (See also
lichen simplex.)
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