SCIATICA
SCOLIOSIS
S
The sciatic nerves
are formed from
nerve roots in the
spinal cord.
scintigraphy An
alternative name
for
radionuclide
various forms of
delusions
such as those
of persecution (which are typical of
paranoid schizophrenia);
hallucinations,
which are usually auditory (hearing
voices), but which may also be visual or
tactile; and thought disorder, leading to
impaired concentration and thought
processes. Disordered thinking is often
reflected in muddled and disjointed
speech. Behaviour is eccentric, and self-
neglect common. In a rare form of
schizophrenia, catatonia may occur, in
which rigid postures are adopted for
prolonged periods, or there are out-
bursts of repeated movement.
Diagnosis of schizophrenia may take
some time and, in some cases, it may
be difficult to make a diagnosis at all.
Treatment is mainly with
antipsychotic
drugs,
such as
phenothiazine drugs,
and
new atypical antipsychotic drugs such
as risperidone. In some cases, the drugs
are given as monthly depot injections.
Once the symptoms are controlled,
community care, vocational opportu-
nities, and family counselling can help
to prevent a relapse.
Some people may make a complete
recovery. However, the majority have
relapses punctuated with partial or full
recovery. A small proportion have a
severe life-long disability.
sciatica Pain that radiates along the
sci-
atic nerve
. The pain usually affects the
buttock and thigh, sometimes extending
down the leg to the foot. In severe cases,
the pain may be accompanied by numb-
ness and/or weakness in the affected area.
The most common cause is a prolapsed
intervertebral disc pressing on the nerve
root (see
disc prolapse
). Other causes
include a muscle spasm, sitting awkward-
ly for long periods, or, less commonly,
pressure on the nerve from a tumour.
Sometimes the cause is unknown.
Treatment of sciatica is with
analgesic
drugs
. If the pain is severe, a short per-
iod of bed rest may be helpful, although
prolonged rest may cause the condition
to worsen.
Physiotherapy
,
osteopathy
, or
chiropractic
may help in some cases. It
is important to maintain a healthy
posture and weight.
sciatic nerve The main
nerve
in each
leg and the largest nerve in the body.
scanning
.
scirrhous A term
that means hard
and fibrous and is
usually applied to
malignant tumours
containing dense,
fibrous tissue.
sclera The white
fibrous outer coat
that protects the
eye
from injury.
The
most
com-
mon disorder of
the sclera is
scleritis.
In
osteogenesis
imperfecta
, the sclera is very thin.
scleritis Inflammation of the
sclera
that
usually accompanies a
collagen disease
such as
rheumatoid arthritis.
Scleritis also
occurs in
herpes zoster
ophthalmicus and
Wegener's granulomatosis. It may lead to
areas of thinning and perforation of the
sclera. It is usually persistent but often
responds to
corticosteroid
eye-drops.
scleroderma See
systemic sclerosis.
scleromalacia Softening of the
sclera,
commonly a complication of
scleritis
,
especially scleritis of
rheumatoid arthritis.
sclerosing cholangitis A rare condition
in which many of the bile ducts are nar-
rowed, causing progressive liver damage
for which the only treatment may be a
liver transplant.
(See also
cholangitis.)
sclerosis A medical term for hardening
of a body tissue, usually used to refer to
hardening of blood vessels (as in
arterio-
sclerosis)
or of nerve tissue (as occurs in
the later stages of
multiple sclerosis)
.
sclerotherapy A method of treating
varicose veins
, especially in the legs;
haemorrhoids;
and
oesophageal varices
.
The vein is injected with an irritant solu-
tion, which causes inflammation in the
vessel lining, leading to scar tissue for-
mation and the obliteration of the vein.
scoliosis A deformity in which the
spine
is bent to one side. The thoracic or lum-
bar regions are most commonly affected.
SCIATIC NERVE
500
previous page 498 BMA Illustrated Medical Dictionary read online next page 500 BMA Illustrated Medical Dictionary read online Home Toggle text on/off